WorldWideScience

Sample records for platinum azido complexes

  1. Probing platinum azido complexes by 14N and 15N NMR spectroscopy.

    Science.gov (United States)

    Farrer, Nicola J; Gierth, Peter; Sadler, Peter J

    2011-10-17

    Metal azido complexes are of general interest due to their high energetic properties, and platinum azido complexes in particular because of their potential as photoactivatable anticancer prodrugs. However, azido ligands are difficult to probe by NMR spectroscopy due to the quadrupolar nature of (14)N and the lack of scalar (1)H coupling to enhance the sensitivity of the less abundant (15)N by using polarisation transfer. In this work, we report (14)N and (15)N NMR spectroscopic studies of cis,trans,cis-[Pt(N(3))(2)(OH)(2)(NH(3))] (1) and trans,trans,trans-[Pt(N(3))(2)(OH)(2)(X)(Y)], where X=Y=NH(3) (2); X=NH(3), Y=py (3) (py=pyridine); X=Y=py (4); and selected Pt(II) precursors. These studies provide the first (15)N NMR data for azido groups in coordination complexes. We discuss one- and three-bond J((15)N,(195)Pt) couplings for azido and am(m)ine ligands. The (14)N(α) (coordinated azido nitrogen) signal in the Pt(IV) azido complexes is extremely broad (W(1/2)≈2124 Hz for 4) in comparison to other metal azido complexes, attributable to a highly asymmetrical electric field gradient at the (14)N(α) atom. Through the use of anti-ringing pulse sequences, the (14)N NMR spectra, which show resolution of the broad (14)N(α) peak, were obtained rapidly (e.g., 1.5 h for 10 mM 4). The linewidths of the (14)N(α) signals correlate with the viscosity of the solvent. For (15) N-enriched samples, it is possible to detect azido (15)N resonances directly, which will allow photoreactions to be followed by 1D (15)N NMR spectroscopy. The T(1) relaxation times for 3 and 4 were in the range 5.7-120 s for (15)N, and 0.9-11.3 ms for (14)N. Analysis of the (1)J((15)N,(195)Pt) coupling constants suggests that an azido ligand has a moderately strong trans influence in octahedral Pt(IV) complexes, within the series 2-picIV)-NH(3) bond to a greater extent than an axial OH(-) ligand. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. New water-soluble azido- and derived tetrazolato-platinum(II) complexes with PTA. Easy metal-mediated synthesis and isolation of 5-substituted tetrazoles.

    Science.gov (United States)

    Smoleński, Piotr; Mukhopadhyay, Suman; Guedes da Silva, M Fátima C; Charmier, M Adília Januário; Pombeiro, Armando J L

    2008-12-14

    The water-soluble four- and five-coordinate diazido-platinum(II) complexes cis-[Pt(N3)2(PTA)2] (1) (PTA = 1,3,5-triaza-7-phosphaadamantane), cis-[Pt(N3)2(Me-PTA)2]I2 (2) (Me-PTA = N-methyl-1,3,5-triaza-7-phosphaadamantane cation) and [Pt(N3)2(PTA)3] (3) were obtained by reactions of cis-[Pt(N3)2(PPh3)2] with PTA or [Me-PTA]I in dichloromethane. [2 + 3] cycloadditions of with organonitriles NCR gave the bis(tetrazolato) complexes trans-[Pt(N4CR)2(PTA)2] (R = Ph (4), 4-ClC6H4 (5) or 3-NC5H4 (6)), the reactions being greatly accelerated by microwave irradiation. 5-R-1H-Tetrazoles N4CR (R = Ph, 4-ClC6H4 and 3-NC5H4) were easily liberated from the tetrazolato complexes and isolated in high yields, in a single-pot process, upon reaction with aqueous diluted HCl, with concomitant formation of the water soluble cis-[Pt(Cl)2(PTA-H)2] complex 7. Alternatively, in a less convenient method, the tetrazoles could be liberated on reaction of 4-6 with propionitrile which also leads to the dicyano trans-[Pt(CN)2(PTA)2] complex 8. The compounds were characterized by IR, 1H, 13C and 31P[1H] NMR spectroscopies, FAB+-MS or ESI-MS, elemental analyses and (for and 4) also by X-ray diffraction.

  3. [Formylation of porphyrin platinum complexes].

    Science.gov (United States)

    Rumiantseva, V D; Konovalenko, L I; Nagaeva, E A; Mironov, A F

    2005-01-01

    The formylation reaction of platinum complexes of beta-unsubstituted porphyrins was studied. The interaction of deuteroporphyrin IX derivatives with the Vilsmeyer reagent led to the selective formylation of their macrocycles in the beta position. The resulting formyl derivatives of the porphyrins are of interest for fluorescent immunoassay.

  4. Heterogeneous platinum-catalyzed hydrogenation of dialkyl(diolefin)platinum(II) complexes: A new route to platinum surface alkyls

    OpenAIRE

    McCarthy, Thomas J.; Shih, Yen-Shiang; Whitesides, George M.

    1981-01-01

    Platinum metal catalyzes the reduction of dialkyl(diolefin)platinum(II) complexes by dihydrogen to alkanes and platinum(0). The reaction involves adsorption of the platinum(II) complex on the platinum(0) catalyst surface with conversion of the alkyl moieties to platinum surface alkyls; these appear as alkane products. The platinum atom originally present in the soluble organoplatinum species becomes part of the platinum(0) surface.

  5. De novo generation of singlet oxygen and ammine ligands by photoactivation of a platinum anticancer complex.

    Science.gov (United States)

    Zhao, Yao; Farrer, Nicola J; Li, Huilin; Butler, Jennifer S; McQuitty, Ruth J; Habtemariam, Abraha; Wang, Fuyi; Sadler, Peter J

    2013-12-16

    Worth the excitement: Highly reactive oxygen and nitrogen species are generated by photoactivation of the anticancer platinum(IV) complex trans,trans,trans-[Pt(N3 )2 (OH)2 (MA)(Py)] (MA=methylamine, Py=pyridine). Singlet oxygen is formed from the hydroxido ligands and not from dissolved oxygen, and ammine ligands are products from the conversion of azido ligands to nitrenes. Both processes can induce oxidation of guanine.

  6. Antitumor effect of arabinogalactan and platinum complex.

    Science.gov (United States)

    Starkov, A K; Zamay, T N; Savchenko, A A; Ingevatkin, E V; Titova, N M; Kolovskaya, O S; Luzan, N A; Silkin, P P; Kuznetsova, S A

    2016-03-01

    The article presents the results of investigation of antitumor properties of platinum-arabinogalactan complex. We showed the ability of the complex to inhibit the growth of Ehrlich ascites tumor cells. It is found that the distribution of the platinum-arabinogalactan complex is not specific only for tumor cells in mice. The complex was found in all tissues and organs examined (ascites cells, embryonic cells, kidney, and liver). The mechanism of action of the arabinogalactan-platinum complex may be similar to cisplatin as the complex is able to accumulate in tumor cells.

  7. A Photoactivatable Platinum(IV) Anticancer Complex Conjugated to the RNA Ligand Guanidinoneomycin.

    Science.gov (United States)

    Shaili, Evyenia; Fernández-Giménez, Marta; Rodríguez-Astor, Savina; Gandioso, Albert; Sandín, Lluís; García-Vélez, Carlos; Massaguer, Anna; Clarkson, Guy J; Woods, Julie A; Sadler, Peter J; Marchán, Vicente

    2015-12-07

    A photoactivatable platinum(IV) complex, trans,trans,trans-[Pt(N3 )2 (OH)(succ)(py)2 ] (succ=succinylate, py=pyridine), has been conjugated to guanidinoneomycin to study the effect of this guanidinum-rich compound on the photoactivation, intracellular accumulation and phototoxicity of the pro-drug. Surprisingly, trifluoroacetic acid treatment causes the replacement of an azido ligand and the axial hydroxide ligand by trifluoroacetate, as shown by NMR spectroscopy, MS and X-ray crystallography. Photoactivation of the platinum-guanidinoneomycin conjugate in the presence of 5'-guanosine monophosphate (5'-GMP) led to the formation of trans-[Pt(N3 )(py)2 (5'-GMP)](+) , as does the parent platinum(IV) complex. Binding of the platinum(II) photoproduct {PtN3 (py)2 }(+) to guanine nucleobases in a short single-stranded oligonucleotide was also observed. Finally, cellular uptake studies showed that guanidinoneomycin conjugation improved the intracellular accumulation of the platinum(IV) pro-drug in two cancer cell lines, particularly in SK-MEL-28 cells. Notably, the higher phototoxicity of the conjugate in SK-MEL-28 cells than in DU-145 cells suggests a degree of selectivity towards the malignant melanoma cell line.

  8. Tetrakis(azido-κN(di-2-pyridylamine-κ2N2,N2′platinum(IV

    Directory of Open Access Journals (Sweden)

    Kwang Ha

    2012-04-01

    Full Text Available In the title complex, [Pt(N34(C10H9N3], the PtIV ion is six-coordinated in a slightly distorted octahedral environment by the two pyridine N atoms of the chelating di-2-pyridylamine (dpa ligand and four N atoms from four azide anions. The dpa ligand is not planar, the dihedral angle between the pyridine rings being 20.0 (3°. The azide ligands are slightly bent [N—N—N = 173.5 (8–175.1 (8°]. In the crystal, the complex molecules are connected by N—H...N hydrogen bonds, forming a chain along the b axis. An intermolecular π–π interaction between the chains is also present, the ring centroid–centroid distance being 3.713 (4 Å.

  9. Synthesis and characterization of new platinum(II) and platinum(IV) triphyrin complexes.

    Science.gov (United States)

    Xue, Zhaoli; Kuzuhara, Daiki; Ikeda, Shinya; Okujima, Tetsuo; Mori, Shigeki; Uno, Hidemitsu; Yamada, Hiroko

    2013-02-18

    Metalation of 6,13,20,21-tetrakis(4-methylphenyl)-22H-tribenzo[14]triphyrin(2.1.1) with PtCl(2) gave a platinum(II) complex having a square-planar coordination structure with two pyrrolic nitrogen atoms and two chloride ions, with a saddle-shaped macrocycle. This platinum(II) complex was easily oxidized by air to an octahedral platinum(IV) complex coordinated by three pyrrolic nitrogen atoms as a tridentate monoanionic cyclic ligand and three chloride ions. When platinum(II) triphyrin was crystallized in air, an oxygen atom was incorporated between two α-carbon atoms of the pyrroles as an oxygen bridge to intercept the 14π aromatic system.

  10. 2-Methoxycycloocta-1,5-dienyl platinum complexes as precursors for platinum nanoparticles

    Indian Academy of Sciences (India)

    Ninad Ghavale; Sandip Dey; Vimal K Jain; R Tewari

    2009-02-01

    Thermolysis of [Pt2 (-OR)2 (C8H12OMe)2] (R = Me or Ac) in hexadecylamine (HDA) at 210°C under argon atmosphere gave platinum nanoparticles which were characterized by XRD, EDAX and TEM analysis. Both spherical (∼ 10 nm) and rod-like (∼ 19 nm length with aspect ratio of 2.3) face centred cubic (fcc) platinum metal nanoparticles could be isolated. The thermogravimetric analyses of these complexes revealed that they undergo a single step decomposition leading to the formation of platinum metal powder.

  11. Interaction of novel bis(platinum) complexes with DNA.

    OpenAIRE

    Roberts, J D; Van Houten, B; Qu, Y; Farrell, N P

    1989-01-01

    Bis(platinum) complexes [[cis-PtCl2(NH3)]2H2N(CH2)nNH2] are a novel series of potential anticancer agents in which two cis-diamine(platinum) groups are linked by an alkyldiamine of variable length. These complexes are potentially tetrafunctional, a unique feature in comparison with known anticancer agents. Studies of DNA interactions of bis(platinum) complexes in comparison with cisplatin demonstrate significant differences. Investigations of interstrand crosslink formation in which crosslink...

  12. New Perfluorophtalate Complexes of Platinum(II) With Chemotherapeutic Potential

    OpenAIRE

    de Oliveira, M. B.; J. Miller; Banks, R. E.; Kelland, L R; McAuliffe, C. A.; Mahmood, N; Rowland, I. J.

    1996-01-01

    Two new platinum(II) complexes have been synthesized and their anti-tumour and anti-HIV activities have been evaluated. The new complexes are: (i) cis-tetrafluorophthalate-ammine-morpholine-platinum(II) or MMF3 and (ii) cis-tetrafluorophthalate- ammine-piperidine-platinum(II) or MPF4. They were characterized by elemental analysis, IR spectra and 1H and 13C NMR spectra. They were tested against five human ovarian carcinoma cell lines, viz., CH1, CH1cisR, A2780, A2780cisR and SKOV-3. They were ...

  13. Internalization of Ineffective Platinum Complex in Nanocapsules Renders It Cytotoxic.

    Science.gov (United States)

    Vrana, Oldrich; Novohradsky, Vojtech; Medrikova, Zdenka; Burdikova, Jana; Stuchlikova, Olga; Kasparkova, Jana; Brabec, Viktor

    2016-02-18

    Anticancer therapy by platinum complexes, based on nanocarrier-based delivery, may offer a new approach to improve the efficacy and tolerability of the platinum family of anticancer drugs. The original rules for the design of new anticancer platinum drugs were affected by the fact that, although cisplatin (cis-[PtCl2 (NH3)2) was an anticancer drug, its isomer transplatin was not cytotoxic. For the first time, it is demonstrated that simple encapsulation of an inactive platinum compound in phospholipid bilayers transforms it into an efficient cytotoxic agent. Notably, the encapsulation of transplatin makes it possible to overcome the resistance mechanisms operating in cancer cells treated with cisplatin and prevents inactivation of transplatin in the extracellular environment. It is also shown that transplatin delivered to the cells in nanocapsules, in contrast to free (nonencapsulated) complex, forms cytotoxic cross-links on DNA.

  14. CROWN FUNCTIONALIZED LINEAR POLYSILOXANE PLATINUM COMPLEX AS HYDROSILYLATION CATALYST

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; LU Xueran; GONG Shuling; ZHANG Baolian

    1994-01-01

    A modified method of preparing crown functionalized linear polysiloxane has been described.4'-allylbenzo-15-crown-5 was subjected to hydrosilylation with methyldichlorosilane,followed by polycondensation with silanol-terminated polydimethylsiloxane to give the title crown functionalized linear polysiloxane. It was found that the polysiloxane could be coordinated with platinum salt to form platinum complex, which could catalyze the hydrosilylation of olefins with triethoxysilane efficiently.

  15. Synthesis and characterization of a 1D chain-like Cu{sub 6} substituted sandwich-type phosphotungstate with pendant dinuclear Cu–azido complexes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yan-Ying [MOE Key Laboratory of Cluster Science, School of Chemistry, Beijing Institute of Technology, Beijing 100081 (China); Zhao, Jun-Wei, E-mail: zhaojunwei@henu.edu.cn [Henan Key Laboratory of Polyoxometalate Chemistry, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Wei, Qi [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Yang, Bai-Feng [MOE Key Laboratory of Cluster Science, School of Chemistry, Beijing Institute of Technology, Beijing 100081 (China); Yang, Guo-Yu, E-mail: ygy@bit.edu.cn [MOE Key Laboratory of Cluster Science, School of Chemistry, Beijing Institute of Technology, Beijing 100081 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2014-02-15

    A novel Cu–azido complex modified hexa-Cu{sup II} substituted sandwich-type phosphotungstate [Cu(en){sub 2}]([Cu{sub 2}(en){sub 2}(μ-1,1-N{sub 3}){sub 2}(H{sub 2}O)]{sub 2}[Cu{sub 6}(en){sub 2}(H{sub 2}O){sub 2}(B-α-PW{sub 9}O{sub 34}){sub 2}])·6H{sub 2}O (1) (en=ethylene-diamine) has been prepared under hydrothermal conditions and structurally characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. 1 displays a beautiful 1-D chain architecture constructed from sandwich-type [Cu{sub 2}(en){sub 2}(μ-1,1-N{sub 3}){sub 2}(H{sub 2}O)]{sub 2}[Cu{sub 6}(en){sub 2}(H{sub 2}O){sub 2}(B-α-PW{sub 9}O{sub 34}){sub 2}]{sup 2−} units and [Cu(en){sub 2}]{sup 2+} linkers. To our knowledge, 1 represents the first hexa-Cu{sup II} sandwiched phosphotungstate with supporting Cu–azido complexes. - Graphical abstract: The first hexa-Cu{sup II} sandwiched phosphotungstate with supporting Cu–azido complexes has been prepared and characterized. Display Omitted - Highlights: • Hexa-copper-substituted phosphotungstate. • Cu–azido complexes modified hexa-Cu{sup II} substituted sandwich-type polyoxometalate. • 1-D chain architecture built by hexa-copper-substituted polyoxotungstate units.

  16. A 3D complex containing novel 2D Cu{sup II}-azido layers: Structure, magnetic properties and effects of 'Non-innocent' reagent

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Xue-Miao; Guo, Qian [School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384 (China); Zhao, Jiong-Peng, E-mail: horryzhao@yahoo.com [School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384 (China); Liu, Fu-Chen, E-mail: fuchenliutj@yahoo.com [School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin 300384 (China); Lanzhou Petrochemical College of Vocational Technology, Lanzhou 730060 (China)

    2012-12-15

    A novel copper-azido coordination polymer, [Cu{sub 2}(N{sub 3}){sub 3}(L)]{sub n} (1, HL=pyrazine-2-carboxylic acid), has been synthesized by hydrothermal reaction with 'Non-innocent' reagent in the aqueous solution. In the reaction system, Cu{sup II} ions are avoided to reduce to Cu{sup I} ions due to the existence of Nd{sup III}. It is found that the complex is a 3D structure based on two double EO azido bridged trimmers and octahedron Cu{sup II} ions, in which the azide ligands take on EO and {mu}{sub 1,1,3} mode to form Cu{sup II}-azido 2D layers, furthermore L ligands pillar 2D layers into an infinite 3D framework with the Schlaefli symbol of {l_brace}4;6{sup 2}{r_brace}4{l_brace}4{sup 2};6{sup 12};8{sup 10};10{sup 4}{r_brace}{l_brace}4{sup 2};6{sup 4}{r_brace}. Magnetic studies revealed that the interactions between the Cu{sup II} ions in the trimmer are ferromagnetic for the Cu-N-Cu angle nearly 98 Degree-Sign , while the interactions between the trimmer and octahedron Cu{sup II} ion are antiferromgantic and result in an antiferromagnetic state. - Graphical abstract: A 3D complex containing novel 2D Cu{sup II}-azido layers, [Cu{sub 2}(N{sub 3}){sub 3}(L)]{sub n} (HL=pyrazine-2-carboxylic acid), was synthesized by hydrothermal reaction and exhibit interesting structure and magnetic properties. Highlights: Black-Right-Pointing-Pointer 'Non-innocent' reagents plays a key role in the process of formation of this complex. Black-Right-Pointing-Pointer 2D layer is formed only by Cu{sup II} ions and azido ligands. Black-Right-Pointing-Pointer Pyrazine-2-carboxylate ligands reinforce 2D layers and pillar them into an infinite 3D framework. Black-Right-Pointing-Pointer Magnetic study indicates that alternating FM-AF coupling exists in the complex.

  17. A dual-emissive ionic liquid based on an anionic platinum(II) complex

    OpenAIRE

    Ogawa, Tomohiro; Yoshida, Masaki; Ohara, Hiroki; Kobayashia, Atsushi; Kato, Masako

    2015-01-01

    An ionic liquid fabricated froman anionic cyclometalated platinum(II) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.

  18. A dual-emissive ionic liquid based on an anionic platinum(ii) complex.

    Science.gov (United States)

    Ogawa, Tomohiro; Yoshida, Masaki; Ohara, Hiroki; Kobayashi, Atsushi; Kato, Masako

    2015-09-07

    An ionic liquid fabricated from an anionic cyclometalated platinum(ii) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.

  19. Polyamide platinum anticancer complexes designed to target specific DNA sequences.

    Science.gov (United States)

    Jaramillo, David; Wheate, Nial J; Ralph, Stephen F; Howard, Warren A; Tor, Yitzhak; Aldrich-Wright, Janice R

    2006-07-24

    Two new platinum complexes, trans-chlorodiammine[N-(2-aminoethyl)-4-[4-(N-methylimidazole-2-carboxamido)-N-methylpyrrole-2-carboxamido]-N-methylpyrrole-2-carboxamide]platinum(II) chloride (DJ1953-2) and trans-chlorodiammine[N-(6-aminohexyl)-4-[4-(N-methylimidazole-2-carboxamido)-N-methylpyrrole-2-carboxamido]-N-methylpyrrole-2-carboxamide]platinum(II) chloride (DJ1953-6) have been synthesized as proof-of-concept molecules in the design of agents that can specifically target genes in DNA. Coordinate covalent binding to DNA was demonstrated with electrospray ionization mass spectrometry. Using circular dichroism, these complexes were found to show greater DNA binding affinity to the target sequence: d(CATTGTCAGAC)(2), than toward either d(GTCTGTCAATG)(2,) which contains different flanking sequences, or d(CATTGAGAGAC)(2), which contains a double base pair mismatch sequence. DJ1953-2 unwinds the DNA helix by around 13 degrees , but neither metal complex significantly affects the DNA melting temperature. Unlike simple DNA minor groove binders, DJ1953-2 is able to inhibit, in vitro, RNA synthesis. The cytotoxicity of both metal complexes in the L1210 murine leukaemia cell line was also determined, with DJ1953-6 (34 microM) more active than DJ1953-2 (>50 microM). These results demonstrate the potential of polyamide platinum complexes and provide the structural basis for designer agents that are able to recognize biologically relevant sequences and prevent DNA transcription and replication.

  20. SILICA-BOUND CROWN ETHERS PLATINUM COMPLEX AS HYDROSILYLATION CATALYST

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; MENG Lingzhi; LI Liping; LUO Jieqi; HU Jinchang

    1993-01-01

    Silica-bound 15-Crown-5, 18-Crown-6 with a spacer of propyloxymethyl and their platinum complexes have been synthesized. It was found that they were efficient catalysts for the hydrosilylation of olefins with triethoxysilane in the temperature range of 60 to 130 ℃ .

  1. POLYMER-PLATINUM COMPLEX CATALYSTS FOR OXIDATION OF METHANOL TO FORMALDEHYDE

    Institute of Scientific and Technical Information of China (English)

    HUANG Meiyu; HUANG Li; ZHENG Qingyao; WANG Dianxun; JIANG Yingyan

    1984-01-01

    Two kinds of polymer-platinum complexes: silica-supported poly-γ-diphenylphosphinopropyl-siloxane-platinum complex and silica-supported polyphenylsilazane-platinum complex, have been found very active and selective in catalyzation of oxidation of methanol to formaldehyde at room temperature and under an atmospheric oxygen pressure. Their catalytic activities are greatly affected by P or N/Pt gram atomic ratio.

  2. Azido, triazolyl, and alkynyl complexes of gold(I): syntheses, structures, and ligand effects.

    Science.gov (United States)

    Robilotto, Thomas J; Deligonul, Nihal; Updegraff, James B; Gray, Thomas G

    2013-08-19

    Gold(I) triazolyl complexes are prepared in [3 + 2] cycloaddition reactions of (tertiary phosphine)gold(I) azides with terminal alkynes. Seven such triazolyl complexes, not previously prepared, are described. Reducible functional groups are accommodated. In addition, two new (N-heterocyclic carbene)gold(I) azides and two new gold(I) alkynyls are described. Eight complexes are crystallographically authenticated; aurophilic interactions appear in one structure only. The packing diagrams of gold(I) triazolyls all show intermolecular hydrogen bonding between N-1 of one molecule and N-3 of a neighbor. This hydrogen bonding permeates the crystal lattice. Density-functional theory calculations of (triphenylphosphine)gold(I) triazolyls and the corresponding alkynyls indicate that the triazolyl is a stronger trans-influencer than is the alkynyl, but the alkynyl is more electron-releasing. These results suggest that trans-influences in two-coordinate gold(I) complexes can be more than a simple matter of ligand donicity.

  3. Mononuclear thiocyanate containing nickel(II) and binuclear azido bridged nickel(II) complexes of N4-coordinate pyrazole based ligand: Syntheses, structures and magnetic properties

    Science.gov (United States)

    Solanki, Ankita; Monfort, Montserrat; Kumar, Sujit Baran

    2013-10-01

    Two mononuclear nickel(II) complexes [NiL1(NCS)2] (1) and [NiL2(NCS)2] (2) and two azido bridged binuclear nickel(II) complexes [Ni(()2()2] (3) and [Ni(()2()2] (4), where L1, L2, L1‧ and L2‧ are N,N-diethyl-N‧,N‧-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1), N,N-bis((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2), N,N-diethyl-N‧-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1‧) and N-((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2‧) have been synthesized and characterized by microanalyses and physico-chemical methods. Single crystal X-ray diffraction analyses revealed that complexes 1 and 2 are mononuclear NCS- containing Ni(II) complex with octahedral geometry and complexes 3 and 4 are end-on (μ-1,1) azido bridged binuclear Ni(II) complexes with distorted octahedral geometry. Variable temperature magnetic studies of the complexes 3 and 4 display ferromagnetic interaction with J values 19 and 32 cm-1, respectively.

  4. Platinum(II) and platinum(IV) complexes stabilized by abnormal/mesoionic C4-bound dicarbenes.

    Science.gov (United States)

    Khlebnikov, Vsevolod; Heckenroth, Marion; Müller-Bunz, Helge; Albrecht, Martin

    2013-03-28

    Platinum(II) complexes comprising abnormal diimidazolylidene ligands were synthesized from cis-PtMe(2)(DMSO)(2) using microwave-assisted double C-H bond activation. NMR analysis revealed an unusual solvolysis process, induced by coordinating solvents such as DMSO and MeCN, which has not been observed in related normal dicarbene complexes. NMR and IR spectroscopy and crystallographic analysis of the mono-substituted DMSO complex indicate a sulfur-bonding of the DMSO ligand to the platinum(II) center. Analysis of the DMSO exchange kinetics provided for the first time a quantitative measure of the trans effect of abnormal carbene ligands. The kinetic exchange rate in these bidentate abnormal dicarbene complexes is 0.050(±2) s(-1) and thus similar to analogous platinum(II) complexes containing phenylpyridine, yet significantly slower than that induced by pyridylidene pyridine. Reaction of the dicarbene platinum(II) complexes with PhICl(2), Br(2) and I(2) afforded the corresponding platinum(IV) complexes. Linkage isomerism of the Pt(IV)-bound DMSO was observed when the bromination reaction was performed in DMSO solution. Moreover, solvolysis was less pronounced in the platinum(IV) complexes than in the corresponding platinum(II) analogues.

  5. Azido- and chlorido-cobalt complex as carrier-prototypes for antitumoral prodrugs.

    Science.gov (United States)

    Pires, Bianca M; Giacomin, Letícia C; Castro, Frederico A V; Cavalcanti, Amanda dos S; Pereira, Marcos D; Bortoluzzi, Adailton J; Faria, Roberto B; Scarpellini, Marciela

    2016-04-01

    Cobalt(III) complexes are well-suited systems for cytotoxic drug release under hypoxic conditions. Here, we investigate the effect of cytotoxic azide release by cobalt-containing carrier-prototypes for antitumoral prodrugs. In addition, we study the species formed after reduction of Co(3+) → Co(2+) in the proposed models for these prodrugs. Three new complexes, [Co(III)(L)(N3)2]BF4(1), [{Co(II)(L)(N3)}2](ClO4)2(2), and [Co(II)(L)Cl]PF6(3), L=[(bis(1-methylimidazol-2-yl)methyl)(2-(pyridyl-2-yl)ethyl)amine], were synthesized and studied by several spectroscopic, spectrometric, electrochemical, and crystallographic methods. Reactivity and spectroscopic data reveal that complex 1 is able to release N3(-) either after reduction with ascorbic acid, or by ambient light irradiation, in aqueous phosphate buffer (pH6.2, 7.0 and 7.4) and acetonitrile solutions. The antitumoral activities of compounds 1-3 were tested in normoxia on MCF-7 (human breast adenocarcinoma), PC-3 (human prostate) and A-549 (human lung adenocarcinoma epithelial) cell lines, after 24h of exposure. Either complexes or NaN3 presented IC50 values higher than 200 μM, showing lower cytotoxicity than the clinical standard antitumoral complex cisplatin, under the same conditions. Complexes 1-3 were also evaluated in hypoxia on A-549 and results indicate high IC50 data (>200 μM) after 24h of exposure. However, an increase of cancer cell susceptibility to 1 and 2 was observed at 300 μM. Regarding complex 3, no cytotoxic activity was observed in the same conditions. The data presented here indicate that the tridentate ligand L is able to stabilize both oxidation states of cobalt (+3 and +2). In addition, the cobalt(III) complex generates the low cytotoxic cobalt(II) species after reduction, which supports their use as as carrier prototypes for antitumoral prodrugs.

  6. EGFR-targeting peptide-coupled platinum(IV) complexes.

    Science.gov (United States)

    Mayr, Josef; Hager, Sonja; Koblmüller, Bettina; Klose, Matthias H M; Holste, Katharina; Fischer, Britta; Pelivan, Karla; Berger, Walter; Heffeter, Petra; Kowol, Christian R; Keppler, Bernhard K

    2017-06-01

    The high mortality rate of lung cancer patients and the frequent occurrence of side effects during cancer therapy demonstrate the need for more selective and targeted drugs. An important and well-established target for lung cancer treatment is the occasionally mutated epidermal growth factor receptor (EGFR). As platinum(II) drugs are still the most important therapeutics against lung cancer, we synthesized in this study the first platinum(IV) complexes coupled to the EGFR-targeting peptide LARLLT (and the shuffled RTALLL as reference). Notably, HPLC-MS measurements revealed two different peaks with the same molecular mass, which turned out to be a transcyclization reaction in the linker between maleimide and the coupled cysteine moiety. With regard to the EGFR specificity, subsequent biological investigations (3-day viability, 14-day clonogenic assays and platinum uptake) on four different cell lines with different verified EGFR expression levels were performed. Unexpectedly, the results showed neither an enhanced activity nor an EGFR expression-dependent uptake of our new compounds. Consequently, fluorophore-coupled peptides were synthesized to re-evaluate the targeting ability of LARLLT itself. However, also with these molecules, flow cytometry measurements showed no correlation of drug uptake with the EGFR expression levels. Taken together, we successfully synthesized the first platinum(IV) complexes coupled to an EGFR-targeting peptide; however, the biological investigations revealed that LARLLT is not an appropriate peptide for enhancing the specific uptake of small-molecule drugs into EGFR-overexpressing cancer cells.

  7. Platinum(II) complexes as spectroscopic probes for biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Ratilla, E.

    1990-09-21

    The use of platinum(II) complexes as tags and probes for biomolecules is indeed advantageous for their reactivities can be selective for certain purposes through an interplay of mild reaction conditions and of the ligands bound to the platinum. The use of {sup 195}Pt NMR as a method of detecting platinum and its interactions with biomolecules was carried out with the simplest model of platinum(II) tagging to proteins. Variable-temperature {sup 195}Pt NMR spectroscopy proved useful in studying the stereodynamics of complex thioethers like methionine. The complex, Pt(trpy)Cl{sup +}, with its chromophore has a greater potential for probing proteins. It is a noninvasive and selective tag for histidine and cysteine residues on the surface of cytochrome c at pH 5. The protein derivatives obtained are separable, and the tags are easily quantitated and differentiated through the metal-to-ligand charge transfer bands which are sensitive to the environment of the tag. Increasing the pH to 7.0 led to the modification by Pt(trpy)Cl{sup +}of Arg 91 in cytochrome c. Further studies with guanidine-containing ligands as models for arginine modification by Pt(trpy)Cl{sup +} showed that guanidine can act as a terminal ligand and as a bridging ligand. Owing to the potential utility of Pt(trpy)L{sup n+} as electron dense probes of nucleic acid structure, interactions of this bis-Pt(trpy){sup 2+} complex with nucleic acids was evaluated. Indeed, the complex interacts non-covalently with nucleic acids. Its interactions with DNA are not exactly the same as those of its precedents. Most striking is its ability to form highly immobile bands of DNA upon gel electrophoresis. 232 refs.

  8. Three-dimensional structure of thymidine phosphorylase from E. coli in complex with 3'-azido-2'-fluoro-2',3'-dideoxyuridine

    Science.gov (United States)

    Timofeev, V. I.; Abramchik, Yu. A.; Fateev, I. V.; Zhukhlistova, N. E.; Murav'eva, T. I.; Kuranova, I. P.; Esipov, R. S.

    2013-11-01

    The three-dimensional structures of thymidine phosphorylase from E. coli containing the bound sulfate ion in the phosphate-binding site and of the complex of thymidine phosphorylase with sulfate in the phosphate-binding site and the inhibitor 3'-azido-2'-fluoro-2',3'-dideoxyuridine (N3F-ddU) in the nucleoside-binding site were determined at 1.55 and 1.50 Å resolution, respectively. The amino-acid residues involved in the ligand binding and the hydrogen-bond network in the active site occupied by a large number of bound water molecules are described. A comparison of the structure of thymidine phosphorylase in complex with N3F-ddU with the structure of pyrimidine nucleoside phosphorylase from St. Aureus in complex with the natural substrate thymidine (PDB_ID: 3H5Q) shows that the substrate and the inhibitor in the nucleoside-binding pocket have different orientations. It is suggested that the position of N3F-ddU can be influenced by the presence of the azido group, which prefers a hydrophobic environment. In both structures, the active sites of the subunits are in the open conformation.

  9. Organo-platinum complexes as antitumor agents (review).

    Science.gov (United States)

    Hill, J M; Speer, R J

    1982-01-01

    Rosenberg et al discovered in the coordination complexes of platinum a new, novel type of potential antitumor agent. Cisplatin [cis-dichlorodiammine platinum (II)4 proved active against a variety of rodent tumors and acted synergistically when combined with other chemotherapeutic agents. Initial clinical tests by Hill et al in 1971, showed cisplatin to be active against malignant lymphoma, Hodgkin's disease, and certain other malignancies. Significant nephrotoxicity, nausea, and vomiting were noted. Since then, cisplatin has been tested alone and in combination chemotherapy and has proven an efficacious anticancer agent in squamous cell carcinoma of head and neck, ovarian carcinoma, disseminated testicular cancer, and others. Its therapeutic value was acknowledged when approved in 1978 by the U.S. FDA for treatment of the latter cancer. The current clinical literature indicates clearly that the full potential of this drug has not yet been realized. Hydration and diuresis have served to mitigate much of the nephrotoxicity, while significant strides toward amelioration of the nausea and vomiting have also been achieved. Literally, thousands of chemically-related congeners have been synthesized, and many have shown marked potency against rodent tumors. Very few, however, have been evaluated clinically, vis-a-vis malonato trans(-)-1,2-diaminocyclohexane platinum(II); this appears a most promising and fertile area of future investigation.

  10. Recent Advances in Platinum (IV) Complex-Based Delivery Systems to Improve Platinum (II) Anticancer Therapy.

    Science.gov (United States)

    Han, Xiaopeng; Sun, Jin; Wang, Yongjun; He, Zhonggui

    2015-11-01

    Cisplatin and its platinum (Pt) (II) derivatives play a key role in the fight against various human cancers such as testicular, ovarian, head and neck, lung tumors. However, their application in clinic is limited due to dose- dependent toxicities and acquired drug resistances, which have prompted extensive research effort toward the development of more effective Pt (II) delivery strategies. The synthesis of Pt (IV) complex is one such an area of intense research fields, which involves their in vivo conversion into active Pt (II) molecules under the reducing intracellular environment, and has demonstrated encouraging preclinical and clinical outcomes. Compared with Pt (II) complexes, Pt (IV) complexes not only exhibit an increased stability and reduced side effects, but also facilitate the intravenous-to-oral switch in cancer chemotherapy. The overview briefly analyzes statuses of Pt (II) complex that are in clinical use, and then focuses on the development of Pt (IV) complexes. Finally, recent advances in Pt (IV) complexes in combination with nanocarriers are highlighted, addressing the shortcomings of Pt (IV) complexes, such as their instability in blood and irreversibly binding to plasma proteins and nonspecific distribution, and taking advantage of passive and active targeting effect to improve Pt (II) anticancer therapy. © 2015 Wiley Periodicals, Inc.

  11. Dialkyl bisphosphonate platinum(II) complex as a potential drug for metastatic bone tumor.

    Science.gov (United States)

    Nakatake, Hidetoshi; Ekimoto, Hisao; Aso, Mariko; Ogawa, Atsushi; Yamaguchi, Asami; Suemune, Hiroshi

    2011-01-01

    Bisphosphonates have high affinity for hydroxyapatite (HA), which is abundantly present in bone. Also, platinum complexes are known that have a wide spectrum of antitumor activities. The conjugate of bisphosphonate and a platinum complex might have HA affinity and antitumor activity, and become a drug for metastatic bone tumor. In this study, the authors synthesized platinum complexes that had dialkyl bisphosphonic acid as a ligand, and evaluated the possibility of the synthesized complexes as a drug for metastatic bone tumor. The synthesized dialkyl bisphosphonate platinum(II) complex was characterized, and its stability in an aqueous solution was also confirmed. The synthesized platinum complex showed higher HA affinity than other platinum complexes such as cisplatin and carboplatin in an experiment of adsorption to HA. In vitro, the platinum complex showed tumor growth inhibitory effect stronger than or equal to cisplatin, which is the most commonly used antitumor agent. Moreover, the platinum complex showed a bone absorption inhibitory effect on the osteoclast. These results suggest potential of dialkyl bisphosphonate platinum(II) complexes as a drug for metastatic bone tumor.

  12. On the reactivity of platinum(IV) complexes: Synthesis and spectroscopic studies of platinum(IV) complexes with hypoxanthine

    Science.gov (United States)

    Gaballa, Akmal S.

    2006-01-01

    Na 2[PtCl 6] was found to react with (HypH)Cl·H 2O ( 2) (Hyp=hypoxanthine) in aqueous solution at room temperature yielding (HypH) 2[PtCl 6] ( 3). The same compound was obtained from hexachloroplatinic acid and hypoxanthine. Performing this reaction in methanol at 50 °C complex formation took place yielding the hypoxanthine complex [PtCl 4(Hyp) 2] ( 4). Both compounds were isolated in good yields as faint orange ( 3) and yellow ( 4) precipitates, respectively and characterized by microanalyses, IR and NMR ( 1H, 13C, 195Pt) spectroscopies as well as thermal analysis. Based on the data obtained an octahedral molecular structure is proposed for complex 4 with two hypoxanthine ligands coordinated through N7 to platinum(IV).

  13. Photolysis of an arylalkyl-triazenido-platinum-IV complex

    Science.gov (United States)

    Lippert, T.; Dauth, J.; Deubzer, B.; Weis, J.; Wokaun, A.

    1996-06-01

    The photolytic decomposition of tetrakis(1-phenyl-3-hexyl-triazenido)-platinum(IV) is studied in a variety of media, and found to proceed according to simple first order kinetics. Two excimer laser wavelengths, an excimer-laser pumped dye laser, and a broadband mercury lamp are used for excitation. As referred to the incident power, selective irradiation near the complex-specific absorption maximum is found to be most efficient for inducing the photolytic decomposition. A different influence of degassing and oxygen saturation is observed for tetrahydrofurane and for technical siloxane solvents. To elucidate the origins of the observed behaviour, decomposition products of the complex, and products of hydrosilylation reactions catalyzed by this compound, are identified by GC/MS analysis.

  14. Design and development of polynuclear ruthenium and platinum polypyridyl complexes in search of new anticancer agents

    NARCIS (Netherlands)

    Schilden, Karlijn van der

    2006-01-01

    The research described in this Ph.D. Thesis has been devoted to the design and development of polynuclear polypyridyl ruthenium and ruthenium-platinum complexes in search of new anticancer agents. A variety of polynuclear ruthenium and ruthenium-platinum complexes has been synthesized with a long an

  15. Tuning the activity of platinum(IV) anticancer complexes through asymmetric acylation.

    Science.gov (United States)

    Chin, Chee Fei; Tian, Quan; Setyawati, Magdiel Inggrid; Fang, Wanru; Tan, Emelyn Sue Qing; Leong, David Tai; Ang, Wee Han

    2012-09-13

    Platinum(II) anticancer drug cisplatin is one of the most important chemotherapeutic agents in clinical use but is limited by its high toxicity and severe side effects. Platinum(IV) anticancer prodrugs can overcome these limitations by resisting premature aquation and binding to essential plasma proteins. Structure-activity relationship studies revealed a link between the efficacy of platinum(IV) complexes with the nature of their axial ligands, which can be modified to enhance the properties of the prodrug. The existing paradigm of employing platinum(IV) complexes with symmetrical axial carboxylate ligands does not fully exploit their vast potential. A new approach was conceived to control properties of platinum(IV) prodrugs using contrasting axial ligands via sequential acylation. We report a novel class of asymmetric platinum(IV) carboxylates based on the cisplatin template containing both hydrophilic and lipophilic ligands on the same scaffold designed to improve their aqueous properties and enhance their efficacy against cancer cells in vitro.

  16. New platinum(II complexes with benzothiazole ligands

    Directory of Open Access Journals (Sweden)

    José A. Carmona-Negrón

    2016-03-01

    Full Text Available Four new platinum(II complexes, namely tetraethylammonium tribromido(2-methyl-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C8H7NS] (1, tetraethylammonium tribromido(6-methoxy-2-methyl-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C9H9NOS] (2, tetraethylammonium tribromido(2,5,6-trimethyl-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C10H11NS] (3, and tetraethylammonium tribromido(2-methyl-5-nitro-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C8H6N2O2S] (4, have been synthesized and structurally characterized by single-crystal X-ray diffraction techniques. These species are precursors of compounds with potential application in cancer chemotherapy. All four platinum(II complexes adopt the expected square-planar coordination geometry, and the benzothiazole ligand is engaged in bonding to the metal atom through the imine N atom (Pt—N. The Pt—N bond lengths are normal: 2.035 (5, 2.025 (4, 2.027 (5 and 2.041 (4 Å for complexes 1, 2, 3 and 4, respectively. The benzothiazole ligands are positioned out of the square plane, with dihedral angles ranging from 76.4 (4 to 88.1 (4°. The NEt4 cation in 3 is disordered with 0.57/0.43 occupancies.

  17. Induction of immunogenic cell death by chemotherapeutic platinum complexes.

    Science.gov (United States)

    Wong, Daniel Yuan Qiang; Ong, Wendy Wei Fang; Ang, Wee Han

    2015-05-26

    There is compelling evidence suggesting that the immune-modulating effects of many conventional chemotherapeutics, including platinum-based agents, play a crucial role in achieving clinical response. One way in which chemotherapeutics can engage a tumor-specific immune response is by triggering an immunogenic mode of tumor cell death (ICD), which then acts as an "anticancer vaccine". In spite of being a mainstay of chemotherapy, there has not been a systematic attempt to screen both existing and upcoming Pt agents for their ICD ability. A library of chemotherapeutically active Pt agents was evaluated in an in vitro phagocytosis assay, and no correlation between cytotoxicity and phagocytosis was observed. A Pt(II) N-heterocyclic carbene complex was found to display the characteristic hallmarks of a type II ICD inducer, namely focused oxidative endoplasmic reticulum (ER) stress, calreticulin exposure, and both HMGB1 and ATP release, and thus identified as the first small-molecule immuno-chemotherapeutic agent.

  18. Sulfur containing platinum(II) complexes with N-heterocyclic carbene ligands obtained by reactions of a hydrosulfido complex.

    Science.gov (United States)

    Maeda, Yuri; Hashimoto, Hideki; Nishioka, Takanori

    2012-10-21

    A hydrosulfido platinum(ii) complex with a chelated N-heterocyclic carbene (NHC) ligand was oxidised with O(2) in the presence of excess hydrogen sulfide, to give a linear tetrasulfido complex, and without hydrogen sulfide, to give a thiosulfato-bridged dinuclear complex. The hydrosulfido complex also reacted with an acetato complex containing the chelating NHC platinum unit to afford a trinuclear platinum complex with two triply bridging sulfido ligands showing an equilibrium in solution between two isomers based on the arrangement of the chelating NHC ligands.

  19. The Versatile Behavior of Platinum Alkyne Complexes towards XeF2 : Formation of Fluorovinyl and Fluorido Complexes.

    Science.gov (United States)

    Berger, Josefine; Braun, Thomas; Ahrens, Theresia; Kläring, Paul; Laubenstein, Reik; Braun-Cula, Beatrice

    2017-07-03

    Reactions of platinum(0) tolane complexes, bearing a chelating ligand with P and N donor atoms, with the electrophilic fluorinating agent XeF2 give facile access to platinum(II) β-fluorovinyl fluorido complexes. A series of new platinum(II) β-fluorovinyl complexes have been synthesized and were structurally characterized. Further oxidation with XeF2 led to ortho-metalated platinum(IV) fluorido compounds. Additional reactions of platinum(0) tolane complexes, bearing a chelating P,P donor ligand, with XeF2 led to a variety of fluorido and fluorovinyl complexes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Unsaturated platinum-rhenium cluster complexes. Synthesis, structures and reactivity.

    Science.gov (United States)

    Adams, Richard D; Captain, Burjor; Smith, Mark D; Beddie, Chad; Hall, Michael B

    2007-05-09

    Two new compounds PtRe3(CO)12(PBut3)(micro-H)3, 9, and PtRe2(CO)9(PBut3)(micro-H)2, 10, were obtained from the reaction of Pt(PBut3)2 with Re3(CO)12(micro-H3), 8, at room temperature. Compound 9 contains a butterfly cluster of four metals formed by the insertion of the platinum atom from a Pt(PBut3) group into one of the hydride-bridged metal-metal bonds of 8. The three hydrido ligands are bridging ligands across each of three new Pt-Re bonds. Compound 10 contains a triangular PtRe2 cluster with two hydrido ligands; one bridges a Pt-Re bond, and the other bridges the Re-Re bond. The new compound Pt2Re2(CO)7(PBut3)2(micro-H)2, 11, was obtained from the reaction of 8 with Pt(PBut3)2 in hexane at reflux. Compound 11 was also obtained from 10 by reaction with an additional quantity of Pt(PBut3)2. Compound 11 contains a tetrahedral cluster of four metal atoms with two dynamically active hydrido ligands. A CO ligand on one of the two platinum atoms also exchanges between the two platinum atoms rapidly on the NMR time scale. Compound 11 is electronically unsaturated and was found to add hydrogen at room temperature to form the tetrahydrido cluster complex, Pt2Re2(CO)7(PBut3)2(micro-H)4, 12. Compound 12 has a structure similar to 11 but contains one triply bridging hydrido ligand, two edge bridging hydrido ligands, and one terminal hydrido ligand on one of the two platinum atoms. A kinetic isotope effect D/H of 1.5(1) was determined for the addition of H2 to 11. Hydrogen can be eliminated from 12 by heating to 97 degrees C or by the application of UV-vis irradiation at room temperature. Compound 12 adds CO at room temperature to yield the complex Pt2Re2(CO)8(PBut3)2(micro-H)4, 13, which contains a planar cluster of four metal atoms with a Pt-Pt bond and four edge bridging hydrido ligands. Compounds 11 and 12 react with Pt(PBut3)2 to yield the known five metal cluster complexes Pt3Re2(CO)6(PBut3)3(micro-H)2, 14, and Pt3Re2(CO)6(PBut3)3(micro-H)4, 15, respectively. Density

  1. Synthesis and characterization of phosphorescent platinum complexes containing phenylpyridazine

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Jin; Kang, Seok; Lee, Seung Hee; Hwang, Kwang Jin; Park, Noh Kil; Kim, Young Sik

    2004-01-05

    Synthesis and characterization of a series of square planar Pt(II)-phenylpyridazine complexes are reported. The complexes have the general structure of (C-N)Pt(O-O), where HC-N is 3-phenyl-pyridazine (ppdz), 3-(3'-trifluoromethylphenyl)pyridazine (3'tfmppdz), 3-(3'-methoxyphenyl)-pyridazine (3'meoppdz), 3-(4'-methoxyphenyl)pyridazine (4'meoppdz), or 3-phenyl-6-chloro-pyridazine (6Clppdz) and HO-O is acetylacetone (Hacac). Reaction of K{sub 2}PtCl{sub 4} with a HC-N ligand forms the dimer, (C-N)Pt({mu}-Cl){sub 2}Pt(C-N), which is cleaved with Hacac to give the corresponding monomer, (C-N)Pt(O-O). The emission characteristics of these complexes are governed by the substituents of the cyclometalating ligands, showing emission {lambda}{sub max} values from 508 to 610 nm. Strong spin-orbit coupling of the platinum atom allows for the formally forbidden mixing of the {sup 1}MLCT with the {sup 3}MCLT and {sup 3}({pi}-{pi}*) states.

  2. Efficient organic light-emitting devices with platinum-complex emissive layer

    KAUST Repository

    Yang, Xiaohui

    2011-01-18

    We report efficient organic light-emitting devices having a platinum-complex emissive layer with the peak external quantum efficiency of 17.5% and power efficiency of 45 lm W−1. Variation in the device performance with platinum-complex layer thickness can be attributed to the interplay between carrier recombination and intermolecular interactions in the layer. Efficient white devices using double platinum-complex layers show the external quantum efficiency of 10%, the Commission Internationale d’Énclairage coordinates of (0.42, 0.41), and color rendering index of 84 at 1000 cd m−2.

  3. Structure and reactivity of a unique Y-shaped tricoordinate bis(silyl)platinum(II)-NHC complex

    NARCIS (Netherlands)

    Berthon-Gelloz, G.; de Bruin, B.; Tinant, B.; Markó, I.E.

    2009-01-01

    A unique, three-coordinate Y-shaped bis(silyl)platinum(II) complex was isolated and characterized. DFT studies on a model system shed light on the nature of this unusual coordination mode for platinum(II).

  4. Non-bridging ligand effects on the kinetics of reduction of chloro- and azido-pentaamminecobalt(III by some polypyridyl complexes of ruthenium(II

    Directory of Open Access Journals (Sweden)

    Olayinka A. Oyetunji

    2006-12-01

    Full Text Available Pentaamminecobalt(III complexes, [Co(NH35X]2+ (X = Cl-, N3-, are reduced by [Ru(bipy3]2+ and [Ru(terpy(bipyCl] + in aqueous media at a constant ionic strength of 0.5 M (HCl/LiCl. At 308 K, the second order rate constants (M-1 s-1 are as follows: 17.9 for the reduction of the azidocobalt(III complex by [Ru(bipy3]2+, and 1.41 and 2.63 for the [Ru(terpy(bipyCl]+ reduction of the azido- and chlorocobalt(III complexes, respectively. Activation enthalpies (ΔH‡ and entropies (ΔS‡ were determined from temperature dependence measurements with the following results: ΔH‡= 72.1 kJ mol-1 and ΔS‡ = 13.3 J mol-1 K-1 for the [Ru(bipy3]2+ reduction of the azidocobalt(III complex, while for the reduction of the cobalt(III complexes by [Ru(terpy(bipyCl] +, ΔH‡ (N3- = 20.3 kJ mol-1, ΔH‡ (Cl- = 40.6 kJ mol-1, ΔS‡(N3- = -177 J mol-1 K-1, and ΔS‡ (Cl- = -106 J mol-1 K-1. The relative rates of electron transfer in the different reactions and the influence of π-acceptor ligands on the ruthenium(II reduction of the cobalt(III complexes are discussed.

  5. Platinum(iv) N-heterocyclic carbene complexes: their synthesis, characterisation and cytotoxic activity.

    Science.gov (United States)

    Bouché, M; Dahm, G; Wantz, M; Fournel, S; Achard, T; Bellemin-Laponnaz, S

    2016-07-28

    Platinum(ii) N-heterocyclic carbene complexes have been oxidized by bromine or iodobenzene dichloride to provide the fully characterised corresponding platinum(iv) NHC complexes. Antiproliferative activities of Pt(iv) NHC complexes were assayed against several cancer cell lines and the results were correlated with respect to their stability. Mechanistic investigations revealed that mitochondrial dysfunction and ROS production were associated with the cytotoxic process induced by these compounds.

  6. SYNTHESIS OF POLYSILOXANE-SUPPORTED SELENAETHER PLATINUM COMPLEX AND ITS CATALYTIC PROPERTY FOR HYDROSILYLATION OF OLEFINS

    Institute of Scientific and Technical Information of China (English)

    LU Xueran; CHEN Zhen; DUAN Heping; CHEN Yifan

    1996-01-01

    A new type of selenious polymer, silica-bound polybispropoxyethyl-selenidesilsesquioxane,and its platinum complex were synthesized from bis-allyloxyethyl selenide via hydrosilylation with triethoxysilane, followed by immobilized on fumed silica, and then reacting with potassium chloroplatinite under nitrogen atmosphere in acetone. It was found that the platinum complex can catalyze the hydrosilylation of olefins with triethoxysilane effectively. The effects of the nature of the substrate, the amount of complex used, and the reaction temperature on the catalytic activity were investigated.

  7. A NEW TYPE OF CROWN FUNCTIONALIZED POLYSILOXANE AND ITS PLATINUM COMPLEX

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; HONG Liwu; LI Jun; LU Xueran

    1993-01-01

    A new type of crown functionalized polysiloxane, in which the crown moieties were incorporated into main chain, and its platinum complex were synthesized. The polysiloxane was synthesized from 3, 16- dihydroxy- 1 - thia - 5, 8, 11, 14- tetraoxacycloheptadecane via etherification with ω- chloroundecene, followed by hydrosilylation with triethoxysilane, cohydrolysis with D4, sequentially. Treating the polysiloxane with potassium cholroplatinite, the title complex was obtained. It was found that the platinum complex exhibited high catalytic activity in the hydrosilylation of olefins with triethoxysilane.

  8. Platinum Complexes with Edda (Ethylenediamine -N, N - Diacetate Ligands as Potential Anticancer Agents

    Directory of Open Access Journals (Sweden)

    Jurisevic Milena

    2016-12-01

    Full Text Available The design of platinum based drugs is not a new field of interest. Platinum complexes are widely used as anticancer agents and currently, approximately 30 platinum(II and platinum(IV entered into some of the phases of clinical trials. A special place in today’s research belongs to platinum complexes with diammine ligands. A large number of edda (ethylenediamine- N, N’-diacetate-type ligands and their corresponding metal complexes has been successfully synthesized. This article summarizes recent progress in research on edda-type-platinum complexes. Some of these agents achieves better effect compared to the gold standard (cisplatin. It has been shown that there is a possible relationship between the length of the ligand ester group carbon chain and its cytotoxic effect. In most cases the longer the ester chain is the greater is the antitumor activity. Of particular interest are the noticeable effects of some new platinum compound with edda-type ligand on cell lines that are known to have a high level of cisplatin-resistance. Exanimate complexes appear to have a different mode of mechanism of action compared with cisplatin which includes apoptotic and necrotic cell death. There are indications that further investigations of these compounds may be very useful in overcoming the problems associated global cancer statistic.

  9. Synthesis and photophysical and electrochemical properties of new cyclometalated platinum complex containing oxadiazole ligand

    Institute of Scientific and Technical Information of China (English)

    DENG Ji-yong; LIU Yu; HU Zheng-yong; ZHU Mei-xiang; ZHU Wei-guo

    2007-01-01

    A new cyclometalated platinum complex containing 2, 5-bis(naphthalene-1-y1)-1,3,4-oxadiazole ligand was synthesized and characterized. The UV-Vis absorptions and photoluminescent properties of the ligand and its platinum complex were investigated.A characteristic metal-ligand charge transfer absorption peak at 439 nm in the UV spectrum and a strong emission peak at 625 nm in the photoluminescence spectrum were observed for this complex in dichloromethane. Cyclic voltammtry (CV) analysis shows that the EHOMO (energy level of the highest occupied molecular orbital) and ELUMO (energy level of the lowest unoccupied molecular orbital) of the platinum complex are about -5.69 and -3.25 eV, respectively, indicating that the oxadiazole-based platinum complex has a potential application in electrophosphorescent devices used as a red-emitting material.

  10. Synthesis and characterisation of platinum (II) salphen complex and its interaction with calf thymus DNA

    Energy Technology Data Exchange (ETDEWEB)

    Sukri, Shahratul Ain Mohd; Heng, Lee Yook; Karim, Nurul Huda Abd [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43650 Bangi, Selangor (Malaysia)

    2014-09-03

    A platinum (II) salphen complex was synthesised by condensation reaction of 2,4-dihydroxylbenzaldehyde and o-phenylenediamine with potassium tetrachloroplatinate to obtain N,N′-Bis-4-(hydroxysalicylidene)-phenylenediamine-platinum (II). The structure of the complex was confirmed by {sup 1}H and {sup 13}C NMR spectroscopy, FTIR spectroscopy, CHN elemental analyses and ESI-MS spectrometry. The platinum (II) salphen complex with four donor atoms N{sub 2}O{sub 2} from its salphen ligand coordinated to platinum (II) metal centre were determined. The binding mode and interaction of this complex with calf thymus DNA was determined by UV/Vis DNA titration and emission titration. The intercalation between the DNA bases by π-π stacking due to its square planar geometry and aromatic rings structures was proposed.

  11. Synthesis and characterisation of platinum (II) salphen complex and its interaction with calf thymus DNA

    Science.gov (United States)

    Sukri, Shahratul Ain Mohd; Heng, Lee Yook; Karim, Nurul Huda Abd

    2014-09-01

    A platinum (II) salphen complex was synthesised by condensation reaction of 2,4-dihydroxylbenzaldehyde and o-phenylenediamine with potassium tetrachloroplatinate to obtain N,N'-Bis-4-(hydroxysalicylidene)-phenylenediamine-platinum (II). The structure of the complex was confirmed by 1H and 13C NMR spectroscopy, FTIR spectroscopy, CHN elemental analyses and ESI-MS spectrometry. The platinum (II) salphen complex with four donor atoms N2O2 from its salphen ligand coordinated to platinum (II) metal centre were determined. The binding mode and interaction of this complex with calf thymus DNA was determined by UV/Vis DNA titration and emission titration. The intercalation between the DNA bases by π-π stacking due to its square planar geometry and aromatic rings structures was proposed.

  12. Chemistry of Platinum and Palladium Metal Complexes in Homogeneous and Heterogeneous Catalysis: A Mini Review

    Directory of Open Access Journals (Sweden)

    Mehrban Ashiq

    2013-04-01

    Full Text Available Transition metal complexes of platinum and palladium are most widely used in catalysis. Many synthetic reactions have been carried out with such complexes (used as a catalyst which have specifically polymer ligands, through hydrosilylation, acetoxylation, hydrogenation, hydro-formylation, oligo-merisation and polymerization. Almost many platinum and palladium catalysts are heterogeneous in nature i.e. the reaction taking place on a solid surface. Now from few years homogeneous catalysts which are completely soluble in the liquid phase reactant, has acknowledged too much attention, yet having small industrial applications, mainly due to the striving of platinum and palladium complexes separation from the catalytic products. More recently a transitional type of platinum and palladium catalysts have been synthesized through attachment of the activated transition metal complexes on the surface of polymer support particularly insoluble which has been establish to offer encouraging new collection of catalysts for effective research on synthesis. Many of such complexes will be based on the palladium and platinum metals group. The major objective of this review is to inaugurate the relationship among the reactivity’s of homogeneous platinum and palladium complexes and heterogeneous complexes of these metals (those bonded to the surface of metals.

  13. Development of Platinum(iv) Complexes as Anticancer Prodrugs: the Story so Far

    Science.gov (United States)

    Wong, Daniel Yuan Qiang; Ang, Wee Han

    2012-06-01

    The serendipitous discovery of the antitumor properties of cisplatin by Barnett Rosenberg some forty years ago brought about a paradigm shift in the field of medicinal chemistry and challenged conventional thinking regarding the role of potentially toxic heavy metals in drugs. Platinum(II)-based anticancer drugs have since become some of the most effective and widely-used drugs in a clinician's arsenal and have saved countless lives. However, they are limited by high toxicity, severe side-effects and the incidence of drug resistance. In recent years, attention has shifted to stable platinum(IV) complexes as anticancer prodrugs. By exploiting the unique chemical and structural attributes of their scaffolds, these platinum(IV) prodrugs offer new strategies of targeting and killing cancer cells. This review summarizes the development of anticancer platinum(IV) prodrugs to date and some of the exciting strategies that utilise the platinum(IV) construct as targeted chemotherapeutic agents against cancer.

  14. PLATINUM: a web tool for analysis of hydrophobic/hydrophilic organization of biomolecular complexes.

    Science.gov (United States)

    Pyrkov, Timothy V; Chugunov, Anton O; Krylov, Nikolay A; Nolde, Dmitry E; Efremov, Roman G

    2009-05-01

    The PLATINUM (Protein-Ligand ATtractions Investigation NUMerically) web service is designed for analysis and visualization of hydrophobic/hydrophilic properties of biomolecules supplied as 3D-structures. Furthermore, PLATINUM provides a number of tools for quantitative characterization of the hydrophobic/hydrophilic match in biomolecular complexes e.g. in docking poses. These complement standard scoring functions. The calculations are based on the concept of empirical Molecular Hydrophobicity Potential (MHP). The PLATINUM web tool as well as detailed documentation and tutorial are available free of charge for academic users at http://model.nmr.ru/platinum/. PLATINUM requires Java 5 or higher and Adobe Flash Player 9. Supplementary data are available at Bioinformatics online.

  15. Modeling platinum group metal complexes in aqueous solution.

    Science.gov (United States)

    Lienke, A; Klatt, G; Robinson, D J; Koch, K R; Naidoo, K J

    2001-05-07

    We construct force fields suited for the study of three platinum group metals (PGM) as chloranions in aqueous solution from quantum chemical computations and report experimental data. Density functional theory (DFT) using the local density approximation (LDA), as well as extended basis sets that incorporate relativistic corrections for the transition metal atoms, has been used to obtain equilibrium geometries, harmonic vibrational frequencies, and atomic charges for the complexes. We found that DFT calculations of [PtCl(6)](2-).3H(2)O, [PdCl(4)](2-).2H(2)O, and [RhCl(6)](3-).3H(2)O water clusters compared well with molecular mechanics (MM) calculations using the specific force field developed here. The force field performed equally well in condensed phase simulations. A 500 ps molecular dynamics (MD) simulation of [PtCl(6)](2-) in water was used to study the structure of the solvation shell around the anion. The resulting data were compared to an experimental radial distribution function derived from X-ray diffraction experiments. We found the calculated pair correlation functions (PCF) for hexachloroplatinate to be in good agreement with experiment and were able to use the simulation results to identify and resolve two water-anion peaks in the experimental spectrum.

  16. A Photoactivatable Platinum(IV) Complex Targeting Genomic DNA and Histone Deacetylases.

    Science.gov (United States)

    Kasparkova, Jana; Kostrhunova, Hana; Novakova, Olga; Křikavová, Radka; Vančo, Ján; Trávníček, Zdeněk; Brabec, Viktor

    2015-11-23

    We report toxic effects of a photoactivatable platinum(IV) complex conjugated with suberoyl-bis-hydroxamic acid in tumor cells. The conjugate exerts, after photoactivation, two functions: activity as both a platinum(II) anticancer drug and histone deacetylase (HDAC) inhibitor in cancer cells. This approach relies on the use of a Pt(IV) pro-drug, acting by two independent mechanisms of biological action in a cooperative manner, which can be selectively photoactivated to a cytotoxic species in and around a tumor, thereby increasing selectivity towards cancer cells. These results suggest that this strategy is a valuable route to design new platinum agents with higher efficacy for photodynamic anticancer chemotherapy.

  17. Bis- and Tetrakis(carboxylato)platinum(IV) complexes with mixed axial ligands - synthesis, characterization, and cytotoxicity.

    Science.gov (United States)

    Hoffmeister, Björn R; Hejl, Michaela; Adib-Razavi, Mahsa S; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K

    2015-04-01

    A series of twelve novel diamminetetrakis(carboxylato)platinum(IV) and 18 novel bis(carboxylato)dichlorido(ethane-1,2-diamine)platinum(IV) complexes with mixed axial carboxylato ligands was synthesized and characterized by multinuclear (1) H-, (13) C-, (15) N-, and (195) Pt-NMR spectroscopy. Their cytotoxic potential was evaluated (by MTT assay) against three human cancer cell lines derived from ovarian teratocarcinoma (CH1/PA-1), lung (A549), and colon carcinoma (SW480). In the cisplatin-sensitive CH1/PA-1 cancer cell line, diamminetetrakis(carboxylato)platinum(IV) complexes showed IC50 values in the low micromolar range, whereas, for the most lipophilic compounds of the bis(carboxylato)dichlorido(ethane-1,2-diamine)platinum(IV) series, IC50 values in the nanomolar range were found. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

  18. Photoinduced DNA damage and cytotoxicity by a triphenylamine-modified platinum-diimine complex.

    Science.gov (United States)

    Zhang, Zhigang; Dai, Ruihui; Ma, Jiajia; Wang, Shuying; Wei, Xuehong; Wang, Hongfei

    2015-02-01

    Many planar photosensitizers tend to self-aggregate via van der Waals interactions between π-conjugated systems. The self-aggregation of the photosensitizer may reduce the efficiency of the photosensitizer to generate singlet oxygen, thereby diminishing its photodynamic activity. Efforts have been made to improve the photodynamic activity of bis-(o-diiminobenzosemiquinonato)platinum(II) which has planar geometry by the introduction of the sterically hindered triphenylamine moiety into the ligand. Herein we report the photoinduced DNA damage and cytotoxicity by a triphenylamine-modified platinum-diimine complex in red light studied by fluorescence spectra, agarose gel assay and cell viability assay. The results suggest that the triphenylamine-modified platinum-diimine complex has better capability to generate singlet oxygen than bis-(o-diiminobenzosemiquinonato)platinum(II), and it can induce DNA damage in red light, causing high photocytotoxicity in HepG-2 cells in vitro.

  19. Synthesis and characterization of polymeric azido Zn(II) and Ni(II) complexes based on 3-hydroxypyridine

    Science.gov (United States)

    Mautner, Franz A.; Berger, Christian; Domian, Elisabeth; Fischer, Roland C.; Massoud, Salah S.

    2016-10-01

    The synthesis and structural characterization of two new complexes catena-[Ni(3-O-py)(3-HO-py)2(μ1,3-N3)(H2O)] (1) and catena-[Zn(μ-3-O-py)(μ1,1-N3)] (2), where 3-HO-py = 3-hydroxypyridine, are reported. The complexes were characterized by the elemental microanalyses, IR, and X-ray crystallography and by UV-Vis spectroscopy for complex 1. Single crystal X-ray crystallography revealed the polymeric nature of the complexes: 1 as 1D with a single EE azide bridging, and 2 as 2D with μ(O,O‧,N) bridging of the deprotonated 3-O-py anions and di-EO azide groups, respectively. In 1 the neutral and deprotonated 3-hydroxypyridine molecules act only as N-terminal ligands. The emission spectral properties of the Zn(II) complex were investigated.

  20. Synthesis, biological evaluation and SAR studies of novel bicyclic antitumor platinum(IV) complexes.

    Science.gov (United States)

    Lorenzo, Julia; Delgado, Aida; Montaña, Ángel M; Mesas, Juan M; Alegre, María-Teresa; Rodríguez, María del Carmen; Avilés, Francesc-Xavier

    2014-08-18

    The present study describes the synthesis, anticancer activity and SAR studies of novel platinum(IV) complexes having 1,2-bis(aminomethyl)carbobicyclic or oxabicyclic carrier ligands, bearing chlorido and/or hydroxido ligands in axial position and chlorido or malonato ligands in equatorial position (labile ligands). These complexes were synthetized with the aim of obtaining new anticancer principles more soluble in water and therefore more bioavailable. Several substitution patterns on the platinum atom have been designed in order to evaluate their antiproliferative activity and to establish structure-activity relationship rules. The synthesis of platinum(IV) complexes with axial hydroxyl ligands on the platinum(IV) were carried out by reaction of K2Pt(OH)2Cl4 with the corresponding diamines. The complexes with axial chlorido ligands on the platinum(IV) atom were synthesized by direct reaction of diamines with K2PtCl6. Carboxylated complexes were synthesized by the substitution reaction of equatorial chlorido ligands by silver dicarboxylates. The most actives complexes were those having malonate as a labile ligand, no matter of the structure of the carrier ligand. Regarding the influence of the structure of the non-labile 1,4-diamine carrier ligand on the cytotoxicity, it was found that the complexes having the more lipophilic and symmetrical bicyclo[2.2.2]octane framework were much more active than those having an oxygen or methylene bridge.

  1. Rearrangement of a (dithiolato)platinum(II) complex formed by reaction of cyclic disulfide 7,8-dithiabicyclo[4.2.1]nona-2,4-diene with a platinum(0) complex: Oxidation of the rearranged (dithiolato)platinum(II) complex

    OpenAIRE

    石井, 昭彦

    2007-01-01

    Reaction of the title bicyclic disulfide 16 with [(Ph3P)(2)Pt(eta(2)-C2H4)] (2) yielded the corresponding (dithiolato)platinum(II) complex 17 by oxidative addition. The initial product 17 isomerized at room temperature in a [1,5]-sulfur rearrangement to give another (dithiolato)platinum(II) complex 18 in high isolated yield. Oxidation reactions of 18 with dimethyldioxirane (DMD) provided (sulfenato-thiolato)platinum(II) 23, (sulfinato-thiolato)platinum(II) 24, (sulfenato-sulfinato)platinum(II...

  2. Differences Between Asymmetric cis and trans Platinum Complexes. Applications in Cancer Chemotherapy

    NARCIS (Netherlands)

    Pantoja López, Elena

    2005-01-01

    This thesis describes a variety of asymmetric cis- and trans-platinum(II) complexes. The major aim of this research has been the design of complexes with high antitumor activity that may overcome cisplatin resistance, and to establish a comparison between complexes with both geometries. These new ty

  3. Exploring the Hydrolytic Behavior of the Platinum(IV) Complexes with Axial Acetato Ligands.

    Science.gov (United States)

    Zhao, Jian; Xu, Zichen; Lin, Jing; Gou, Shaohua

    2017-08-21

    Platinum(IV) complexes are generally thought to be kinetically inert, and are expected to be stable enough to resist premature aquation before entering the cancer cells. Nevertheless, in this work, complex 2 with axial acetato ligands can hydrolyze relatively quickly under biologically relevant conditions with a half-life of 91.7 min, resulting in the loss of the equatorial chlorido ligand. Further study indicated that the fast hydrolysis of complex 2 may be attributed to the strong σ-donor ability of N-isopropyl-1R,2R-diaminocyclohexane, and an increasing σ-donor ability of the amine group can promote the hydrolysis rate of the corresponding platinum(IV) complex. The experiment results were proven by the corresponding DFT calculation. Our study can help to re-evaluate the aqueous properties of the platinum(IV) complexes with axial acetate, which may be less inert to hydrolysis than expected under biologically relevant conditions.

  4. Synthesis and Analysis of the Structure, Diffusion and Cytotoxicity of Heterocyclic Platinum(IV) Complexes.

    Science.gov (United States)

    Macias, Freddy J; Deo, Krishant M; Pages, Benjamin J; Wormell, Paul; Clegg, Jack K; Zhang, Yingjie; Li, Feng; Zheng, Gang; Sakoff, Jennette; Gilbert, Jayne; Aldrich-Wright, Janice R

    2015-11-16

    We have developed six dihydroxidoplatinum(IV) compounds with cytotoxic potential. Each derived from active platinum(II) species, these complexes consist of a heterocyclic ligand (HL) and ancillary ligand (AL) in the form [Pt(HL)(AL)(OH)2](2+), where HL is a methyl-functionalised variant of 1,10-phenanthroline and AL is the S,S or R,R isomer of 1,2-diaminocyclohexane. NMR characterisation and X-ray diffraction studies clearly confirmed the coordination geometry of the octahedral platinum(IV) complexes. The self-stacking of these complexes was determined using pulsed gradient stimulated echo nuclear magnetic resonance. The self-association behaviour of square planar platinum(II) complexes is largely dependent on concentration, whereas platinum(IV) complexes do not aggregate under the same conditions, possibly due to the presence of axial ligands. The cytotoxicity of the most active complex, exhibited in several cell lines, has been retained in the platinum(IV) form.

  5. Diazido mixed-amine platinum(IV) anticancer complexes activatable by visible-light form novel DNA adducts.

    Science.gov (United States)

    Zhao, Yao; Woods, Julie A; Farrer, Nicola J; Robinson, Kim S; Pracharova, Jitka; Kasparkova, Jana; Novakova, Olga; Li, Huilin; Salassa, Luca; Pizarro, Ana M; Clarkson, Guy J; Song, Lijiang; Brabec, Viktor; Sadler, Peter J

    2013-07-15

    Platinum diam(m)ine complexes, such as cisplatin, are successful anticancer drugs, but suffer from problems of resistance and side-effects. Photoactivatable Pt(IV) prodrugs offer the potential of targeted drug release and new mechanisms of action. We report the synthesis, X-ray crystallographic and spectroscopic properties of photoactivatable diazido complexes trans,trans,trans-[Pt(N3)2(OH)2(MA)(Py)] (1; MA=methylamine, Py=pyridine) and trans,trans,trans-[Pt(N3)2(OH)2(MA)(Tz)] (2; Tz=thiazole), and interpret their photophysical properties by TD-DFT modelling. The orientation of the azido groups is highly dependent on H bonding and crystal packing, as shown by polymorphs 1p and 1q. Complexes 1 and 2 are stable in the dark towards hydrolysis and glutathione reduction, but undergo rapid photoreduction with UVA or blue light with minimal amine photodissociation. They are over an order of magnitude more potent towards HaCaT keratinocytes, A2780 ovarian, and OE19 oesophageal carcinoma cells than cisplatin and show particular potency towards cisplatin-resistant human ovarian cancer cells (A2780cis). Analysis of binding to calf-thymus (CT), plasmids, oligonucleotide DNA and individual nucleotides reveals that photoactivated 1 and 2 form both mono- and bifunctional DNA lesions, with preference for G and C, similar to transplatin, but with significantly larger unwinding angles and a higher percentage of interstrand cross-links, with evidence for DNA strand cross-linking further supported by a comet assay. DNA lesions of 1 and 2 on a 50 bp duplex were not recognised by HMGB1 protein, in contrast to cisplatin-type lesions. The photo-induced platination reactions of DNA by 1 and 2 show similarities with the products of the dark reactions of the Pt(II) compounds trans-[PtCl2(MA)(Py)] (5) and trans-[PtCl2(MA)(Tz)] (6). Following photoactivation, complex 2 reacted most rapidly with CT DNA, followed by 1, whereas the dark reactions of 5 and 6 with DNA were comparatively slow

  6. Cytotoxicity of platinum(IV) and platinum(II) complexes containing 1R,2R-cyclohexanediamine as a ligand.

    Science.gov (United States)

    Yamashita, T; Hirose, J; Noji, M; Saito, R; Tomida, H; Kidani, Y

    1993-10-01

    Several Pt(IV) and Pt(II) complexes containing 1R,2R-cyclohexanediamine (1R,2R-dach) as a carrier ligand were synthesized. The cytotoxicities and the uptake of the platinum complexes by leukemia L1210 cells were compared in order to study the correlation between their structures and cytotoxicities. [Pt(II)Cl2(1R,2R-dach)], [(Pt(II)(oxalato)(1R,2R-dach)], and [Pt(II)(malonato)(1R,2R-dach)], which have excellent anticancer properties, exhibited very high cytotoxicities and were easily taken up by leukemia L1210 cells. [Pt(IV)Cl4(1R,2R-dach)], trans(Cl)-[Pt(IV)Cl2(oxalato)(1R,2R-dach)], and trans(Cl)-[Pt(IV)Cl2(malonato)(1R,2R-dach)] also had high cytotoxicities. After a short incubation time, the uptake of [Pt(II)Cl2(1R,2R-dach)], [Pt(II)(oxalato)(1R,2R-dach)], and [Pt(II)(malonato)(1R,2R-dach)] by leukemia L1210 cells were respectively very similar to those of [Pt(IV)Cl4(1R,2R-dach)], trans(Cl)-[Pt(IV)Cl2(oxalato)(1R,2R-dach)], and trans(Cl)-[Pt(IV)Cl2(malonato)(1R,2R-dach)]. In addition, trans(OH)-[Pt(IV)(OH)2Y2(1R,2R-dach)] (Y2: oxalato or malonato) did not exhibit cytotoxicity towards leukemia L1210 cells, whereas trans(Cl)-[Pt(IV)Cl2Y2(1R,2R-dach)] (Y2: oxalato or malonato) were highly cytotoxic. The accumulation of trans(OH)-[Pt(IV)(OH)2Y2(1R,2R-dach)] in leukemia L1210 cells was much lower than that of trans(Cl)-[Pt(IV)Cl2Y2(1R,2R-dach)]. Platinum(IV) complexes, in which leaving groups are replaced by hydroxide groups, have decreased cytotoxic activity, because the hydroxide groups of the platinum(IV) complex reduce the uptake of platinum by the cells. trans(OH),cis(Cl)-[Pt(IV)(OH)2Cl2(1R,2R-dach)], which has hydroxide and chloride groups, was easily incorporated into the cells and exhibited the high cytotoxic activity. This behavior indicates that the chloride group apparently overcomes the ameliorating effect of the hydroxide group.

  7. SYNTHESIS AND CATALYTIC BEHAVIOR OF POLYSILOXANE-SUPPORTED FULLERENE PLATINUM OR RHODIUM COMPLEXES

    Institute of Scientific and Technical Information of China (English)

    Peng-fei Fang; Yuan-yin Chen; Shu-ling Gong; Lei Guo; Qiu-sheng Lu; Ling Zhu

    1999-01-01

    Two polysiloxanes with pendant fullerene moieties and their platinum or rhodium complexes have been prepared from C60 via amination with ω-decenylamine, followed by hydrosilylation with triethoxysilane and immobilization on fumed silica or by hydrosilylation with methyldichlorosilane and polycondensation with polydimethylsiloxanol, and then by reacting them with potassium chloroplatinite or rhodium chloride in acetone respectively under argon atmosphere. It was found that the four noble metal complexes are effective catalysts for the hydrosilylation of olefins with triethoxysilane. The regioselectivity of platinum complexes for styrene increases remarkably by introducing C60 moiety. Factors influencing catalytic activity and the mechanism have been investigated.

  8. Synthesis and Crystal Structure of a Dinuclear Cu(II) Complex with Tridentate Schiff Base and Azido Bridge

    Institute of Scientific and Technical Information of China (English)

    LIN Hong; FENG Yun Long; GAO Shan

    2005-01-01

    A new dinuclear copper(II) complex ([Cu(C12H17N2O)(N3)]2, C24H34Cu2N10O2) has been synthesized and characterized by X-ray structure determination. It crystallizes in the monoclinic system, space group P21/c with a = 18.529(4), b = 10.933(2), c = 14.534(3)(A),β = 111.07(3)(A), V = 2748(1)(A)3, Z = 4, Mr = 621.69, F(000) = 1288, Dc = 1.503 g/cm3 and μ(MoKα) = 1.590 mm(1. The structure was refined to R = 0.0647 and wR = 0.1846 for 4406 observed reflections (I > 2σ(I)). The asymmetric unit comprises two halfmolecules. The complex is a centrosymmetric dimmer in which the copper atoms are penta-coordinated by three coordination atoms from the corresponding tridentate Schiff base ligand and two bridging azide anions. The Cu(II)…Cu(II) average distance is 3.350(1)(A).

  9. Biotin-tagged platinum(iv) complexes as targeted cytostatic agents against breast cancer cells.

    Science.gov (United States)

    Muhammad, Nafees; Sadia, Nasreen; Zhu, Chengcheng; Luo, Cheng; Guo, Zijian; Wang, Xiaoyong

    2017-09-05

    A biotin-guided platinum(IV) complex is highly cytotoxic against breast cancer cells but hypotoxic against mammary epithelial cells. The mono-biotinylated Pt(IV) complex is superior to the di-biotinylated one and hence a promising drug candidate for the targeted therapy of breast cancer.

  10. Efficient light-emitting devices based on platinum-complexes-anchored polyhedral oligomeric silsesquioxane materials

    KAUST Repository

    Yang, Xiaohui

    2010-08-24

    The synthesis, photophysical, and electrochemical characterization of macromolecules, consisting of an emissive platinum complex and carbazole moieties covalently attached to a polyhedral oligomeric silsesquioxane (POSS) core, is reported. Organic light-emitting devices based on these POSS materials exhibit a peak external quantum efficiency of ca. 8%, which is significantly higher than that of the analogous devices with a physical blend of the platinum complexes and a polymer matrix, and they represent noticeable improvement in the device efficiency of solution-processable phosphorescent excimer devices. Furthermore, the ratio of monomer and excimer/aggregate electroluminescent emission intensity, as well as the device efficiency, increases as the platinum complex moiety presence on the POSS macromolecules decreases. © 2010 American Chemical Society.

  11. Synthesis, spectral characterization, thermal and photoluminescence properties of Zn(II) and Cd(II)-azido/thiocyanato complexes with thiazolylazo dye and 1,2-bis(diphenylphoshino)ethane.

    Science.gov (United States)

    Yamgar, B A; Sawant, V A; Bharate, B G; Chavan, S S

    2011-01-01

    A series of complexes of the type [M(L)(dppe)X2]; where M=Zn(II) or Cd(II); L=4-(2'-thiazolylazo)chlorobenzene (L1), 4-(2'-thiazolylazo)bromobenzene (L2) and 4-(2'-thiazolylazo) iodobenzene (L3); dppe=1,2-bis(diphenylphosphino)ethane; X=N3- or NCS- have been prepared and characterized on the basis of their microanalysis, molar conductance, thermal, IR, UV-vis and 1H NMR spectral studies. IR spectra show that the ligand L is coordinated to the metal atom in bidentate manner via azo nitrogen and thiazole nitrogen. An octahedral structure is proposed for all the complexes. The thermal behavior of the complexes revealed that the thiocyanato complexes are thermally more stable than the azido complexes. All the complexes exhibit blue-green emission with high quantum yield as the result of the fluorescence from the intraligand emission excited state.

  12. Noncovalent interactions between a trinuclear monofunctional platinum complex and human serum albumin.

    Science.gov (United States)

    Wang, Yanqing; Wang, Xiaoyong; Wang, Jing; Zhao, Yongmei; He, Weijiang; Guo, Zijian

    2011-12-19

    Interactions between platinum complexes and human serum albumin (HSA) play crucial roles in the metabolism, distribution, and efficacy of platinum-based anticancer drugs. Polynuclear monofunctional platinum(II) complexes represent a new class of anticancer agents that display distinct molecular characters of pharmacological action from those of cisplatin. In this study, the interaction between a trinuclear monofunctional platinum(II) complex, [Pt(3)LCl(3)](ClO(4))(3) (L = N,N,N',N',N",N"-hexakis(2-pyridylmethyl)-1,3,5-tris(aminomethyl)benzene) (1), and HSA was investigated using ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, circular dichroism spectroscopy, fluorescence spectroscopy, molecular docking, and inductively coupled plasma mass spectrometry. The spectroscopic and thermodynamic data show that the interaction is a spontaneous process with the estimated enthalpy and entropy changes being 14.6 kJ mol(-1) and 145.5 J mol(-1) K(-1), respectively. The reactive sites of HSA to complex 1 mainly locate within its hydrophobic cavity in domain II. Noncovalent actions such as π-π stacking and hydrophobic bonding are the primary contributors to the interaction between HSA and complex 1, which is different from the scenario for cisplatin in similar conditions. The results suggest that the connection between complex 1 and HSA is reversible, and therefore the cytotoxic activity of the complex could be preserved during blood circulation.

  13. Isolation of homoleptic platinum oxyanionic complexes with doubly protonated diazacrown cation

    Science.gov (United States)

    Vasilchenko, Danila; Tkachev, Sergey; Baidina, Iraida; Romanenko, Galina; Korenev, Sergey

    2017-02-01

    Doubly protonated diazacrown ether cation (1,4,10,13-tetraoxa-7,16-diazoniacyclooctadecane DCH22+) was used for the efficient isolation of the homoleptic platinum complexes [Pt(NO3)6]2- and [Pt(C2O4)2]2- to crystalline solid phases from solutions containing mixtures of related platinum complexes. DCH22+ molecules in nitric acid solution were shown to prevent the condensation of mononuclear [Pt(H2O)n(NO3)6-n]n-2 species.

  14. Photoinduced cytotoxicity by a platinum diimine complex employing magnetite-silica nanocomposites as delivery vehicles.

    Science.gov (United States)

    Zhang, Zhigang; Li, Haisha; Dai, Ruihui; Chai, Aiyun

    2015-10-01

    Tartaric acid-modified core-shell magnetite-silica nanocomposites were prepared by a sol-gel method, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and dynamic light scattering. Then the nanocomposites were employed as carriers of a photoactive platinum diimine complex. Photoinduced cytotoxicity by the photosensitizer-loaded nanocomposites in different human carcinoma cells has been studied by cell viability assay. The results suggest that the as-synthesized nanocomposites have good stability in water, and the cytotoxicity induced by the platinum diimine complex in red light can be significantly enhanced when the photosensitizer is loaded with the magnetic nanocomposites.

  15. Azido-based propellants

    Energy Technology Data Exchange (ETDEWEB)

    Sayles, D.C.

    1987-04-07

    This patent describes an azido-based solid propellant composition having an improved burning rate comprising: a high energy plasticizer of tris-1,2,3(bis(1,2-difluoroamino)ethoxy)propane in an amount from about 24 to about 30 weight percent of the propellant composition; a curative and crosslinking agent of 4,5-epoxycyclohexylmethyl 4'5'-epoxycyclohexylcarboxylate in an amount from about 0.75 to about 1.5 weight percent of the propellant composition; a carboranyl burning rate catalyst of carboranyl-methyl propionate in an amount from about 2 to about 6 weight percent of the propellant composition; graphite linters of about 100 micrometers lengths in an amount from about 1 to about 3 weight percent of the propellant composition; aluminum powder in an amount from about 10 to about 12 weight percent of the propellant composition; aluminum flake in an amount from about 0.5 to about 2 weight percent of the propellant composition; ammonium perchlorate of about 0.9 micrometer diameter in an amount from about 46 to about 52 weight percent of the composition; a processing aid of lecithin in an amount from about 0.1 to about 0.2 weight percent of the propellant composition; and a binder of 2-azidoethyl acrylateacrylic acid copolymer in an amount from about 3 to about 8 weight percent of the propellant composition.

  16. Síntese e atividade citotóxica de alguns azido-ciclopaladados estabilizados com ligantes bifosfínicos Synthesis and cytotoxicity of some cyclometallated palladium (II complexes containing coordinated azide and diphosphines

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Fávero Caires

    1999-06-01

    Full Text Available Some cyclopalladated compounds containing the azido group ligand and the (C-N ring of N,N-dimethylbenzylamine have been prepared by bridge opening reactions of dimmer azide complex precursor with some diphosphines in different stoichiometric quantities. The neutral or ionic, mono or binuclear complexes synthesized were characterized by elemental analyses, I. R. spectroscopy and NMR techniques. The series of complexes was screened for cytotoxicity against a panel three human tumour cells lines(C6,Hep-2,HeLa. All complexes were found to be cytotoxic (IC50 at µM concentrations while one complex having the coordination bond N-Pd ruptured also displayed some differential cytotoxicity.

  17. Cellular and biomolecular responses of human ovarian cancer cells to cytostatic dinuclear platinum(II) complexes.

    Science.gov (United States)

    Lin, Miaoxin; Wang, Xiaoyong; Zhu, Jianhui; Fan, Damin; Zhang, Yangmiao; Zhang, Junfeng; Guo, Zijian

    2011-03-01

    Polynuclear platinum(II) complexes represent a class of potential anticancer agents that have shown promising pharmacological properties in preclinical studies. The nature of cellular responses induced by these complexes, however, is poorly understood. In this research, the cellular responses of human ovarian cancer COC1 cells to dinuclear platinum(II) complexes {[cis-Pt(NH₃)₂Cl]₂L¹}(NO₃)₂ (1) and {[cis-Pt(NH₃)₂Cl]₂L²}(NO₃)₂ (2) (L¹ = α,α'-diamino-p-xylene, L² = 4,4'-methylenedianiline) has been studied using cisplatin as a reference. The effect of platinum complexes on the proliferation, death mode, mitochondrial membrane potential, and cell cycle progression has been examined by MTT assay and flow cytometry. The activation of cell cycle checkpoint kinases (CHK1/2), extracellular signal-regulated kinases (ERK1/2), and p38 mitogen-activated protein kinase (p38 MAPK) of the cells by the complexes has also been analyzed using phospho-specific flow cytometry. Complex 1 is more cytotoxic than complex 2 and cisplatin at most concentrations; complex 2 and cisplatin are comparably cytotoxic. These complexes kill the cells through an apoptotic or apoptosis-like pathway characterized by exposure of phosphatidylserine and dissipation of mitochondrial membrane potential. Complex 1 shows the strongest inductive effect on the morphological changes of the cells, followed by cisplatin and complex 2. Complexes 1 and 2 arrest the cell cycle in G2 or M phase, while cisplatin arrests the cell cycle in S phase. The influence of these complexes on CHK1/2, ERK1/2, and p38 MAPK varies with the dose of the drugs or reaction time. Activation of phospho-ERK1/2 and phospho-p38 MAPK by these complexes is closely related to the cytostatic activity. The results demonstrate that dinuclear platinum(II) complexes can induce some cellular responses different from those caused by cisplatin.

  18. Facile preparation of mono-, di- and mixed-carboxylato platinum(IV) complexes for versatile anticancer prodrug design.

    Science.gov (United States)

    Zhang, Jenny Z; Bonnitcha, Paul; Wexselblatt, Ezequiel; Klein, Alice V; Najajreh, Yousef; Gibson, Dan; Hambley, Trevor W

    2013-01-28

    Facile strategies were developed for the versatile functionalization of platinum(IV) axial sites, allowing for easy accessibility to unsymmetric mono- and mixed-carboxylato, as well as symmetric di-substituted platinum(IV) complexes. The first method involves the direct oxidation and carboxylation of the platinum(II) center using an appropriate peroxide and the carboxylate of choice to firstly yield a monocarboxylato monohydroxido platinum(IV) complex. This platinum(IV) intermediate can undergo further carboxylation to give rise to a mixed-carboxylato platinum(IV) complex. The second method involves the activation of the carboxylate of choice by a common carbodiimide coupling reagent, and its reaction with a dihydroxido platinum(IV) precursor to give the monocarboxylato platinum(IV) complex. Uronium salts can be employed to promote efficient dicarboxylation of the dihydroxido platinum(IV) precursor. Lastly, an axial azide pendant group was demonstrated to be suitable for orthogonal "click" conjugation reactions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Direct measurement of interaction forces between a platinum dichloride complex and DNA molecules.

    Science.gov (United States)

    Muramatsu, Hiroshi; Shimada, Shogo; Okada, Tomoko

    2017-06-29

    The interaction forces between a platinum dichloride complex and DNA molecules have been studied using atomic force microscopy (AFM). The platinum dichloride complex, di-dimethylsulfoxide-dichloroplatinum (II) (Pt(DMSO)2Cl2), was immobilized on an AFM probe by coordinating the platinum to two amino groups to form a complex similar to Pt(en)Cl2, which is structurally similar to cisplatin. The retraction forces were measured between the platinum complex and DNA molecules immobilized on mica plates using force curve measurements. The histogram of the retraction force for λ-DNA showed several peaks; the unit retraction force was estimated to be 130 pN for a pulling rate of 60 nm/s. The retraction forces were also measured separately for four single-base DNA oligomers (adenine, guanine, thymine, and cytosine). Retraction forces were frequently observed in the force curves for the DNA oligomers of guanine and adenine. For the guanine DNA oligomer, the most frequent retraction force was slightly lower than but very similar to the retraction force for λ-DNA. A higher retraction force was obtained for the adenine DNA oligomer than for the guanine oligomer. This result is consistent with a higher retraction activation energy of adenine with the Pt complex being than that of guanine because the kinetic rate constant for retraction correlates to exp(FΔx - ΔE) where ΔE is an activation energy, F is an applied force, and Δx is a displacement of distance.

  20. 2-Deoxyglucose conjugated platinum (II) complexes for targeted therapy: design, synthesis, and antitumor activity.

    Science.gov (United States)

    Mi, Qian; Ma, Yuru; Gao, Xiangqian; Liu, Ran; Liu, Pengxing; Mi, Yi; Fu, Xuegang; Gao, Qingzhi

    2016-11-01

    Malignant neoplasms exhibit an elevated rate of glycolysis over normal cells. To target the Warburg effect, we designed a new series of 2-deoxyglucose (2-DG) conjugated platinum (II) complexes for glucose transporter 1 (GLUT1)-mediated anticancer drug delivery. The potential GLUT1 transportability of the complexes was investigated through a comparative molecular docking analysis utilizing the latest GLUT1 protein crystal structure. The key binding site for 2-DG as GLUT1's substrate was identified with molecular dynamics simulation, and the docking study demonstrated that the 2-DG conjugated platinum (II) complexes can be recognized by the same binding site as potential GLUT1 substrate. The conjugates were synthesized and evaluated for in vitro cytotoxicity study with seven human cancer cell lines. The results of this study revealed that 2-DG conjugated platinum (II) complexes are GLUT1 transportable substrates and exhibit improved cytotoxicities in cancer cell lines that over express GLUT1 when compared to the clinical drug, Oxaliplatin. The correlation between GLUT1 expression and antitumor effects are also confirmed. The study provides fundamental information supporting the potential of the 2-DG conjugated platinum (II) complexes as lead compounds for further pharmaceutical R&D.

  1. Liquid Crystals of Dendron-Like Pt Complexes Processable Into Nanofilms Dendrimers. Phase 2. Cholesteric Liquid Crystal Glass Platinum Acetylides

    Science.gov (United States)

    2014-08-01

    ciqa.edu.mx AFOSR FA9550-12-1-0234 August 2014 Cholesteric liquid crystal glass platinum acetylides Eduardo Arias...to be vitrified on cooling and form long time stability cholesteric glasses at room temperature, a series of platinum acetylide complexes modified...OCH3 and F, the cholesteric pitch was determined to be 1.7, 3.4 and 9.0 µ, respectively. INTRODUCTION Platinum acetylides are nonlinear

  2. Synthesis, characterization, and biological activity of platinum II, III, and IV pivaloamidine complexes.

    Science.gov (United States)

    Sinisi, Marilù; Gandin, Valentina; Saltarella, Teresa; Intini, Francesco P; Pacifico, Concetta; Marzano, Christine; Natile, Giovanni

    2014-10-01

    Imino ligands have proven to be able to activate the trans geometry of platinum(II) complexes towards antitumor activity. These ligands, like aromatic N-donor heterocycles, have a planar shape but, different from the latter, have still an H atom on the coordinating nitrogen which can be involved in H-bond formation. Three classes of imino ligands have been extensively investigated: iminoethers (HN=C(R)OR'), ketimines (HN=CRR'), and amidines (HN=C(R)NR'R″). The promising efficacy of the platinum compounds with amidines (activity comparable to that of cisplatin for cis complexes and much greater than that of transplatin for trans complexes) prompted us to extend the investigation to amidine complexes with a bulkier organic residue (R = t-Bu). The tert-butyl group can confer greater affinity for lipophilic environments, thus potentiating the cellular uptake of the compound. In the present study we describe the synthesis and characterization of pivaloamidine complexes of platinum(II), (cis and trans-[PtCl2(NH3){Z-HN=C(t-Bu)NH2}] and cis and trans-[PtCl2{Z-HN=C(t-Bu)NH2}2]), platinum(III) ([Pt2Cl4{HN=C(t-Bu)NH}2(NH3)2]), and platinum(IV) (trans-[PtCl4(NH3){Z-HN=C(t-Bu)NH2}] and trans-[PtCl4{Z-HN=C(t-Bu)NH2}2]). The cytotoxicity of all new Pt complexes was tested toward a panel of cultured cancer cell lines, including cisplatin and multidrug resistant variants. In addition, cellular uptake and DNA binding, perturbations of cell cycle progression, induction of apoptosis, and p53 activation were investigated for the most promising compound trans-[PtCl2(NH3){Z-HN=C(t-Bu)NH2}]. Remarkably, the latter complex was able to overcome both acquired and intrinsic cisplatin resistance.

  3. Trigeminal star-like platinum complexes induce cancer cell senescence through quadruplex-mediated telomere dysfunction.

    Science.gov (United States)

    Zheng, Xiao-Hui; Mu, Ge; Zhong, Yi-Fang; Zhang, Tian-Peng; Cao, Qian; Ji, Liang-Nian; Zhao, Yong; Mao, Zong-Wan

    2016-12-01

    Two trigeminal star-like platinum complexes were synthesized to induce the formation of human telomere G-quadruplex (hTel G4) with extremely high selectivity and affinity. The induced hTel G4 activates strong telomeric DNA damage response (TDDR), resulting in telomere dysfunction and cell senescence.

  4. SYNTHESIS AND CATALYTIC ACTIVITY OF PLATINUM COMPLEX OF ACRYLATE TERPOLYMER WITH Se,N BIDENTATE LIGAND

    Institute of Scientific and Technical Information of China (English)

    MengLingzhi; QiLiangwei; 等

    1998-01-01

    Acrylate terpolymer-bound Se,N bidentate ligand was synthesized from the side chain chlorine of copolymer and β-dimethylamino-β′-hydroxyl-diethyl selenoether.The polymer-supported platinum complex exhibited high catalytic activity in the hydrosilylation of olefins with triethoxysilane.

  5. SYNTHESIS AND CHARACTERIZATION OF DVE-CO-MA DERIVATIVES OF CIS- PLATINUM COMPLEXES

    Institute of Scientific and Technical Information of China (English)

    WANG Zhuting

    1989-01-01

    Copolymer of divinyl ether and maleic anhydride (DVE- co - MA) derivatives of cis- platinum complexes were synthesized and characterized by elementary analysis, IR and XPS ( X- ray photoelectron spectroscopy). The behavior of the products in biological environment was also studied. UV- visible and fluorescence spectra show that these polymer derivatives are able to exchange ligands with selected nucleophilic groups in biological environment.

  6. Synthesis and Luminescent Properties of an Acetylide-Bridged Dinuclear Platinum(II) Terpyridyl Complex

    Institute of Scientific and Technical Information of China (English)

    WANG,You-Wei(王幼薇); YANG,Qing-Zheng(杨清正); WU,Li-Zhu(吴骊珠); ZHANG,Li-Ping(张丽萍); TUNG,Chen-Ho(佟振合)

    2004-01-01

    An acetylide-bridged dinuclear platinum(II) terpyridyl complex, [Pt(4'-p-tolyl-terpy)-≡-phenyl-≡-(4'-p-tolyl- terpy)Pt](ClO4)2 (1), has been successfully synthesized and its photophysical properties are reported.

  7. Synthesis and ion-binding studies of platinum(Ⅱ) phenanthroline complexes containing crown ether moiety

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Two new benzo-[15]-crown-5 attached phenanthroline platinum(Ⅱ) complexes with the general formula Pt(phen)X2, where X = Cl (1), C≡CC6H5 (2) have been synthesized, and their absorption and luminescence response towards metal ions have been studied.

  8. Palladium, platinum, and rhodium contents of rocks near the lower margin of the Stillwater complex, Montana.

    Science.gov (United States)

    Zientek, M.L.; Foose, M.P.; Leung, Mei

    1986-01-01

    Statistical summaries are reported for Pd, Pt and Rh contents of rocks from the lower part of the Stillwater complex, the underlying contact-metamorphosed sediments, and post-metamorphic dykes and sills wholly within the hornfelses. Variability of the data among the rock types is attributed largely to differences in sulphide content. Non-correlation of sulphur with platinum-group assays of many rock types leads to the suggestion that the immiscible sulphide and silicate liquids did not completely equilibrate with respect to platinum-group elements. -G.J.N.

  9. Diamino-ligated platinum(II) and platinum(IV) phenoxide complexes; syntheses and crystal structures

    NARCIS (Netherlands)

    Koten, G. van; Kapteijn, G.M.; Meijer, M.D.; Grove, D.M.; Veldman, N.; Spek, A.L.

    1997-01-01

    The reaction of the diamino-ligated dimethylplatinum(II) complex [Pt(Me){2}(bpy)] (bpy=2, 2'-bipyridyl) with phenol affords the new complex [Pt(Me)(OPh)(bpy)] (1). The X-ray crystal structure of square-planar 1 is reported: orthorhombic, space group P2{1}2{1}2{1} (No. 19), a = 9.1625(12), b =

  10. Bent Dinuclear Platinum(II Halo-Bridged Carbonyl Complexes

    Directory of Open Access Journals (Sweden)

    Fabio Marchetti

    2011-07-01

    Full Text Available Crystals of trans-Pt2(μ-X2X2(CO2 (X = Br, I have been grown and their molecular and crystalline structures have been solved by X-ray diffraction methods. In both cases the dinuclear molecules are bent, with a bending angle of 164.6° and 156.5° for the bromide and the iodide, respectively. While the structure of the bromo-derivative is reported here for the first time, a modification of trans-Pt2(μ-I2I2(CO2 with planar centrosymmetric molecules is known. This appears to be a rare case of a platinum(II halo-bridged derivative structurally characterized in both bent and planar forms.

  11. Cyclometalated NCN platinum(II) acetylide complexes - Synthesis, photophysics and OLEDs fabrication

    Science.gov (United States)

    Szafraniec-Gorol, Grazyna; Slodek, Aneta; Schab-Balcerzak, Ewa; Grucela, Marzena; Siwy, Mariola; Filapek, Michal; Matussek, Marek; Zych, Dawid; Mackowski, Sebastian; Buczynska, Dorota; Grzelak, Justyna; Erfurt, Karol; Chrobok, Anna; Krompiec, Stanislaw

    2016-12-01

    The novel cyclometalated NCN platinum(II) acetylide complexes were synthesized. As precursors of acetylide ligands were used 9,9-dibutyl-2-ethynylfluorene, 9-butyl-3-ethynylcarbazole, and 5-ethynyl-2,2‧-bithiophene, whereas 1,3-di(2-pirydyl)benzene derivatives were cyclometalating NCN ligands. Variable character of ligands allowed to prepare a series of novel platinum(II) complexes, which showed light emission in a wide wavelength range from 410 to 625 nm. The optical and electrochemical properties of new complexes were examined and compared with theoretical DFT calculations. Complexes containing fluorenyl and carbazyl motif were used as emitters in an organic light-emitting diodes. The applicability of these Pt(II) complexes for electroluminescence was examined.

  12. Characterization of the Sukinda and Nausahi ultramafic complexes, Orissa, India by platinum-group element geochemistry

    Science.gov (United States)

    Page, N.J.; Banerji, P.K.; Haffty, J.

    1985-01-01

    Samples of 20 chromitite, 14 ultramafic and mafic rock, and 9 laterite and soil samples from the Precambrian Sukinda and Nausahi ultramafic complexes, Orissa, India were analyzed for platinum-group elements (PGE). The maximum concentrations are: palladium, 13 parts per billion (ppb); platinum, 120 ppb; rhodium, 21 ppb; iridium, 210 ppb; and ruthenium, 630 ppb. Comparison of chondrite-normalized ratios of PGE for the chromitite samples of lower Proterozoic to Archean age with similar data from Paleozoic and Mesozoic ophiolite complexes strongly implies that these complexes represent Precambrian analogs of ophiolite complexes. This finding is consistent with the geology and petrology of the Indian complexes and suggests that plate-tectonic and ocean basin developement models probably apply to some parts of Precambrian shield areas. ?? 1985.

  13. Diamino-ligated platinum(II) and platinum(IV) phenoxide complexes; syntheses and crystal structures

    NARCIS (Netherlands)

    Koten, G. van; Kapteijn, G.M.; Meijer, M.D.; Grove, D.M.; Veldman, N.; Spek, A.L.

    1997-01-01

    The reaction of the diamino-ligated dimethylplatinum(II) complex [Pt(Me){2}(bpy)] (bpy=2, 2'-bipyridyl) with phenol affords the new complex [Pt(Me)(OPh)(bpy)] (1). The X-ray crystal structure of square-planar 1 is reported: orthorhombic, space group P2{1}2{1}2{1} (No. 19), a = 9.1625(12), b = 12.392

  14. Cellular accumulation, lipophilicity and photocytotoxicity of diazido platinum(IV) anticancer complexes.

    Science.gov (United States)

    Pizarro, Ana M; McQuitty, Ruth J; Mackay, Fiona S; Zhao, Yao; Woods, Julie A; Sadler, Peter J

    2014-06-01

    The lipophilicity of ten photoactivatable platinum(IV) diazido prodrugs of formula trans,trans,trans-[Pt(N3 )2 (OH)2 (R)(R')] (where R and R' are NH3 , methylamine, ethylamine, pyridine, 2-picoline, 3-picoline or thiazole) has been determined by their retention times on reversed-phase HPLC. The lipophilicity of the complexes shows a linear dependence on the lipophilicity (partition coefficient) of the ligands. Accumulation of platinum in A2780 human ovarian cancer cells after one hour drug exposure in the dark is compared with their cytotoxic potency on activation with UVA (365 nm) and to their lipophilicity. No correlation between lipophilicity and intracellular accumulation of platinum was observed, perhaps suggesting involvement of active transport and favoured influx of selected structures. Furthermore, no correlation between platinum accumulation and photocytotoxicity was observed in A2780 cancer cells, implying that the type of intracellular damage induced by these complexes plays a key role in their cytotoxic effects. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Gold and Platinum in Silicon - Isolated Impurities Complexes

    CERN Multimedia

    Mcglynn, P

    2002-01-01

    %IS357 :\\\\ \\\\ Gold and platinum impurities in silicon are exploited for the control of minority carrier lifetimes, and this important feature has resulted in sustained research interest over several decades. Although the properties of isolated substitutional Au~atoms are well understood, this is not the case for Pt. Considerable uncertainty exists regarding the nature of several Pt related defects observed in Electron Paramagnetic Resonance~(EPR) and Photo~Luminescence~(PL). One of the objectives of this experiment is to exploit the transformation of radioactive Au isotopes as a means of producing specific Pt centres, and to use our thorough knowledge of Au in silicon to guide in the interpretation of data obtained for the centres when they transform to Pt.\\\\ \\\\ In addition to isolated impurities, the experiment also addresses the question of pairs of atoms formed by Au and Pt. Studies of these impurity pairs have been reported, but the benefits of a direct comparison of the defects in both the Au and Pt form...

  16. Biological Recovery of Platinum Complexes from Diluted Aqueous Streams by Axenic Cultures

    Science.gov (United States)

    Maes, Synthia; Props, Ruben; Fitts, Jeffrey P.; De Smet, Rebecca; Vanhaecke, Frank; Boon, Nico; Hennebel, Tom

    2017-01-01

    The widespread use of platinum in high-tech and catalytic applications has led to the production of diverse Pt loaded wastewaters. Effective recovery strategies are needed for the treatment of low concentrated waste streams to prevent pollution and to stimulate recovery of this precious resource. The biological recovery of five common environmental Pt-complexes was studied under acidic conditions; the chloro-complexes PtCl42- and PtCl62-, the amine-complex Pt(NH3)4Cl2 and the pharmaceutical complexes cisplatin and carboplatin. Five bacterial species were screened on their platinum recovery potential; the Gram-negative species Shewanella oneidensis MR-1, Cupriavidus metallidurans CH34, Geobacter metallireducens, and Pseudomonas stutzeri, and the Gram-positive species Bacillus toyonensis. Overall, PtCl42- and PtCl62- were completely recovered by all bacterial species while only S. oneidensis and C. metallidurans were able to recover cisplatin quantitatively (99%), all in the presence of H2 as electron donor at pH 2. Carboplatin was only partly recovered (max. 25% at pH 7), whereas no recovery was observed in the case of the Pt-tetraamine complex. Transmission electron microscopy (TEM) revealed the presence of both intra- and extracellular platinum particles. Flow cytometry based microbial viability assessment demonstrated the decrease in number of intact bacterial cells during platinum reduction and indicated C. metallidurans to be the most resistant species. This study showed the effective and complete biological recovery of three common Pt-complexes, and estimated the fate and transport of the Pt-complexes in wastewater treatment plants and the natural environment. PMID:28046131

  17. Bis-NHC chelate complexes of nickel(0) and platinum(0).

    Science.gov (United States)

    Brendel, Matthias; Braun, Carolin; Rominger, Frank; Hofmann, Peter

    2014-08-11

    For a long time d(10)-ML2 fragments have been known for their potential to activate unreactive bonds by oxidative addition. In the development of more active species, two approaches have proven successful: the use of strong σ-donating ligands leading to electron-rich metal centers and the employment of chelating ligands resulting in a bent coordination geometry. Combining these two strategies, we synthesized bis-NHC chelate complexes of nickel(0) and platinum(0). Bis(1,5-cyclooctadiene)nickel(0) and -platinum(0) react with bisimidazolium salts, deprotonated in situ at room temperature, to yield tetrahedral or trigonal-planar bis-NHC chelate olefin complexes. The synthesis and characterization of these complexes as well as a first example of C-C bond activation with these systems are reported. Due to the enforced cis arrangement of two NHCs, these compounds should open interesting perspectives for bond-activation chemistry and catalysis.

  18. Prophage induction and mutagenicity of a series of anti-tumour platinum(II) and platinum(IV) co-ordination complexes

    NARCIS (Netherlands)

    Mattern, I.E.; Cocchiarella, L.; Kralingen, C.G. van; Lohman, P.H.M.

    1982-01-01

    Eleven platinum compounds with nitrogen donor ligands, previously tested for anti-tumour activity were studied for induction of prophage lambda and for mutagenicity in the Ames assay, with various strains of Salmonella. The compounds included cis and trans isomers of Pt(II) and Pt(IV) complexes and

  19. DFT-based QSAR and QSPR models of several cis-platinum complexes: solvent effect.

    Science.gov (United States)

    Sarmah, Pubalee; Deka, Ramesh C

    2009-06-01

    Cytotoxic activities of cis-platinum complexes against parental and resistant ovarian cancer cell lines were investigated by quantitative structure-activity relationship (QSAR) analysis using density functional theory (DFT) based descriptors. The calculated parameters were found to increase the predictability of each QSAR model with incorporation of solvent effects indicating its importance in studying biological activity. Given the importance of logarithmic n-octanol/water partition coefficient (log P(o/w)) in drug metabolism and cellular uptake, we modeled the log P(o/w) of 24 platinum complexes with different leaving and carrier ligands by the quantitative structure-property relationship (QSPR) analysis against five different concentrations of MeOH using DFT and molecular mechanics derived descriptors. The log P(o/w) values of an additional set of 20 platinum complexes were also modeled with the same descriptors. We investigated the predictability of the model by calculating log P(o/w) of four compounds in the test set and found their predicted values to be in good agreement with the experimental values. The QSPR analyses performed on 24 complexes, combining the training and test sets, also provided significant values for the statistical parameters. The solvent medium played an important role in QSPR analysis by increasing the internal predictive ability of the models.

  20. Antitumor activities and interaction with DNA of oxaliplatin-type platinum complexes with linear or branched alkoxyacetates as leaving groups.

    Science.gov (United States)

    Yin, Runting; Gou, Shaohua; Liu, Xia; Lou, Liguang

    2011-08-01

    Five oxaliplatin-typed platinum complexes containing trans-1R, 2R-diaminocyclohexane chelating platinum cores, characteristic of linear or branched alkoxycarboxylates as leaving groups, were biologically evaluated. These compounds showed higher antitumor activity, lower toxicity in vivo than cisplatin or oxaliplatin. And the results revealed that the antitumor activity and interaction with DNA of these compounds were highly related to the nature of leaving groups. Among these complexes, 5a, cis-(trans-1R, 2R-diaminocyclohexane) bis (2-tert-butoxyacetate) platinum(II), showed the highest antitumor activity and the lowest toxicity.

  1. Heterolytic activation of dihydrogen by platinum and palladium complexes

    NARCIS (Netherlands)

    Almeida Leñero, K.Q.; Guari, Y.; Kramer, P.C.J.; van Leeuwen, P.W.N.M.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B.; Lutz, M.; Spek, A.L.

    2013-01-01

    Wide bite angle diphosphine ligands were used to prepare [(diphosphine)M(2-(diphenylphosphino)pyridine)]2+ complexes (M = Pd, Pt). Except for the ligand with the largest bite angle, 2-(diphenylphosphino)pyridine coordinates in a bidentate mode leading to bis-chelate complexes. In the case of Xantpho

  2. Heterolytic activation of dihydrogen by platinum and palladium complexes

    NARCIS (Netherlands)

    Lenero, K.Q.A.; Guari, Y.; Kamer, P.C.J.; van Leeuwen, P.W.N.M.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B.; Lutz, M.; Spek, A.L.

    2013-01-01

    Wide bite angle diphosphine ligands were used to prepare [(diphosphine)M(2-(diphenylphosphino)pyridine)] (2+) complexes (M = Pd, Pt). Except for the ligand with the largest bite angle, 2-(diphenylphosphino) pyridine coordinates in a bidentate mode leading to bis-chelate complexes. In the case of Xan

  3. Heterolytic activation of dihydrogen by platinum and palladium complexes

    NARCIS (Netherlands)

    Almeida Leñero, K.Q.; Guari, Y.; Kramer, P.C.J.; van Leeuwen, P.W.N.M.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B.; Lutz, M.; Spek, A.L.

    2013-01-01

    Wide bite angle diphosphine ligands were used to prepare [(diphosphine)M(2-(diphenylphosphino)pyridine)]2+ complexes (M = Pd, Pt). Except for the ligand with the largest bite angle, 2-(diphenylphosphino)pyridine coordinates in a bidentate mode leading to bis-chelate complexes. In the case of

  4. Heterolytic activation of dihydrogen by platinum and palladium complexes

    NARCIS (Netherlands)

    Almeida Leñero, K.Q.; Guari, Y.; Kramer, P.C.J.; van Leeuwen, P.W.N.M.; Donnadieu, B.; Sabo-Etienne, S.; Chaudret, B.; Lutz, M.; Spek, A.L.

    2013-01-01

    Wide bite angle diphosphine ligands were used to prepare [(diphosphine)M(2-(diphenylphosphino)pyridine)]2+ complexes (M = Pd, Pt). Except for the ligand with the largest bite angle, 2-(diphenylphosphino)pyridine coordinates in a bidentate mode leading to bis-chelate complexes. In the case of Xantpho

  5. A new member of the oxygen-photosensitizers family: a water-soluble polymer binding a platinum complex.

    Science.gov (United States)

    Ricciardi, Loredana; Puoci, Francesco; Cirillo, Giuseppe; La Deda, Massimo

    2012-08-28

    The grafting of a 2-picolylamine Pt(II) complex into polymethacrylic acid has been successfully performed. The obtained polymer is water soluble, and it represents the first example of a platinum-containing polymer able to photogenerate singlet oxygen.

  6. Developing strongly luminescent platinum(IV) complexes: facile synthesis of bis-cyclometalated neutral emitters.

    Science.gov (United States)

    Juliá, Fabio; Bautista, Delia; González-Herrero, Pablo

    2016-01-28

    A straightforward, one-pot procedure has been developed for the synthesis of bis-cyclometalated chloro(methyl)platinum(IV) complexes with a wide variety of heteroaromatic ligands of the 2-arylpyridine type. The new compounds exhibit phosphorescent emissions in the blue to orange colour range and represent the most efficient Pt(IV) emitters reported to date, with quantum yields up to 0.81 in fluid solutions at room temperature.

  7. Cytotoxicity of cyclometalated platinum complexes based on tridentate NCN and CNN-coordinating ligands: remarkable coordination dependence.

    Science.gov (United States)

    Vezzu, Dileep A K; Lu, Qun; Chen, Yan-Hua; Huo, Shouquan

    2014-05-01

    A series of cyclometalated platinum complexes with diverse coordination patterns and geometries were screened for their anticancer activity. It was discovered that the N^C^N-coordinated platinum complex based on 1,3-di(pyridyl)benzene displayed much higher cytotoxicity against human lung cancer cells NCI-H522, HCC827, and NCI-H1299, and human prostate cancer cell RV1 than cisplatin. In a sharp contrast, the C^N^N-coordinated platinum complex based on 6-phenyl-2,2'-bipyridine was ineffective on these cancer cells. This remarkable difference in cytotoxicity displayed by N^C^N- and C^N^N-coordinated platinum complexes was related to the trans effect of the carbon donor in the cyclometalated platinum complexes, which played a crucial role in facilitating the dissociation of the chloride ligand to create an active binding site. The DNA binding was studied for the N^C^N-coordinated platinum complex using electrophoresis and emission titration. The cellular uptake observed by fluorescent microscope showed that the complex is largely concentrated in the cytoplasm. The possible pathways for the cell apoptosis were studied by western blot analysis and the activation of PARP via caspase 7 was observed.

  8. Diazo transfer for azido-functional surfaces

    Directory of Open Access Journals (Sweden)

    Laura Russo

    2011-04-01

    Full Text Available Preparation of azido-functionalized polymers is gaining increasing attention. We wish to report an innovative, novel strategy for azido functionalization of polymeric materials, coupling plasma technology and solution processed diazo transfer reactions. This novel approach allows the azido group to be introduced downstream of the material preparation, thus preserving its physicochemical and mechanical characteristics, which can be tailored a priori according to the desired application. The whole process involves the surface plasma functionalization of a material with primary amino groups, followed by a diazo transfer reaction, which converts the amino functionalities into azido groups that can be exploited for further chemoselective reactions. The diazo transfer reaction is performed in a heterogeneous phase, where the azido group donor is in solution. Chemical reactivity of the azido functionalities was verified by subsequent copper-catalyzed azide-alkyne cycloaddition.

  9. CATALYTIC BEHAVIOR OF A SILICA-SUPPORTED POLYTITAZANE-PLATINUM COMPLEX FOR THE HYDROGENATION OF PHENOL

    Institute of Scientific and Technical Information of China (English)

    CHEN Chunwei; HUANG Meiyu; JIANG Yingyan

    1996-01-01

    A new kind of inorganic polymer, viz. silica-supported polytitazane (Ti-N), and its platinum complex (Ti-N-Pt) were prepared. Cyclohexanone can be obtained in a maximum yield of about 62.2% in the hydrogenation of phenol over Ti-N-Pt at room temperature under atmospheric pressure. The effects of mole ratio of N/Pt in the complex, concentration of the catalyst and reaction temperature on the catalytic activity and selectivity have been studied. The complex can be reused several times without loss in its catalytic activity.

  10. SYNTHESIS AND CATALYTIC HYDROSILYLATION PROPERTY OF POLYSILOXANE-SUPPORTED MERCAPTOSELENAETHER PLATINUM OR RHODIUM COMPLEX

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Silica-bound mercaptoselenaether-containing silsesquioxane and its platinum or rhodium complex were synthesized from γ-(2,3-epithiopropyl) propyltrimethoxysilane via ring-opening reaction with bis(2-hydroxyethyl) selenide, followed by hydrolysis and immobilization on fumed silica, and then reacting with potassium chloroplatinite or rhodium chloride in acetone under nitrogen atmosphere. It was found that two noble metal complexes can catalyze the hydrosilylation of olefins with triethoxysilane effectively. The influences of temperature, the amount of complex used, the nature of olefin on catalytic activity were investigated.

  11. Reactions of Dinuclear Platinum(II) Complexes with Peptides.

    Science.gov (United States)

    Rajković, Snežana; Živković, Marija D; Djuran, Miloš I

    2016-01-01

    The present review article highlights recent findings in the reactions between different dinuclear Pt(II) complexes with peptides containing cysteine, methionine and histidine residues. The reactions of {trans-[Pt(NH3)2Cl]2(μ-X)}(2+) and {trans-[Pt(NH3)2(H2O)]2(μ-X)}(4+) type complexes with different bridging ligands (X) (X = pyrazine, 4,4'-bipyridyl and 1,2-bis(4-pyridyl)ethane) with the tripeptide glutathione proceeded in two steps. In the first step, one water or chlorido ligand of the dinuclear Pt(II) complex was substituted by the sulfhydryl group of GSH, while in the second step, the remaining water or chlorido ligand from the dinuclear Pt(II)-peptide complex was replaced by the second molecule of glutathione, finally leading to the formation of the {trans-[Pt(NH3)2(GS)]2(μ-X)}(2+) complex. It was shown that the bridging ligand had an important influence on the reactivity of these complexes with glutathione. No hydrolytic cleavage of any amide bond was observed in the reactions between these complexes and glutathione. However, in reactions performed in acidic media (2.0 complexes with the general formulae {[Pt(L)(H2O)]2(μ-diazine)}(4+) (L is different bidentate coordinated diamine ligands and diazine is a pyrazine- or pyridazine-bridging ligand) and Nacetylated peptides containing L-methionine and L-histidine amino acids in the side chains (Ac-L-Met-Gly, Ac-L-His-Gly and Ac-L-Met-Gly-L-His-GlyNH2), regioselective cleavage of these peptides occurred. The mechanism of these hydrolytic reactions was discussed in relation to the structure of the diazine-bridged Pt(II) complex and the investigated peptides. A systematic summary of these results could contribute to the future design of new dinuclear Pt(II) complexes as potential reagents for regioselective cleavage of peptides and proteins.

  12. Magnetocaloric effect and slow magnetic relaxation in two only azido bridged ferromagnetic tetranuclear metal clusters.

    Science.gov (United States)

    Zhao, Jiong-Peng; Zhao, Ran; Yang, Qian; Hu, Bo-Wen; Liu, Fu-Chen; Bu, Xian-He

    2013-10-28

    Two M(II) tetranuclear complexes bridged only by azido, Mn4(N3)(7.3)Cl(0.7)L4 (1) and Co4(N3)8L4 (2) in which the four M(II) ions are precisely coplanar bridged only by six azido anions, were obtained by using 4,5-diazafluoren-9-one (L) as a corner ligand. Magnetic studies indicate that ferromagnetic coupling was conducted by the azido anions between M(II) ions. At low temperature, 1 exhibits a large magnetocaloric effect and 2 shows field-induced multiple magnetic relaxations.

  13. Biological Properties Of Benzopyran-Based Platinum (Ii Complexes

    Directory of Open Access Journals (Sweden)

    Malinowska Katarzyna

    2014-04-01

    Full Text Available The aim of the study was to analyze the physicochemical synthesized complex 3 [(1,3- thiazol -2- ylimino methyl]-4H- chromene -4 -one with tetrachloroplatinate(II dipotassium and determination peroxidase activity and glutathione (GPX in red blood cells of cancer patients and healthy subjects. Materials and methods. Tests were carried out with the approval of the Bioethics Committee No. RNN/260/08/KB. Blood was collected into tubes with anticoagulant (heparin lithium. Determination of glutathione peroxidase activity was performed by methods of Little and O’Brien in 20 person groups hospitalized at the Department of General and Colorectal Surgery Veterans General Hospital in Łódź. Results. The study was an increase of activity in the control without the compound and after the introduction of the complex relative to the treatment groups. In healthy subjects, without the use of glutathione peroxidase complex averaged 73.25 ± 23.88 U / g Hb after application of the compound corresponds to the reference group 81.01 ± 25.94 U / g Hb. In contrast, in patients without the use of the complex activity amounted to 42.85 ± 27.49 U / g Hb. In the study group, which uses synthesized complex GPX activity corresponds to 67.72 ± 13.44 U / g Hb. Conclusions. The obtained results underline that the introduction of significant blood antioxidant complex research has a significant impact on the results of the determinations. Statistically significant (p < 0.05 difference occurred in both test and no relation to the administration of the complex in relation to the control of 1. 2.

  14. The effect of intermolecular hydrogen bonding on the fluorescence of a bimetallic platinum complex.

    Science.gov (United States)

    Zhao, Guang-Jiu; Northrop, Brian H; Han, Ke-Li; Stang, Peter J

    2010-09-02

    The bimetallic platinum complexes are known as unique building blocks and arewidely utilized in the coordination-driven self-assembly of functionalized supramolecular metallacycles. Hence, photophysical study of the bimetallic platinum complexes will be very helpful for the understanding on the optical properties and further applications of coordination-driven self-assembled supramolecular metallacycles. Herein, we report steady-state and time-resolved spectroscopic experiments as well as quantum chemistry calculations to investigate the significant intermolecular hydrogen bonding effects on the intramolecular charge transfer (ICT) fluorescence of a bimetallic platinum compound 4,4'-bis(trans-Pt(PEt(3))(2)OTf)benzophenone 3 in solution. We demonstrated that the fluorescent state of compound 3 can be assigned as a metal-to-ligand charge transfer (MLCT) state. Moreover, it was observed that the formation of intermolecular hydrogen bonds can effectively lengthen the fluorescence lifetime of 3 in alcoholic solvents compared with that in hexane solvent. At the same time, the electronically excited states of 3 in solution are definitely changed by intermolecular hydrogen bonding interactions. As a consequence, we propose a new fluorescence modulation mechanism by hydrogen bonding to explain different fluorescence emissions of 3 in hydrogen-bonding solvents and nonhydrogen-bonding solvents.

  15. Strongly luminescing ruthenium(II)/ruthenium(II) and ruthenium(II)/platinum(II) binuclear complexes

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, R.; Baucom, D.A.; Rillema, D.P.

    1986-10-08

    Two strongly luminescing complexes, ruthenium(II)/ruthenium(II) homobinuclear complex and ruthenium(II)/platinum(II) heterobinuclear complex, have been prepared and characterized. The organic part of the complex is 4,4'-dimethyl-2,2' bipyridine dimer. The luminescence behavior of the homobinuclear and heterobinculear complexes was found to be comparable to that of Ru(bpy)/sub 3//sup 2 +/, although the luminescence maxima were shifted from 615 to 620 nm. These complexes exhibit good stability due to the bidentate chelating capability of the bridging ligand. These new complexes can provide the opportunity for detailed photophysical studies related to donor-acceptor interactions and to the possibility of two simultaneous single-electron transfer events. 17 references, 2 figures.

  16. Synthesis and cytotoxicity of new platinum(IV) complexes of mixed carboxylates.

    Science.gov (United States)

    Song, Rita; Park, Sun Young; Kim, Yeong Sang; Kim, Youngmee; Kim, Sung Jin; Ahn, Byung Tae; Sohn, Youn Soo

    2003-08-01

    In order to develop new antitumor platinum(IV) complexes with highly tuned lipophilicity, a series of (diamine)Pt(IV) complexes of the formula [Pt(IV)(dach)L(3)L'] or [Pt(IV)(dach)L(2)L"(2)] (dach=trans-(+/-)-1,2-diaminocyclohexane; L=acetato, propionato; L'=acetato, propionato, valerato or pivalato; L"=trifluoroacetato) have been synthesized by electrophilic substitution of the tris(carboxylato)hydroxoplatinum(IV) complexes, [Pt(IV)(dach)L(3)OH] (L=acetato, propionato), with various carboxylic anhydrides such as acetic, trifluoroacetic, pivalic and valeric anhydrides. The present platinum(IV) complexes were fully characterized by means of elemental analyses, 1H NMR, mass and IR spectroscopies. The complexes 8 and 10, satisfying the appropriate range of lipophilicity (logP=0.18-1.54), exhibited high activity (ED(50), 5.1 and 1.3 microM, respectively) compared with other complexes, which implies that the lipophilicity is an important factor for the antitumor activity of this series of complexes.

  17. Novel dinuclear platinum(II) complexes containing mixed nitrogen-sulfur donor ligands.

    Science.gov (United States)

    Hochreuther, Stephanie; Puchta, Ralph; van Eldik, Rudi

    2011-12-19

    A series of novel dinuclear platinum(II) complexes were synthesized containing a mixed nitrogen-sulfur donor bidentate chelate system in which the two platinum centers are connected by an aliphatic chain of variable length. The bidentate chelating ligands were selected to stabilize the complex toward decomposition. The pK(a) values and reactivity of the four synthesized complexes, namely, [Pt(2)(S(1),S(4)-bis(2-pyridylmethyl)-1,4-butanedithioether)(OH(2))(4)](4+) (4NSpy), [Pt(2)(S(1),S(6)-bis(2-pyridylmethyl)-1,6-hexanedithioether)(OH(2))(4)](4+) (6NSpy), [Pt(2)(S(1),S(8)-bis(2-pyridylmethyl)-1,8-octanedithioether)(OH(2))(4)](4+) (8NSpy), and [Pt(2)(S(1),S(10)-bis(2-pyridylmethyl)-1,10-decanedithioether)(OH(2))(4)](4+) (10NSpy), were investigated. This system is of special interest because only little is known about the substitution behavior of dinuclear platinum complexes that contain a bidentate chelate that forms part of the aliphatic bridging ligand. Moreover, the ligands as well as the dinuclear complexes were examined in terms of their cytotoxic activity, and the 10NSpy complex was found to be active. Spectrophotometric acid-base titrations were performed to determine the pK(a) values of all the coordinated water molecules. The substitution of coordinated water by thiourea was studied under pseudo-first-order conditions as a function of nucleophile concentration, temperature, and pressure, using stopped-flow techniques and UV-vis spectroscopy. The results for the dinuclear complexes were compared to those for the corresponding mononuclear reference complex [Pt(methylthiomethylpyridine)(OH(2))(2)](2+) (Pt(mtp)), by which the effect of the increasing aliphatic chain length of the bridged complexes could be investigated. The results indicate that there is a clear interaction between the two platinum centers, which becomes weaker as the chain length between the metal centers increases. Furthermore, differences and similarities of the N,S-system were compared to

  18. Surfactant gel adsorption of platinum(II), (IV) and palladium(II) as chloro-complexes and kinetic separation of palladium from platinum using EDTA.

    Science.gov (United States)

    Murakami, Yoshiko; Hiraiwa, Kaoru; Sasaki, Yoshiaki; Fujiwara, Isamu; Tagashira, Shoji

    2007-09-01

    A micellar solution of cetylpyridinium chloride (CPC) can separate into two phases due to a temperature change or to the addition of salts. Platinum(II), (IV) and palladium(II) reacted with chloride ions to form stable anionic complexes of PtCl4(2-), PtCl6(2-) and PdCl4(2-), respectively, and were adsorbed onto the CPC gel phase. The CPC phase plays the role of an ion-exchange adsorbent for the anionic complexes. By such a procedure, the precious metals of platinum and palladium could be separated from base metals such as copper, zinc and iron. The kinetic separation was performed by a ligand exchange reaction of the palladium(II) chloro-complex with EDTA at 60 degrees C. The anionic palladium(II)-EDTA complex could not bind the opposite charged CP+ and was desorbed from the CPC phase. In the aqueous phase, the recovery of palladium(II) by the double-desorption was 101.1 +/- 1.2%. The platinum(II) and (IV) chloro-complexes were stable for at least 30 min and remained in the CPC phase.

  19. Preparation, characterization, and antitumor activity of new ethylenediamine platinum(IV) complexes containing mixed carboxylate ligands.

    Science.gov (United States)

    Khokhar, A R; Deng, Y; Kido, Y; Siddik, Z H

    1993-05-01

    A series of ethylenediamine platinum(IV) complexes of the type PtIV(en)XA2 and PtIV(en)X'2A2, where X = 1,1-cyclobutanedicarboxylato or malonato, X' = chloro, cyclobutanecarboxylato, cyclopentanecarboxylato, or cyclohexanecarboxylato, and A = acetato or trifluoroacetato were synthesized and characterized by elemental analysis, infrared, and NMR (13C and 195Pt) spectroscopic techniques. These compounds had good to excellent antitumor activity against murine leukemia L1210 cells. Complexes with axial trifluoroacetate groups were superior to those with acetate ligands. Those possessing both axial trifluoroacetate groups and monodentate bis-carboxylate ligands in the equatorial positions were the most active in the series investigated.

  20. Hydrogenation of Toluidines Catalyzed by Silica-supported Carboxymethylcellulose-platinum Complex

    Institute of Scientific and Technical Information of China (English)

    WANG Xin; YANG Ji-huo; HUANG Mei-yu; JIANG Ying-yan

    2004-01-01

    The hydrogenation of toluidines catalyzed by silica-supported carboxymethyl cellulose platinum complex forms methylcyclohexlamines in high yields, such as m-toluidine to 3-methylcyclohexylamine, o-toluidine to 2-methylcyclohexylamine, and p-toluidine to 4-methylcyclohexylamine in 97%, 96.7% and 98.2% yields,respectively, at 30 C and under atmospheric hydrogen pressure. The yields were remarkably affected by the Pt content in the complex, the kind of solvent and the reaction temperature. The catalyst was very stable and could be reused several times without remarkable change in the catalytic activity.

  1. Novel platinum(IV) complexes induce rapid tumor cell death in vitro.

    Science.gov (United States)

    Kaludjerović, Goran N; Miljković, Djordje; Momcilović, Miljana; Djinović, Vesna M; Mostarica Stojković, Marija; Sabo, Tibor J; Trajković, Vladimir

    2005-09-01

    The anticancer activity of platinum complexes has been known since the discovery of classical Pt(II)-based drug cisplatin. However, Pt(IV) complexes have greater inertness than corresponding Pt(II) complexes, thus allowing the oral administration and reducing the toxicity associated with platinum-based chemotherapy. Here, we describe the in vitro antitumor activity of some novel Pt(IV)-based agents against mouse fibrosarcoma L929 cells and human astrocytoma U251 cells. The cytotoxicity of 2 Pt(IV) complexes with bidentate ethylenediamine-N,N'-di-3-propanoato esters was found to be markedly higher than that of their Pt(II) counterparts and comparable to the antitumor action of cisplatin. In contrast to cisplatin, which caused oxidative stress-independent apoptotic cell death of tumor cells, these Pt(IV) complexes induced oxygen radical-mediated tumor cell necrosis. Importantly, the cytotoxic action of novel Pt(IV) complexes was markedly more rapid than that of cisplatin, indicating their potential usefulness in anticancer therapy.

  2. Equilibria, Kinetics, and Mechanism for Rapid Substitution Reactions Trans to Triphenylsilyl in Platinum(II) Complexes.

    Science.gov (United States)

    Wendt, Ola F.; Elding, Lars I.

    1997-12-17

    Fast substitution of chloride for bromide and iodide trans to triphenylsilyl in trans-PtCl(SiPh(3))(PMe(2)Ph)(2) has been studied by stopped-flow spectrophotometry in acetonitrile solution. Substitution is reversible with an observable solvent path via the solvento complex trans-[Pt(SiPh(3))(MeCN)(PMe(2)Ph)(2)](+), which has also been synthesized and characterized in solution. Rate constants for the forward and reverse direct substitution pathways are 2900 +/- 100 and 7500 +/- 300 for bromide and 14300 +/- 1100 and 81000 +/- 11000 M(-)(1) s(-)(1) for iodide as nucleophile. The solvento complex reacts ca. 10(3) times faster with iodide than the parent chloride complex, and its reactivity is some 2 orders of magnitude higher than the most reactive solvento species of platinum(II) studied so far. Halide substitution occurs with negative volumes and entropies of activation, but the nucleophilic discrimination is low, and the leaving ligand plays the most important role in the activation process, indicating an I(d) mechanism. Triphenylsilyl has a very high trans effect, comparable to that of ethene and methylisocyanide, due to extensive bond-weakening in the ground state, probably enforced by pi-acception in the transition state. Due to electronic and solvational effects the platinum(II) silyl moiety acts as a hard or borderline metal center in acetonitrile, the thermodynamic stability sequence of its halide complexes being Cl > Br > I, i.e. the reverse of what is usually observed for platinum(II) complexes.

  3. Electrocatalytic oxidation of methanol at platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified el...

  4. Reactivity studies of pincer bis-protic N-heterocyclic carbene complexes of platinum and palladium under basic conditions

    Science.gov (United States)

    Marelius, David C; Moore, Curtis E; Rheingold, Arnold L

    2016-01-01

    Summary Bis-protic N-heterocyclic carbene complexes of platinum and palladium (4) yield dimeric structures 6 when treated with sodium tert-butoxide in CH2Cl2. The use of a more polar solvent (THF) and a strong base (LiN(iPr)2) gave the lithium chloride adducts monobasic complex 7 or analogous dibasic complex 8. PMID:27559382

  5. Reactivity studies of pincer bis-protic N-heterocyclic carbene complexes of platinum and palladium under basic conditions

    Directory of Open Access Journals (Sweden)

    David C. Marelius

    2016-06-01

    Full Text Available Bis-protic N-heterocyclic carbene complexes of platinum and palladium (4 yield dimeric structures 6 when treated with sodium tert-butoxide in CH2Cl2. The use of a more polar solvent (THF and a strong base (LiN(iPr2 gave the lithium chloride adducts monobasic complex 7 or analogous dibasic complex 8.

  6. SILICA—BOUND 1,7—DITHIA—4—AZA—10,13,16—TRIOXACYCLOOCTADECANE AND ITS PLATINUM COMPLEX

    Institute of Scientific and Technical Information of China (English)

    CHENYuanyin; MENGLingzhi; 等

    1992-01-01

    Dithia-monoaza 18-Crown-6 and its immobilization product,silica-bound 1,7-dithia-4-aza-10,13,16-trioxa-cyclooctadecane via a spacer of three carbon atoms,and its platinum complex have been synthesized.It is found that the platinum complex is an efficient hydrosilylation catalyst for olefins.The XPS data of the platinum complex are reported.

  7. Synthesis of diorganoplatinum(IV) complexes by the Ssbnd S bond cleavage with platinum(II) complexes

    Science.gov (United States)

    Niroomand Hosseini, Fatemeh; Rashidi, Mehdi; Nabavizadeh, S. Masoud

    2016-12-01

    Reaction of [PtR2(NN)] (R = Me, p-MeC6H4 or p-MeOC6H4; NN = 2,2‧-bipyridine, 4,4‧-dimethyl-2,2‧-bipyridine, 1,10-phenanthroline or 2,9-dimethyl-1,10-phenanthroline) with MeSSMe gives the platinum(IV) complexes cis,trans-[PtR2(SMe)2(NN)]. They are characterized by NMR spectroscopy and elemental analysis. The geometries and the nature of the frontier molecular orbitals of Pt(IV) complexes containing Ptsbnd S bonds are studied by means of the density functional theory.

  8. Conjugated platinum(IV)-peptide complexes for targeting angiogenic tumor vasculature.

    Science.gov (United States)

    Mukhopadhyay, Sumitra; Barnés, Carmen M; Haskel, Ariel; Short, Sarah M; Barnes, Katie R; Lippard, Stephen J

    2008-01-01

    The integrins alpha vbeta3 and alpha vbeta5 and the membrane-spanning surface protein aminopeptidase N (APN) are highly expressed in tumor-induced angiogenesis, making them attractive targets for therapeutic intervention. Both integrins and APN recognize a broad range of peptides containing RGD (Arg-Gly-Asp) and NGR (Asn-Gly-Arg) motifs, respectively. Here, we describe the design, synthesis, and characterization of a series of mono- and difunctionalized platinum(IV) complexes in which a conjugated peptide motif, containing RGD, (CRGDC)c, (RGDfK)c, or NGR, is appended as a "tumor-homing device" to target tumor endothelial cells selectively over healthy cells. Platinum(IV)-peptide complexes with nonspecific amino acids or peptide moieties were prepared as controls. Concentration-response curves of these compounds were evaluated against primary proliferating endothelial cells and tumor cell lines and compared to those of cisplatin, a well-described platinum-based chemotherapeutic agent. The Pt(IV)-RGD conjugates were highly and specifically cytotoxic to cell lines containing alpha vbeta3 and alpha vbeta5, approaching the activity of cisplatin. The Pt(IV)-NGR complexes were less active than Pt(IV)-RGD-containing compounds but more active than nonspecific Pt-peptide controls. Integrin alpha vbeta3 mediated, at least in part, the anti-proliferative effect of a Pt(IV)-RGD conjugate, as demonstrated by a decreased inhibitory response when endothelial cells were either (1) incubated with an excess of alpha vbeta3/alpha vbeta5-specific RGD pentapeptides or (2) transfected with RNAi for beta 3, but not beta 1, integrins. These results suggest a rational approach to improved chemotherapy with Pt(IV)-peptide conjugates by selective drug delivery to the tumor compartment.

  9. Mapping the UV Photophysics of Platinum Metal Complexes Bound to Nucleobases

    Science.gov (United States)

    Sen, Ananya; Dessent, Caroline

    2015-03-01

    We report the first UV laser spectroscopic study of isolated gas-phase complexes of Platinum metal complex anions bound to a nucleobase as model systems for exploring at the molecular level the key photophysical processes involved in photodynamic therapy. Spectra of the PtIV CN 6 2 - • Uracil and PtII CN 4 2 - • Uracil complexes were acquired across the 220 -320 nm range using mass-selective photodepletion and photofragment action spectroscopy. The spectra of both complexes reveal prominent UV absorption bands that we assign primarily to excitation of the Uracil π - π * localized chromophore. Distinctive UV photofragments are observed for the complexes, with PtIV CN 6 2 - • Uracil photoexcitation resulting in complex fission, while PtII CN 4 2 - • Uracil photoexcitation initiates a nucleobase proton-transfer reaction across 4.4 -5.2 eV and electron detachment above 5.2 eV. The observed photofragments are consistent with ultrafast decay of a Uracil localized excited state back to the electronic ground state followed by intramolecular vibrational relaxation and ergodic complex fragmentation. In addition, we present recent results to explore how the photophysics of the Platinum complex-nucleobase clusters evolves as a function of nucleobase. Results are presented for PtII CN 4 2 - • Uracil complexed to Cytosine, Thymine and Adenine, reveal distinctive decay dynamics which we attribute to the intrinsic decay dynamics of the nucleobase. JPC. Lett. 2014, 5, 3281 to 3285 and PCCP 2014, 16, 15490 to 15500.

  10. Platinum(IV) Carboxylate Prodrug Complexes as Versatile Platforms for Targeted Chemotherapy.

    Science.gov (United States)

    Ong, Jun Xiang; Yap, Siew Qi; Wong, Daniel Yuan Qiang; Chin, Chee Fei; Ang, Wee Han

    2015-01-01

    Kinetically-inert Pt(IV) carboxylate complexes have emerged in recent years as candidates for the development of next-generation platinum anticancer drugs. Being native prodrugs of clinically-important Pt(II) chemotherapeutic agents, the Pt(IV) scaffold can be exploited to incorporate additional functionalities while keeping the Pt(II) pharmacophore intact. This mini-review examines recent work performed to illuminate the mechanism of Pt(IV) prodrug activation and their use as versatile platforms for targeted chemotherapy.

  11. Platinum Group Thiophenoxyimine Complexes: Syntheses,Crystallographic and Computational Studies of Structural Properties

    Energy Technology Data Exchange (ETDEWEB)

    Krinsky, Jamin L.; Arnold, John; Bergman, Robert G.

    2006-10-03

    Monomeric thiosalicylaldiminate complexes of rhodium(I) and iridium(I) were prepared by ligand transfer from the homoleptic zinc(II) species. In the presence of strongly donating ligands, the iridium complexes undergo insertion of the metal into the imine carbon-hydrogen bond. Thiophenoxyketimines were prepared by non-templated reaction of o-mercaptoacetophenone with anilines, and were complexed with rhodium(I), iridium(I), nickel(II) and platinum(II). X-ray crystallographic studies showed that while the thiosalicylaldiminate complexes display planar ligand conformations, those of the thiophenoxyketiminates are strongly distorted. Results of a computational study were consistent with a steric-strain interpretation of the difference in preferred ligand geometries.

  12. Novel platinum(IV) complexes conjugated with a wogonin derivative as multi-targeted anticancer agents.

    Science.gov (United States)

    Qin, Xiaodong; Xu, Gang; Chen, Feihong; Fang, Lei; Gou, Shaohua

    2017-04-15

    Platinum-based complexes like cisplatin and oxaliplatin are well known the mainstay of chemotherapy regimens on clinic. Wogonin, a natural product that possesses wide biological activities, is now in phase I clinical test as an anticancer agent in China. Herein reported are a series of novel Pt(IV) complexes that conjugated a wogonin derivative (compound 3) to the axial position via a linker group. After being tethered to the platinum(IV) complexes, the wogonin derivative provided multiple anticancer effects, especially in compound 10, a fusion containing wogonin and cisplatin units. Compound 10 not only inherited the genotoxicity from cisplatin, but also obtained the COX inhibitory property from the wogonin derivative. Further mechanistic investigation revealed that compound 10 caused the accumulation of ROS, decreased the mitochondrial membrane potential (ΔΨm) and then activated the p53 pathway. Overall, the research demonstrates that the "integrative" prodrug can be an effective strategy to promote the anticancer potency of Pt-based drugs for cancer treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Synthesis and antitumor activity of iodo-bridged-binuclear platinum complex

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Iodo-bridged binuclear platinum(II) com- plex[Pt((◇)-NH2)I2]2(BPA) has been synthesized and characterized by elemental analysis, conductivity, differential thermal analysis, IR, UV and 1HNMR spectra techniques. The cytotoxicity of the complex was tested by MTT and SRB assays. The results show that complex BPA demonstrates better cytotoxicity than that of the clinically established cisplatin against EJ, HCT-8, BGC-823, HL-60 and MCF-7 cell lines. The complex BPA at concentrations of 1.00 and 2.00 μmol/L induces G1 cell cycle arrest in HL-60 cells. The level of total platinum bound to DNA in HL-60 cells is significantly higher than that of cisplatin under the same experimental conditions. Acute toxicity experimental results indiacte that LD50 of BPA is 815.3 mg/kg by intraperitoneal administration. BPA at dose of 12 mg/kg significantly inhibits the growth of nude mice implanted by human A2780 and HCT-116 carcinomas, and inhibition rate is similar to that of cisplatin at dose of 4 mg/kg by intraperitoneal administration. BPA at dose of 20 mg/kg inhibits the growth of nude mice implanted by human A549 carcinomas, but there was no significant statistical difference.

  14. The Effect of Β-casein Nanoparticles on Bioavailability and Cellular Uptake of Platinum Complex as a Cancer Drug

    Directory of Open Access Journals (Sweden)

    M Razmi

    2013-12-01

    Full Text Available Abstract Background & aim: Due to the low solubility and high toxicity of drugs, treatment of cancers is problematic therefore, the encapsulation and targeted delivery of therapeutic effect is required. The aim of this study was to investigate the effect of nanoparticles on cellular uptake and bioavailability of beta-casein on platinum complexes as cancer drugs. Methods: In the present experimental study, the physicochemical properties of nanoparticles as drug carriers of beta-casein devices using dynamic light scattering (DLS and scanning electron microscopy (SEM were investigated. In order to evaluate the toxicity effects of platinum complexes, the colon cancer cells in the absence or presence of free platinum complex concentration and nanoparticle loaded with platinum complexes were incubated for 24 and 48 hours. LD50 Values (concentration of compound causing 50% mortality in the cells was determined using the MTT assay. Data were analyzed by ANOVA and post-hoc test. Results: At a concentration of 1 mg ml, beta-casein nanoparticle drug carriers were synthesized in the range of 100 to 300 µM. In addition, the mortality rate in cancer cells by the release of platinum complexes (without and with the capsule, were 70 and 26 in 24 hours, and 60 µM and 21 µM in 48 hours respectively, Conclusion: The study showed that the bioavailability of the encapsulated platinum complexes increases and new drug delivery system may be a good candidate for the treatment of cancer. Key words: Beta-casein, Pt (II Complex, Bioavalibility, Nanocarrier, Micelle

  15. DNA interactions of new cytotoxic tetrafunctional dinuclear platinum complex trans,trans-[{PtCl2(NH3)}2(piperazine)].

    Science.gov (United States)

    Brabec, Viktor; Christofis, Petros; Slámová, Martina; Kostrhunová, Hana; Nováková, Olga; Najajreh, Yousef; Gibson, Dan; Kaspárková, Jana

    2007-06-15

    A new tetrafunctional dinuclear platinum complex trans,trans-[{PtCl2(NH3)}2(piperazine)] with sterically rigid linking group was designed, synthesized and characterized. In this novel molecule, the DNA-binding features of two classes of the platinum compounds with proven antitumor activity are combined, namely trans oriented bifunctional mononuclear platinum complexes with a heterocyclic ligand and polynuclear platinum complexes. DNA-binding mode of this new complex was analyzed by various methods of molecular biology and biophysics. The complex coordinates DNA in a unique way and interstrand and intrastrand cross-links are the predominant lesions formed in DNA in cell-free media and in absence of proteins. An intriguing aspect of trans,trans-[{PtCl2(NH3)}2(piperazine)] is that, using a semi-rigid linker, interstrand cross-linking is diminished relative to other dinuclear platinum complexes with flexible linking groups and lesions that span several base pairs, such as tri- and tetrafunctional adducts, become unlikely. In addition, in contrast to the inability of trans,trans-[{PtCl2(NH3)}2(piperazine)] to cross-link two DNA duplexes, the results of the present work convincingly demonstrate that this dinuclear platinum complex forms specific DNA lesions which can efficiently cross-link proteins to DNA. The results substantiate the view that trans,trans-[{PtCl2(NH3)}2(piperazine)] or its analogues could be used as a tool for studies of DNA properties and their interactions or as a potential antitumor agent. The latter view is also corroborated by the observation that trans,trans-[{PtCl2(NH3)}2(piperazine)] is a more effective cytotoxic agent than cisplatin against human tumor ovarian cell lines.

  16. Antitumor activity of platinum(II) complexes of 1,2-diamino-cyclohexane isomers.

    Science.gov (United States)

    Kidani, Y; Noji, M; Tashiro, T

    1980-10-01

    Dichloro, dibromo, oxalato, malonato, dinitrato, sulfato and mono and bis-(D-glucuronato) platinum(II) complexes of 1,2-diaminocyclohexane (dach) isomers were prepared and tested on L1210 mouse leukemia employing the NCI protocol for evaluation of Pt analogs. A large number of long-term survivors were observed with certain analogs, though the therapeutic indices (optimal dose/minimum effective dose) were not large. Among the analogs tested, the oxalato, malonato, dinitrato and mono-(D-glucuronato) Pt(II) complexes of trans-1,2-diaminocyclohexane were found to be particularly effective. The glucuronato Pt complexes appear to be promising candidates for clinical trial since they have the highest solubility in water.

  17. Synthesis and antitumor activity of 1,2-diaminocyclohexane platinum(IV) complexes.

    Science.gov (United States)

    Khokhar, A R; al-Baker, S; Siddik, Z H

    1994-04-01

    The synthesis, characterization, and antitumor activity of a series of platinum(IV) complexes of the type DACH-PtIV(X)2Y (where DACH = trans-dl, or trans-l-1,2-diaminocyclohexane, X = OH or Cl, and Y = oxalato, malonato, methylmalonato, tartronato, ketomalonato, 1,1-cyclopropanedicarboxylato, or 1,1-cyclobutanedicarboxylato, are described. These complexes have been characterized by elemental analysis, HPLC, and infrared and 195Pt NMR spectroscopic techniques. The complexes had good in vitro cytotoxic activity (IC50 = 0.14-7.6 micrograms/ml) and were highly active in vivo against leukemia L1210 cells (%T/C = 152- > 600, cisplatin = 218). In addition, excellent in vivo antitumor activities against B16 melanoma (%T/C = 309), M5076 reticulosarcoma (100% cures) and cisplatin-resistant L1210/DDP (%T/C = 217) cell lines were also exhibited by an analog selected for further evaluation.

  18. Platinum (IV) thiohydrazide, thiodiamine and thiohydrazone complexes: A spectral, antibacterial and cytotoxic study

    Science.gov (United States)

    Mishra, A. K.; Mishra, S. B.; Manav, N.; Kumar, R.; Sharad; Chandra, R.; Saluja, D.; Kaushik, N. K.

    2007-04-01

    Some platinum (IV) complexes [Pt(L) 2Cl 2] [where, L = 2-aminopyridine- N-thiohydrazide (L 1), (2-aminopyridine- N-thio)-1,3-propanediamine (L 2), benzaldehyde-2-aminopyridine- N-thiohydrazone (L 3) and salicylaldehyde-2-aminopyrtidine- N-thiohydrazone (L 4)] have been synthesized. The thiohydrazides, thiodiamine and thiohydrazones can exist as thione-thiol tautomer and coordinate as a bidentate N-S ligand. The ligands found to act in monobasic bidentate fashion. Analytical data reveals that metal to ligand stoichiometry is 1:2. The complexes have been characterized by elemental analysis, IR, mass, electronic and 1H NMR spectroscopic studies. In vitro antibacterial and cytotoxic study have also been carried out for some complexes.

  19. Novel endothall-containing platinum(IV) complexes: synthesis, characterization, and cytotoxic activity.

    Science.gov (United States)

    Reithofer, Michael R; Valiahdi, Seied M; Galanski, Markus; Jakupec, Michael A; Arion, Vladimir B; Keppler, Bernhard K

    2008-10-01

    Two platinum(IV) complexes (OC-6-33)-dichlorido(ethane-1,2-diamine)dihydroxidoplatinum(IV) and (OC-6-33)-diammine(dichlorido)dihydroxidoplatinum(IV) were carboxylated using demethylcantharidin as carboxylation agent. The complexes were characterized by elemental analysis, mass spectrometry, multinuclear (1H, 13C, 15N, and 195Pt) NMR spectroscopy, and, in case of (OC-6-33)-diamminebis(3-carboxy-7exo-oxabicyclo[2.2.1]heptane-2-carboxylato)dichloridoplatinum(IV) via X-ray diffraction. Cytotoxicity of the complexes was studied in seven human cancer cell lines representing five tumor entities, i.e., ovarian carcinoma (CH1, SK-OV-3), cervical carcinoma (HeLa), colon carcinoma (SW480, HCT-116), osteosarcoma (U-2 OS), and hepatocellular carcinoma (Hep G2) by means of the MTT (=3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium hydrobromide) assay.

  20. New heteronuclear gold(I)-platinum(II) complexes with cytotoxic properties : Are two metals better than one?

    NARCIS (Netherlands)

    Wenzel, Margot; Bigaeva, Emilia; Richard, Philippe; Le Gendre, Pierre; Picquet, Michel; Casini, Angela; Bodio, Ewen

    2014-01-01

    A series of mono- and heterodinuclear gold(I) and platinum(II) complexes with a new bipyridylamine-phosphine ligand have been synthesized and characterized. The X-ray structures of the ligand precursor 4-iodo-N,N-di(pyridin-2-yl)benzamide, and of one gold derivative are reported. All the complexes d

  1. Two mixed-NH3/amine platinum (II) anticancer complexes featuring a dichloroacetate moiety in the leaving group

    Science.gov (United States)

    Liu, Weiping; Su, Jia; Jiang, Jing; Li, Xingyao; Ye, Qingsong; Zhou, Hongyu; Chen, Jialin; Li, Yan

    2013-08-01

    Two mixed-NH3/amine platinum (II) complexes of 3-dichoroacetoxylcyclobutane-1, 1-dicarboxylate have been prepared in the present study and characterized by elemental analysis and IR, HPLC-MS and 1H, 13C-NMR. The complexes exist in equilibrium between two position isomeric forms and undergo hydrolysis reaction in aqueous solution, releasing the platinum pharmacophores and dichloroacetate which is a small-molecular cell apoptosis inducer. Both complexes were evaluated for in vitro cytotoxic profile in A549, SGC-7901 and SK-OV-3 caner cells as well as in BEAS-2B normal cells. They exhibit markedly cytoxicity toward cancer cells by selectively inducing the apoptosis of cancer cells, whereas leaving normal cells less affected. They have also the ability to overcome the resistance of SK-OV-3 cancer cells to cisplatin. Our findings offer an alternative novel way to develop platinum drugs which can both overcome the drug resistance and selectively target tumor cells.

  2. A monofunctional platinum complex coordinated to a rhodium metalloinsertor selectively binds mismatched DNA in the minor groove.

    Science.gov (United States)

    Weidmann, Alyson G; Barton, Jacqueline K

    2015-10-05

    We report the synthesis and characterization of a bimetallic complex derived from a new family of potent and selective metalloinsertors containing an unusual Rh-O axial coordination. This complex incorporates a monofunctional platinum center containing only one labile site for coordination to DNA, rather than two, and coordinates DNA nonclassically through adduct formation in the minor groove. This conjugate displays bifunctional, interdependent binding of mismatched DNA via metalloinsertion at a mismatch as well as covalent platinum binding. DNA sequencing experiments revealed that the preferred site of platinum coordination is not the traditional N7-guanine site in the major groove, but rather N3-adenine in the minor groove. The complex also displays enhanced cytotoxicity in mismatch repair-deficient and mismatch repair-proficient human colorectal carcinoma cell lines compared to the chemotherapeutic cisplatin, and it triggers cell death via an apoptotic pathway, rather than the necrotic pathway induced by rhodium metalloinsertors.

  3. Síntese e caracterização de um novo complexo de platina (IV a partir de seu análogo de platina (II utilizando iodo molecular como agente oxidante: uma rota sintética interessante para obtenção de novos complexos de platina Synthesis and characterization of a novel platinum (IV complex from its platinum (II analogue using molecular iodine as an oxidizing agent: an interesting synthetic route for the preparation of new platinum complexes

    Directory of Open Access Journals (Sweden)

    Wendell Guerra

    2007-02-01

    Full Text Available In an attempt to reduce toxicity and widen the spectrum of activity of cisplatin and its analogues, much attention has been focused on designing new platinum complexes. This work reports the synthesis and characterization of novel compounds of the platinum (II and platinum (IV containing 2-furoic hydrazide acid and iodide as ligands. Although the prepared compounds do not present the classical structure of biologically active platinum analogues, they could be potentially active or useful as precursors to prepare antitumor platinum complexes. The reported compounds were characterized by ¹H NMR, 13C NMR, 195Pt NMR, IR and elemental analyses.

  4. A monofunctional trinuclear platinum complex with steric hindrance demonstrates strong cytotoxicity against tumor cells.

    Science.gov (United States)

    Wu, Shangnong; Wang, Xiaoyong; He, Yafeng; Zhu, Zhenzhu; Zhu, Chengcheng; Guo, Zijian

    2014-10-01

    Polynuclear platinum complexes constitute a special class of hopeful antitumor agents. In this study, a Y-type monofunctional trinuclear platinum complex (MTPC) with 1,3,5-tris(pyridin-2-ylmethoxy)benzene, ammine and chloride as ligands was synthesized and characterized by (1)H NMR and electrospray ionization mass spectrometry (ESI-MS). The DNA binding mode of MTPC was investigated using circular dichroism spectroscopy and gel electrophoresis, and the reactivity of MTPC towards glutathione was studied by (1)H NMR and ESI-MS. The results show that MTPC can affect the conformation of calf-thymus DNA (CT-DNA) significantly and tends to form 1,4-GG rather than 1,2-GG intrastrand crosslinks, which are different from the instance of cisplatin. MTPC reacts with glutathione quite slowly in comparison with cisplatin because of the steric hindrance. The cytotoxicity of MTPC was tested on the human breast cancer cell line MCF-7, the human non-small-cell lung cancer cell line A549, and the human ovarian cancer cell line Skov-3 by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. MTPC is more potent than or comparable to cisplatin. The cellular inhibition mode of MTPC was examined by flow cytometry using MCF-7 cells. MTPC arrests the cell cycle mainly in G2 or M phase, while cisplatin arrests the cell cycle in S phase. Similar to cisplatin, MTPC kills the cells predominantly through an apoptotic pathway.

  5. Simple cerium-triethanolamine complex: Synthesis, characterization, thermal decomposition and its application to prepare ceria support for platinum catalysts used in methane steam reforming

    Science.gov (United States)

    Wattanathana, Worawat; Nootsuwan, Nollapan; Veranitisagul, Chatchai; Koonsaeng, Nattamon; Laosiripojana, Navadol; Laobuthee, Apirat

    2015-06-01

    Cerium-triethanolamine complex was synthesized by simple complexation method in 1-propanol solvent using cerium(III) chloride as a metal source and triethanolamine as a ligand. The structures of the prepared complex were proposed based on FT-IR, FT-Raman and ESI-MS results as equimolar of triethanolamine and cerium chelated complex having monomeric tricyclic structure with and without chloride anion as another coordinating group known as ceratrane. The complex was used as a precursor for ceria material done by thermal decomposition. XRD result revealed that when calcined at 600 °C for 2 h, the cerium complex was totally turned into pure ceria with cubic fluorite structure. The obtained ceria was then employed to synthesize platinum doped ceria catalysts for methane steam reforming. Various amounts of platinum i.e. 1, 3, 5 and 10 mol percents were introduced on the ceria support by microwave-assisted wetness impregnation using ammonium tetrachloroplatinate(II). The platinum-impregnated ceria powders were subjected to calcination in 10% hydrogen/helium atmosphere at 500 °C for 3 h to reduce platinum(II) to platinum(0). XRD patterns of the catalysts confirmed that the platinum particles doped on the ceria support were in the form of platinum(0). Catalytic activity test showed that the catalytic activities got higher as the amounts of platinum doped increased. Besides, the portions of coke formation on the surface of catalysts were reduced as the amounts of platinum doped increased.

  6. Modulation of Intersystem Crossing Rate by Minor Ligand Modifications in Cyclometalated Platinum(II) Complexes.

    Science.gov (United States)

    Shafikov, Marsel Z; Kozhevnikov, Dmitry N; Bodensteiner, Michael; Brandl, Fabian; Czerwieniec, Rafał

    2016-08-01

    Photophysical properties of four new platinum(II) complexes comprising extended ppy (Hppy = 2-phenylpyridine) and thpy (Hthpy = 2-(2'-thienyl)pyridine) cyclometalated ligands and acetylacetonate (acac) are reported. Substitution of the benzene ring of Pt-ppy complexes 1 and 2 with a more electron-rich thiophene of Pt-thpy complexes 3 and 4 leads to narrowing of the HOMO-LUMO gap and thus to a red shift of the lowest energy absorption band and phosphorescence band, as expected for low-energy excited states of the intraligand/metal-to-ligand charge transfer character. However, in addition to these conventional spectral shifts, another, at first unexpected, substitution effect occurs. Pt-thpy complexes 3 and 4 are dual emissive showing fluorescence about 6000 cm(-1) (∼0.75 eV) higher in energy relative to the phosphorescence band, while for Pt-ppy complexes 1 and 2 only phosphorescence is observed. For dual-emissive complexes 3 and 4, ISC rates kISC are estimated to be in order of 10(9)-10(10) s(-1), while kISC of Pt-ppy complexes 1 and 2 is much faster amounting to 10(12) s(-1) or more. The relative intensities of the fluorescence and phosphorescence signals of Pt-thpy complexes 3 and 4 depend on the excitation wavelength, showing that hyper-intersystem crossing (HISC) in these complexes is observably significant.

  7. Comparative Studies with Zwitterionic Platinum(II) Bis(pyrazolyl)borate and 2,2‘-Bipyridylborate Complexes

    OpenAIRE

    Thomas, Christine M.; Peters, Jonas C.

    2005-01-01

    A comparison between the mononuclear platinum complexes of three structurally different monoanionic borato ligands is presented:  [Ph_2B(pyrazolyl)_2]- ([Ph_2B(pz)_2], 1), [4-Ph_3B(2,2‘-bipyridine)]- ([(4-BPh_3)bpy], 2), and [Ph_2B(CH_2PPh_2)_2]- ([Ph_2BP_2], 3). The new bipyridylborate ligand 2 is introduced in this study. The relative trans influence of these ligands has been assessed by comparison of the structural and spectroscopic (NMR) data of the platinum dimethyl complexes [[Ph_2B(pz)...

  8. Dinuclear Pt(II)-bisphosphonate complexes: a scaffold for multinuclear or different oxidation state platinum drugs.

    Science.gov (United States)

    Piccinonna, Sara; Margiotta, Nicola; Pacifico, Concetta; Lopalco, Antonio; Denora, Nunzio; Fedi, Serena; Corsini, Maddalena; Natile, Giovanni

    2012-08-28

    Geminal bisphosphonates (BPs), used in the clinic for the treatment of hypercalcaemia and skeletal metastases, have been also exploited for promoting the specific accumulation of platinum antitumor drugs in bone tissue. In this work, the platinum dinuclear complex [{Pt(en)}(2)(μ-AHBP-H(2))](+) (1) (the carbon atom bridging the two phosphorous atoms carrying a 2-ammonioethyl and a hydroxyl group, AHBP-H(2)) has been used as scaffold for the synthesis of a Pt(II) trinuclear complex, [{Pt(en)}(3)(μ-AHBP)](+) (2), and a Pt(IV) adamantane-shaped dinuclear complex featuring an oxo-bridge, [{Pt(IV)(en)Cl}(2)(μ-O)(μ-AHBP-H(2))](+) (3) (X-ray structure). Compound 2 undergoes a reversible, pH dependent, rearrangement with a neat switch point around pH = 5.4. Compound 3 undergoes a one-step electrochemical reduction at E(pc) = -0.84 V affording compound 1. Such a potential is far lower than that of glutathione (-0.24 V), nevertheless compound 3 can undergo chemical reduction to 1 by GSH, most probably through a different (inner-sphere) mechanism. In vitro cytotoxicity of the new compounds, tested against murine glioma (C6) and human cervix (HeLa) and hepatoma (HepG2) cell lines, has shown that, while the Pt(IV) dimer 3 is inactive up to a concentration of 50 μM, the two Pt(II) polynuclear compounds 1 and 2 have a cytotoxicity comparable to that of cisplatin with the trinuclear complex 2 generally more active than the dinuclear complex 1.

  9. Antitumor activity of phenylene bridged binuclear bis(imino-quinolyl)palladium(II) and platinum(II) complexes.

    Science.gov (United States)

    Motswainyana, William M; Onani, Martin O; Madiehe, Abram M; Saibu, Morounke

    2014-04-01

    Antitumor effects of a known bis(imino-quinolyl)palladium(II) complex 1 and its newly synthesized platinum(II) analogue 2 were evaluated against human breast (MCF-7) and human colon (HT-29) cancer cell lines. The complexes gave cytotoxicity profiles that were better than the reference drug cisplatin. The highest cytotoxic activities were pronounced in complex 2 across the two examined cancer cell lines. Both compounds represent potential active drugs based on bimetallic complexes.

  10. Synthesis, characterization and biological activity of trans-platinum(II) complexes with chloroquine

    Science.gov (United States)

    Navarro, Maribel; Castro, William; Higuera-Padilla, Angel R; Sierraalta, Anibal; Abad, María Jesús; Taylor, Peter; Sánchez-Delgado, Roberto A.

    2012-01-01

    Three platinum-chloroquine complexes, trans-Pt(CQDP)2(I)2 [1], trans-Pt(CQDP)2(Cl)2 [2] and trans-Pt(CQ)2(Cl)2 [3], were prepared and their most probable structure was established through a combination of spectroscopic analysis and density functional theory (DFT) calculations. Their interaction with DNA was studied and their activity against 6 tumor cell lines was evaluated. Compounds 1 and 2 interact with DNA primarily through electrostatic contacts and hydrogen bonding, with a minor contribution of a covalent interaction, while compound 3 binds to DNA predominantly in a covalent fashion, with weaker secondary electrostatic interactions and possibly hydrogen bonding, this complex also exerted greater cytotoxic activity against the tumor cell lines. PMID:22001497

  11. Synthesis of platinum and palladium complexes with bis-(hydroxy imines

    Directory of Open Access Journals (Sweden)

    Lucas M. Arantes

    2012-06-01

    Full Text Available The Schiff bases are an important class of compounds well used as ligands in coordination chemistry. The functionalized bis-imines, that represent a specific group of Schiff base, have been studied in our research group both for the evaluation of biological activity, against fungi and cancer, as for organocatalyst. Here the bis-imines 1 and 4 were synthesized in good yields by condensation of hydroxylated benzaldehydes with phenylenediamines. After that they were matched with Platinum and palladium salts providing three metallic complex (2, 3 and 5 that were fully characterized by nuclear magnetic resonance and mass spectrometry with electrospray ionization. Now these complexes are being tested in cross-coupling reactions of Heck and Suzuki.

  12. PALLADIUM, PLATINUM, RHODIUM, RUTHENIUM AND IRIDIUM IN PERIDOTITES AND CHROMITITES FROM OPHIOLITE COMPLEXES IN NEWFOUNDLAND.

    Science.gov (United States)

    Page, Norman J; Talkington, Raymond W.

    1984-01-01

    Samples of spinel lherzolite, harzburgite, dunite, and chromitite from the Bay of Islands, Lewis Hills, Table Mountain, Advocate, North Arm Mountain, White Hills Periodite Point Rousse, Great Bend and Betts Cove ophiolite complexes in Newfoundland were analyzed for the platinum-group elements (PGE) Pd, Pt, Rh, Ru and Ir. The ranges of concentration (in ppb) observed for all rocks are: less than 0. 5 to 77 (Pd), less than 1 to 120 (Pt), less than 0. 5 to 20 (Rh), less than 100 to 250 (Ru) and less than 20 to 83 (Ir). Chondrite-normalized PGE ratios suggest differences between rock types and between complexes. Samples of chromitite and dunite show relative enrichment in Ru and Ir and relative depletion in Pt and Pd.

  13. N6-Benzyladenosine Derivatives as Novel N-Donor Ligands of Platinum(II Dichlorido Complexes

    Directory of Open Access Journals (Sweden)

    Ján Vančo

    2013-06-01

    Full Text Available The platinum(II complexes trans-[PtCl2(Ln2]∙xSolv 1–13 (Solv = H2O or CH3OH, involving N6-benzyladenosine-based N-donor ligands, were synthesized; Ln stands for N6-(2-methoxybenzyladenosine (L1, involved in complex 1, N6-(4-methoxy-benzyladenosine (L2, 2, N6-(2-chlorobenzyladenosine (L3, 3, N6-(4-chlorobenzyl-adenosine (L4, 4, N6-(2-hydroxybenzyladenosine (L5, 5, N6-(3-hydroxybenzyl-adenosine (L6, 6, N6-(2-hydroxy-3-methoxybenzyladenosine (L7, 7, N6-(4-fluoro-benzyladenosine (L8, 8, N6-(4-methylbenzyladenosine (L9, 9, 2-chloro-N6-(3-hydroxy-benzyladenosine (L10, 10, 2-chloro-N6-(4-hydroxybenzyladenosine (L11, 11, 2-chloro-N6-(2-hydroxy-3-methoxybenzyladenosine (L12, 12 and 2-chloro-N6-(2-hydroxy-5-methylbenzyladenosine (L13, 13. The compounds were characterized by elemental analysis, mass spectrometry, IR and multinuclear (1H-, 13C-, 195Pt- and 15N- and two-dimensional NMR spectroscopy, which proved the N7-coordination mode of the appropriate N6-benzyladenosine derivative and trans-geometry of the title complexes. The complexes 1–13 were found to be non-toxic in vitro against two selected human cancer cell lines (HOS and MCF7; with IC50 > 50.0 µM. However, they were found (by ESI-MS study to be able to interact with the physiological levels of the sulfur-containing biogenic biomolecule L-methionine by a relatively simple 1:1 exchange mechanism (one Ln molecule was replaced by one L-methionine molecule, thus forming a mixed-nitrogen/sulfur-ligand dichlorido-platinum(II coordination species.

  14. Comparative studies of oxaliplatin-based platinum(iv) complexes in different in vitro and in vivo tumor models.

    Science.gov (United States)

    Göschl, Simone; Schreiber-Brynzak, Ekaterina; Pichler, Verena; Cseh, Klaudia; Heffeter, Petra; Jungwirth, Ute; Jakupec, Michael A; Berger, Walter; Keppler, Bernhard K

    2017-03-22

    Using platinum(iv) prodrugs of clinically established platinum(ii) compounds is a strategy to overcome side effects and acquired resistances. We studied four oxaliplatin-derived platinum(iv) complexes with varying axial ligands in various in vitro and in vivo settings. The ability to interfere with DNA (pUC19) in the presence and absence of a reducing agent (ascorbic acid) was investigated in cell-free experiments. Cytotoxicity was compared under normoxic and hypoxic conditions in monolayer cultures and multicellular spheroids of colon carcinoma cell lines. Effects on the cell cycle were investigated by flow cytometry, and the capacity of inducing apoptosis was confirmed by flow cytometry and Western blotting. The anti-cancer activity of one complex was studied in vivo in immunodeficient and immunocompetent mice, and the platinum levels in various organs and the tumor after treatment were quantified. The results demonstrate that modification of the axial ligands can improve the cytotoxic potency. The complexes are able to interfere with plasmid DNA, which is enhanced by co-incubation with a reducing agent, and cause cell cycle perturbations. At higher concentrations, they induce apoptosis, but generate only low levels of reactive oxygen species. Two of the complexes increase the life span of leukemia (L1210) bearing mice, and one showed effects similar to oxaliplatin in a CT26 solid tumor model, despite the low platinum levels in the tumor. As in the case of oxaliplatin, activity in the latter model depends on an intact immune system. These findings show new perspectives for the development of platinum(iv) prodrugs of the anticancer agent oxaliplatin, combining bioreductive properties and immunogenic aspects.

  15. Platinum (II) and (IV) spermidine complexes. Synthesis, characterization, and biological studies.

    Science.gov (United States)

    Navarro-Ranninger, C; Ochoa, P A; Pérez, J M; González, V M; Masaguer, J R; Alonso, C

    1994-02-15

    By reaction of K2PtCl4 with spermidine we have synthesized two tris-platinum covalent compounds of formula (PtI2)3(sper)2 and (PtCl2)3(sper)2, one ionic compound of formula (sperH3)2(PtCl4)3, and another one of a covalent nature of formula (PtCl2sperH)2 (PtCl4) having a partially protonated spermidine residue. Treatment of the tris-platinum compounds with hydrogen peroxide and hydrochloric acid led to the production of two compounds of formula cis-trans-cis-(PtIVCl2(OH)2)3(sper)2 and cis-(PtIVCl4)3(sper)2, respectively. All of them have been characterized by IR and 1H MNR spectroscopy and tested for their ability to interact with pUC8 plasmid DNA by the use of UV, CD, and electrophoretic techniques. The results suggest that all of these compounds modify the secondary structure of the double helix. We observed that the alteration in electrophoretic mobility of nicked and closed circular forms of DNA induced by the Pt(II) complexes is higher than that induced by the Pt(IV) complexes. The synthesized compounds were also assayed for antitumor activity in vitro against breast (MDA-MB468) and leukemia (HL-60) tumor cells. Only three of these complexes may be regarded as potential antitumor agents, since their ID50 values are lower than 10 micrograms/ml.

  16. Copper-, palladium-, and platinum-containing complexes of an asymmetric dinucleating ligand.

    Science.gov (United States)

    Halvagar, Mohammad Reza; Neisen, Benjamin; Tolman, William B

    2013-01-18

    The coordination chemistry of an asymmetric dinucleating hexadentate ligand LH(2) comprising neutral alkyltriamine and potentially dianionic dicarboxamido-pyridyl donor sets with copper, palladium, and platinum has been explored. Monometallic, dicopper, and heterodinuclear Cu-Pd and -Pt complexes have been prepared and characterized, including by NMR, EPR, UV-vis, and IR spectroscopy and X-ray crystallography. For example, the monometallic complexes [(LH(2))MCl]X (M = Cu, X = OTf; M = Pd or Pt, X = Cl) were prepared, wherein the metal(II) ions are coordinated to the triamine portion and the pyridyldicarboxamide is unperturbed. Treatment of LH(2) with [MesCu](x) (Mes = mesityl) provided a monocopper(I) complex, again with the metal coordinated only to the trialkylamine donor set. Reaction of [(LH(2))CuCl]OTf with NaOMe resulted in an unexpected migration of the copper(II)-chloride fragment to the pyridyldicarboxamide site to yield Na[LCuCl], from which a dicopper complex LCu(2)Cl(2) and mixed-metal complexes LCu(Cl)M(Cl) (M = Pd, Pt) were prepared by addition of CuCl(2) or MCl(2), respectively. The heterodinuclear complexes were also prepared by addition of CuCl(2) to [(LH(2))MCl]Cl.

  17. Cytotoxic properties of a new organometallic platinum(II) complex and its gold(I) heterobimetallic derivatives.

    Science.gov (United States)

    Serratrice, Maria; Maiore, Laura; Zucca, Antonio; Stoccoro, Sergio; Landini, Ida; Mini, Enrico; Massai, Lara; Ferraro, Giarita; Merlino, Antonello; Messori, Luigi; Cinellu, Maria Agostina

    2016-01-14

    A novel platinum(ii) organometallic complex, [Pt(pbi)(Me)(DMSO)], bearing the 2-(2'-pyridyl)-benzimidazole (pbiH) ligand, was synthesized and fully characterized. Interestingly, the reaction of this organometallic platinum(ii) complex with two distinct gold(i) phosphane compounds afforded the corresponding heterobimetallic derivatives with the pbi ligand bridging the two metal centers. The antiproliferative properties in vitro of [Pt(pbi)(Me)(DMSO)] and its gold(i) derivatives as well as those of the known coordination platinum(ii) and palladium(ii) complexes with the same ligand, of the general formula [MCl2(pbiH)], were comparatively evaluated against A2780 cancer cells, either sensitive or resistant to cisplatin. A superior biological activity of the organometallic compound clearly emerged compared to the corresponding platinum(ii) complex; the antiproliferative effects are further enhanced upon attaching the gold(i) triphenylphosphine moiety to the organometallic Pt compound. Remarkably, these novel metal species are able to overcome nearly complete resistance to cisplatin. Significant mechanistic insight into the study compounds was gained after investigating their reactions with a few representative biomolecules by electrospray mass spectrometry and X-ray crystallography. The obtained results are comprehensively discussed.

  18. A self-polishing platinum ring voltammetric sensor and its application to complex media.

    Science.gov (United States)

    Cavanillas, Santiago; Winquist, Fredrik; Eriksson, Mats

    2015-02-15

    A self-polishing voltammetric sensor was recently developed and has been applied to samples of urea, milk and sewage water. The polishing device continuously grinds a platinum ring electrode, offering a reproducible and clean electrode surface. Principal component analysis (PCA) and partial least squares (PLS) techniques were applied to interpret the data and to build prediction models. In an evaluation of samples with different urea concentrations, the grinding step allows for repeatable measurements, similar to those after electrochemical cleaning. Furthermore, for the determination of sewage water concentrations in drinking water and for the evaluation of different fat contents in milk samples, the polishing eliminates sensor drift produced by electrode fouling. The results show that the application of a self-polishing unit offers a promising tool for electrochemical studies of difficult analytes and complex media. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Platinum Complexes And Their Anti-Tumour Activity Against Chronic Lymphocytic Leukaemia Cells

    Directory of Open Access Journals (Sweden)

    Silconi Žana Besser

    2015-09-01

    Full Text Available Since the discovery of the antitumor activity of cisplatin by Rosenberg and co-workers, the use of metal complexes in cancer treatment has caused a huge interest. Today, platinum-based drugs are part of standard chemotherapy in the management of a variety of ca ncers, germ cell tumours, sarcomas, and lymphomas. Unfortunately, toxicity and drug resistance are major obstacles to wider clinical application of these drugs. Their use is greatly limited by severe side effects such as nephrotoxicity, ototoxicity, and neurotoxicity. Although cisplatin is one of the most successful anticancer drugs to date, its biochemical mechanism of action is still unclear. Cisplatin is generally accepted as having the ability to interact with the purine bases on the DNA, causing DNA damage, interfering with DNA repair mechanisms, and subsequently inducing apoptosis in cancer cells.

  20. Preparation and Biological Properties of Platinum(II Complex-Loaded Copolymer PLA-TPGS

    Directory of Open Access Journals (Sweden)

    Ha Phuong Thu

    2013-01-01

    Full Text Available A new nanodrug system containing bis(menthone thiosemicarbazonato Platinum(II complex (Pt-thiomen encapsulated with the block copolymers polylactide-d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-TPGS was prepared by a modified solvent extraction/evaporation technique. The characteristics of the nanoparticles including surface morphology, size distribution, structure, and biological activities such as antimicrobial and cytotoxic activities were in vitro investigated. The spherical nanoparticles were around 50 nm in size with core-shell structure and narrow-size distribution. The encapsulated Pt-thiomen can avoid interaction with proteins in the blood plasma. The inhibitory activity of Pt-thiomen-loaded PLA-TPGS nanoparticles on the growth of some bacteria, fungi, and Hep-G2 cells suggests a possibility of developing PLA-TPGS-Pt-thiomen nanoparticles as one of the potential chemotherapeutic agents.

  1. Comparison of the effects of the oral anticancer platinum(IV) complexes oxoplatin and metabolite cis-diammine-tetrachlorido-platinum(IV) on global gene expression of NCI-H526 cells.

    Science.gov (United States)

    Olszewski, Ulrike; Ulsperger, Ernst; Geissler, Klaus; Hamilton, Gerhard

    2011-01-01

    Platinum(IV) coordination complexes like oxoplatin (cis,cis,trans-diammine-dichlorido-dihydroxido-platinum[IV]) show high stability and therefore can be utilized orally for outpatient care. Although oxoplatin is capable of binding directly to DNA after prolonged incubation, platinum(IV) agents are considered to be largely inert prodrugs that are converted to highly cytotoxic platinum(II) compounds by reducing substances, enzymes, or microenviron-mental conditions. Reaction of oxoplatin with 0.1 M hydrogen chloride mimicking gastric acid yields cis-diammine-tetrachlorido-platinum(IV) (DATCP[IV]), which exhibits two-fold increased activity. The presence of chlorides as ligands in the axial position results in a high reduction potential that favors transformation to platinum(II) complexes. In this study, the intracellular effect of the highly reactive tetrachlorido derivative was investigated in comparison with an equipotent dose of cisplatin. Genome-wide expression profiling of NCI-H526 small cell lung cancer cells treated with these platinum species revealed clear differences in the expression pattern of affected genes and concerned cellular pathways between DATCP(IV) and cisplatin. Application of DATCP(IV) resulted in extensive downregulation of protein and ATP synthesis, cell cycle regulation, and glycolysis, in contrast to cisplatin, which preferentially targeted glutathione conjugation, pyruvate metabolism, citric acid cycle, and the metabolism of amino acids and a range of carbohydrates. Thus, the oxoplatin metabolite DATCP(IV) constitutes a potent cytotoxic derivative that may be produced by gastric acid or acidic areas prevailing in larger solid tumors, depending on the respective pharmaceutical formulation of oxoplatin. Furthermore, DATCP(IV) exhibits intracellular effects that are clearly different from the expected reduced product cisplatin(II). In conclusion, activation of the platinum(IV) complex oxoplatin seems to involve the generation of a cytotoxic

  2. Photodynamic killing of cancer cells by a Platinum(II) complex with cyclometallating ligand

    Science.gov (United States)

    Doherty, Rachel E.; Sazanovich, Igor V.; McKenzie, Luke K.; Stasheuski, Alexander S.; Coyle, Rachel; Baggaley, Elizabeth; Bottomley, Sarah; Weinstein, Julia A.; Bryant, Helen E.

    2016-03-01

    Photodynamic therapy that uses photosensitizers which only become toxic upon light-irradiation provides a strong alternative to conventional cancer treatment due to its ability to selectively target tumour material without affecting healthy tissue. Transition metal complexes are highly promising PDT agents due to intense visible light absorption, yet the majority are toxic even without light. This study introduces a small, photostable, charge-neutral platinum-based compound, Pt(II) 2,6-dipyrido-4-methyl-benzenechloride, complex 1, as a photosensitizer, which works under visible light. Activation of the new photosensitizer at low concentrations (0.1-1 μM) by comparatively low dose of 405 nm light (3.6 J cm-2) causes significant cell death of cervical, colorectal and bladder cancer cell lines, and, importantly, a cisplatin resistant cell line EJ-R. The photo-index of the complex is 8. We demonstrate that complex 1 induces irreversible DNA single strand breaks following irradiation, and that oxygen is essential for the photoinduced action. Neither light, nor compound alone led to cell death. The key advantages of the new drug include a remarkably fast accumulation time (diffusion-controlled, minutes), and photostability. This study demonstrates a highly promising new agent for photodynamic therapy, and attracts attention to photostable metal complexes as viable alternatives to conventional chemotherapeutics, such as cisplatin.

  3. Synthesis, characterization, and biological evaluation of Schiff base-platinum(II) complexes.

    Science.gov (United States)

    Shiju, C; Arish, D; Bhuvanesh, N; Kumaresan, S

    2015-06-15

    The platinum complexes of Schiff base ligands derived from 4-aminoantipyrine and a few substituted aldehydes were synthesized and characterized by elemental analysis, mass, (1)H NMR, IR, electronic spectra, molar conductance, and powder XRD. The structure of one of the ligands L5 was confirmed by a single crystal XRD analysis. The Schiff base ligand crystallized in the triclinic, space group P-1 with a=7.032(2)Ǻ, b=9.479(3)Ǻ, c=12.425(4)Ǻ, α=101.636(3)°, β=99.633(3)°, γ=94.040(3)°, V=795.0(4)Ǻ(3), Z=2, F(000)=352, Dc=1.405 mg/m(3), μ=0.099 mm(-1), R=0.0378, and wR=0.0967. The spectral results show that the Schiff base ligand acts as a bidentate donor coordinating through the azomethine nitrogen and the carbonyl oxygen atoms. The geometrical structures of these complexes are found to be square planar. Antimicrobial studies indicate that these complexes exhibit better activity than the ligand. The anticancer activities of the complexes have also been studied towards human cervical cancer cell line (HeLa), Colon Cancer Cells (HCT116) and Epidermoid Carcinoma Cells (A431) and it was found that the [Pt(L3)Cl2] complex is more active.

  4. Photodynamic killing of cancer cells by a Platinum(II) complex with cyclometallating ligand.

    Science.gov (United States)

    Doherty, Rachel E; Sazanovich, Igor V; McKenzie, Luke K; Stasheuski, Alexander S; Coyle, Rachel; Baggaley, Elizabeth; Bottomley, Sarah; Weinstein, Julia A; Bryant, Helen E

    2016-03-04

    Photodynamic therapy that uses photosensitizers which only become toxic upon light-irradiation provides a strong alternative to conventional cancer treatment due to its ability to selectively target tumour material without affecting healthy tissue. Transition metal complexes are highly promising PDT agents due to intense visible light absorption, yet the majority are toxic even without light. This study introduces a small, photostable, charge-neutral platinum-based compound, Pt(II) 2,6-dipyrido-4-methyl-benzenechloride, complex 1, as a photosensitizer, which works under visible light. Activation of the new photosensitizer at low concentrations (0.1-1 μM) by comparatively low dose of 405 nm light (3.6 J cm(-2)) causes significant cell death of cervical, colorectal and bladder cancer cell lines, and, importantly, a cisplatin resistant cell line EJ-R. The photo-index of the complex is 8. We demonstrate that complex 1 induces irreversible DNA single strand breaks following irradiation, and that oxygen is essential for the photoinduced action. Neither light, nor compound alone led to cell death. The key advantages of the new drug include a remarkably fast accumulation time (diffusion-controlled, minutes), and photostability. This study demonstrates a highly promising new agent for photodynamic therapy, and attracts attention to photostable metal complexes as viable alternatives to conventional chemotherapeutics, such as cisplatin.

  5. Structure and reactivity of a pyridine-1-imido-2-thiolato complex of iridium(III), CpIr(1-N-2-Spy), generated by photolysis of the (azido)(pyridine-2-thiolato) complex, CpIr(2-Spy)(N3).

    Science.gov (United States)

    Sekioka, Yusuke; Kaizaki, Sumio; Mayer, James M; Suzuki, Takayoshi

    2005-11-14

    Photolysis of the (azido)(pyridine-2-thiolato)iridium(III) complex CpIr(2-Spy)(N3) (1) gave a pyridine-1-imido-2-thiolato complex, CpIr(1-N-2-Spy) (2), in which one of the nitrogen atoms of the azide ligand has been inserted into the Ir-N(py) bond (Cp = eta5-C5Me5). Complex 2 reacted quantitatively with methyl iodide to give the N-methylated product, [CpIr(1-NMe-2-Spy)]I (3). X-ray crystallography revealed that both 2 and 3 have similar two-legged piano stool structures with planar 1-N-2-Spy2- or 1-NMe-2-Spy- ligands, which form iridacyclopentadienyl-like rings by moderate S(ppi)/N(ppi) to Ir(dpi) pi donation.

  6. Radiochemical synthesis and preliminary in vivo evaluation of new radioactive platinum complexes with carnosine.

    Science.gov (United States)

    Maurin, Michał; Garnuszek, Piotr

    2010-02-01

    Pt(II)(IT-[(125)I]Carnosine) complex; however, at the same time the lowest concentration in kidneys was noted. Preliminary studies in the rat's tumor model indicated for this complex a favorable tumor to muscle ratio. In the case of Pt(IV)(IT-[*I]Carnosine) apart from ca. 12-times decrease of the liver accumulation, additional 4-times decrease of an accumulation in kidneys was observed in comparison to the Pt(IV)([*I]Hist)(2) complex. Our study showed that the short peptides can be efficiently substituted to the platinum core via the reactive sulfhydryl group introduced by SATA or 2-IT. The new radioactive platinum complexes with carnosine possess favorable biodistribution schemes, which make them potential candidates for radio-chemotherapeutical agents. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  7. Impact of the equatorial coordination sphere on the rate of reduction, lipophilicity and cytotoxic activity of platinum(IV) complexes.

    Science.gov (United States)

    Höfer, Doris; Varbanov, Hristo P; Hejl, Michaela; Jakupec, Michael A; Roller, Alexander; Galanski, Markus; Keppler, Bernhard K

    2017-09-01

    The impact of the equatorial coordination sphere on the reduction behavior (i.e. rate of reduction) of platinum(IV) complexes with axial carboxylato ligands was studied. Moreover, the influence of equatorial ligands on the stability, lipophilicity and cytotoxicity of platinum(IV) compounds was evaluated. For this purpose, a series of platinum(IV) complexes featuring axial carboxylato ligands (succinic acid monoesters) was synthesized; anionic carboxylato (OAc(-), oxalate) and halido (Cl(-), Br(-), I(-)) ligands served as leaving groups and am(m)ine carrier ligands were provided by monodentately (isopropylamine, ammine+cyclohexaneamine) or bidentately (ethane-1,2-diamine) coordinating am(m)ines. All platinum(IV) products were fully characterized based on elemental analysis, high resolution mass spectrometry and multinuclear ((1)H, (13)C, (15)N, (195)Pt) NMR spectroscopy as well as by X-ray diffraction in some cases. The rate of reduction in the presence of ascorbic acid was determined by NMR spectroscopy and the lipophilicity of the complexes was investigated by analytical reversed phase HPLC measurements. Cytotoxic properties were studied by means of a colorimetric microculture assay in three human cancer cell lines derived from cisplatin sensitive ovarian teratocarcinoma (CH1/PA-1) as well as cisplatin insensitive colon carcinoma (SW480) and non-small cell lung cancer (A549). Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Fast cleavage of a diselenide induced by a platinum(II)-methionine complex and its biological implications.

    Science.gov (United States)

    Liu, Qin; Wang, Xiaoyong; Yang, Xiaoliang; Liang, Xiao; Guo, Zijian

    2010-11-01

    Platinum-based anticancer drugs such as cisplatin induce increased oxidative stress and oxidative damage of DNA and other cellular components, while selenium plays an important role in the antioxidant defense system. In this study, the interaction between a platinum(II) methionine (Met) complex [Pt(Met)Cl(2)] and a diselenide compound selenocystine [(Sec)(2)] was studied by electrospray ionization mass spectrometry, high performance liquid chromatography mass spectrometry, and (1)H NMR spectroscopy. The results demonstrate that the diselenide bond in (Sec)(2) can readily and quickly be cleaved by the platinum complex. Formation of the selenocysteine (Sec) bridged dinuclear complex [Pt(2)(Met-S,N)(2)(μ-Sec-Se,Cl)](3+) and Sec chelated species [Pt(Met-S,N)(Sec-Se,N)](2+) was identified at neutral and acidic media, which seems to result from the intermediate [Pt(Met-S,N)(Sec-Se)Cl](+). An accelerated formation of S-Se and S-S bonds was also observed when (Sec)(2) reacted with excessive glutathione in the presence of [Pt(Met)Cl(2)]. These results imply that the mechanism of activity and toxicity of platinum drugs may be related to their fast reaction with seleno-containing biomolecules, and the chemoprotective property of selenium agents against cisplatin-induced toxicity could also be connected with such reactions.

  9. On the electronic structure of nitro-substituted bipyridines and their platinum complexes.

    Science.gov (United States)

    Murray, Paul R; Crawford, Stephen; Dawson, Alice; Delf, Alexander; Findlay, Calum; Jack, Lorna; McInnes, Eric J L; Al-Musharafi, Salma; Nichol, Gary S; Oswald, Iain; Yellowlees, Lesley J

    2012-01-07

    We report the preparation and electrochemical studies of a systematic series of mono- and di-nitro-substituted 2,2'-bipyridine (bipy) compounds [x-NO(2)-bipy (x = 3,4) and x,x'-(NO(2))(2)-bipy (x,x' = 3, 4, 5)] and their complexes with platinum(II), [Pt(x-NO(2)-bipy)Cl(2)] and [Pt(x,x'-(NO(2))(2)-bipy)Cl(2)]. The effect of the number and substitution pattern of the nitro groups on the low-lying acceptor molecular orbitals (involved in charge transfer transitions) is probed by in situ UV/Vis/NIR and EPR spectroelectrochemical methods, supported by DFT calculations. The LUMOs of x-NO(2)-bipy (x = 3-5) are largely localised on the NO(2)-pyridyl moiety; this is also true of their {PtCl(2)} complexes but with a small but significant shift of electron density from the nitro groups. The LUMOs of x,x'-(NO(2))(2)-bipy with x = 3 and 5 are delocalised over both NO(2)-pyridyl rings, but for 4,4'-(NO(2))(2)-bipy is localised on a single NO(2)-pyridyl ring. In all cases the LUMO of the [Pt(x,x'-(NO(2))(2)-bipy)Cl(2)] complexes is delocalised over both nitro-pyridyl rings. For all complexes, the 4(4') derivatives allows greatest overlap with metal valence orbitals in the LUMO.

  10. Anticancer and DNA binding activities of platinum (IV) complexes; importance of leaving group departure rate.

    Science.gov (United States)

    Pouryasin, Zahra; Yousefi, Reza; Nabavizadeh, S Masoud; Rashidi, Mehdi; Hamidizadeh, Peyman; Alavianmehr, Mohammad-Mehdi; Moosavi-Movahedi, Ali Akbar

    2014-03-01

    The two six-coordinate Pt(IV) complexes, containing bidentate nitrogen donor/methyl ligands with general formula [Pt(X)2Me2((t)bu2bpy)], where (t)bu2bpy = 4,4'-ditert-butyl-2,2'-bipyridine and X = Cl (C1) or Br (C2), serving as the leaving groups were synthesized for evaluation of their anticancer activities and DNA binding properties. To examine anticancer activities of the synthetic complexes, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and ethidium bromide/acridine orange (EB/AO) staining method were performed. The binding properties of these complexes to DNA and purine nucleotides were examined, using different spectroscopic techniques. These complexes demonstrated significant anticancer activities against three cancer cell lines Jurkat, K562, and MCF-7. On the basis of the results of EB/AO staining, C1 and C2 were also capable to induce apoptosis in cancer cells. These complexes comprise halide leaving groups, displaying different departure rates; accordingly, they demonstrated slightly dissimilar anticancer activity and significantly different DNA/purine nucleotide binding properties. The results of DNA interaction studies of these complexes suggest a mixed-binding mode, comprising partial intercalation and groove binding. Overall, the results presented herein indicate that the newly synthesized Pt(IV) complexes are promising class of the potential anticancer agents which can be considered as molecular templates in designing novel platinum anticancer drugs. This study also highlights the importance of leaving group in anticancer activity and DNA binding properties of Pt(IV) complexes.

  11. Copper(II) coordination chain complex with the 2,5-bis(2-pyridyl)-1,3,4-thiadiazole ligand and an asymmetric μ2-1,1-azido double-bridged: Synthesis, crystal structure and magnetic properties

    Science.gov (United States)

    Laachir, Abdelhakim; Guesmi, Salaheddine; Saadi, Mohamed; El Ammari, Lahcen; Mentré, Olivier; Vezin, Hervé; Colis, Silviu; Bentiss, Fouad

    2016-11-01

    A new asymmetric μ2-1,1-azido double bridged cooper (II), with 2,5-bis(2-pyridyl)-1,3,4-thiadiazole (L), has been synthesized and characterized using single crystal X-ray diffraction, FT-IR, UV-Visible spectroscopic and magnetic measurements. The asymmetric unit of the title compound contains half molecule of formula, C12H8CuN10S, which crystallizes in the triclinic system, space group P 1 bar , with a = 6.5916 (4)Å, b = 10.6905 (7) Å, c = 11.5037 (7) Å, α = 106.508 (3)°, β = 105.538 (3)°, γ = 90.233 (4)°, V = 745.99 (8) Å3 and Z = 2. The structure consists of two [CuN5] prismatic polyhedra linked together by edge-sharing to build up a [Cu2N8] dimer arranged in chain. The connectivity along the chain is performed by Nsbnd N edge sharing between dimers. In the crystal, the molecules are linked together by Csbnd H⋯N hydrogen bonds and by π---π interactions between parallel pyridyl rings of neighboring molecules. The interpretation of FT-IR and UV-Vis spectra is consistent with the crystal structure determined by X-ray diffraction. The magnetic properties of the complex confirm the picture of an alternated … Cu-J1-Cu ….J2 … Cu-J1-Cu … magnetic chains. We found in the dimers weak antiferromagnetic exchange interactions J1/k = -5.9 (1) k and between them J2/k = -2.3 k.

  12. A platinum complex that binds non-covalently to DNA and induces cell death via a different mechanism than cisplatin.

    Science.gov (United States)

    Suntharalingam, Kogularamanan; Mendoza, Oscar; Duarte, Alexandra A; Mann, David J; Vilar, Ramon

    2013-05-01

    Cisplatin and some of its derivatives have been shown to be very successful anticancer agents. Their main mode of action has been proposed to be via covalent binding to DNA. However, one of the limitations of these drugs is their poor activity against some tumours due to intrinsic or acquired resistance. Therefore, there is interest in developing complexes with different binding modes and mode of action. Herein we present a novel platinum(ii)-terpyridine complex (1) which interacts non-covalently with DNA and induces cell death via a different mechanism than cisplatin. The interaction of this complex with DNA was studied by UV/Vis spectroscopic titrations, fluorescent indicator displacement (FID) assays and circular dichroism (CD) titrations. In addition, computational docking studies were carried out with the aim of establishing the complex's binding mode. These experimental and computational studies showed the complex to have an affinity constant for DNA of ∼10(4) M(-1), a theoretical free energy of binding of -10.83 kcal mol(-1) and selectivity for the minor groove of DNA. Long-term studies indicated that 1 did not covalently bind (or nick) DNA. The cancer cell antiproliferative properties of this platinum(ii) complex were probed in vitro against human and murine cell lines. Encouragingly the platinum(ii) complex displayed selective toxicity for the cancerous (U2OS and SH-SY5Y) and proliferating NIH 3T3 cell lines. Further cell based studies were carried out to establish the mode of action. Cellular uptake studies demonstrated that the complex is able to penetrate the cell membrane and localize to the nucleus, implying that genomic DNA could be a cellular target. Detailed immunoblotting studies in combination with DNA-flow cytometry showed that the platinum(ii) complex induced cell death in a manner consistent with necrosis.

  13. NETWORK CROWN ETHER POLYMERS WITH CENTRIC FUNCTIONAL GROUP (Ⅳ) SYNTHESIS OF NETWORK CROWN ETHER POLYMER WITH PENDANT DIETHYLAMINO THIAALKYL GROUP AND ITS PLATINUM COMPLEX

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; MENG Lingzhi; YIN Yihua; GENG Chengai

    1994-01-01

    The title polymer was prepared from 5-diethylamino-3-thia-pentyl glycidyl ether and diethylene glycol bisglycidyl ether via ring-opening copolymerization. It was found that this reaction could be catalyzed by sodium, but not Lewis acid. The obtained polymer can coordinate with platinum compound, and the platinum complex is a new kind of catalyst for the hydrosilylation of olefins with triethoxysilane.

  14. Conjugation of platinum(IV) complexes with chlorambucil to overcome cisplatin resistance via a "joint action" mode toward DNA.

    Science.gov (United States)

    Qin, Xiaodong; Fang, Lei; Chen, Feihong; Gou, Shaohua

    2017-09-08

    Two platinum(IV) complexes were designed and prepared by conjugation of cisplatin and oxaliplatin units with a DNA-damaging agent, chlorambucil, respectively. By taking a joint action to enhance the damage of DNA, the conjugates displayed potent antitumor activity against all the tested cancer cell lines comparable to cisplatin and oxaliplatin, and notably could overcome cisplatin resistance at certain degree. Complex 4, a hybrid of cisplatin and chlorambucil, arrested the cell cycle at the S and G2 phases, distinctive from those of cisplatin and oxaliplatin. Apoptosis studies revealed that complex 4 could induce cell apoptosis significantly in both SGC7901 and SGC7901/CDDP cells. Moreover, further investigation indicated that complex 4 suppressed the drug resistance by the improvement of the platinum uptake and the inhibition of PRAP-1 protein. These results show that the "joint action" on DNA is an effective strategy to overcome cisplatin resistance. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. Circular dichroism spectroscopy study of crystalline-to-amorphous transformation in chiral platinum(II) complexes.

    Science.gov (United States)

    Zhang, Xiao-Peng; Wu, Tao; Liu, Jian; Zhao, Jin-Cheng; Li, Cheng-Hui; You, Xiao-Zeng

    2013-07-01

    Two couples of enantiomeric platinum(II) complexes: Pt(L1a )Cl (1a), Pt(L1b )Cl (1b) and Pt(L1a )(C ≡ C - Ph) (2a), Pt(L1b )(C ≡ C - Ph) (2b) (L1a  = (+)-1,3-di-(2-(4,5-pinene)pyridyl)benzene, L1b  = (-)-1,3-di-(2-(4,5-pinene)pyridyl)benzene) were synthesized and characterized. Their absolute configurations were determined by single crystal X-ray diffraction and further verified by circular dichroism (CD) spectra (including electronic circular dichroism [ECD] and vibrational circular dichroism [VCD]). These complexes show interesting mechanoluminescence and/or vapoluminescence due to crystalline-to-amorphous transformation. The crystalline solids, grinding-induced amorphous powders, and vapor-induced amorphous powders of complexes 2a and 2b were comparatively investigated by solid-state ECD and VCD spectra. The transformation from crystalline solids to amorphous powders was accompanied by significant variances of the spectral feature in both ECD and VCD spectra. © 2013 Wiley Periodicals, Inc.

  16. Synthesis, Characterization and Cytotoxicity of Ammine/Methylamine Platinum(Ⅱ) Complexes with Carboxylates

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Seven novel platinum (Ⅱ) complexes [Pt (Ⅱ) (NH3) (CH3NH2) X2] (Ⅰ -Ⅶ) (X: CH3COO- ,CH2 ClCOO - , CHCl2COO -, C6H5-COO - , p-CH3O-C6H4 -COO - , p-NH2-C6 H4 -COO - , p-NO2 -C6 H4 -COO-) were prepared and characterized by means of elemental analysis, molar conductivity, thermal analysis,IR, UV, and 1 H NMR spectrometries. The cytotoxicity against HCT-8, BGC-823, MCF-7, EJ, and HL-60 cell lines increases in the following sequence: cisplatin >Ⅳ>Ⅴ>Ⅵ>Ⅶ>Ⅰ>Ⅱ>Ⅲ. Moreover, the complexes(Ⅰ -Ⅶ) display substantially greater activities against EJ and HL-60 cell lines than those against the cell lines from other carcinomas. They can induce a concentration-dependent accumulation of HL-60 cells in the G2/M phase of the cell cycle as cisplatin. There is no significant correlation between total DNA platination levels and cytotoxicity of the complexes.

  17. Novel 3-(aminomethyl)naphthoquinone mannich base-platinum(IV) complexes: synthesis, characterization, electrochemical and cytotoxic studies

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Gustavo B. da; Neves, Amanda P.; Vargas, Maria D., E-mail: mdvargas@vm.uff.br [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Quimica; Alves, Wagner A. [Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropedica, RJ (Brazil). Departamento de Quimica; Marinho-Filho, Jose D.B.; Pessoa, Claudia; Moraes, Manoel O.; Costa-Lotufo, Leticia V. [Universidade Federal do Ceara (UFCE), Fortaleza, CE (Brazil). Centro de Ciencias da Saude. Departamento de Fisiologia e Farmacologia

    2013-04-15

    Three novel platinum(IV) complexes cis,cis,trans-[Pt(HL1-3)Cl{sub 2}(OH){sub 2}] 1b-3b(HL = 2-hydroxy-3-[(R{sup 1} -amino)(pyridin-2-yl)methyl]-1,4-naphthoquinone, R{sup 1} = n-butyl, HL1; n-heptyl, HL2 and n-decyl, HL3) have been obtained from the oxidation of the respective precursors cis-[Pt(HL1-3)Cl{sub 2}] 1a-3a. Cyclic voltammetry studies of 1b-3b in MeCN showed the quasi reversible naphthoquinonate (NQO{sup -}, i.e., L{sup -}) redox process and irreversible process attributed to the reduction of the Pt{sup 4+}/Pt{sup 2+} pair, at potentials about 400 mV less negative than for the cisplatin precursor cis,cis,trans-[Pt(NH{sub 3}){sub 2}Cl{sub 2}(OH){sub 2}]. Hydrogen bond interaction between the naphthoquinone 2-hydroxyl group and an axially coordinated hydroxide ligand in 1b-3b has been proposed to favor the Pt{sup 4+}/Pt{sup 2+} reduction. The cytotoxicity studies against four human cancer cell lines have shown that in general the platinum(IV) and platinum(II)derivatives exhibit the same cytotoxic profile and are all more active than cisplatin. The lowest in vitro IC{sub 50} values have been observed for 2b-3b, which bear ligands with the largest R{sup 1} groups (HL2-HL3) being the most lipophilic. Furthermore similar IC{sub 50} values for platinum(II) and platinum(IV) complexes of the same ligands have been associated with rapid in vitro reduction of the latter complexes to afford 1a-3a. (author)

  18. Synthesis and Structural Properties of Aza[n]helicene Platinum Complexes: Control of Cis and Trans Stereochemistry.

    Science.gov (United States)

    Mendola, Daniele; Saleh, Nidal; Hellou, Nora; Vanthuyne, Nicolas; Roussel, Christian; Toupet, Loïc; Castiglione, Franca; Melone, Federica; Caronna, Tullio; Fontana, Francesca; Martí-Rujas, Javier; Parisini, Emilio; Malpezzi, Luciana; Mele, Andrea; Crassous, Jeanne

    2016-03-07

    The synthesis and structural characterization of azahelicene platinum complexes obtained from cis-PtCl2(NCEt)(PPh3) and from ligands that differ in terms of both the position of the nitrogen atom and the number of fused rings are reported. These square-planar complexes of the general formula PtCl2(nHm)(PPh3) (n = 4, 5; m = 5, 6) display mainly a cis configuration. However, by X-ray crystallographic analysis, we show that for both PtCl2(4H6)(PPh3) and PtCl2(5H6)(PPh3) there is chirality control of the cis/trans stereochemistry. Indeed, starting from a racemic mixture of aza[6]helicene, platinum complexes with a cis configuration are invariably obtained, and the more thermodynamically stable trans isomers are formed when using enantiopure ligands. We further corroborated these results by NMR analysis in solution.

  19. Easy Synthesis and Characterization of Poly(alkoxysilane)s Promoted by Silver-Platinum Mixed Complexes.

    Science.gov (United States)

    Roh, Sung-Hee; Lee, In-Hwa; Cheong, Hyeonsook; Noh, Ji Eun; Lee, Ki Bok; Woo, Hee-Gweon; Kim, Bo Hye; Jun, Jin; Sohn, Honglae

    2015-01-01

    One-pot Si-Si/Si-O dehydrocoupling of hydrosilanes with alcohols (1:1.5 mole ratio), promoted by a mixture of AgNO3-H2PtCl6 (150/1 mole ratio) readily gave poly(alkoxysilane)s in good yield (62-91%). The addition of small amount of platinum complex to form nanoparticles facilitated the silicon polymer formation when compared to the reaction rate with AgNO3 alone. The primary/secondary hydrosilanes [p-X-C6H4SiH3 (X = H, CH3, OCH3, F), PhCH2SiH3, and (PhSiH2)2] and alcohols [MeOH, EtOH, (i)PrOH, PhOH, and CF3(CF2)2CH2OH] were used for the reaction. The weight average molecular weight and polydispersity of the poly(alkoxysilane)s were in the range of 1,690-7,100 Dalton and 1.44-3.49, respectively. The reaction of phenylsilane with ethanol (1:3 mole ratio) using the Ag-Pt complexes produced triethoxyphenylsilane only, as expected. The reaction of phenylsilane with Ge-132 produced an insoluble cross-linked gel.

  20. Structural properties of platinum(II) biphenyl complexes containing 1,10-phenanthroline derivatives

    Science.gov (United States)

    Rillema, D. Paul; Cruz, Arvin J.; Tasset, Brandon J.; Moore, Curtis; Siam, Khamis; Huang, Wei

    2013-06-01

    Seven platinum(II) complexes formulated as Pt(bph)L, where bph is the 2,2'-biphenyl dianion and L = 4-methyl-1,10-phenanthroline (4-Mephen), 5-methyl-1,10-phenanthroline (5-Mephen), 5-chloro-1,10-phenanthroline (5-Clphen), 5,6-dimethyl-1,10-phenanthroline (5,6-Me2phen), 4,7-dimethyl-1,10-phenanthroline (4,7-Me2phen), 4,7-diphenyl-1,10-phenanthroline (4,7-Ph2phen) and 3,4,7,8-tetramethyl-1,10-phenanthroline (3,4,7,8-Me4phen) are reported. Protons attached to the phen ligand resonate downfield from those attached to the bph ligand and two proton signals are split by interaction with 195Pt. Pt(bph)(3,4,7,8-Me4phen), Pt(bph)(4,7-Me2phen), Pt(bph)(5,6-Me2phen), Pt(bph)(4,7-Ph2phen) and Pt(bph)(5-Mephen) crystallize in the space groups Pna21, P21/n, P21/c, P - 1 and Pca21, respectively. The structures of the complexes deviate from true planarity and divide themselves into two groups where the bph and phen ligands cross in an X configuration or bow out in a butterfly (B) configuration. Circular dichroism revealed two different spectra with respect to the X and B configurations.

  1. Photolysis and thermolysis of platinum(IV) 2,2'-bipyridine complexes lead to identical platinum(II)-DNA adducts.

    Science.gov (United States)

    Loup, Christophe; Tesouro Vallina, Ana; Coppel, Yannick; Létinois, Ulla; Nakabayashi, Yasuo; Meunier, Bernard; Lippert, Bernhard; Pratviel, Geneviève

    2010-10-04

    Two Pt(IV) and two Pt(II) complexes containing a 2,2'-bipyridine ligand were treated with a short DNA oligonucleotide under light irradiation at 37°C or in the dark at 37 and 50°C. Photolysis and thermolysis of the Pt(IV) complexes led to spontaneous reduction of the Pt(IV) to the corresponding Pt(II) complexes and to binding of Pt(II) 2,2'-bipyridine complexes to N7 of guanine. When the reduction product was [Pt(bpy)Cl(2)], formation of bis-oligonucleotide adducts was observed, whereas [Pt(bpy)(MeNH(2))Cl](+) gave monoadducts, with chloride ligands substituted in both cases. Neither in the dark nor under light irradiation was the reductive elimination process of these Pt(IV) complexes accompanied by oxidative DNA damage. This work raises the question of the stability of photoactivatable Pt(IV) complexes toward moderate heating conditions.

  2. In vitro and in vivo anti-tumor effects of selected platinum(IV) and dinuclear platinum(II) complexes against lung cancer cells.

    Science.gov (United States)

    Arsenijevic, Milos; Milovanovic, Marija; Jovanovic, Snezana; Arsenijevic, Natalija; Markovic, Bojana Simovic; Gazdic, Marina; Volarevic, Vladislav

    2017-08-01

    In the present study, cytotoxic effects of cisplatin, the most usually used chemotherapeutic agent, were compared with new designed platinum(IV) ([PtCl4(en)] (en = ethylenediamine) and [PtCl4(dach)]) (dach = (±)-trans-1,2-diaminocyclohexane) and platinum(II) complexes ([{trans-Pt(NH3)2Cl}2(μ-pyrazine)](ClO4)2 (Pt1), [{trans-Pt(NH3)2Cl}2(μ-4,4'-bipyridyl)](ClO4)2DMF(Pt2),[{trans-Pt(NH3)2Cl}2(μ-1,2-bis(4pyridyl)ethane)](ClO4)2 (Pt3)), in vitro and in vivo against human and murine lung cancer cells, to determine anti-tumor potential of newly synthesized platinum-based drugs in the therapy of lung cancer. Results obtained by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], Lactate dehydrogenase and Annexin V/Propidium Iodide assays showed that, among all tested complexes, [PtCl4(en)] had the highest cytotoxicity against human and murine lung carcinoma cells in vitro. [PtCl4(en)] showed significantly higher cytotoxicity then cisplatin in all tested concentrations, mainly by inducing apoptosis in lung cancer cells. [PtCl4(en)] was well tolerated in vivo. Clinical signs of [PtCl4(en)]-induced toxicity, such as changes in food, water consumption or body weight, nephrotoxicity or hepatotoxicity was not observed in [PtCl4(en)]-treated mice. [PtCl4(en)] managed to increase presence of CD45+ leukocytes, including F4/80+ macrophages, CD11c+ dendritic cells, CD4+ helper and CD8+ cytotoxic T cells (CTLs) in the lungs, cytotoxic NK, NKT and CTLs in the spleens of tumor bearing mice, resulting with reduction of metastatic lesions in the lungs, indicating its potential to stimulate anti-tumor immune response in vivo. Due to its anti-tumor cytotoxicity, biocompatibility, and potential for stimulation of anti-tumor immune response, [PtCl4(en)] may be a good candidate for further testing in the field of medicinal chemistry.

  3. Polynuclear Hydroxido-Bridged Complexes of Platinum(IV) with Terminal Nitrato Ligands.

    Science.gov (United States)

    Vasilchenko, Danila; Berdugin, Semen; Tkachev, Sergey; Baidina, Iraida; Romanenko, Galina; Gerasko, Olga; Korenev, Sergey

    2015-05-18

    For the first time the polynuclear hydroxido-bridged platinum(IV) nitrato complexes with nuclearity higher than two were isolated from nitric acid solutions of [Pt(H2O)2(OH)4] and crystallized as supramolecular compounds of macrocyclic cavitands cucurbit[n]uril (CB[n], n = 6,8) and 18-crown-6 ether: [Pt4(μ3-OH)2(μ2-OH)4(NO3)10]·CB[6]·25H2O (I), [Pt6(μ3-OH)4(μ2-OH)6(NO3)12](NO3)2·CB[8]·50H2O (II), and [H3O⊂18-crown-6]2[Pt2(μ2-OH)2(NO3)8][Pt4(μ3-OH)2(μ2-OH)4(NO3)10] (III). The isolation of the compounds in the single crystalline state allows the determination of the structure of the tetranuclear and hexanuclear complexes [Pt4(μ3-OH)2(μ2-OH)4(NO3)10] and [Pt6(μ3-OH)4(μ2-OH)6(NO3)12](2+), which have been previously unknown in the solid state. Stability of Ptx(OH)y cores of the polynuclear nitrato complexes toward alkaline hydrolysis was verified by (195)Pt NMR spectroscopy. Analysis of (195)Pt NMR spectra of the compound III reveals that addition of every Pt(μ-OH)2Pt ring results in ∼260 ppm downfield shift relative to the mononuclear form, which allows the prediction of signal positions for complexes of higher nuclearity.

  4. Half-Lantern Pt(II and Pt(III Complexes. New Cyclometalated Platinum Derivatives

    Directory of Open Access Journals (Sweden)

    Violeta Sicilia

    2014-08-01

    Full Text Available The divalent complex [{Pt(bzq(μ-L}2] (1 [Hbzq = benzo[h]quinolone, HL = CF3C4H2N2SH: 4-(trifluoromethylpyrimidine-2-thiol] was obtained from equimolar amounts of [Pt(bzq(NCMe2]ClO4 and 4-(trifluoromethylpyrimidine-2-thiol with an excess of NEt3. The presence of a low intensity absorption band at 486 nm (CH2Cl2, assignable to a metal-metal-to-ligand charge transfer transition (1MMLCT [dσ*(Pt2→π*(bzq], is indicative of the existence of two platinum centers located in close proximity because the rigidity of the half-lantern structure allows the preservation of these interactions in solution. Compound 1 undergoes two-electron oxidation upon treatment with halogens X2 (X2: Cl2, Br2 or I2 to give the corresponding dihalodiplatinum (III complexes [{Pt(bzq(μ-LX}2] (L = CF3C4H2N2S-κN,S; X: Cl 2, Br 3, I 4. Complexes 2–4 were also obtained by reaction of 1 with HX (molar ratio 1:2, 10% excess of HX in THF with yields of about 80% and compound 2 was also obtained by reaction of [{Pt(bzq(μ-Cl}2] with HL (4-(trifluoromethylpyrimidine-2-thiol in molar ratio 1:2 in THF, although in small yield. The X-ray structures of 2 and 3 confirmed the half-lantern structure and the anti configuration of the molecules. Both of them show Pt–Pt distances (2.61188(15 Å 2, 2.61767(16 Å 3 in the low range of those observed in Pt2(III,IIIX2 half-lantern complexes.

  5. Tetracarboxylatoplatinum(IV) complexes featuring monodentate leaving groups - A rational approach toward exploiting the platinum(IV) prodrug strategy.

    Science.gov (United States)

    Höfer, Doris; Varbanov, Hristo P; Legin, Anton; Jakupec, Michael A; Roller, Alexander; Galanski, Markus; Keppler, Bernhard K

    2015-12-01

    A series of novel symmetrically and unsymmetrically coordinated platinum(IV) complexes with monodentate carboxylato ligands was synthesized. The compounds exhibit a general coordination sphere of [Pt(en)(OCOR)2(OCOR')(OCOR″)], where the carboxylato ligands are represented by acetato and succinic acid monoester ligands. Dicarboxylatoplatinum(II) complexes were synthesized and oxidized symmetrically or unsymmetrically to obtain platinum(IV) complexes, which were subsequently carboxylated with noncyclic anhydrides. The compounds were investigated in detail by elemental analysis, mass spectrometry, infrared and multinuclear ((1)H, (13)C, (15)N, (195)Pt) NMR spectroscopy as well as by X-ray diffraction in some cases. The reduction behavior was followed by NMR spectroscopy, while stability and lipophilicity were examined by analytical reversed phase HPLC measurements. Cytotoxic properties were studied in three human cancer cell lines derived from cisplatin sensitive ovarian teratocarcinoma (CH1/PA-1), cisplatin insensitive colon carcinoma (SW480) and non-small cell lung cancer (A549). Thereby, the most lipophilic (yet water soluble) platinum(IV) complexes showed promising IC50 values in the low micromolar and even nanomolar range, demonstrating the significant advantage of using equatorially coordinated monodentate carboxylato ligands. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Calculation of lipophilicity of a large, diverse dataset of anticancer platinum complexes and the relation to cellular uptake.

    Science.gov (United States)

    Oldfield, Steven P; Hall, Matthew D; Platts, James A

    2007-10-18

    A quantitative structure--property relationship (QPSR) for the octanol--water partition of platinum complexes was constructed using molecular descriptors derived from density functional (DFT) calculations. A dataset of partition data for 64 complexes, consisting of 43 square-planar platinum(II) and 21 octahedral platinum(IV) complexes, was drawn from literature sources. Not only does this dataset include considerable structural diversity of complexes considered but also a variety of techniques for the measurement of partition coefficients. These data were modeled using descriptors drawn from electrostatic potentials and hardness/softness indices projected onto molecular surfaces. This required initial descriptor selection using a genetic algorithm approach, followed by partial least-squares regression against log Po/w data. In this way, a statistically robust model was constructed, with errors of similar size to the variation in log Po/w from multiple experimental measurements. Implications of lipophilicity for cellular accumulation of Pt-based drugs, and hence for design of new drugs, are discussed, as is the uptake of metabolites of cisplatin.

  7. Synthesis, characterization and reactivity of carbohydrate platinum(IV) complexes with thioglycoside ligands.

    Science.gov (United States)

    Vetter, Cornelia; Pornsuriyasak, Papapida; Schmidt, Jürgen; Rath, Nigam P; Rüffer, Tobias; Demchenko, Alexei V; Steinborn, Dirk

    2010-07-21

    Reactions of fac-[PtMe3(4,4'-R2bpy)(Me2CO)][BF4] (R = H, 1a; tBu, 1b) and fac-[PtMe3(OAc-kappa2O,O')(Me2CO)] (2), respectively, with thioglycosides containing thioethyl (ch-SEt) and thioimidate (ch-STaz, Taz = thiazoline-2-yl) anomeric groups led to the formation of the carbohydrate platinum(IV) complexes fac-[PtMe3(4,4-R2bpy)(ch*)][BF4] (ch* = ch-SEt, 8-14; ch-STaz, 15-23) and fac-[PtMe3(OAc-kappa2O,O')(ch*)] (ch* = ch-SEt, 24-28; ch-STaz = 29-35), respectively. NMR (1H, 13C, 195Pt) spectroscopic investigations and a single-crystal X-ray diffraction analysis of 19 (ch-STaz = 2-thiazolinyl 2,3,4,6-tetra-O-benzoyl-1-thio-beta-D-galactopyranose) revealed the S coordination of the ch-SEt glycosides and the N coordination of the ch-STaz glycosides. Furthermore, X-ray structure analyses of the two decomposition products fac-[PtMe3(bpy)(STazH-kappaS)][BF4] (21a) and 1,6-anhydro-2,3,4-tri-O-benzoyl-beta-D-glucopyranose (23a), where a cleavage of the anomeric C-S bond had occurred in both cases, gave rise to the assumption that this decomposition was mediated due to coordination of the thioglycosides to the high electrophilic platinum(IV) atom, in non-strictly dried solutions. Reactions of fac-[PtMe3(Me2CO)3][BF4] (3) with ch-SEt as well as with ch-SPT and ch-Sbpy thioglycosides (PT = 4-(pyridine-2-yl)-thiazole-2-yl; bpy = 2,2'-bipyridine-6-yl), having N,S and N,N heteroaryl anomeric groups, respectively, led to the formation of platinum(IV) complexes of the type fac-[PtMe3(ch*)][BF4] (ch* = ch-SEt, 36-40, ch-SPT 42-44, ch-Sbpy 45, 46). The thioglycosides were found to be coordinated in a tridentate kappaS,kappa2O,O, kappaS,kappaN,kappaO and kappaS,kappa2N,N coordination mode, respectively. Analogous reactions with ch-STaz ligands succeeded for 2-thiazolinyl 2,3,4-tri-O-benzyl-6-O-(2,2'-bipyridine-6-yl)-1-thio-beta-D-glucopyranoside (5h) resulting in fac-[PtMe3(ch-STaz)][BF4] (41, ch-STaz = 5h), having a kappa3N,N',N''coordinated thioglycoside ligand.

  8. Synthesis, characterization and reactivity of carbohydrate platinum(IV) complexes with thioglycoside ligands†

    Science.gov (United States)

    Vetter, Cornelia; Pornsuriyasak, Papapida; Schmidt, Jürgen; Rath, Nigam P.; Rüffer, Tobias; Demchenko, Alexei V.; Steinborn, Dirk

    2011-01-01

    Reactions of fac-[PtMe3(4,4′-R2bpy)(Me2CO)][BF4] (R = H, 1a; tBu, 1b) and fac-[PtMe3-(OAc-κ2O,O′)(Me2CO)] (2), respectively, with thioglycosides containing thioethyl (ch-SEt) and thioimidate (ch-STaz, Taz = thiazoline-2-yl) anomeric groups led to the formation of the carbohydrate platinum(IV) complexes fac-[PtMe3(4,4′-R2bpy)(ch*)][BF4] (ch* = ch-SEt, 8–14; ch-STaz, 15–23) and fac-[PtMe3(OAc-κ2O,O′)(ch*)] (ch* = ch-SEt, 24–28; ch-STaz = 29–35), respectively. NMR (1H, 13C, 195Pt) spectroscopic investigations and a single-crystal X-ray diffraction analysis of 19 (ch-STaz = 2-thiazolinyl 2,3,4,6-tetra-O-benzoyl-1-thio-β-d-galactopyranose) revealed the S coordination of the ch-SEt glycosides and the N coordination of the ch-STaz glycosides. Furthermore, X-ray structure analyses of the two decomposition products fac-[PtMe3(bpy)(STazH-κS)][BF4] (21a) and 1,6-anhydro-2,3,4-tri-O-benzoyl-β-d-glucopyranose (23a), where a cleavage of the anomeric C–S bond had occurred in both cases, gave rise to the assumption that this decomposition was mediated due to coordination of the thioglycosides to the high electrophilic platinum(IV) atom, in non-strictly dried solutions. Reactions of fac-[PtMe3(Me2CO)3][BF4] (3) with ch-SEt as well as with ch-SPT and ch-Sbpy thioglycosides (PT = 4-(pyridine-2-yl)-thiazole-2-yl; bpy = 2,2′-bipyridine-6-yl), having N,S and N,N heteroaryl anomeric groups, respectively, led to the formation of platinum(IV) complexes of the type fac-[PtMe3(ch*)][BF4] (ch* = ch-SEt, 36–40, ch-SPT 42–44, ch-Sbpy 45, 46). The thioglycosides were found to be coordinated in a tridentate κS,κ2O,O′, κS,κN,κO and κS,κ2N,N′ coordination mode, respectively. Analogous reactions with ch-STaz ligands succeeded for 2-thiazolinyl 2,3,4-tri-O-benzyl-6-O-(2,2′-bipyridine-6-yl)-1-thio-β-d-glucopyranoside (5h) resulting in fac-[PtMe3(ch-STaz)][BF4] (41, ch-STaz = 5h), having a κ3N,N′,N″ coordinated thioglycoside ligand. PMID:20517543

  9. Theoretical investigations and density functional theory based quantitative structure-activity relationships model for novel cytotoxic platinum(IV) complexes.

    Science.gov (United States)

    Varbanov, Hristo P; Jakupec, Michael A; Roller, Alexander; Jensen, Frank; Galanski, Markus; Keppler, Bernhard K

    2013-01-10

    Octahedral platinum(IV) complexes are promising candidates in the fight against cancer. In order to rationalize the further development of this class of compounds, detailed studies on their mechanisms of action, toxicity, and resistance must be provided and structure-activity relationships must be drawn. Herein, we report on theoretical and QSAR investigations of a series of 53 novel bis-, tris-, and tetrakis(carboxylato)platinum(IV) complexes, synthesized and tested for cytotoxicity in our laboratories. The hybrid DFT functional wb97x was used for optimization of the structure geometry and calculation of the descriptors. Reliable and robust QSAR models with good explanatory and predictive properties were obtained for both the cisplatin sensitive cell line CH1 and the intrinsically cisplatin resistant cell line SW480, with a set of four descriptors.

  10. Theoretical Investigations and Density Functional Theory Based Quantitative Structure–Activity Relationships Model for Novel Cytotoxic Platinum(IV) Complexes

    Science.gov (United States)

    2012-01-01

    Octahedral platinum(IV) complexes are promising candidates in the fight against cancer. In order to rationalize the further development of this class of compounds, detailed studies on their mechanisms of action, toxicity, and resistance must be provided and structure–activity relationships must be drawn. Herein, we report on theoretical and QSAR investigations of a series of 53 novel bis-, tris-, and tetrakis(carboxylato)platinum(IV) complexes, synthesized and tested for cytotoxicity in our laboratories. The hybrid DFT functional wb97x was used for optimization of the structure geometry and calculation of the descriptors. Reliable and robust QSAR models with good explanatory and predictive properties were obtained for both the cisplatin sensitive cell line CH1 and the intrinsically cisplatin resistant cell line SW480, with a set of four descriptors. PMID:23214999

  11. Competitive platinum-group-metal (PGM) supply from the Eastern Limb, Bushveld Complex: Geological, mining and mineral economic aspects

    CSIR Research Space (South Africa)

    McGill, JE

    2011-08-01

    Full Text Available -GROUP-METAL (PGM) SUPPLY FROM THE EASTERN LIMB, BUSHVELD COMPLEX: GEOLOGICAL, MINING, AND MINERAL ECONOMIC ASPECTS Dr. Jeannette E. McGill & Prof. Murray W. Hitzman ACKNOWLEDGEMENTS ? COUNCIL FOR SCIENTIFIC AND INDUSTRIAL RESEARCH (CSIR) ? Centre for Mining... Innovation ? Office of Graduate Studies, Fogarty Endowment ? Mr. VISHNU PILLAY (EXECUTIVE HEAD: JV?S ? Anglo Platinum) ? ACADEMIC ADVISORS Prof. Murray Hitzman (Economic Geology); Dr. Hugh Miller (Mining Engineering); Prof. Rodderick Eggert (Mineral...

  12. Crystal structures and vibrational spectroscopy of neutral platinum(IV) amine iodo complexes

    Science.gov (United States)

    Thiele, G.; Danzeisen, O. F.; Rotter, H. W.; Goanta, M.

    1999-05-01

    A series of platinum(IV) amine iodo complexes of the type [PtL 2I 4] was synthesized for the first time and their infrared and Raman spectra were recorded. The crystal structures of cis-[Pt(net) 2I 4], (net=ethylamine) (space group Pnma, a=14.668(3), b=8.787(2), c=11.433(2) Å), trans-[Pt(net) 2I 4] (space group C2/c, a=11.276(2), b=8.866(2), c=12.542(3) Å, β=114.86(3)°) and [Pt(en)I 4] (en=ethylendiamine) (space group P1, a=6.780(1), b=11.613(2), c=14.703(3) Å, α=71.87(3), β=80.78(3), γ=80.08 (3)°) were determined. Formation of linear chains of molecules with short intermolecular I-I distances was observed for cis-[Pt(net) 2I 4]. The spectroscopic behavior is discussed according to these results.

  13. Stable and efficient sky-blue organic light emitting diodes employing a tetradentate platinum complex

    Science.gov (United States)

    Li, Guijie; Klimes, Kody; Fleetham, Tyler; Zhu, Zhi-Qiang; Li, Jian

    2017-03-01

    A tetradentate Pt(II) complex platinum (II) [10-(9-(4-tert-butylpyridin-2-yl-κN)-9H-carbazol-2-yl-κC1)-9,10-dihydro-9,9-dimethyl-3-(1H-pyrazol-1-yl-κN2)acridine-1-yl-κC1] (PtN'1N-tBu) incorporating pyrazolyl-acridine as the lumophore was demonstrated to act as a stable and efficient sky-blue emitter. Phosphorescent organic light-emitting diode (OLED) employing PtN'1N-tBu without the electron blocking layer (EBL) achieved a high external quantum efficiency (EQE) of 15.9% and an estimated operational lifetime LT70 of 635 h at an initial luminance of 1000 cd/cm2. The device efficiency could be further improved by adding TrisPCz as EBL, reaching EQE of 17.3% and operational lifetime up to 482 h at 1000 cd/cm2.

  14. Reaction Mechanism for Olefin Exchange at Chloro Ethene Complexes of Platinum(II).

    Science.gov (United States)

    Plutino, Maria Rosaria; Otto, Stefanus; Roodt, Andreas; Elding, Lars I.

    1999-03-22

    Complex equilibria in methanol/chloroform/dichloromethane solutions containing Zeise's anion, [PtCl(3)(C(2)H(4))](-) (1), the solvento species, trans-[PtCl(2)(C(2)H(4))(MeOH)] (2), and the dinuclear complex, trans-[PtCl(2)(C(2)H(4))](2) (3), have been studied by UV-vis, (1)H, and (195)Pt NMR spectroscopy, giving average values of K(Cl) = (1.6 +/- 0.2)10(3) M(-)(1) and K(S) = (0.16 +/- 0.02) M(-)(1) for the equilibrium constants between 2 and 1 and 3 and 2, respectively. The bridged complex 3 is completely split into monomeric solvento complexes 2 in methanol and in chloroform or dichloromethane solutions with [MeOH] > 0.5 M. Ethene exchange at the mononuclear complexes 1 and 2 was studied by (1)H NMR line-broadening experiments in methanol-d(4). Observed overall exchange rate constants decrease with an increase in free chloride concentration due to the displacement of the rapid equilibrium between 1 and 2 toward the more slowly exchanging parent chloro complex 1. Ethene exchange rate constants at 298 K for complexes 1 and 2 are k(ex1) = (2.1 +/- 0.1)10(3) M(-)(1) s(-)(1)and k(ex2) = (5.0 +/- 0.2)10(5) M(-)(1) s(-)(1), respectively, with corresponding activation parameters DeltaH(1)() = 19.1 +/- 0.3 kJ mol(-)(1), DeltaS(1)() = -117 +/- 1 J K(-)(1) mol(-)(1), DeltaH(2)() = 10.2 +/- 0.4 kJ mol(-)(1), and DeltaS(2)() = -102 +/- 2 J K(-)(1) mol(-)(1). The activation process is largely entropy controlled; the enthalpy contributions only amounting to approximately 30% of the free energy of activation. Ethene exchange takes place via associative attack by the entering olefin at the labile site trans to the coordinated ethene, which is either occupied by a chloride or a methanol molecule in the ground state. The intimate mechanism might involve a two-step process via trans-[PtCl(2)(C(2)H(4))(2)] in steady state or a concerted process via a pentacoordinated transition state with two ethene molecules bound to the platinum(II).

  15. Importance of platinum(II)-assisted platinum(IV) substitution for the oxidation of guanosine derivatives by platinum(IV) complexes.

    Science.gov (United States)

    Choi, Sunhee; Vastag, Livia; Larrabee, Yuri C; Personick, Michelle L; Schaberg, Kurt B; Fowler, Benjamin J; Sandwick, Roger K; Rawji, Gulnar

    2008-02-18

    Guanosine derivatives with a nucleophilic group at the 5' position (G-5') are oxidized by the Pt (IV) complex Pt( d, l)(1,2-(NH 2) 2C 6H 10)Cl 4 ([Pt (IV)(dach)Cl 4]). The overall redox reaction is autocatalytic, consisting of the Pt (II)-catalyzed Pt (IV) substitution and two-electron transfer between Pt (IV) and the bound G-5'. In this paper, we extend the study to improve understanding of the redox reaction, particularly the substitution step. The [Pt (II)(NH 3) 2(CBDCA-O,O')] (CBDCA = cyclobutane-1,1-dicarboxylate) complex effectively accelerates the reactions of [Pt (IV)(dach)Cl 4] with 5'-dGMP and with cGMP, indicating that the Pt (II) complex does not need to be a Pt (IV) analogue to accelerate the substitution. Liquid chromatography/mass spectroscopy (LC/MS) analysis showed that the [Pt (IV)(dach)Cl 4]/[Pt (II)(NH 3) 2(CBDCA-O,O')]/cGMP reaction mixture contained two Pt (IV)cGMP adducts, [Pt (IV)(NH 3) 2(cGMP)(Cl)(CBDCA-O,O')] and [Pt (IV)(dach)(cGMP)Cl 3]. The LC/MS studies also indicated that the trans, cis-[Pt (IV)(dach)( (37)Cl) 2( (35)Cl) 2]/[Pt (II)(en)( (35)Cl) 2]/9-EtG mixture contained two Pt (IV)-9-EtG adducts, [Pt (IV)(en)(9-EtG)( (37)Cl)( (35)Cl) 2] and [Pt (IV)(dach)(9-EtG)( (37)Cl)( (35)Cl) 2]. These Pt (IV)G products are predicted by the Basolo-Pearson (BP) Pt (II)-catalyzed Pt (IV)-substitution scheme. The substitution can be envisioned as an oxidative addition reaction of the planar Pt (II) complex where the entering ligand G and the chloro ligand from the axial position of the Pt (IV) complex are added to Pt (II) in the axial positions. From the point of view of reactant Pt (IV), an axial chloro ligand is thought to be substituted by the entering ligand G. The Pt (IV) complexes without halo axial ligands such as trans, cis-[Pt(en)(OH) 2Cl 2], trans, cis-[Pt(en)(OCOCF 3) 2Cl 2], and cis, trans, cis-[Pt(NH 3)(C 6H 11NH 2)(OCOCH 3) 2Cl 2] ([Pt (IV)(a,cha)(OCOCH 3) 2Cl 2], satraplatin) did not react with 5'-dGMP. The bromo complex, [Pt (IV

  16. Structures of polynuclear complexes of palladium(II) and platinum(II) formed by slow hydrolysis in acidic aqueous solution.

    Science.gov (United States)

    Torapava, Natallia; Elding, Lars I; Mändar, Hugo; Roosalu, Kaspar; Persson, Ingmar

    2013-06-07

    The aqua ions of palladium(II) and platinum(II) undergo extremely slow hydrolysis in strongly acidic aqueous solution, resulting in polynuclear complexes. The size and structures of these species have been determined by EXAFS and small angle X-ray scattering, SAXS. For palladium(II), the EXAFS data show that the Pd-O and Pd···Pd distances are identical to those of crystalline palladium(II) oxide, but the intensities of the Pd···Pd distances in the Fourier transform at 3.04 and 3.42 Å are significantly lower compared to those of crystalline PdO. Furthermore, no Pd···Pd distances beyond 4 Å are observed. These observations strongly indicate that the polynuclear palladium(II) complexes are oxido- and hydroxido-bridged species with the same core structure as solid palladium(II) oxide. Based on the number of Pd···Pd distances, as derived from the EXAFS data, their size can be estimated to be approximately two unit cells, or ca. 1.0 nm(3). For platinum(II), EXAFS data of the polynuclear species formed in the slow hydrolysis process show Pt-O and Pt···Pt distances identical to those of amorphous platinum(II) oxide, precipitating from the solution studied. The Pt···Pt distances are somewhat different from those reported for crystalline platinum(II) oxide. The polynuclear platinum(II) complexes have a similar structure to the palladium ones, but they are somewhat larger, with an estimated diameter of 1.5-3.0 nm. It has not been possible to precipitate any of these species by ultracentrifugation. They are detectable by SAXS, indicating diameters between 0.7 and 2 nm, in excellent agreement with the EXAFS observations. The number of oxido- relative to hydroxido bridges will increase with increasing size of the complex. The charge of the complexes will remain about the same, +4, at growth, with approximate formulas [Pd10O4(OH)8(H2O)12](4+) and [Pt14O8(OH)8(H2O)12](4+) for complexes with a size of 2 and 3 unit cells of the corresponding solid metal oxide

  17. Synthesis, characterization and cytotoxic activity of novel platinum(II) iodido complexes.

    Science.gov (United States)

    Savić, Aleksandar; Filipović, Lana; Aranđelović, Sandra; Dojčinović, Biljana; Radulović, Siniša; Sabo, Tibor J; Grgurić-Šipka, Sanja

    2014-07-23

    Novel Pt(II) complexes of general formula [PtI2(L(1-3))], (C1-C3): where L(1-3) are isobutyl, n-pentyl and isopentyl esters of (S,S)-1,3-propanediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid has been synthesized and characterized by elemental analysis, UV/Vis, IR, ((1)H, (13)C and HSQC, Pt) NMR spectroscopy and ESI mass spectrometry. Spectroscopic data and computational studies have shown the usual square planar coordination geometry of synthesized complexes, with coordination of ligands via nitrogen donor atoms. The cytotoxic activity of novel ligands and corresponding complexes were investigated on a palette of different cells line. Complexes C1-C3 exhibited activity comparable to cisplatin, with IC50 values (μM) ranging from 4.6 ± 0.6 to 17.2 ± 2, and showed the highest potential in HeLa, LS-174 and EA.hy.926 cells. Ligands L1-L3 exhibited two- to four-times less activity than corresponding complexes. Analysis of the mode of action in HeLa cells, by ICP-MS study, showed markedly higher intracellular accumulation and DNA binding affinity of C1-C3 versus cisplatin, after 4 h and 20 h post-treatment. Annexin-V-FITC assay, flow cytometry and fluorescence microscopy study demonstrated occurrence of cell death through both apoptotic and necrotic changes. Tested complexes, at corresponding IC50 concentrations, caused considerable "sub-G1" peak, without other substantial alterations of cell cycle, while only C1 induced higher level of phosphatidylserine externalization (11.7%), comparing to ligand L1 (4.9%) and cisplatin (8.4%). Structure-activity comparison indicated variations of C1-C3 cytotoxicity, related to the drug/ligand lipophilicity (C log P value), while intracellular platinum content and DNA platination increased on increase of length and branching of ester chain, in sequence: C1 (isobutyl) < C2 (n-pentyl) < C3 (isopentyl).

  18. Platinum(IV)-nitroxyl complexes as possible candidates to circumvent cisplatin resistance in RT112 bladder cancer cells.

    Science.gov (United States)

    Cetraz, Maria; Sen, Vasily; Schoch, Sarah; Streule, Karolin; Golubev, Valery; Hartwig, Andrea; Köberle, Beate

    2017-02-01

    The therapeutic efficacy of the anticancer drug cisplatin is limited by the development of resistance. We therefore investigated newly synthesized platinum-nitroxyl complexes (PNCs) for their potential to circumvent cisplatin resistance. The complexes used were PNCs with bivalent cis-Pt(II)(R(·)NH2)(NH3)Cl2 and cis-Pt(II)(DAPO)Ox and four-valent platinum cis,trans,cis-Pt(IV)(R(·)NH2)(NH3)(OR)2Cl2 and cis,trans,cis-Pt(IV)(DAPO)(OR)2Ox, where R(·) are TEMPO or proxyl nitroxyl radicals, DAPO is trans-3,4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl, and OR and Ox are carboxylato and oxalato ligands, respectively. The complexes were characterized by spectroscopic methods, HPLC, log P ow data and elemental analysis. We studied intracellular platinum accumulation, DNA platination and cytotoxicity upon treatment with the PNCs in a model system of the bladder cancer cell line RT112 and its cisplatin-resistant subline RT112-CP. Platinum accumulation and DNA platination were similar in RT112 and RT112-CP cells for both bivalent and four-valent PNCs, in contrast to cisplatin for which a reduction in intracellular accumulation and DNA platination was observed in the resistant subline. The PNCs were found to platinate DNA in relation to the length of their axial RO-ligands. Furthermore, the PNCs were increasingly toxic in relation to the elongation of their axial RO-ligands, with similar toxicities in RT112 and its cisplatin-resistant subline. Using a cell-free assay, we observed induction of oxidative DNA damage by cisplatin but not PNCs suggesting that cisplatin exerts its toxic action by platination and oxidative DNA damage, while cells treated with PNCs are protected against oxidatively induced lesions. Altogether, our study suggests that PNCs may provide a more effective treatment for tumors which have developed resistance toward cisplatin.

  19. Cytotoxicity and antitumor activity of bis(platinum) complexes. A novel class of platinum complexes active in cell lines resistant to both cisplatin and 1,2-diaminocyclohexane complexes.

    Science.gov (United States)

    Farrell, N; Qu, Y; Hacker, M P

    1990-08-01

    The in vitro cytotoxicity and in vivo antitumor activity of bis(platinum) complexes of general formula [(PtX2-(L))2H2N(CH2)nNH2] (L = NH3, X = Cl or X2 = malonato or where L = py, X = Cl) is reported. Chloride complexes [(PtCl2(NH3]2H2N(CH2)nNH2] may exist as three possible isomers: those containing both coordination units in the cis configuration (2,2/c,c), both coordination units in the trans configuration (2,2/t,t), and the mixed cis,trans species (2,2/c,t), whose synthesis is reported here. The preparation of further complexes with sterically hindered diamine backbones, such as 2,5-dimethyl-2,5-hexanediamine, is exemplified. The biological activity of all complexes were compared. The 2,2/c,c complexes are particularly active in tissue culture in cells resistant both to cisplatin and its 1,2-diaminocyclohexane (dach) analogue. The inhibition of DNA synthesis in L1210/0 cells by the 2,2/c,c complexes is equivalent to that of cisplatin. The presence of at least one cis-[Pt(amine)2] unit appears necessary for activity in cell lines sensitive to cisplatin.

  20. Design, synthesis and DNA interactions of a chimera between a platinum complex and an IHF mimicking peptide.

    Science.gov (United States)

    Rao, Harita; Damian, Mariana S; Alshiekh, Alak; Elmroth, Sofi K C; Diederichsen, Ulf

    2015-12-28

    Conjugation of metal complexes with peptide scaffolds possessing high DNA binding affinity has shown to modulate their biological activities and to enhance their interaction with DNA. In this work, a platinum complex/peptide chimera was synthesized based on a model of the Integration Host Factor (IHF), an architectural protein possessing sequence specific DNA binding and bending abilities through its interaction with a minor groove. The model peptide consists of a cyclic unit resembling the minor grove binding subdomain of IHF, a positively charged lysine dendrimer for electrostatic interactions with the DNA phosphate backbone and a flexible glycine linker tethering the two units. A norvaline derived artificial amino acid was designed to contain a dimethylethylenediamine as a bidentate platinum chelating unit, and introduced into the IHF mimicking peptides. The interaction of the chimeric peptides with various DNA sequences was studied by utilizing the following experiments: thermal melting studies, agarose gel electrophoresis for plasmid DNA unwinding experiments, and native and denaturing gel electrophoresis to visualize non-covalent and covalent peptide-DNA adducts, respectively. By incorporation of the platinum metal center within the model peptide mimicking IHF we have attempted to improve its specificity and DNA targeting ability, particularly towards those sequences containing adjacent guanine residues.

  1. DNA interaction studies of a platinum(II) complex containing L-histidine and 1,10-phenanthroline ligands.

    Science.gov (United States)

    Shahabadi, Nahid; Nemati, Leila

    2012-05-01

    The aim of this study was developing coordination complexes that can be used as inorganic medicinal agents. The water soluble [Pt(phen)(His)]NO(3)·3H(2)O complex in which phen=1,10-phenantheroline and His=L-histidine was synthesized and characterized using physicochemical methods. Binding interaction of this complex with calf thymus (CT) DNA was investigated by emission, absorption, circular dichroism, and viscosity measurement techniques. Upon addition of CT-DNA, changes were observed in the characteristic ultraviolet-visible (UV-Vis) bands (hypochromism) of the complex. The complex binds to CT-DNA in an intercalative mode. The calculated binding constant, K(b), was 8 ± 0.2 × 10(4) M(-1). In addition, circular dichroism (CD) study showed that the phenanthroline ligand was inserted between the base pair stack of the double-helical structure of DNA. Also, the fluorescence spectral characteristics showed an increase in fluorescence intensity of the platinum complex in the presence of increasing amounts of DNA solution. The experimental results showed that the platinum complex binds to DNA via intercalative and hydrogen bonding mode.

  2. Triphenyl phosphine adducts of platinum(IV) and palladium(II) dithiocarbamates complexes: a spectral and in vitro study

    Science.gov (United States)

    Manav, N.; Mishra, A. K.; Kaushik, N. K.

    2004-11-01

    Triphenyl phosphine adducts of dithiocarbamate complexes of platinum(IV) and palladium(II) of the type [Pt(L) 2PPh 3Cl 2] and [Pd(L) 2PPh 3] [L: morpholine dithiocarbamate (L 1), aniline dithiocarbamate (L 2) and N-(methyl, cyclohexyl) dithiocarbamate (L 3)] were prepared and characterized by elemental analysis, electronic, IR, 1H NMR and 13C NMR spectral studies. Thermal studies of the complexes were carried out. In vitro antitumor activity has been screened towards human adenocarcinoma cell lines and showed significant inhibition even at very low concentration.

  3. Synthesis, characterization, cytotoxicity, and DNA binding of some new platinum(II) and platinum(IV) complexes with benzimidazole ligands.

    Science.gov (United States)

    Utku, Semra; Gumus, Fatma; Tezcan, Seda; Serin, Mehmet Sami; Ozkul, Aykut

    2010-08-01

    In this study, two Pt(II) and three Pt(IV) complexes with the structures of [PtL(2)Cl(2)] (1), [PtL(2)I(2)] (2), [PtL(2)Cl(2)(OH)(2)] (3), [PtL(2)Cl(2)(OCOCH(3))(2)] (4), and [PtL(2)Cl(4)] (5) (L = benzimidazole as carrier ligand) were synthesized and evaluated for their in vitro antiproliferative activities against the human MCF-7, HeLa, and HEp-2 cancer cell lines. The influence of compounds 1-5 on the tertiary structure of DNA was determined by their ability to modify the electrophoretic mobility of the form I and II bands of pBR322 plasmid DNA. The inhibition of BamH1 restriction enzyme activity of compounds 1-5 was also determined. In general, it was found that compounds 1-5 were less active than cisplatin and carboplatin against MCF-7 and HeLa cell lines (except for 1, which was found to be more active than carboplatin against the MCF-7 cell line). Compounds 1 and 3 were found to be significantly more active than cisplatin and carboplatin against the HEp-2 cell line.

  4. Theoretical studies on vibrational spectra of mixed cyanide-halide complexes of platinum(IV) and palladium(IV)

    Science.gov (United States)

    Zhang, Yu; Zhang, Lin; Tao, Hanbing; Sun, Xiaojuan; Zhu, Longgen

    2003-02-01

    The vibrational spectra of mixed cyanide-halide complexes, M(CN) 4X 22- and M(CN) 5X 2- (M=Pt and Pd; X=F, Cl, Br and I), have been systematically investigated by ab initio RHF, B3LYP and MP2 methods with LanL2DZ and SDD basis sets. The calculated vibrational frequencies of platinum complexes are evaluated via comparison with the experimental values. In the infrared frequency region, the CN stretching vibrational frequencies calculated at B3LYP level with two basis sets are in good agreement with the observed values with deviations, -16-4 cm -1 for Pt(CN) 4X 22- and -18 to -2 cm -1 for Pt(CN) 5X 2-. However, in far-infrared region, the results obtained at RHF level are better than those calculated at B3LYP and MP2 levels. For RHF/SDD method, the deviations for PtX and PtC stretching vibrational frequencies are -14-1 and -12 to -2 cm -1 in the complex Pt(CN) 4X 22-, -19 to -11 and -15-14 cm -1 in the Pt(CN) 5X 2- complex, respectively. The vibrational frequencies of palladium(IV) and some platinum(IV) complexes that have not been experimentally reported are predicted.

  5. DNA interaction and cytotoxic activities of square planar platinum(II) complexes with N, S-donor ligands

    Science.gov (United States)

    Patel, Mohan N.; Patel, Chintan R.; Joshi, Hardik N.; Thakor, Khyati P.

    2014-06-01

    The platinum(II) complexes with N, S-donor ligands have been synthesized and characterized by physicochemical methods viz. elemental, electronic, FT-IR, 1H NMR and LC-MS spectra. The binding mode and potency of the complexes with HS DNA (Herring Sperm) have been examined by absorption titration and viscosity measurement studies. The results revealed that complexes bind to HS DNA via covalent mode with the intrinsic binding constant (Kb) in the range 1.37-7.76 × 105 M-1. Decrease in the relative viscosity of HS DNA also supports the covalent mode of binding. The DNA cleavage activity of synthesized complexes has been carried out by gel electrophoresis experiment using supercoiled form of pUC19 DNA; showing the unwinding of the negatively charged supercoiled DNA. Brine shrimp (Artemia Cysts) lethality bioassay technique has been applied for the determination of toxic property of synthesized complexes in terms of μM.

  6. The developmental neurotoxicity study of platinum compounds. Effects of cisplatin versus a novel Pt(II) complex on rat cerebellum.

    Science.gov (United States)

    Cerri, Silvia; Piccolini, Valeria M; Santin, Giada; Bottone, Maria G; De Pascali, Sandra A; Migoni, Danilo; Iadarola, Paolo; Fanizzi, Francesco P; Bernocchi, Graziella

    2011-01-01

    In the field of experimental oncology, many efforts are being carried out to search new platinum-based drugs overcoming the CNS toxicity and drug resistance. One of the adopted strategies is the synthesis of platinum compounds able to form Pt-DNA adducts different from the cisplatin ones or to react with other subcellular targets. In this context a novel Pt(II) complex, [Pt(O,O'-acac)(γ-acac)(DMS)](PtAcacDMS), was synthesized which reacts preferentially with protein thiols or thioethers. In this work we investigated the in vivo effects of cisplatin and PtAcacDMS on normal development. Moreover, to verify the dose-dependence of the effects, different groups of animals were treated with 5 μg/g or 10 μg/g body weight of cisPt and PtAcacDMS. We have focused our attention on the cerebellum because it provides a useful model system to evaluate the outcomes of perinatal treatment with chemotherapeutic agents on key CNS developmental processes such as neural cells proliferation, migration and differentiation. We have demonstrated the ability of both cisPt and PtAcacDMS to reach the brain tissue once injected. The brain platinum content after PtAcacDMS treatment was notably higher (approximately 4-fold as much) than after cisPt. The platinum accumulation in the brain was still considerable 7 days after PtAcacDMS administration. However, compared with cisplatin, PtAcacDMS induces less severe changes on fundamental events of neuroarchitecture development, such as no high apoptotic events, less altered granule cell migration and Purkinje cell dendrite growth, suggesting a low neurotoxicity of this new Pt complex for normal CNS. The mild damages could be attributable to the different subcellular target of this compound as well as to a greater efficiency of the cell repair system to recognize the drug-target adducts and to repair them. Together with the previously demonstrated antineoplastic effectiveness in vitro, the findings here reported suggest PtAcacDMS as a potential

  7. Behavior of platinum(iv) complexes in models of tumor hypoxia: cytotoxicity, compound distribution and accumulation.

    Science.gov (United States)

    Schreiber-Brynzak, Ekaterina; Pichler, Verena; Heffeter, Petra; Hanson, Buck; Theiner, Sarah; Lichtscheidl-Schultz, Irene; Kornauth, Christoph; Bamonti, Luca; Dhery, Vineet; Groza, Diana; Berry, David; Berger, Walter; Galanski, Markus; Jakupec, Michael A; Keppler, Bernhard K

    2016-04-01

    Hypoxia in solid tumors remains a challenge for conventional cancer therapeutics. As a source for resistance, metastasis development and drug bioprocessing, it influences treatment results and disease outcome. Bioreductive platinum(iv) prodrugs might be advantageous over conventional metal-based therapeutics, as biotransformation in a reductive milieu, such as under hypoxia, is required for drug activation. This study deals with a two-step screening of experimental platinum(iv) prodrugs with different rates of reduction and lipophilicity with the aim of identifying the most appropriate compounds for further investigations. In the first step, the cytotoxicity of all compounds was compared in hypoxic multicellular spheroids and monolayer culture using a set of cancer cell lines with different sensitivities to platinum(ii) compounds. Secondly, two selected compounds were tested in hypoxic xenografts in SCID mouse models in comparison to satraplatin, and, additionally, (LA)-ICP-MS-based accumulation and distribution studies were performed for these compounds in hypoxic spheroids and xenografts. Our findings suggest that, while cellular uptake and cytotoxicity strongly correlate with lipophilicity, cytotoxicity under hypoxia compared to non-hypoxic conditions and antitumor activity of platinum(iv) prodrugs are dependent on their rate of reduction.

  8. Cytotoxicity of cis-platinum(II) cycloaliphatic amidine complexes: Ring size and solvent effects on the biological activity.

    Science.gov (United States)

    Marzano, Cristina; Sbovata, Silvia Mazzega; Gandin, Valentina; Michelin, Rino A; Venzo, Alfonso; Bertani, Roberta; Seraglia, Roberta

    2009-08-01

    A series of new platinum(II) amidine derivatives of the type cis-[PtCl(2){Z-NHC(NHR)Me}(2)] (R=cyclopropyl, 1; cyclopentyl, 2; cyclohexyl, 3) were prepared in high yield by addition of the corresponding cyclic aliphatic amine RNH(2) to the coordinated acetonitrile ligands in cis-[PtCl(2)(NCMe)(2)]. The solution behaviour of 1-3 has been studied in DMSO, PEG 400 (polyethylene glycol) and PEG-DME 500 (polyethylene glycol dimethylether). The amidine complexes 1-3 were evaluated for their cytotoxic properties against a panel of human tumor cell lines containing examples of cervix (HeLa), breast (MCF7), lung (A549) and colon (HCT-15) cancer. Moreover, the amidine complexes were tested for their cytotoxicity against normal human fibroblasts (HFF-1). For comparison purposes, the cytotoxicity of cisplatin was examined under the same experimental conditions. The results obtained showed that PEG and PEG-DME behave as good solvents to carry out biological assays with platinum complexes which are water-insoluble and unstable in DMSO. Complexes 2 and 3 exhibited a biological activity comparable to that of cisplatin.

  9. Novel platinum(II) complexes of long chain aliphatic diamine ligands with oxalato as the leaving group: Comparative cytotoxic activity relative to chloride precursors

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Heveline; Barra, Carolina V.; Rocha, Fillipe V.; Fontes, Ana Paula S. [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Dept. de Quimica; Lopes, Miriam T.P. [Universidade Federal deMinas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Farmacologia; Frezard, Frederic, E-mail: frezard@icb.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisiologia e Biofisica

    2010-07-01

    Platinum complexes play an important role in the development of anticancer drugs. Their cytotoxicity can be influenced by the nature of the leaving ligands, due to the hydrolysis reaction that occurs prior to the binding of the platinum complex to DNA. Also, non-leaving groups such as lipophilic diamines may affect cellular uptake. In this work, we describe the synthesis of platinum(II) complexes having oxalato and long chain aliphatic N-alkyl ethylenediamines as ligands. The products were characterized by elemental analyses, infrared spectroscopy and {sup 1}H, {sup 13}C and {sup 195}Pt NMR spectroscopy. Biological activity was assessed against tumor cell lines (A{sub 549}, B16-F1, B16-F10, MDA-MB-231) and non-tumor cell lines (BHK-21 and CHO). The length of the carbon chain affects the cytotoxicity and the oxalato complexes were less cytotoxic than the respective chloride-containing analogues. (author)

  10. Highly luminescent half-lantern cyclometalated platinum(II) complex: synthesis, structure, luminescence studies, and reactivity.

    Science.gov (United States)

    Sicilia, Violeta; Forniés, Juan; Casas, José Ma; Martín, Antonio; López, José A; Larraz, Carmen; Borja, Pilar; Ovejero, Carmen; Tordera, Daniel; Bolink, Henk

    2012-03-19

    The half-lantern compound [{Pt(bzq)(μ-C(7)H(4)NS(2)-κN,S)}(2)]·Me(2)CO (1) was obtained by reaction of equimolar amounts of potassium 2-mercaptobenzothiazolate (KC(7)H(4)NS(2)) and [Pt(bzq)(NCMe)(2)]ClO(4). The Pt(II)···Pt(II) separation in the neutral complex [{Pt(bzq)(μ-C(7)H(4)NS(2)-κN,S)}(2)] is 2.910 (2) Å, this being among the shortest observed in half-lantern divalent platinum complexes. Within the complex, the benzo[h]quinoline (bzq) groups lie in close proximity with most C···C distances being between 3.3 and 3.7 Å, which is indicative of significant π-π interactions. The reaction of 1 with halogens X(2) (X(2) = Cl(2), Br(2), or I(2)) proceeds with a two-electron oxidation to give the corresponding dihalodiplatinum(III) complexes [{Pt(bzq)(μ-C(7)H(4)NS(2)-κN,S)X}(2)] (X = Cl 2, Br 3, I 4). Their X-ray structures confirm the retention of the half-lantern structure and the coordination mode of the bzq and the bridging ligand μ-C(7)H(4)NS(2)-κN,S. The Pt-Pt distances (Pt-Pt = 2.6420(3) Å 2, 2.6435(4) Å 3, 2.6690(3) Å 4) are shorter than that in 1 because of the Pt-Pt bond formation. Time dependent-density functional theory (TD-DFT) studies performed on 1 show a formal bond order of 0 between the metal atoms, with the 6p(z) contribution diminishing the antibonding character of the highest occupied molecular orbital (HOMO) and being responsible for an attractive intermetallic interaction. A shortening of the Pt-Pt distance from 2.959 Å in the ground state S(0) to 2.760 Å in the optimized first excited state (T(1)) is consistent with an increase in the Pt-Pt bond order to 0.5. In agreement with TD-DFT calculations, the intense, structureless, red emission of 1 in the solid state and in solution can be mainly attributed to triplet metal-metal-to-ligand charge transfer ((3)MMLCT) [dσ*(Pt-Pt) → π*(bzq)] excited states. The high quantum yields of this emission measured in toluene (44%) and solid state (62%) at room temperature indicate

  11. Quantitative measurement of the reduction of platinum(IV) complexes using X-ray absorption near-edge spectroscopy (XANES).

    Science.gov (United States)

    Hall, Matthew D; Daly, Helen L; Zhang, Jenny Z; Zhang, Mei; Alderden, Rebecca A; Pursche, Daniel; Foran, Garry J; Hambley, Trevor W

    2012-06-01

    The platinum(II) drugs cisplatin, carboplatin and oxaliplatin are usefully employed against a range of malignancies, but toxicities and resistance have spurred the search for improved analogs. This has included investigation of the platinum(IV) oxidation state, which provides greater kinetic inertness. It is generally accepted that Pt(IV) complexes must be reduced to Pt(II) for activation. As such, the ability to monitor reduction of Pt(IV) complexes is critical to guiding the design of candidates, and providing mechanistic understanding. Here we report in full that the white line height of X-ray absorption near-edge spectra (XANES) of Pt complexes, normalized to the post-edge minima, can be used to quantitatively determine the proportion of each oxidation state in a mixture. A series of Pt(IV) complexes based on the Pt(II) complexes cisplatin and transplatin were prepared with chlorido, acetato or hydroxido axial ligands, and studies into their reduction potential and cytotoxicity against A2780 human ovarian cancer cells were performed, demonstrating the relationship between reduction potential and cytotoxicity. Analysis of white line height demonstrated a clear and consistent difference between Pt(II) (1.52 ± 0.05) and Pt(IV) (2.43 ± 0.19) complexes. Reduction of Pt(IV) complexes over time in cell growth media and A2780 cells was observed by XANES, and shown to correspond with their reduction potentials and cytotoxicities. We propose that this method is useful for monitoring reduction of metal-based drug candidates in complex biological systems.

  12. Trans-platinum(II)/(IV) Complexes with Acetylpyridine Ligands as Antivascular Agents in vitro: Cytotoxic and Antiangiogenic Potential.

    Science.gov (United States)

    Lana, Filipović; Sandra, Aranđelović; Ana, Krivokuća; Radmila, Janković; Biljana, Dojčinović; Siniša, Radulović

    2016-01-01

    In vitro biological studies of four trans-platinum complexes of structural formulas trans-[PtCl2(n-acetylpyridine)2] (n = 3 or 4, complex 1 or 2) and [Pt(n-acetylpyridine)2Cl4] (n = 3 or 4, complex 3 or 4) were performed in human endothelial EA.hy 926 cells, in order to evaluate and compare their cytotoxic and antiangiogenic potential. MTT results revealed that trans-Pt(II) complexes exhibited significantly lower IC50 values: 4.0±0.9 μM (1) and 2.1±0.0 μM (2), than cisplatin (27.7±1.3 μM). Combinational drug treatment with N-Acetyl-L-cysteine and L-buthioninesulfoximine strongly counteracted effect of 1 and 2, while the same treatment rather enhanced cytotoxicity of Pt(IV) analogues. ICP-MS results suggested that differential endothelial toxicity of cisplatin and trans-platinum complexes correlated to the differences in their cellular accumulation, rather than to the different affinity of DNA binding. Intracellular accumulation of complexes (ng Pt/106 cells) for 24 h treatment, decreased in order: 1>2>4>3>CDDP, while ratio of DNA binding (pg Pt/μg DNA) decreased as following: 2>1>CDDP>4>3. FACS/Annexin-V-FITC analysis, and morphological study demonstrated that the enhanced cytotoxic and apoptotic potential (18.1%) of complex 2 was related to its highest affinity to bind nuclear DNA. Pt(IV) complexes exhibited the lowest reactivity to cellular DNA and proteins. Regardless of their antiproliferative action, 1-4 at subtoxic concentrations demonstrated in vitro inhibitory effect on tubulogenesis and matrix metalloproteinases (MMPs) 2 and 9 gelatinolitic activity, while 1 and 2 additionally downregulated MMP-2 gene expression.

  13. A new platinum complex with tryptophan: synthesis, structural characterization, DFT studies and biological assays in vitro over human tumorigenic cells.

    Science.gov (United States)

    Carvalho, Marcos A; Shishido, Silvia M; Souza, Bárbara C; de Paiva, Raphael E F; Gomes, Alexandre F; Gozzo, Fábio C; Formiga, André L B; Corbi, Pedro P

    2014-03-25

    A new platinum(II) complex with the amino acid L-tryptophan (trp), named Pt-trp, was synthesized and characterized. Elemental, thermogravimetric and ESI-QTOF mass spectrometric analyses led to the composition [Pt(C11H11N2O2)2]⋅6H2O. Infrared spectroscopic data indicate the coordination of trp to Pt(II) through the oxygen of the carboxylate group and also through the nitrogen atom of the amino group. The (13)C CP/MAS NMR spectroscopic data confirm coordination through the oxygen atom of the carboxylate group, while the (15)N CP/MAS NMR data confirm coordination of the nitrogen of the NH2 group to the metal. Density functional theory (DFT) studies were applied to evaluate the cis and trans coordination modes of trp to platinum(II). The trans isomer was shown to be energetically more stable than the cis one. The Pt-trp complex was evaluated as a cytotoxic agent against SK-Mel 103 (human melanoma) and Panc-1 (human pancreatic carcinoma) cell lines. The complex was shown to be cytotoxic over the considered cells.

  14. Zwitterionic and Cationic Bis(phosphine) Platinum(II) Complexes:  Structural, Electronic, and Mechanistic Comparisons Relevant to Ligand Exchange and Benzene C−H Activation Processes

    OpenAIRE

    Thomas, J. Christopher; Peters, Jonas C.

    2003-01-01

    Structurally similar but charge-differentiated platinum complexes have been prepared using the bidentate phosphine ligands [Ph_(2)B(CH_(2)PPh_(2))_(2)], ([Ph_(2)BP_(2)], [1]), Ph_(2)Si(CH_(2)PPh_(2))_(2), (Ph_(2)SiP_(2), 2), and H_(2)C(CH_(2)PPh_(2))_(2), (dppp, 3). The relative electronic impact of each ligand with respect to a coordinated metal center's electron-richness has been examined using comparative molybdenum and platinum model carbonyl and alkyl complexes. Complexes supported by an...

  15. SYNTHESIS OF DI(ETHYLMERCAPTOETHYL) AMINO GROUP—CONTAINING POLYSESQUISILOXANE PLATINUM COMPLEX AND ITS CATALYSIS IN HYDROSIL YLATION OF OLEFINS WITH TRIETHOXYSILANE

    Institute of Scientific and Technical Information of China (English)

    CHENYuanyin; HUXubo; 等

    1992-01-01

    Three new polysesquisiloxane-bound platinum complexes were synthesized via hydrolysis of N,N-di(β-ethylmercaptoethyl)γ-(triethoxysilyl)propylamine or cohydrolysis of the monomer with dodecyltriethoxysilane or with phenylpropylthiethoxysilane and immobilixation on fumed silica,followed by reacting with potassium platinite in acetone under argon atmosphere.The platinum complexes exhibited high catalytic activity for the hydrosilylation of olefins by triethoxysilane. The effects of temperature and the amount of complex on the catalytic activity,as well as the recovery and reusability of the catalysts were investigated.

  16. Preparation and Biological Evaluation of Two Novel Platinum(II Complexes Based on the Ligands of Dipicolyamine Bisphosphonate Esters

    Directory of Open Access Journals (Sweden)

    Ling Qiu

    2016-02-01

    Full Text Available Two new platinum(II-based complexes bearing a bone-targeting group were synthesized and characterized. They both have excellent affinity for hydroxyapatite (HA, which is abundant in human bone tissues. Their antitumor activities against five human cancer cell lines (U2OS, A549, HCT116, MDA-MB-231 and HepG2 were evaluated and compared with cisplatin (CDDP. Though the antitumor efficacies of new complexes are lower than that of CDDP, they show higher selectivity against the HepG2 hepatoma cell line than the L02 normal liver cell line. Morphology studies exhibited typical characteristics of cell apoptosis and the cell cycle distribution analysis indicated that the complexes can inhibit cancer cells by inducing cell cycle arrest at the G2/M phase, a similar mechanism of action to CDDP.

  17. Highly water-soluble platinum(II) complexes as GLUT substrates for targeted therapy: improved anticancer efficacy and transporter-mediated cytotoxic properties.

    Science.gov (United States)

    Liu, Pengxing; Lu, Yanhui; Gao, Xiangqian; Liu, Ran; Zhang-Negrerie, Daisy; Shi, Ying; Wang, Yiqiang; Wang, Songqing; Gao, Qingzhi

    2013-03-25

    Glucose-conjugated malonato-platinum(II) complexes are designed and synthesized to target tumor-specific active transporters, namely, glucose transporters (GLUTs); the complexes exhibit much higher aqueous solubility by 150 times, improved potency in cytotoxicities by 10 times, and increased therapeutic index by over 30 fold compared to the newest generation of clinical drugs oxaliplatin.

  18. Application of cellulose anion-exchangers to separation of palladium from platinum or iridium with glycine as complexing agent and atomic-absorption spectrometry for detection.

    Science.gov (United States)

    Brajter, K; Słonawska, K

    1983-07-01

    The use of glycine as complexing agent for chromatographie separation of palladium from platinum, or palladium from iridium, on cellulose anion-exchangers has been investigated and found possible over a wide range of concentration ratios. The method can be used for analysis of Pd-Ir alloys. The nature of the complexes taking part in the ion-exchange has been identified.

  19. Dicyclohexylammonium (S-2-azido-3-phenylpropanoate

    Directory of Open Access Journals (Sweden)

    Sebastian J. Petrik

    2012-07-01

    Full Text Available The asymmetric unit of the title compound, C12H24N+·C9H8N3O2−, consists of two dicyclohexylammonium cations linked to two (S-2-azido-3-phenylpropanoate anions by four short N—H...O hydrogen bonds with N...O distances in the range 2.712 (3–2.765 (3 Å. The dicyclohexylammonium cations and the aryl and carboxylate groups of the anion are related by a pseudo-inversion centre, with overall crystallographic inversion symmetry for the structure broken by the chirality of the α-C atoms of the anions.

  20. SYNTHESIS AND CHARACTERIZATION OF A SILICA-SUPPORTED CARBOXYMETHYLCELLULOSE PLATINUM COMPLEX AND ITS CATALYTIC BEHAVIORS FOR HYDROGENATION OF AROMATICS

    Institute of Scientific and Technical Information of China (English)

    TANG Liming; HUANG Meiyu; JIANG Yingyan

    1996-01-01

    A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydrogenation of aromatic compounds were studied. The results showed that this catalyst could catalyze the hydrogenation of phenol, anisol, p-cresol, benzene and toluene to cyclohexanol, cyclohexyl methyl ether, p-methyl cyclohexanol, cyclohexane and methylcyclohexane, respectively in 100% yield at 30℃ and 1 atm. In the hydrogenation of phenol,COO/Pt ratio in SiO2-CMC-Pt has much influence on the initial hydrogenation rate and the selectivity for the intermediate product, cyclohexanone. The highest initial rate and the highest yield of cyclohexanone both occur at COO/Pt ratio of 6. The complex is stable during the reaction and can be used repeatedly.

  1. Synthesis and antitumor activity of a series of [2-substituted-4,5-bis(aminomethyl)-1,3-dioxolane]platinum(II) complexes.

    Science.gov (United States)

    Kim, D K; Kim, G; Gam, J; Cho, Y B; Kim, H T; Tai, J H; Kim, K H; Hong, W S; Park, J G

    1994-05-13

    The synthesis, physical properties, antitumor activity, structure-activity relationships, and nephrotoxicity of a series of [2-substituted-4,5-bis(aminomethyl)-1,3-dioxolane]platinum(II) complexes are described. The 42 platinum(II) complexes having a seven-membered ring structure in this series have been prepared and characterized by 1H NMR, 13C NMR, IR, FAB-MS, and elemental analysis. All members of the series were designed to have a 1,3-dioxolane ring moiety in their carrier ligands to increase water solubility. The solubility of platinum complexes was related to the nature of leaving ligands and 2-substituents in the 4,5-bis(aminomethyl)-1,3-dioxolane carrier ligands. In general, compounds having two different R1 and R2 substituents in the 4,5-bis(aminomethyl)-1,3-dioxolane moiety were more water-soluble than those having the same substituents. Most members of this series showed the excellent antitumor activity against murine L1210 leukemia cells transplanted in mice and were superior to cisplatin and carboplatin. The (4R,5R)-stereoisomer 1a-h exhibited the higher antitumor activity than the corresponding (4S,5S)-stereoisomer 2a-h in the (1,1-cyclobutanedicarboxylato)platinum(II) complexes. The (glycolato)-platinum(II) complexes were highly cytotoxic toward four human stomach cancer cell lines, SNU-1, SNU-5, SNU-16, and NCI-N87, and among them, complexes 3d-g were even more cytotoxic than cisplatin. The (malonato)platinum(II) complex 1m and the (glycolato)platinum(II) complexes 3d-g were selected for further studies based on the greater in vivo and in vitro antitumor activity and desirable physical properties. The complexes 3e-g were almost equally cytotoxic to cisplatin toward human stomach cancer cell lines, KATO-III and MKN-45, and a human non-small cell lung cancer cell line, PC14. In contrast with cisplatin and carboplatin, five complexes selected significantly increased in life span in mice transplanted with cisplatin-resistant L1210 cells. Nephrotoxicity

  2. Platinum-group elements and minerals in the lower and middle group chromitites of the western Bushveld Complex, South Africa

    Science.gov (United States)

    Junge, Malte; Oberthür, Thomas; Osbahr, Inga; Gutter, Paul

    2016-10-01

    The chromitites of the Bushveld Complex in South Africa contain vast resources of platinum-group elements (PGE). However, knowledge of the distribution and the mineralogical siting of the PGE in the lower group (LG) and middle group (MG) chromitite seams of the Bushveld Complex is limited. We studied concentrates from the LG-6 and MG-2 chromitites of the western Bushveld Complex by a variety of microanalytical techniques. The dominant PGM are sulfides, namely laurite, cooperite-braggite, and malanite-cuprorhodsite, followed by PGE-sulfarsenides, sperrylite, and Pt-Fe alloys. Laurite is the most abundant PGM (vol%). The matching sets of PGM present in the LG and MG chromitites of both the western and the eastern Bushveld Complex, and in the UG-2 chromitite, show strong similarities which support the assumption of a characteristic and general chromitite-related PGM assemblage. Palladium and Rh contents in pentlandite are low and erratic although maximum contents of 7730 ppm Pd and 6020 ppm Rh were detected. Rare thiospinels of the polydymite-linnaeite-greigite series have PGE contents of 1430 ppm Pt, 5370 ppm Rh, and 1460 ppm Pd. The various PGE occur in different deportment: Platinum is generally present in the form of discrete PGM (sulfides, arsenides, alloys). Palladium is present as a large variety of discrete PGM and also incorporated in pentlandite. Rhodium forms discrete PGM and is occasionally present in pentlandite. The IPGE (Os, Ir, and Ru) are dominantly incorporated in laurite (often as inclusions in chromite) and also occur as sulfarsenides.

  3. Density functional theory studies on the oxidation of 5'-dGMP and 5'-dAMP by a platinum(IV) complex.

    Science.gov (United States)

    Ariafard, Alireza; Tabatabaie, Elham S; Aghmasheh, Simin; Najaflo, Sahar; Yates, Brian F

    2012-08-06

    Density functional theory has been used to investigate the oxidation of a guanine nucleotide by platinum(IV), a process that can be important in the degradation of DNA. For the first time, we have provided a comprehensive mechanism for all of the steps in this process. A number of intermediates are predicted to occur but with short lifetimes that would make them difficult to observe experimentally. A key step in the mechanism is electron transfer from guanine to platinum(IV), and we show that this is driven by the loss of a chloride ligand from the platinum complex after nucleophilic attack of 5'-phosphate to C8 of guanine. We have investigated several different initial platinum(IV) guanine adducts and shown that the adduct formed from replacement of an axial chlorine ligand in the platinum(IV) complex undergoes oxidation more easily. We have studied adenine versus guanine adducts, and our results show that oxidation of the former is more difficult because of disruption of the aromatic π system that occurs during the process. Finally, our results show that the acidic hydrolysis step to form the final oxidized product occurs readily via an initial protonation of N7 of the guanine.

  4. Synthesis, characterization and multi-spectroscopic DNA interaction studies of a new platinum complex containing the drug metformin

    Science.gov (United States)

    Shahabadi, Nahid; Heidari, Leila

    2014-07-01

    A new platinum(II) complex; [Pt(Met)(DMSO)Cl]Cl in which Met = metformin and DMSO: dimethylsulfoxide, was synthesized and characterized by 1H NMR, IR, UV-Vis spectra, molar conductivity and computational methods. Binding interaction of this complex with calf thymus (CT) DNA has been investigated by using absorption, emission, circular dichroism, viscosity measurements, differential pulse voltammetry and cleavage studies by agarose gel electrophoresis. UV-Vis absorption studies showed hyperchromism. CD studies showed less perturbation on the base stacking and helicity bands in the CD spectrum of CT-DNA (B → C structural transition). In fluorimeteric studies, the Pt(II) complex can bind with DNA-NR complex and forms a new non-fluorescence adduct. The anodic peak current in the differential pulse voltammogram of the Pt(II) complex decreased gradually with the addition of DNA. Cleavage experiments showed that the Pt(II) complex does not induce any cleavage under the experimental setup. Finally all results indicated that Pt(II) complex interact with DNA via groove binding mode.

  5. Synthesis, characterization and multi-spectroscopic DNA interaction studies of a new platinum complex containing the drug metformin.

    Science.gov (United States)

    Shahabadi, Nahid; Heidari, Leila

    2014-07-15

    A new platinum(II) complex; [Pt(Met)(DMSO)Cl]Cl in which Met = metformin and DMSO: dimethylsulfoxide, was synthesized and characterized by (1)H NMR, IR, UV-Vis spectra, molar conductivity and computational methods. Binding interaction of this complex with calf thymus (CT) DNA has been investigated by using absorption, emission, circular dichroism, viscosity measurements, differential pulse voltammetry and cleavage studies by agarose gel electrophoresis. UV-Vis absorption studies showed hyperchromism. CD studies showed less perturbation on the base stacking and helicity bands in the CD spectrum of CT-DNA (B→C structural transition). In fluorimeteric studies, the Pt(II) complex can bind with DNA-NR complex and forms a new non-fluorescence adduct. The anodic peak current in the differential pulse voltammogram of the Pt(II) complex decreased gradually with the addition of DNA. Cleavage experiments showed that the Pt(II) complex does not induce any cleavage under the experimental setup. Finally all results indicated that Pt(II) complex interact with DNA via groove binding mode.

  6. Spectrophotometric determination of platinum(IV) in alloys, complexes, environmental, and pharmaceutical samples using 4-[N,N-(diethyl)amino] benzaldehyde thiosemicarbazone.

    Science.gov (United States)

    Naik, P Parameshwara; Karthikeyan, J; Shetty, A Nityananda

    2010-12-01

    4-[N,N-(Diethyl)amino] benzaldehyde thiosemicarbazone (DEABT) is proposed as an analytical reagent for the spectrophotometric determination of platinum(IV). The DEABT forms 1:2 yellow complex with Pt(IV), which is sparingly soluble in water and completely soluble in water-ethanol-DMF medium. The Pt(IV)-DEABT complex shows maximum absorbance at 405 nm. Beer's law is valid up to 7.80 μg cm(-3), and optimum concentration range for the determination of platinum(IV) is 0.48-7.02 μg cm(-3). The molar absorptivity and Sandell's sensitivity of the method are found to be 1.755 × 10(4) dm(3) mol(-1) cm(-1) and 0.0012 μg cm(-2), respectively. The relative error and coefficient of variation (n=6) for the method does not exceed ± 0.43% and 0.35%, respectively. Since the method tolerates a number of metal ions commonly associated with platinum, it can be employed for the determination of platinum in environmental samples, pharmaceutical samples, alloys, catalysts, and complexes. The method is rapid as the Pt(IV)-DEABT complex is soluble in water-ethanol-DMF medium and not requiring any time consuming extraction method for the complex.

  7. Complexes of platinum and palladium with β-diketones and DMSO: Synthesis, characterization, molecular modeling, and biological studies

    Science.gov (United States)

    do Couto Almeida, J.; Marzano, I. M.; de Paula, F. C. Silva; Pivatto, M.; Lopes, N. P.; de Souza, P. C.; Pavan, F. R.; Formiga, A. L. B.; Pereira-Maia, E. C.; Guerra, W.

    2014-10-01

    This work reports on the synthesis and characterization of new complexes of the type [MCl(L)DMSO], where L = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (HTPB) or 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (HTTA) and M = Pt2+ or Pd2+. These complexes were characterized by elemental analyses, conductivity measurements, FT-IR, UV-Vis, high-resolution mass spectra (HRESIMS) and TG/DTA. In the complexes, the metallic ions bind to β-diketone via the oxygen atoms and to DMSO molecule via sulfur atom. The structures of complexes were optimized and theoretical data showed good agreement with the experimental results. The cytotoxic activity of the compounds was evaluated in a chronic myelogenous leukemia cell line. The platinum complexes were more cytotoxic than the free ligands and carboplatin and are promising candidates for further investigations. As example, the compound [PtCl(TPB)(DMSO)] inhibits the growth of K562 cells with an IC50 value equal to 2.5 μM. Furthermore, microbiological assays against Mycobacterium tuberculosis showed that all complexes exhibit low cytotoxicity against this bacterial strain while the free ligands exhibited MIC values of approximately 10 μg mL-1.

  8. DNA interaction studies of a platinum (II) complex containing an antiviral drug, ribavirin: the effect of metal on DNA binding.

    Science.gov (United States)

    Shahabadi, Nahid; Mirzaei kalar, Zeinab; Moghadam, Neda Hosseinpour

    2012-10-01

    The water-soluble Pt (II) complex, [PtCl (DMSO)(N(4)N(7)-ribavirin)]· H(2)O (ribavirin is an antiviral drug) has been synthesized and characterized by physico-chemical and spectroscopic methods. The binding interactions of this complex with calf thymus DNA (CT-DNA) were investigated using fluorimetry, spectrophotometry, circular dichroism and viscosimetry. The complex binds to CT-DNA in an intercalative mode. The calculated binding constant, K(b), was 7.2×10(5) M(-1). In fluorimetric studies, the enthalpy (ΔH0) changes of the reaction between the Pt (II) complex with CT-DNA showed hydrophobic interaction. In addition, CD study showed stabilization of the right-handed B form of CT-DNA. All these results prove that the complex interacts with CT-DNA via intercalative mode of binding. In comparison with the previous study of the DNA interaction with ribavirin, these results show that platinum complex has greater affinity to CT-DNA.

  9. New binary and ternary platinum(II) formamidine complexes: Synthesis, characterization, structural studies and in-vitro antitumor activity

    Science.gov (United States)

    Soliman, Ahmed A.; Alajrawy, Othman I.; Attaby, Fawzy A.; Linert, W.

    2016-07-01

    A series of new binary and ternary platinum(II) complexes of the type [Pt(L1-4)Cl2].xH2O and [Pt(L1-4)ox].xH2O where L = formamidine ligands and ox = oxalate, have been synthesized and characterized by elemental analyses, magnetic susceptibility, UV-vis, infrared (IR), mass spectroscopy, thermal analysis and theoretical calculations. The spectroscopic data indicated that the formamidine ligands act as bidentate N2 donors. The complexes (1-8) are diamagnetic and the optimization of their structures indicated that the geometry is distorted square planar with Cl-Pt-Cl, O-Pt-O and N-Pt-N bond angles ranged 81.73°-95.82° which is acceptable for the heteroleptic complexes. The electronic energies (a.u.) of the complexes (-893.53 to -1989.84) indicate that the complexes are more stable than the ligands. The energies of the HOMO (-0.218 to -0.244) and LUMO (-.0111to -0.134) orbitals of the complexes were negative which indicates that the complexes are stable compounds. The dipole moment of the complexes (6.23-19.89 Debye) indicates that the complexes are polarized. The complexes are thermally stable as shown from their relatively higher overall activation energies (889-2066 kJ mol-1). The complexes are proved to have a good cytotoxicity with IC50 (μM) against MCF-7 (0.040-0.117), HCT-116 (0.085-0.119) and HepG-2 (0.058-0.131) cell lines, which open the field for further application as antitumor compounds.

  10. SO2-binding properties of cationic η6,η1-NCN-pincer arene ruthenium platinum complexes: spectroscopic and theoretical studies

    NARCIS (Netherlands)

    Bonnet, S.A.; van Lenthe, J.H.; van Dam, H.J.J.; van Koten, G.; Klein Gebbink, R.J.M.

    2011-01-01

    The SO2-binding properties of a series of h6,h1-NCN-pincer ruthenium platinum complexes (NCN = 2,6-bis[(dimethylamino)methyl]phenyl anion) have been studied by both UV-visible spectroscopy and theoretical calculations. When an electron-withdrawing [Ru(C5R5)]+ fragment (R = H or Me) is h6-coordinated

  11. SO2-binding properties of cationic η6,η1-NCN-pincer arene ruthenium platinum complexes: spectroscopic and theoretical studies

    NARCIS (Netherlands)

    Bonnet, S.A.; van Lenthe, J.H.; van Dam, H.J.J.; van Koten, G.; Klein Gebbink, R.J.M.

    2011-01-01

    The SO2-binding properties of a series of h6,h1-NCN-pincer ruthenium platinum complexes (NCN = 2,6-bis[(dimethylamino)methyl]phenyl anion) have been studied by both UV-visible spectroscopy and theoretical calculations. When an electron-withdrawing [Ru(C5R5)]+ fragment (R = H or Me) is h6-coordinated

  12. Platinum metals in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Zereini, Fathi [Frankfurt Univ. (Germany). Dept. of Environmental Analytical Chemistry; Wiseman, Clare L.S. (ed.) [Toronto Univ. (Canada). School of the Environment

    2015-03-01

    This book contains the five chapters with the following topics: 1. SOURCES OF PGE EMISSIONS ELEMENTS: Sources of Platinum Group Elements (PGE) in the Environment; Impact of Platinum Group Element Emissions from Mining and Production Activities. 2. ANALYTICAL METHODS FOR THE DETERMINATION OF PGE IN BIOLOGICAL AND ENVIRONMENTAL MATRICES: Appraisal of Biosorption for Recovery, Separation and Determination of Platinum, Palladium and Rhodium in Environmental Samples; On the Underestimated Factors Influencing the Accuracy of Determination of Pt and Pd by Electrothermal Atomic Absorption Spectrometry in Road Dust Samples; Application of Solid Sorbents for Enrichment and Separation of Platinum Metal Ions; Voltammetric Analysis of Platinum in Environmental Matrices; Speciation Analysis of Chloroplatinates; Analysis of Platinum Group Elements in Environmental Samples: A Review. 3. OCCURRENCE, CHEMICAL BEHAVIOR AND FATE OF PGE IN THE ENVIRONMENT: Brazilian PGE Research Data Survey on Urban and Roadside Soils; Platinum, Palladium and Rhodium in a Bavarian Roadside Soil; Increase of Platinum Group Element Concentrations in Soils and Airborne Dust During the Period of Vehicular Exhaust Catalysts Introduction; Platinum-Group Elements in Urban Fluvial Bed Sediments-Hawaii; Long-Term Monitoring of Palladium and Platinum Contents in Road Dust of the City of Munich, Germany; Characterization of PGEs and Other Elements in Road Dusts and Airborne Particles in Houston, Texas; Accumulation and Distribution of Pt and Pd in Roadside Dust, Soil and Vegetation in Bulgaria; Increase of the Environmental Pt Concentration in the Metropolitan Area of Mexico City Associated to the Use of Automobile Catalytic Converters; Solubility of Emitted Platinum Group Elements (Pt, Pd and Rh) in Airborne Particulate Matter (PM10) in the Presence of Organic Complexing Agents; The Influence of Anionic Species (Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup 2-}) on the Transformation and Solubility of Platinum in

  13. Unsymmetric mono- and dinuclear platinum(IV) complexes featuring an ethylene glycol moiety: synthesis, characterization, and biological activity.

    Science.gov (United States)

    Pichler, Verena; Heffeter, Petra; Valiahdi, Seied M; Kowol, Christian R; Egger, Alexander; Berger, Walter; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K

    2012-12-27

    Eight novel mononuclear and two dinuclear platinum(IV) complexes were synthesized and characterized by elemental analysis, one- and two-dimensional NMR spectroscopy, mass spectrometry, and reversed-phase HPLC (log k(w)) and in one case by X-ray diffraction. Cytotoxicity of the compounds was studied in three human cancer cell lines (CH1, SW480, and A549) by means of the MTT assay, featuring IC(50) values to the low micromolar range. Furthermore a selected set of compounds was investigated in additional cancer cell lines (P31 and P31/cis, A2780 and A2780/cis, SW1573, 2R120, and 2R160) with regard to their resistance patterns, offering a distinctly different scheme compared to cisplatin. To gain further insights into the mode of action, drug uptake, DNA synthesis inhibition, cell cycle effects, and induction of apoptosis were determined for two characteristic substances.

  14. Platinum group elements in stream sediments of mining zones: The Hex River (Bushveld Igneous Complex, South Africa)

    Science.gov (United States)

    Almécija, Clara; Cobelo-García, Antonio; Wepener, Victor; Prego, Ricardo

    2017-05-01

    Assessment of the environmental impact of platinum group elements (PGE) and other trace elements from mining activities is essential to prevent potential environmental risks. This study evaluates the concentrations of PGE in stream sediments of the Hex River, which drains the mining area of the Bushveld Igneous Complex (South Africa), at four sampling points. Major, minor and trace elements (Fe, Ca, Al, Mg, Mn, V, Cr, Zn, Cu, As, Co, Ni, Cd, and Pb) were analyzed by FAAS and ETAAS in suspended particulate matter and different sediment fractions (rocks. The highest concentrations were observed closer to the mining area, decreasing with distance and in the cycle, increasing the presence of PGE in the fine fraction of river sediments. We propose that indicators such as airborne particulate matter, and soil and river sediment quality, should be added to the protocols for evaluating the sustainability of mining activities.

  15. Platinum Complexes-Induced Cardiotoxicity of Isolated, Perfused Rat Heart: Comparison of Pt(II) and Pt(IV) Analogues Versus Cisplatin.

    Science.gov (United States)

    Misic, Miroslav M; Jakovljevic, Vladimir L; Bugarcic, Zivadin D; Zivkovic, Vladimir I; Srejovic, Ivan M; Barudzic, Nevena S; Djuric, Dragan M; Novokmet, Slobodan S

    2015-07-01

    We have compared the cardiotoxicity of five platinum complexes in a model of isolated rat heart using the Langendorff technique. These effects were assessed via coronary flow (CF) and cardiac functional parameters. cis-Diamminedichloroplatinum(II) (cisplatin, CDDP), dichloro-(1,2-diaminocyclohexane)platinum(II) (Pt((II))DACHCl2), dichloro-(ethylenediamine)platinum(II) (Pt((II))ENCl2), tetrachloro-(1,2-diaminocyclohexane)platinum(IV) (Pt((IV))DACHCl4) and tetrachloro-(ethylenediamine)platinum(IV) (Pt((II))ENCl4) were perfused at increasing concentrations of 10(-8), 10(-7), 10(-6), 10(-5) and 10(-4) M during 30 min. In this paper, we report that cisplatin-induced dose-dependent effects on cardiac contractility and coronary flow both manifested as decrease in cardiac contractile force (dP/dt)max, heart rate and significant reduction in CF. Pt((II))ENCl2, Pt((IV))ENCl2 and Pt((IV))DACHCl4 did induce dose-dependent response only in case of CF. Our results could be also important for better understanding dose-dependent side effects of potential metal-based anticancer drugs.

  16. Platinum(IV) complexes conjugated with phenstatin analogue as inhibitors of microtubule polymerization and reverser of multidrug resistance.

    Science.gov (United States)

    Huang, Xiaochao; Huang, Rizhen; Gou, Shaohua; Wang, Zhimei; Liao, Zhixin; Wang, Hengshan

    2017-09-01

    Pt(IV) complexes comprising a phenstatin analogue, as dual-targeting Pt(IV) prodrug, were designed and synthesized. They were found not only to carry the DNA binding platinum warhead into the tumor cells, but also to have a small molecular unit to inhibit tubulin polymerization. In vitro evaluation results revealed that Pt(IV) complexes showed better and more potent activity against the test human cancer cells including cisplatin resistant cell lines than their corresponding Pt(II) counterparts. In addition, the Pt(IV) derivative of cisplatin, complex 10, exhibited highly selective inhibition in human cancer cells and displayed no obvious toxicity to two human normal cell lines, respectively. Mechanism study suggested that complex 10 induced cell-cycle arrest at the G2/M phase and caused apoptotic cell death of human lung cancer NCI-H460 cells through the mitochondrial mediated pathway. Moreover, complex 10 effectively inhibited the tumor growth in the NCI-H460 xenograft model. Copyright © 2017. Published by Elsevier Ltd.

  17. Expression of Drug-Resistant Factor Genes in Hepatocellular Carcinoma Patients Undergoing Chemotherapy with Platinum Complex by Arterial Infusion

    Directory of Open Access Journals (Sweden)

    Shiro Ueda

    2010-09-01

    Full Text Available This study investigated gene expression of drug resistance factors in biopsy tissue samples from hepatocellular carcinoma (HCC patients undergoing chemotherapy by platinum complex. Liver biopsy was performed to collect tissue from the tumor site (T and the non-tumor site (NT prior to the start of treatment. For drug-resistant factors, drug excretion transporters cMOAT and MDR-1, intracellular metal binding protein MT2, DNA repair enzyme ERCC-l and inter-nucleic cell transport protein MVP, were investigated. The comparison of the expression between T and NT indicated a significant decrease of MT2 and MDR-1 in T while a significant increase in ERCC-1 was noted in T. Further, expression was compared between the response cases and non-response cases using the ratios of expression in T to those in NT. The response rate was significantly low in the high expression group when the cutoff value of cMOAT and MT2 was set at 1.5 and 1.0, respectively. Furthermore, when the patients were classified into A group (cMOAT ≧ 1.5 or MT2 ≧ 1.0 and B group (cMOAT < 1.5 and MT2 < 1.0, the response rate of A group was significantly lower than B group when we combined the cutoff values of cMOAT and MT2. It is considered possible to estimate the therapeutic effect of platinum complex at a high probability by combining the expression condition of these two genes.

  18. Comparative in vitro and in vivo pharmacological investigation of platinum(IV) complexes as novel anticancer drug candidates for oral application.

    Science.gov (United States)

    Theiner, Sarah; Varbanov, Hristo P; Galanski, Markus; Egger, Alexander E; Berger, Walter; Heffeter, Petra; Keppler, Bernhard K

    2015-01-01

    Platinum(IV) complexes are promising candidates as prodrugs for oral application in anticancer chemotherapy. However, only a few Pt(IV) compounds entered (pre)clinical trials, e.g. satraplatin, while most of the others were only tested in vitro. Aim of the study was investigation of the in vivo pharmacological behavior as well as the anticancer activity of two novel platinum(IV) complexes vs. satraplatin. The drugs were selected due to significantly different in vitro cytotoxicity while sharing some physicochemical properties (e.g. lipophilicity). Initial experiments indicated that the highly in vitro cytotoxic compound 1 ((OC-6-33)-dichloridobis((4-ethoxy)-4-oxobutanoato)-bis(ethylamine)platinum(IV)) was also characterized by high drug absorption and tissue platinum levels after oral application. Interestingly, analysis of serum samples using SEC-ICP-MS revealed that the administered drugs have completely been metabolized and/or bound to proteins in serum within 2 h after treatment. With regard to the activity in vivo, the outcomes were rather unexpected: although potent anticancer effect of 1 was observed in cell culture, the effects in vivo were rather minor. Nevertheless, 1 was superior to 2 ((OC-6-33)-diammine(cyclobutane-1,1-dicarboxylato)-bis((4-cyclopentylamino)-4-oxobutanoato)platinum(IV)) after i.p. administration, which was, at least to some extent, in accordance to the cell culture experiments. After oral gavage, both compounds exhibited comparable activity. This is remarkable considering the distinctly lower activity of 2 in cell culture as well as the low platinum levels detected both in serum and tissues after oral application. Consequently, our data indicate that the prediction of in vivo anticancer activity by cell culture experiments is not trivial, especially for orally applied drugs.

  19. Air-stable platinum and palladium complexes featuring bis[2,4-bis(trifluoromethyl)phenyl]phosphinous acid ligands.

    Science.gov (United States)

    Kurscheid, Boris; Neumann, Beate; Stammler, Hans-Georg; Hoge, Berthold

    2011-12-23

    Secondary phosphane oxides, R(2)P(O)H, are commonly used as preligands for transition-metal complexes of phosphinous acids, R(2)P-OH (R=alkyl, aryl), which are relevant as efficient catalysts in cross-coupling processes. In contrast to previous work by other groups, we are interested in the ligating properties of an electron-deficient phosphinous acid, (R(f))(2)P-OH, bearing the strongly electron-withdrawing and sterically demanding 2,4-bis(trifluoromethyl)phenyl group towards catalysis-relevant metals, such as palladium and platinum. The preligand bis[2,4-bis(trifluoromethyl)phenyl]phosphane oxide, (R(f))(2)P(O)H, reacts smoothly with solid platinum(II) dichloride yielding the trans-configured phosphinous acid platinum complex trans-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)]. The deprotonation of one phosphinous acid ligand with an appropriate base leads to the cis-configured monoanion complex cis-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H](-), featuring the quasi-chelating phosphinous acid phosphinito unit, (R(f))(2)P-O-H···O=P(R(f))(2), which exhibits a strong hydrogen bridge substantiated by an O···O distance of 245.1(4) pm. The second deprotonation step is accompanied by a rearrangement to afford the trans-configured dianion trans-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)](2-). The reaction of (R(f))(2)P(O)H with solid palladium(II) dichloride initially yields a mononuclear palladium complex [PdCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)], which condenses under liberation of HCl to the neutral dinuclear palladium complex [Pd(2)(μ-Cl)(2){({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H}(2)]. The equilibrium between the mononuclear [PdCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)] and dinuclear [Pd(2)(μ-Cl)(2){({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H}(2)] palladium complexes is reversible and can be shifted in each direction by the addition of base or HCl, respectively. Treatment of palladium(II) hexafluoroacetylacetonate, [Pd(F(6)acac)(2)], with a slight excess of (R(f))(2)P

  20. Síntese e caracterização de complexos de platina(IV com derivados N-benzilados da 1,3-propanodiamina Synthesis and characterization of platinum(IV complexes derived from N-benzyl-propanediamine

    Directory of Open Access Journals (Sweden)

    Ana Paula Soares Fontes

    2010-01-01

    Full Text Available The present work describes the synthesis of a series of platinum(IV complexes with N-benzyl 1,3-propanediamine derivatives. Since substitution of the axial ligands in the platinum(IV complexes may alter their pharmacological properties, we have prepared complexes with different groups, such as hydroxide, chloride and acetate using a sequence of substitution reactions. The resulting complexes were fully characterized by IR, ¹H, 13C and 195Pt NMR spectroscopies, and elemental analysis.

  1. Unprecedented 1D Mixed-metal Polynuclear Cyclometalated Platinum Complexes: Synthesis,Structural Characterization and Spectroscopic Properties

    Institute of Scientific and Technical Information of China (English)

    CAO Qian-Yong; GAN Xin; ZHANG Jun-Feng; CHI Shao-Ming; LI Hui-Fangjie; FU Wen-Fu

    2007-01-01

    The complexes [Pt2L2(μ-dppm)](ClO4)2.(1) and {[Pt2L2(μ-dppm)Li(CH3CN)2](ClO4)3}n (2),where HL is 6-[4-(diethoxyphosphorylmethyl)phenyl]-2,2'-bipyridinyl and dppm is bis(diphenylphosphino)methane,have been synthesized and characterized.In complex 1 the platinum(Ⅱ) center adopts a distorted square planar coordination geometry.The polymer 2 exhibits a "stairstep" configuration with one-dimensional Pt(Ⅱ)N^N^CPO- Li(Ⅰ)-OPC^N^NPt(Ⅱ) mixed-metal units which are linked through dppm.Both complexes have metal-metal interaction with PtPt distances of 3.325(2) and 3.1432(9) (A),respectively,and display strong metal-metal-to-ligand charge-transfer (MMLCT) triplet state emission.The density-functional-theory calculation was used to interpret the absorption spectra of the complexes.

  2. Synthesis and biological evaluation of novel platinum complexes of imidazolyl-containing bisphosphonates as potential anticancer agents.

    Science.gov (United States)

    Qiu, Ling; Lv, Gaochao; Cao, Yang; Chen, Liping; Yang, Hui; Luo, Shineng; Zou, Meifen; Lin, Jianguo

    2015-12-01

    Four novel platinum complexes, [Pt(en)]2ZL (1), [Pt(en)]2IPrBP (2), [Pt(en)]2MIBP (3) and [Pt(en)]2EIBP (4) [en = ethylenediamine; ZL = 1-hydroxy-3-(1H-imidazol-1-yl)ethane-1,1-diylbisphosphonic acid, commonly known as zoledronic acid; IPrBP = 1-hydroxy-3-(1H-imidazol-1-yl)propane-1,1-diylbisphosphonic acid; MIBP = 1-hydroxy-2-(2-methyl-1H-imidazol-1-yl)ethane-1,1-diylbisphosphonic acid; EIBP = 1-hydroxy-2-(2-ethyl-1H-imidazol-1-yl)ethane-1,1-diylbisphosphonic acid], were prepared and evaluated against five human cancer cell lines, including U2OS, A549, HCT116, MDA-MB-231 and HepG2. While exhibiting lower efficacy on the inhibition of cancer cell lines than cisplatin (CDDP), four complexes showed higher cytotoxicity than the corresponding ligands and relatively stronger cytotoxic effect on the hepatoma cell lines HepG2, and the complex 1 showed higher cytotoxicity than others on the whole. These complexes have better selectivity than the corresponding ligands in inhibiting hepatocarcinoma cells rather than normal liver cells, and the selective inhibitory effect of the complex 1 at the high concentration (100 μM) is better than that at the low concentration. Morphology studies exhibited typical characteristics of cell apoptosis and the cell cycle distribution analysis indicated that the complexes can inhibit cancer cells by inducing the cell cycle arrest at the G2/M phase, exhibiting a similar mechanism of action to CDDP. The binding interaction of complex with DNA has been explored by circular dichroism (CD) and UV-Vis absorption spectra, demonstrating these new complexes have moderate binding affinity for DNA.

  3. Synthesis of azido derivatives of mucobromic acid

    Directory of Open Access Journals (Sweden)

    N. Mbebe

    2013-04-01

    Full Text Available Mucobromic acid is a highly reactive multicentered molecule. It was converted to its corresponding but unstable diazido derivative by reaction with two equivalents of sodium azide. The resultant 3,4-diazido-5-hydroxyfuran-2(5H-one was obtained in moderate yield (42% but decomposed readily even at low temperatures. Its more stable analogue 3,4-diazido-5-methoxyfuran-2(5H-one was obtained in excellent yield after reacting 5-methoxy-3,4-dibromofuranone with two equivalents of sodium azide. The 4,5-dibromopyridazinones which are in effect masked mucobromic acid derivatives, underwent nucleophilic substitution reactions with various nucleophiles, including azides and afforded corresponding azidopyridazinones in good yields. The synthesized azido-furanone and pyridazinone derivatives are earmarked for click reactions.DOI: http://dx.doi.org/10.4314/bcse.v27i1.17

  4. Platinum group elements geochemistry of ultramafic and associated rocks from Pindar in Madawara Igneous Complex, Bundelkhand massif, central India

    Indian Academy of Sciences (India)

    V Balaram; S P Singh; M Satyanarayanan; K V Anjaiah

    2013-02-01

    Ultramafic rocks comprising dunite, harburgite, lehzolite, olivine webserite and websterite occur as intrusives in the form of small hillocks at around Pindar into the granite–gneisses of Bundelkhand Gneissic Complex (BnGC). The peridotites are dominated by olivine cumulates where chromite and precious metal-bearing sulphides crystallized along with pyroxenes, subsequent to crystallization of olivine into the interstitial spaces of cumulates during cooling. Ultramafic rocks of Pindar are characterized by high MgO (up to 46.0 wt%) and FeO (up to 5.8 wt%); low SiO2 (40.8 to 48.0 wt%), TiO2 (0.2 to 0.5 wt%), Al2O3 (∼3.2 wt% av.), CaO(∼ 2.7 wt% av.) and Cu (11 to 73 g/g). Cr and Ni values range from 2297 to 3150 g/g and 2434 to 2767 g/g, respectively. Distribution of Ir (up to 20 ng/g), Ru (27 to 90 ng/g), Rh (3 to 14 ng/g), Pt (18 to 72 ng/g), Pd (10 to 27 ng/g) and Au (22 to 57 ng/g) indicate platinum group element (PGE) and associated gold mineralization in these ultramafic rocks. A mineral phase representing sperrylite (PtAs2) was also identified within the sulphides in Scanning electron microscopy with energy dispersive spectrometer (SEM–EDS) studies. The primitive mantle-normalized siderophile elements pattern shows platinum group element PGE (PPGE) enrichment (Rh, Pt, Pd). Discrimination diagrams of Pd/Ir vs. Ni/Cu, Pd/Pt vs. Ni/Cu, Cu/Pd vs. Pd, and Cu vs. Pd for the peridotites of Pindar attribute to affinity towards komatiite magma, derived from high degree of partial melting of prolonged depleted mantle, and the sulphur saturation condition incurred during the crystallization of chromite which was favourable for PGE mineralization.

  5. Platinum-group element abundance and distribution in chromite deposits of the Acoje Block, Zambales Ophiolite Complex, Philippines

    Science.gov (United States)

    Bacuta, G.C.; Kay, R.W.; Gibbs, A.K.; Lipin, B.R.

    1990-01-01

    Platinum-group elements (PGE) occur in ore-grade concentration in some of the chromite deposits related to the ultramafic section of the Acoje Block of the Zambales Ophiolite Complex. The deposits are of three types: Type 1 - associated with cumulate peridotites at the base of the crust; Type 2 - in dunite pods from the top 1 km of mantle harzburgite; and Type 3 - like Type 2, but in deeper levels of the harzburgite. Most of the deposites have chromite compositions that are high in Cr with Cr/(Cr + Al) (expressed as chromium index, Cr#) > 0.6; high-Al (Cr# Pd, thought to be characteristic of PGE-barren deposits) and positive slope (Ir Platinum and Pd occur as alloy inclusions (and possibly as solid solution) in interstitial Ni-Cu sulfides and as tellurobismuthides in serpentine and altered sulfides. Variability of PGE distribution may be explained by alteration, crystal fractionation or partial melting processes. Alteration and metamorphism were ruled out, because PGE contents do not correlate with degree of serpentinization or the abundance and type (hydroxyl versus non-hydroxyl) of silicate inclusions in chromite. Preliminary Os isotopic data do not support crustal contamination as a source of the PGEs in the Acoje deposits. The anomalous PGE concentrations in Type 1 high-Cr chromite deposits are attributed to two stages of enrichment: an early enrichment of their mantle source from previous melting events and a later stage of sulfide segregation accompanying chromite crystallization. High-Al chromite deposits which crystallized from basalts derived from relatively low degrees of melting owe their low PGE content to partitioning of PGEs in sulfides and alloys that remain in the mantle. High-Cr deposits crystallized from melts that were previously enriched with PGEs during early melting events of their mantle source; Pt and Pd ore concentrations (ppm levels) are attained by segregation of magmatic sulfides. The Acoje deposits indicate that ophiolites are a

  6. Water soluble azido polyisocyanopeptides as functional β-sheet mimics

    NARCIS (Netherlands)

    Schwartz, Erik; Koepf, Matthieu; Kitto, Heather J.; Espelt, Mónica; Nebot-Carda, Vicent J.; Gelder, de Rene; Nolte, Roeland J.M.; Cornelissen, Jeroen J.L.M.; Rowan, Alan E.

    2009-01-01

    The design and synthesis of functional biomimetic water soluble polymers with a defined secondary structure has been developed using β-sheet polyisocyanopeptide scaffolds. Water soluble isocyanopolymers were prepared by random copolymerisation of the azido functionalized isocyanopeptides with nonfun

  7. A selective colorimetric Hg2+ probe featuring a styryl dithiaazacrown containing platinum (II) terpyridine complex through modulation of the relative strength of ICT and MLCT transitions.

    Science.gov (United States)

    Chung, Sung-Kuang; Tseng, Yong-Ren; Chen, Chan-Yu; Sun, Shih-Sheng

    2011-04-04

    A series of platinum(II) terpyridine complexes featuring an aminostilbene donor-acceptor framework was synthesized. The complex with a dithiaazacrown moiety exhibits a highly sensitive and selective colorimetric response to a Hg(2+) cation through modulation of the relative strength of ICT and MLCT transitions. The results from (1)H NMR titration suggest the existence of a weak Pt(II)···Hg(II) metallophilic interaction at low Hg(2+) concentration.

  8. Structural, spectroscopic and quantum chemical studies of acetyl hydrazone oxime and its palladium(II) and platinum(II) complexes

    Science.gov (United States)

    Kaya, Yunus; Icsel, Ceyda; Yilmaz, Veysel T.; Buyukgungor, Orhan

    2015-09-01

    Acetyl hydrazone oxime, [(1E,2E)-2-(hydroxyimino)-1-phenylethylidene]acetohydrazone (hipeahH2) and its palladium(II) and platinum(II) complexes, [M(hipeahH)2] (M = PdII and PtII), have been synthesized and characterized by elemental analysis, UV-vis IR, NMR and LC-MS techniques. X-ray diffraction analysis of [Pd(hipeahH)2] shows that the two hipeahH2 ligands are not equal; one of the ligands loses the hydrazone proton, while the other one loses the oxime proton, resulting in a different coordination behavior to form five- and six-membered chelate rings. The molecular geometries from X-ray experiments in the ground state were compared using the density functional theory (DFT) with the B3LYP method combined with the 6-311++G(d,p) basis set for the ligand and the LanL2DZ basis set for the complexes. Comprehensive theoretical and experimental structural studies on the molecule have been carried out by FT-IR, NMR and UV-vis spectrometry. In addition, the isomer studies of ligand and its complexes were made by DFT.

  9. Synthesis, Characterization and in Vitro Antitumor Activity of Platinum(II Oxalato Complexes Involving 7-Azaindole Derivatives as Coligands

    Directory of Open Access Journals (Sweden)

    Pavel Štarha

    2014-07-01

    Full Text Available The platinum(II oxalato complexes [Pt(ox(naza2] (1–3 were synthesized and characterized by elemental analysis (C, H, N, multinuclear NMR spectroscopy (1H, 13C, 15N, 195Pt and electrospray ionization mass spectrometry (ESI-MS; naza = 4-chloro-7-azaindole (4Claza; 1, 3-bromo-7-azaindole (3Braza; 2 or 4-bromo-7-azaindole (4Braza; 3. The prepared substances were screened for their in vitro antitumor activity on the osteosarcoma (HOS and breast adenocarcinoma (MCF7 human cancer cell lines, where 2 showed moderate antitumor effect (IC50 = 27.5 μM, and 18.3 μM, respectively. The complex 2 was further tested on a panel of six others human cancer cell lines, including the malignant melanoma (G361, cervix carcinoma (HeLa, ovarian carcinoma (A2780, cisplatin-resistant ovarian carcinoma (A2780R, lung carcinoma (A549 and prostate adenocarcinoma (LNCaP. This substance was found to be moderate antitumor effective against G361 (IC50 = 17.3 μM, HeLa (IC50 = 31.8 μM and A2780 (IC50 = 19.2 μM cell lines. The complex 2 was also studied by NMR for its solution stability and by ESI-MS experiments for its ability to interact with biomolecules, such as cysteine, glutathione or guanosine 5'-monophosphate.

  10. Preparation of two kinds of superparamagnetic carriers-supported cis-platinum complexes and the comparison of their characteristics

    Institute of Scientific and Technical Information of China (English)

    XIE Minqiang; CHEN Shuaijun; XU Xueqing; LI Zhonghan; SHEN Hui; XU Jiarui

    2006-01-01

    The purpose of the research is to explore the effect of different surface modifiers in preparation of magnetic carriers-supported cis-plat- inum (CDDP) complex and their characteristics. Sodium alginate (SA) and N-oleoylsarcosine (NOSARK) were used respectively as linkers between CDDP and magnetic nanometer particles (MNP), and carriers-supported CDDP complex of carboxymethyl dextran (CM-dex) was used as the control. The physical and chemical characteristics of CDDP-MNP were measured by transmission electron microscope, photon correlation spectrum (PCS), spectrophotome- ter, etc. The advantages and disadvantages of the two linkers were analyzed through comparing the stability and quantity of reversibly bound CDDP. The cis-platinum magnetic nanometer particles were found to have the shape of approximately uniformly pellets under transmission electron microscope. The distribution of PCS diameter was 43―52 nm and the diameter of magnetic nucleus of CDDP- MNP complex was about 8.8±1.3 nm. The drug- loading capacity of SA is larger than that of NOSARK, and similar to that of CM-dex. The SA-modified CDDP-MNP solution remained stable after being kept at 4℃ for 40 d. SA is superior to NOSARK as a magnetic nanoparticles surface modifier. Natural SA can supersede CM-dex to serve as linker between CDDP and MNP. In practical application, we should take both the maximal reversible CDDP-bonding capacity and CDDP utilization rate into consideration.

  11. Design, synthesis and anticancer activity of diam(m)ine platinum(II) complexes bearing a small-molecular cell apoptosis inducer dichloroacetate.

    Science.gov (United States)

    Liu, Weiping; Jiang, Jing; Xu, Yongping; Hou, Shuqian; Sun, Liping; Ye, Qingsong; Lou, Liguang

    2015-05-01

    Four new diam(m)ine platinum complexes containing the dichloroacetate moiety in 3-dichoroacetoxylcyclobutane-1,1-dicarboxylate as the leaving group were synthesized, characterized by elemental analysis as well as by ESI(+)-MS (electrospray ionization mass spectrometry in positive mode), FT-IR, (1)H- and (13)C-NMR, and evaluated for their in vitro anticancer activity against human lung cancer cell line (A549) and ovarian cancer cell lines (SK-OV-3, SK-OV-3/DDP). Diam(m)ines used in the present study belong to the carriers of six clinically approved platinum drugs. Among the complexes synthesized, complex 2, cis-[Pt(II)(1R,2R-diaminocyclohexane)·(3-dichoroacetoxylcyclobutane-1,1-dicarboxylate)] is the most promising in terms of water solubility and potential of being totally devoid of cross-drug resistance with cisplatin. Therefore, complex 2 was selected for the dichloroacetate release test. The test shows dichloroacetate can be efficiently released from complex 2 under physiological conditions via the hydrolysis of an ester bond bridging the dichloroacetate moiety and platinum pharmacophores together. Our study supports the further evaluation of this complex as a drug candidate.

  12. Synthesis, characterization, in vitro antitumoral investigations and interaction with plasmid pBR322 DNA of R2eddp-platinum(IV) complexes (R = Et, n-Pr).

    Science.gov (United States)

    Kaluderović, Goran N; Kommera, Harish; Schwieger, Sebastian; Paethanom, Anchan; Kunze, Michael; Schmidt, Harry; Paschke, Reinhard; Steinborn, Dirk

    2009-12-28

    The studies on synthetic, spectroscopic and biological properties of platinum(IV) complexes, [PtCl(4)(R(2)eddp)] (R = Et, 1; n-Pr, 2), containing kappa(2)N,N' bidentate ligands, esters of ethylenediamine-N,N'-di-3-propionic acid (HOOCCH(2)CH(2)NHCH(2)CH(2)NHCH(2)CH(2)COOH, H(2)eddp), are reported. Complexes have been characterized by infrared, (1)H and (13)C NMR spectroscopy and elemental analysis and it was concluded that the coordination of the ligands occurs via nitrogen donor atoms of the ester ligands (R(2)eddp). Cytotoxicity studies were performed for ligand precursors and corresponding platinum(IV) complexes. Although the n-Pr(2)eddp.2HCl itself showed no activity (IC(50) values > 125 microM) in selected cell lines, the activity of complex 2, via apoptotic mode of cell death, has increased significantly for a broad range of cancer cell lines tested in vitro (IC(50) = 8.6-49 microM). As it was found that complexes 1 and 2 are able to interact with pBR322 plasmid DNA, platinum(IV) complexes of this type may act as drugs and pro-drugs.

  13. Electron transfer and hydrogen generation from a molecular dyad: platinum(II) alkynyl complex anchored to [FeFe] hydrogenase subsite mimic.

    Science.gov (United States)

    Wang, Wen-Guang; Wang, Feng; Wang, Hong-Yan; Tung, Chen-Ho; Wu, Li-Zhu

    2012-02-28

    A PS-Fe(2)S(2) molecular dyad 1a directly anchoring a platinum(II) alkynyl complex to a Fe(2)S(2) active site of a [FeFe] H(2)ase mimic, and an intermolecular system of its reference complexes 1b and 2, have been successfully constructed. Time-dependence of H(2) evolution shows that PS-Fe(2)S(2)1a as well as complex 2 with 1b can produce H(2) in the presence of a proton source and sacrificial donor under visible light irradiation. Spectroscopic and electrochemical studies on the electron transfer event reveal that the reduced Fe(I)Fe(0) species generated by the first electron transfer from the excited platinum(II) complex to the Fe(2)S(2) active site in PS-Fe(2)S(2)1a and complex 2 with 1b is essential for photochemical H(2) evolution, while the second electron transfer from the excited platinum(II) complex to the protonated Fe(I)Fe(0) species is thermodynamically unfeasible, which might be an obstacle for the relatively small amount of H(2) obtained by PS-Fe(2)S(2) molecular dyads reported so far.

  14. A circular dichroism study of ethidium bromide binding to Z-DNA induced by dinuclear platinum complexes.

    Science.gov (United States)

    Wu, P K; Kharatishvili, M; Qu, Y; Farrell, N

    1996-07-01

    Dinuclear bis(platinum) complexes have been shown previously to induce the B-->Z transition in synthetic DNAs (Nucleic Acids Res. 7, 1697-1703, J. Inorganic Biochem. 54, 207-220). In this paper, the reversibility of the Z conformation back to the B form was assessed by treatment of the induced Z form in poly(dG-dC).poly(dG-dC) with ethidium bromide (Etd). Z-DNA induced by the tetra-amine cations [{Pt(NH3)3}2(H2N(CH2)nNH2)]4+, which are capable of only electrostatic interactions with the polynucleotide, was readily reversible. The spectroscopic data mirrored that of ethidium bromide/poly(dG-dC).poly(dG-dC) in the presence of 4.4 M NaCl. In contrast, Z-DNA induced by the bifunctional complexes [{trans-PtCl(NH3)2}2(H2N(CH2)nNH2)]2+ did not produce spectra typical of Etd intercalation and reversal to B-form DNA. The original Z-form CD spectra of DNA treated with the bifunctional complexes could be reobtained following removal of Etd by extensive dialysis. The bifunctional complexes are very effective interstrand cross-linking agents. The data suggest that interstrand cross-linking by dinuclear complexes can stabilize or "lock" the Z-conformation prohibiting its reversal to the B-form. The implications for the biological activity of the dinuclear complexes are briefly discussed.

  15. Antitumor activity of platinum(II) complexes with histamine and radioiodinated histamine in a transplantable murine adenocarcinoma model

    Energy Technology Data Exchange (ETDEWEB)

    Garnuszek, Piotr [Department of Radiopharmaceuticals, National Medicines Institute, 00-725 Warsaw (Poland)], E-mail: pgarnuszek@il.waw.pl; Karczmarczyk, Urszula; Maurin, Michal [Department of Radiopharmaceuticals, National Medicines Institute, 00-725 Warsaw (Poland)

    2008-07-15

    Purpose: Antitumor activity of the dichloroplatinum(II)-histamine complexes labeled with I-125 or I-131 was investigated in a transplantable murine adenocarcinoma (MA) model. Methods: The tumor model was obtained in C3H/W female mice after subcutaneous inoculation of the tumor cells derived from the mice bearing a mammary tumor of spontaneous origin. Antitumor activities of the platinum-histamine complexes were investigated in three independent experiments, which differed in applied doses of preparations (PtCl{sub 2}Hist, PtCl{sub 2}[{sup 125}I]Hist, PtCl{sub 2}[{sup 131}I]Hist, PtCl{sub 2}Hist/PtCl{sub 2}[{sup 125}I]Hist and PtCl{sub 2}Hist/PtCl{sub 2}[{sup 131}I]Hist), treatment schedules as well as stages of the disease progress in the animals used. Experiment 1 included long-term, multidose treatment with low single doses (treatment duration 31-32 days; 8-10 doses of ca. 0.25{center_dot}MTD{sub Pt} each). Experiment 2 included short-term, multidose treatment with higher single doses (4xca. 0.5{center_dot}MTD{sub Pt} up to Day 13 of the treatment). Experiment 3 included long-term concomitant multidose treatment with higher single doses (9x0.9-0.4{center_dot}MTD{sub Pt} up to Day 33). Results: The long-term treatment with the platinum-histamine preparations revealed inhibiting activity on the tumor growth and size in comparison to control groups. The most intensive and significant antitumor effects were observed for the radioactive complexes. The tumor growth delay factors (GDFs) observed in Experiment 1 were 0.4, 0.7, and 1.2 for PtCl{sub 2}Hist, PtCl{sub 2}Hist/PtCl{sub 2}[{sup 131}I]Hist, and PtCl{sub 2}Hist/PtCl{sub 2}[{sup 125}I]Hist, respectively. Significant (P<.05) prolongations of median survivals (MS) were found in Experiment 2 following the treatment with higher single doses of PtCl{sub 2}Hist and PtCl{sub 2}His/PtCl{sub 2}[{sup 125}I]Hist (Ratio MS{sub tr}/MS{sub con} ca. 1.4). A slightly less potent activity was observed for PtCl{sub 2}Hist

  16. Relationship between cellular uptake rate and chemical behavior of diammine/diaminocyclohexane platinum (II) complexes with oxygen-ligating anionic groups.

    Science.gov (United States)

    Zou, J; Yang, X D; An, F; Wang, K

    1998-07-01

    The uptake kinetics of the platinum (II) complexes of the formula Pt(NH3)2X, Pt(dach)X by human erythrocyte in the plasma isotonic buffer was studied. The results showed that across-membrane transport of all the platinum complexes studied follows a first-order kinetic process. The uptake rate constants decrease with the change of oxygen-ligating anionic group in the sequence: sulfato > selenato > anion of squaric acid > oxalato > anion of demethylcantharic acid > malonato and increase with increasing lipophilicity of carrier group. The relationship between uptake rate and reactivity of these complexes was established. The stereochemistry of dach isomers was shown without effect on the reactivity and the sequence.

  17. Síntese e caracterização de novos complexos de platina (II com ligantes derivados do furano e nitrofurano Synthesis and characterization of new platinum (II complexes containing furan and nitrofuran derived ligands

    Directory of Open Access Journals (Sweden)

    Wendell Guerra

    2005-10-01

    Full Text Available Platinum (II complexes, for example, cisplatin and carboplatin, have been used as chemotherapeutic agents for the treatment of various types of cancer. Several other complexes of this metallic ion are also under clinical evaluation. This work describes the synthesis of five new platinum (II complexes having furan and 5-nitrofuran derivatives and chloride as ligands. The compounds were characterized by NMR, IR and elemental analysis.

  18. In Vitro Anticancer Evaluation of Platinum(II/IV) Complexes with Diisoamyl Ester of (S,S)-ethylenediamine-N,N'-di-2-propanoic Acid.

    Science.gov (United States)

    Zmejkovski, Bojana B; Pantelić, Nebojša; Filipović, Lana; Aranđelović, Sandra; Radulović, Siniša; Sabo, Tibor J; Kaluđerović, Goran N

    2017-01-01

    Platinum(II) and platinum(IV) complexes [PtCln{(S,S)-(i-Am)2eddip}] (n = 2, 4: 1, 2, respectively; (S,S)-(i-Am)2eddip = O,O'-diisoamyl-(S,S)-ethylenediamine-N,N'-di-2-propanoate) were synthesized and characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy and mass spectrometry. Quantum chemical calculations were used to predict formed isomers of 1 and 2. Furthermore, reduction of 2 with ascorbic acid was followed by time-dependant 13C NMR spectroscopy in order to enable assignation of the formed isomers for complex 1. In vitro cytotoxic activity was determined for 1 and 2 on a panel of five human tumor cell lines derived from cervix adenocarcinoma (HeLa), alveolar basal adenocarcinoma (A549), breast adenocarcinoma (MDA-453), colorectal cancer (LS 174), erythromyeloblastoid leukemia (K562), as well as one non-malignant human lung fibroblast cell line (MRC-5), using MTT assay. Both complexes exhibited high (2 against K562: IC50 = 5.4 μM), more active than cisplatin, to moderate activity (1). Both complexes caused considerable decrease of cell number in K562 cells in G1, S and G2 phases, concordantly increasing subpopulation in sub-G1 fraction. Morphological analysis of K562 cell death induced by platinum(II/IV) complexes indicate apoptosis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  19. Liposome encapsulation of lipophilic N-alkyl-propanediamine platinum complexes: impact on their cytotoxic activity and influence of the carbon chain length

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Heveline; Fontes, Ana Paula S. [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Dept. de Quimica; Lopes, Miriam Teresa P. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Farmacologia; Frezard, Frederic, E-mail: frezard@icb.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisiologia e Biofisica

    2010-07-01

    Antitumor platinum(II) complexes derived from N-alkyl-propanediamine differing in the length of their carbon chain (C8, C10, C12 and C14) were incorporated in liposomes and the cytotoxic activity of these formulations was evaluated against tumor (A{sub 549}, MDA-MB-231, B16-F1 and B16-F10) and non-tumor (BHK-21 and CHO) cell lines. Stable and monodisperse liposome suspensions incorporating the platinum complexes were obtained from the lipid composition consisting of distearoyl-sn-glycero-3-phosphocholine, cholesterol and 1,2-distearoyl-sn-glycero- 3-phosphoethanolamine-N-(methoxy(polyethylene glycol)-2000) at 5:3:0.3 molar ratio. The entrapment efficiency (EE%) of the platinum complexes in liposomes increased with the carbon chain length. EE% was higher than 80% in C12- and C14-derivatives. The effect of liposome encapsulation on the cytotoxic activity of the complexes was found to depend on the carbon chain length. These data indicate that the highest drug bioavailability from liposome formulations was achieved with the complex showing intermediate carbon chain length and partition between the liposome membrane and aqueous phase. (author)

  20. Complex anthropogenic sources of platinum group elements in aerosols on Cape Cod, USA.

    Science.gov (United States)

    Sen, Indra S; Peucker-Ehrenbrink, Bernhard; Geboy, Nicholas

    2013-09-17

    Platinum group elements (PGE) of anthropogenic origin have been reported in rainwater, snow, roadside soil and vegetation, industrial waste, and urban airborne particles around the world. As recent studies have shown that PGE are bioavailable in the environment and pose health risks at chronic levels, the extent of PGE pollution is of global concern. In this study, we report PGE concentrations and osmium isotope ((187)Os/(188)Os) ratios of airborne particles (particulate matter, PM10) collected in Woods Hole, a small coastal village on Cape Cod, Massachusetts, U.S.A. The sampling site is more than 100 km away from the nearest urban centers (Boston, Providence) and has no large industrial emission center within a 30 km radius. The study reveals that, although PGE concentrations in rural airborne particulate matter are orders of magnitude lower than in urban aerosols, 69% of the total osmium is of anthropogenic origin. Anthropogenic PGE signatures in airborne particles are thus not restricted to large cities with high traffic flows and substantial industries; they can also be found in rural environments. We further conclude that the combination of Pt/Rh concentration ratios and (187)Os/(188)Os composition can be used to trace PGE sources. The Pt/Rh and (187)Os/(188)Os composition of Woods Hole aerosols indicate that the anthropogenic PGE fraction is primarily sourced from ore smelting processes, with possible minor contributions from fossil fuel burning and automobile catalyst-derived materials. Our results further substantiate the use of (187)Os/(188)Os in source apportionment studies on continental scales.

  1. bis-Nitrile and bis-Dialkylcyanamide Platinum(II) Complexes as Efficient Catalysts for Hydrosilylation Cross-Linking of Siloxane Polymers.

    Science.gov (United States)

    Islamova, Regina M; Dobrynin, Mikhail V; Ivanov, Daniil M; Vlasov, Andrey V; Kaganova, Elena V; Grigoryan, Galina V; Kukushkin, Vadim Yu

    2016-03-05

    cis- and trans-Isomers of the platinum(II) nitrile complexes [PtCl2(NCR)2] (R = NMe2, N(C₅H10), Ph, CH2Ph) were examined as catalysts for hydrosilylation cross-linking of vinyl-terminated polydimethylsiloxane and trimethylsilyl-terminated poly(dimethylsiloxane-co-ethylhydrosiloxane) producing high quality silicone rubbers. Among the tested platinum species the cis-complexes are much more active catalysts than their trans-congeners and for all studied platinum complexes cis-[PtCl2(NCCH2Ph)2] exhibits the best catalytic activity (room temperature, c = 1.0 × 10(-4) mol/L, τpot-life 60 min, τcuring 6 h). Although cis-[PtCl₂(NCCH2Ph)2] is less active than the widely used Karstedt's catalyst, its application for the cross-linking can be performed not only at room temperature (c = 1.0 × 10(-4) mol/L), but also, more efficiently, at 80 °C (c = 1.0 × 10(-4)-1.0 × 10(-5) mol/L) and it prevents adherence of the formed silicone rubbers to equipment. The usage of the cis- and trans-[PtCl2(NCR)2] complexes as the hydrosilylation catalysts do not require any inhibitors and, moreover, the complexes and their mixtures with vinyl- and trimethylsilyl terminated polysiloxanes are shelf-stable in air. Tested catalysts do not form colloid platinum particles after the cross-linking.

  2. Palladium and platinum complexes of 2-(2'-carboxyphenylazo)-4 methylphenol: Synthesis, structure and spectral properties

    Indian Academy of Sciences (India)

    Sarmistha Halder; Michael G B Drew; Samaresh Bhattacharya

    2008-09-01

    Reaction of 2-(2'-carboxyphenylazo)-4-methylphenol (H2L) with [M(PPh3)2Cl2] (M = Pd, Pt) affords mixed-ligand complexes of type [M(PPh3)(L)]. Structures of both the complexes have been determined by X-ray crystallography. Both the complexes are square planar, where the 2-(2'-carboxyphenylazo)-4-methylphenol is coordinated to the metal center, via dissociation of the two acidic protons, as a dianionic tridentate O,N,O-donor, and the fourth position is occupied by the triphenylphosphine. These complexes show intense MLCT transitions in the visible region.

  3. Synthesis, photovoltaic performances and TD-DFT modeling of push-pull diacetylide platinum complexes in TiO2 based dye-sensitized solar cells.

    Science.gov (United States)

    Gauthier, Sébastien; Caro, Bertrand; Robin-Le Guen, Françoise; Bhuvanesh, Nattamai; Gladysz, John A; Wojcik, Laurianne; Le Poul, Nicolas; Planchat, Aurélien; Pellegrin, Yann; Blart, Errol; Jacquemin, Denis; Odobel, Fabrice

    2014-08-07

    In this joint experimental-theoretical work, we present the synthesis and optical and electrochemical characterization of five new bis-acetylide platinum complex dyes end capped with diphenylpyranylidene moieties, as well as their performances in dye-sensitized solar cells (DSCs). Theoretical calculations relying on Time-Dependent Density Functional Theory (TD-DFT) and a range-separated hybrid show a very good match with experimental data and allow us to quantify the charge-transfer character of each compound. The photoconversion efficiency obtained reaches 4.7% for 8e (see TOC Graphic) with the tri-thiophene segment, which is among the highest efficiencies reported for platinum complexes in DSCs.

  4. Probing the lowest coordination number of dianionic platinum-cyanide complexes in the gas phase: Dynamics of the charge dissociation process

    DEFF Research Database (Denmark)

    Bojesen, G; Hvelplund, P; Jørgensen, Thomas J. D.

    2000-01-01

    in Pt(CN)(5)(2-) and Pt(CN)(4)(2-), but no indication of the existence of Pt(CN)(3)(2-) was found. This indicates that the lifetime of Pt(CN)(3)(2-) is less than 4 mus (the flight time from the collision region to the detector). In contrast, all monoanion platinum-cyanide complexes were observed, i...

  5. A STUDY OF SILICA-SUPPORTED CROSS-LINKED POLY(MALEIC ACID-CO-STYRENE)-PLATINUM COMPLEX IN THE HYDROGENATION OF p-CRESOL

    Institute of Scientific and Technical Information of China (English)

    CHEN Chunwei; WANG Xin; HUANG Meiyu; JIANG Yingyan

    1996-01-01

    A silica-supported cross-linked poly(maleic acid -co- styrene)-platinum complex (PMSPt) has been prepared and found to be active in the hydrogenation of p-cresol under mild conditions (303-323K, 1.01 × 105Pa). In this hydrogenation system water serves as a solvent and p-cresol can be converted to 4-methylcyclohexanol quantitatively via 4-methylcyclohexanone as intermediate.

  6. Influence of equatorial and axial carboxylato ligands on the kinetic inertness of platinum(IV) complexes in the presence of ascorbate and cysteine and within DLD-1 cancer cells.

    Science.gov (United States)

    Chen, Catherine K J; Zhang, Jenny Z; Aitken, Jade B; Hambley, Trevor W

    2013-11-14

    The rapid and premature reduction of platinum(IV) complexes in vivo is a significant impediment to these complexes being successfully employed as anticancer prodrugs. This study investigates the influence of the platinum(IV) coordination sphere on the ease of reduction of the platinum center in various biological contexts. In the presence of the biological reductants, ascorbate and cysteine, platinum(IV) complexes with dicarboxylato equatorial ligands were observed to exhibit lower reduction potentials and slower reduction rates than analogous platinum(IV) complexes with dichlorido equatorial ligands. Diaminetetracarboxylatoplatinum(IV) complexes exhibited unusually long half-lives in the presence of excess reductants; however, the complexes exhibited moderate potency in vitro, indicative of rapid reduction within the intracellular environment. By use of XANES spectroscopy, trans-[Pt(OAc)2(ox)(en)] and trans-[PtCl2(OAc)2(en)] were observed to be reduced at a similar rate within DLD-1 cancer cells. This large variability in kinetic inertness of diaminetetracarboxylatoplatinum(IV) complexes in different biological contexts has significant implications for the design of platinum(IV) prodrugs.

  7. Synthesis and antitumor activity of [1,2-bis(4-fluorophenyl)ethylenediamine][dicarboxylato]platinum(II) complexes.

    Science.gov (United States)

    Gust, R; Krauser, R; Schmid, B; Schönenberger, H

    1998-01-01

    The synthesis of the diastereomeric [1,2-bis(4-fluorophenyl)-ethylenediamine][dicarboxylato]platinum(I I) complexes, rac- and meso-4F-Pt(X) [X: oxalato (Ox), malonato (Mal), hydroxymalonato (OHMal), phenylmalonato (PhMal), tetrahydro-4H-pyran-4,4-dicarboxylato (Thpdc)], the evaluation of their structure, water solubility, resistance against attack by nucleophiles, and growth inhibiting properties on the human MCF-7 breast cancer cell line are described [parent compounds: rac-4F-Pt(CBDC) and meso-4F-Pt(CBDC); reference complexes: carboplatin, cisplatin, rac- and meso-4F-PtCl2]. The most active 4F-Pt(X) complexes, rac-4F-Pt(Mal), rac-4F-Pt(OHMal) and rac-4F-Pt(Thpdc), equal the parent compound rac-4F-Pt(CBDC) as well as cisplatin and surpass carboplatin in their effect on the MCF-7 breast cancer cell line. Their water solubility, which is of importance for an application in the cancer chemotherapy, is higher than that of rac-4F-Pt(CBDC), especially in the case of rac-4F-Pt(OHMal) and rac-4F-Pt(Thpdc). In comparison to the dichloroplatinum(II) analogue (4F-PtCl2) the stability of the three compounds in the presence of the strong nucleophile iodide is markedly enhanced, which means a reduction of the protein bound drug fraction in the blood and tissue compartments accompanied by an increase of the active, free drug level. The found physiochemical properties of these compounds meet the requirements for the transferability of their promising breast cancer inhibiting effects detected in cell culture experiments to in vivo conditions.

  8. Cytotoxicity and DNA interactions of some platinum(II) complexes with substituted benzimidazole ligands.

    Science.gov (United States)

    Ozçelik, Azime Berna; Utku, Semra; Gümüş, Fatma; Keskin, Ayten Çelebi; Açık, Leyla; Yılmaz, Sükran; Ozgüngör, Adeviye

    2012-06-01

    In the present study, four Pt(II) complexes with 2-ethyl (1)/or benzyl (2)/or p-chlorobenzyl (3)/or 2-phenoxymethyl (4) benzimidazole carrier ligands were evaluated for their in vitro cytotoxic activities against the human HeLa cervix, oestrogen receptor-positive MCF-7 breast, and oestrogen receptor-negative MDA-MB 231 breast cancer cell lines. The plasmid DNA interactions and inhibition of the BamHI restriction enzyme activities of the complexes were also studied. Complex 3 was found to be more active than carboplatin for all examined cell lines and comparable with cisplatin, except for the HeLa cell line.

  9. Methyl 6-Amino-6-deoxy-d-pyranoside-Conjugated Platinum(II) Complexes for Glucose Transporter (GLUT)-Mediated Tumor Targeting: Synthesis, Cytotoxicity, and Cellular Uptake Mechanism.

    Science.gov (United States)

    Li, Taoli; Gao, Xiangqian; Yang, Liu; Shi, Yunli; Gao, Qingzhi

    2016-05-19

    Methyl 6-aminodeoxy-d-pyranoside-derived platinum(II) glycoconjugates were designed and synthesized based on the clinical drug oxaliplatin for glucose transporter (GLUT)-mediated tumor targeting. In addition to a substantial improvement in water solubility, the conjugates exhibited cytotoxicity similar to or higher than that of oxaliplatin in six different human cancer cell lines. GLUT-mediated transport of the complexes was investigated with a cell-based fluorescence competition assay and GLUT-inhibitor-mediated cytotoxicity analysis in a GLUT-overexpressing human colorectal adenocarcinoma (HT29) cell line. The antitumor effect of the aminodeoxypyranoside-conjugated platinum(II) complexes was found to depend significantly on the GLUT inhibitor, and the cellular uptake of the molecules was regulated by GLUT-mediated transport. The results from this study demonstrate the potential advantages of aminodeoxypyranosides as sugar motifs for glycoconjugation for Warburg-effect-targeted drug design. These fundamental results also support the potential of aminodeoxypyranoside-conjugated platinum(II) complexes as lead compounds for further preclinical evaluation.

  10. TDDFT study on recognition mechanism for the oxygen sensing of the cyclometalated platinum (II) complex

    Science.gov (United States)

    Tong, Huan; Zhao, Zhengyan; Li, Guanglan; Gao, Liguo; Zhao, Ningjiu; Li, Peng; Jia, Yan; Zhou, Chenyang; Zhang, Mingzhen; Wang, Yong; Hao, Ce; Tang, Xiaoying

    2017-08-01

    The influence of oxygen molecule on the luminescent properties of a cyclometalated Pt(II) complex Lxp1, was investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. Analysis of frontier molecular orbitals and electronic configuration indicated that the highest-occupied molecular orbital of the Lxp1 has a significant mixture of metal Pt (d) as well as 2-phenylpyridine and acetyl acetone(π). The lowest-unoccupied orbital of the Lxp1 primarily locates on π* of 2-phenylpyridineligands. The emission mechanism of the cyclometalated Pt(II) complex Lxp1 is assigned to the mixing of ligand-to-metal charge transfer and ligand-to-ligand charge transfer. The emission mechanism of the Lxp1-O2 complex can be attributed to the charge transfer from the oxygen molecule to the luminescent material Lxp1. Our study showed that intermolecular hydrogen bonding between the Lxp1 and oxygen molecule was strengthened by the calculation of electronic excitation, leading to a luminescence-decreasing phenomenon. The calculation of the radiative and non-radiative decay rate constants of the Lxp1 and the Lxp1-O2 complex demonstrates that the phosphorescence from T1-S0 of the Lxp1 would alter to the internal conversion from T1-T0 of the Lxp1-O2 complex. This alteration further explains the luminescence quenching phenomenon of the cyclometalated Pt(II) complex Lxp1 after interacting with oxygen molecule.

  11. DNA Interaction Studies of a New Platinum(II) Complex Containing Different Aromatic Dinitrogen Ligands.

    Science.gov (United States)

    Shahabadi, Nahid; Mohammadi, Somaye; Alizadeh, Robabeh

    2011-01-01

    A new mononuclear Pt(II) complex, [Pt(DMP)(DIP)]Cl(2).H(2)O, in which DMP is 4,4-dimethyl-2,2-bipyridine and DIP is 4,7-diphenyl-1,10-phenantroline, has been synthesized and characterized by physicochemical and spectroscopic methods. The binding interaction of this complex with calf thymus DNA (CT-DNA) was investigated using fluorimetry, spectrophotometry, circular dichroism, viscosimetry and cyclic voltametry (CV). UV-VIS spectrum showed 4 nm bathochromic shift of the absorption band at 280 nm along with significant hypochromicity for the absorption band of the complex. The intrnisic binding constant (K(b) = 2 × 10(4) M(-1)) is more in keeping with intercalators and suggests this binding mode. The viscosity measurements showed that the complex-DNA interaction can be hydrophobic and confirm intercalation. Moreover, the complex induced detectable changes in the CD spectrum of CT-DNA. The fluorescence studies revealed that the probable quenching mechanism of fluorescence of the complex by CT-DNA is static quenching. The thermodynamic parameters (ΔH > 0 and ΔS > 0) showed that main interaction with hydrogenic forces occurred that is intercalation mode. Also, CV results confirm this mode because, with increasing the CT-DNA concentration, shift to higher potential was observed.

  12. Synthesis and Consecutive Reactions of α-Azido Ketones: A Review

    Directory of Open Access Journals (Sweden)

    Sadia Faiz

    2015-08-01

    Full Text Available This review paper covers the major synthetic approaches attempted towards the synthesis of α-azido ketones, as well as the synthetic applications/consecutive reactions of α-azido ketones.

  13. Organometallic complexes of the platinum metals: Synthesis, structure, and catalytic applications

    Indian Academy of Sciences (India)

    Piyali Paul; Samaresh Bhattacharya

    2012-11-01

    Reaction of a group of N-(aryl)picolinamides (pic-R) with [Ru(PPh3)2(CO)2Cl2] in refluxing 2-methoxyethanol in the presence of a base affords hydrido complexes of two types (1-R and 2-R), which are geometric isomers. Similar reaction with N-(naphthyl)picolinamide (pic-nap) yields an organoruthenium complex (3) via formation of a hydrido intermediate. Reaction of 2-(arylazo)phenols (ap-R) with [Ir(PPh3)3Cl] in refluxing ethanol affords a mono-hydrido intermediate (4-R), a di-hydrido intermediate (5-R) and an organoiridium complex (6-R) as the final product, where the azo-ligand is coordinated as CNO-donor. Reaction of ap-R ligands with [Rh(PPh3)3Cl] yields organorhodium complexes (7-R) analogous to 6-R, but without any hydrido intermediate. N-(2'-hydroxyphenyl)benzaldimines (hpbz-R) react with [Rh(PPh3)3Cl] to yield a group of organorhodium complexes (8-R), where the hpbz-R ligands are coordinated in CNO-fashion. Upon interaction with [Ir(PPh3)3Cl] 2-(2',6'-dimethylphenylazo)-4-methylphenol (dmap) undergoes a methyl C-H activation and affords organoiridium complex 9, while 2-(2'-methylphenylazo)-4-methylphenol (mmap) undergoes a phenyl C-H activation and gives organoiridium complex 10. Reaction of benzaldehyde thiosemicarbazones (bztsc-R) with [Pd(PPh3)2Cl2], carried out with the expectation of inducing CNS-mode of coordination, actually has yielded complexes (11-R) where the bztsc-R is coordinated in an uncommon NS-mode forming a fivemembered chelate ring associated with a restricted rotation around the imine (C=N) bond. These palladium complexes are found to catalyse C-C cross coupling reactions very efficiently. Crystal structures of selected complexes of each type have been determined by X-ray crystallography.

  14. The preparation and characterization of trans-platinum(IV) complexes with unusually high cytotoxicity.

    Science.gov (United States)

    Cubo, Leticia; Hambley, Trevor W; Sanz Miguel, Pablo J; Carnero, Amancio; Navarro-Ranninger, Carmen; Quiroga, Adoración G

    2011-01-14

    The physical and biological properties have been determined for three Pt(IV) complexes with trans amine ligands: trans,trans,trans-[PtCl(2)(OH)(2)(dimethylamine)(isopropylamine)] (1(IV)), trans,trans,trans-[PtCl(2)(OH)(2)(dimethylamine)(methylamine)] (2(IV)) and trans,trans,trans-[PtCl(2)(OH)(2)(isopropylamine)(methylamine)] (3(IV)). The crystal structures of 2(IV) and 3(IV) reveal substantial strain resulting from repulsion between the amine ligands and the chlorido and hydroxido ligands. All three complexes have reduction potentials in the range -666 to -770 mV, values usually associated with high resistance to reduction and low cytotoxicity. However, the complexes all demonstrate surprisingly high cytotoxicity with values and trends that closely follow those seen for the Pt(II) congeners of these complexes. These results are consistent with more rapid reduction of the Pt(IV) complexes than would be expected based on the reduction potentials, perhaps associated with the trans arrangement of the chlorido ligands.

  15. Studies of the Intramolecular Aromatic-ring Stacking Interactions in the Ternary Platinum(Ⅱ) Complexes

    Institute of Scientific and Technical Information of China (English)

    SUN Hong-liang

    2005-01-01

    The stability constants of some ternary mixed-ligand complexes, Pt(Phen)(CA)+, where Phen=1,10-phenanthroline and CA- =carboxylate, were determined by means of potentiometric pH titration in aqueous solutions(I=0.1 mol/L, KNO3; 25 ℃), and the stability of them was compared with that of the corresponding binary complexes. It was revealed that the ternary complexes containing phenylalkane carboxylates ligands(PCA-) are much more stable than those formed with formate and acetate. The results indicate that there exist the intramolecular aromatic-ring interactions between the phenanthroline ring of Phen and the phenyl moiety of ligand PCA- in the ternary mixed-ligand Pt(Phen)(PCA)- complexes. The extent of the stacking interactions, which depends on the number of methylene groups between the phenyl moieties and the coordinated phenylalkane carboxylate groups, was calculated. The best-fitted stack was obtained for the complexes with 2-phenylacetate and 3-phenylpropionate as the ligands.

  16. Kinetics and mechanism for reversible chloride transfer between mercury(II) and square-planar platinum(II) chloro ammine, aqua, and sulfoxide complexes. Stabilities, spectra, and reactivities of transient metal-metal bonded platinum-mercury adducts.

    Science.gov (United States)

    Gröning, O; Sargeson, A M; Deeth, R J; Elding, L I

    2000-09-18

    The Hg2+aq- and HgCl+aq-assisted aquations of [PtCl4]2- (1), [PtCl3(H2O)]- (2), cis-[PtCl2(H2O)2] (3), trans-[PtCl2(H2O)2] (4), [PtCl(H2O)3]+ (5), [PtCl3Me2SO]- (6), trans-[PtCl2(H2O)Me2SO] (7), cis-[PtCl(H2O)2Me2SO]+ (8), trans-[PtCl(H2O)2M32SO]+ (9), trans-[PtCl2(NH3)2] (10), and cis-[PtCl2(NH3)2] (11) have been studied at 25.0 degrees C in a 1.00 M HClO4 medium buffered with chloride, using stopped-flow and conventional spectrophotometry. Saturation kinetics and instantaneous, large UV/vis spectral changes on mixing solutions of platinum complex and mercury are ascribed to formation of transient adducts between Hg2+ and several of the platinum complexes. Depending on the limiting rate constants, these adducts are observed for a few milliseconds to a few minutes. Thermodynamic and kinetics data together with the UV/vis spectral changes and DFT calculations indicate that their structures are characterized by axial coordination of Hg to Pt with remarkably short metal-metal bonds. Stability constants for the Hg2+ adducts with complexes 1-6, 10, and 11 are (2.1 +/- 0.4) x 10(4), (8 +/- 1) x 10(2), 94 +/- 6, 13 +/- 2, 5 +/- 2, 60 +/- 6, 387 +/- 2, and 190 +/- 3 M-1, respectively, whereas adduct formation with the sulfoxide complexes 7-9 is too weak to be observed. For analogous platinum(II) complexes, the stabilities of the Pt-Hg adducts increase in the order sulfoxide < aqua < ammine complex, reflecting a sensitivity to the pi-acid strength of the Pt ligands. Rate constants for chloride transfer from HgCl+ and HgCl2 to complexes 1-11 have been determined. Second-order rate constants for activation by Hg2+ are practically the same as those for activation by HgCl+ for each of the platinum complexes studied, yet resolved contributions for Hg2+ and HgCl+ reveal that the latter does not form dinuclear adducts of any significant stability. The overall experimental evidence is consistent with a mechanism in which the accumulated Pt(II)-Hg2+ adducts are not reactive

  17. Synthesis, spectral characterization and eukaryotic DNA degradation of thiosemicarbazones and their platinum(IV) complexes

    Science.gov (United States)

    Al-Hazmi, G. A.; El-Metwally, N. M.; El-Gammal, O. A.; El-Asmy, A. A.

    2008-01-01

    The condensation products of acetophenone (or its derivatives), salicylaldehyde and o-hydroxy- p-methoxybenzophenone with thiosemicarbazide and ethyl- or phenyl-thiosemicarbazide are the investigated thiosemicarbazones. Their reactions with H 2PtCl 6 produced Pt(IV) complexes characterized by elemental, thermal, mass, IR and electronic spectral studies. The coordination modes were found mononegative bidentate in the acetophenone derivatives and binegative tridentate in the salicylaldehyde derivatives. The complexes were analyzed thermogravimetrically and found highly stable. Some ligands and their complexes were screened against Sarcina sp. and E. coli using the cup-diffusion technique. [Pt( oHAT)(OH)Cl] shows higher activity against E. coli than the other compounds. The degradation power of the tested compounds on the calf thymus DNA supports their selectivity against bacteria and not against the human or related eukaryotic organisms.

  18. Thiosemicarbazone complexes of the platinum metals. A story of variable coordination modes

    Indian Academy of Sciences (India)

    Indrani Pal; Falguni Basuli; Samaresh Bhattacharya

    2002-08-01

    Salicylaldehyde thiosemicarbazone (H2saltsc) reacts with [M(PPh3)3X2] (M = Ru, Os; X = Cl, Br) to afford complexes of type [M(PPh3)2(Hsaltsc)2], in which the salicylaldehyde thiosemicarbazone ligand is coordinated to the metal as a bidentate N,S-donor forming a four-membered chelate ring. Reaction of benzaldehyde thiosemicarbazones (Hbztsc-R) with [M(PPh3)3X2] also affords complexes of similar type, viz. [M(PPh3)2(bztsc-R)2], in which the benzaldehyde thiosemicarbazones have also been found to coordinate the metal as a bidentate N,S-donor forming a fourmembered chelate ring as before. Reaction of the Hbztsc-R ligands has also been carried out with [M(bpy)2X2] (M = Ru, Os; X = Cl, Br), which has afforded complexes of type [M(bpy)2(bztsc-R)]+, which have been isolated as perchlorate salts. Coordination mode of bztsc-R has been found to be the same as before. Structure of the Hbztsc-OMe ligand has been determined and some molecular modelling studies have been carried out determine the reason for the observed mode of coordination. Reaction of acetone thiosemicarbazone (Hactsc) has then been carried out with [M(bpy)2X2] to afford the [M(bpy)2(actsc)]ClO4 complexes, in which the actsc ligand coordinates the metal as a bidentate N,S-donor forming a five-membered chelate ring. Reaction of H2saltsc has been carried out with [Ru(bpy)2Cl2] to prepare the [Ru(bpy)2(Hsaltsc)]ClO4 complex, which has then been reacted with one equivalent of nickel perchlorate to afford an octanuclear complex of type [{Ru(bpy)2(saltsc-H)}4Ni4](ClO4)4.

  19. Microwave assisted synthesis, characterization and biological evaluation of palladium and platinum complexes with azomethines

    Science.gov (United States)

    Sharma, Krishna; Singh, Ritu; Fahmi, Nighat; Singh, R. V.

    2010-01-01

    Reactions of 3-acetyl-2,5-dimethylthiophene with thiosemicarbazide and semicarbazide hydrochloride resulted in the formation of new heterocyclic ketimines, 3-acetyl-2,5-dimethylthiophene thiosemicarbazone (C 9H 13N 3OS 2 or L 1H) and 3-acetyl-2,5- dimethylthiophene semicarbazone (C 9H 13N 3OS or L 2H), respectively. The Pd(II) and Pt(II) complexes have been synthesized by mixing metal salts in 1:2 molar ratios with these ligands by using microwave as well as conventional heating method for comparison purposes. The authenticity of these ligands and their complexes has been established on the basis of elemental analysis, melting point determinations, molecular weight determinations, IR, 1H NMR and UV spectral studies. These studies showed that the ligands coordinate to the metal atom in a monobasic bidentate manner and square planar environment around the metal atoms has been proposed to the complexes. Both the ligands and their complexes have been screened for their antimicrobial activities. The antiamoebic activity of both the ligands and their palladium compounds against the protozoan parasite Entamoeba histolytica has been tested.

  20. A new entry to asymmetric platinum(IV) complexes via oxidative chlorination.

    Science.gov (United States)

    Ravera, Mauro; Gabano, Elisabetta; Pelosi, Giorgio; Fregonese, Federico; Tinello, Stefano; Osella, Domenico

    2014-09-02

    Pt(IV) complexes are usually prepared by oxidation of the corresponding Pt(II) counterparts, typically using hydrogen peroxide or chlorine. A different way to synthesize asymmetrical Pt(IV) compounds is the oxidative chlorination of Pt(II) counterparts with N-chlorosuccinimide. The reaction between cisplatin cis-[PtCl2(NH3)2], carboplatin, cis-[PtCl2(dach)] and cis-[Pt(cbdc)(dach)] (cbdc = cyclobutane-1,1'-dicarboxylato; dach = cyclohexane-1R,2R-diamine) with N-chlorosuccinimide in ethane-1,2-diol was optimized to produce the asymmetric Pt(IV) octahedral complexes [PtA2Cl(glyc)X2] (A2 = 2 NH3 or dach; glyc = 2-hydroxyethanolato; X2 = 2 Cl or cbdc) in high yield and purity. The X-ray crystal structure of the [Pt(cbdc)Cl(dach)(glyc)] complex is also reported. Moreover, the oxidation method proved to be versatile enough to produce other mixed Pt(IV) derivatives varying the reaction medium. The two trichlorido complexes easily undergo a pH-dependent hydrolysis reaction, whereas the dicarboxylato compounds are stable enough to allow further coupling reactions for drug targeting and delivery via the glyc reactive pendant. Therefore, the coupling reaction between the [Pt(cbdc)Cl(dach)(glyc)] and a model carboxylic acid, a model amine, and selectively protected amino acids is reported.

  1. Para-Functionalized NCN-Pincer Palladium and Platinum Complexes as Building Blocks in Organometallic Chemistry

    NARCIS (Netherlands)

    Slagt, Martijn Quico

    2002-01-01

    A rapidly evolving field in chemistry is the application of organometallic and coordination complexes as building blocks or active components for the construction of new materials exhibiting specific catalytic, redox, optical or sensor activities. A central theme in the construction of these inorgan

  2. Solvent induced helical aggregation in the self-assembly of cholesterol tailed platinum complexes.

    Science.gov (United States)

    Mao, Yueyuan; Liu, Keyin; Meng, Luyan; Chen, Liang; Chen, Liming; Yi, Tao

    2014-10-14

    Three alkynylplatinum(ii) bipyridyl complexes in which two cholesterol groups are combined with a bipyridyl group via alkyl chains and amido bonds were designed and synthesized. The complexes have different lengths of ethylene glycol chains at the para-position of 1-phenylethyne. All three complexes can self-assemble to gel networks in DMSO, while only the morphology of 1a without an ether chain shows a well-defined right-handed helical structure in layer packing mode. However, 1c with long ethylene glycol chains forms perfect regular left-handed helical structures in aqueous ethanol solution while the volume percentage of water is less than 5% (v/v). As the ratio of water increases, the chirality changes from a left-handed helix to a right-handed helix and the packing mode alters from a monolayer structure to a hexagonal structure. As the ratio of water further increases to greater than 50% (v/v), the structure of the assembly finally transforms into bilayer vesicles. The process of the morphology transition is traced by circular dichroism spectra, powder X-ray diffraction, SEM and TEM images. The result indicates that a polar solvent (water) acts as a trigger to change the self-assembly of the chiral structures of the complex due to the strong hydrophobic interaction between cholesterol groups and the balance of the hydrophobicity and hydrophilicity of the solvent environment.

  3. Para-Functionalized NCN-Pincer Palladium and Platinum Complexes as Building Blocks in Organometallic Chemistry

    NARCIS (Netherlands)

    Slagt, Martijn Quico

    2002-01-01

    A rapidly evolving field in chemistry is the application of organometallic and coordination complexes as building blocks or active components for the construction of new materials exhibiting specific catalytic, redox, optical or sensor activities. A central theme in the construction of these inorgan

  4. Microwave assisted synthesis, characterization and biological evaluation of palladium and platinum complexes with azomethines.

    Science.gov (United States)

    Sharma, Krishna; Singh, Ritu; Fahmi, Nighat; Singh, R V

    2010-01-01

    Reactions of 3-acetyl-2,5-dimethylthiophene with thiosemicarbazide and semicarbazide hydrochloride resulted in the formation of new heterocyclic ketimines, 3-acetyl-2,5-dimethylthiophene thiosemicarbazone (C(9)H(13)N(3)OS(2) or L(1)H) and 3-acetyl-2,5- dimethylthiophene semicarbazone (C(9)H(13)N(3)OS or L(2)H), respectively. The Pd(II) and Pt(II) complexes have been synthesized by mixing metal salts in 1:2 molar ratios with these ligands by using microwave as well as conventional heating method for comparison purposes. The authenticity of these ligands and their complexes has been established on the basis of elemental analysis, melting point determinations, molecular weight determinations, IR, (1)H NMR and UV spectral studies. These studies showed that the ligands coordinate to the metal atom in a monobasic bidentate manner and square planar environment around the metal atoms has been proposed to the complexes. Both the ligands and their complexes have been screened for their antimicrobial activities. The antiamoebic activity of both the ligands and their palladium compounds against the protozoan parasite Entamoeba histolytica has been tested.

  5. C [bond] H activation by cationic platinum(II) complexes: ligand electronic and steric effects.

    Science.gov (United States)

    Zhong, H Annita; Labinger, Jay A; Bercaw, John E

    2002-02-20

    A series of bis(aryl)diimine-ligated methyl complexes of Pt(II) with various substituted aryl groups has been prepared. The cationic complexes [(ArN=CR [bond] CR=NAr)PtMe(L)](+)[BF(4)](-) (Ar = aryl; R = H, CH(3); L = water, trifluoroethanol) react smoothly with benzene at approximately room temperature in trifluoroethanol solvent to yield methane and the corresponding phenyl Pt(II) cations, via Pt(IV)-methyl-phenyl-hydrido intermediates. The reaction products of methyl-substituted benzenes suggest an inherent reactivity preference for aromatic over benzylic C [bond] H activation, which can however be overridden by steric effects. For the reaction of benzene with cationic Pt(II) complexes bearing 3,5-disubstituted aryl diimine ligands, the rate-determining step is C [bond] H activation, whereas for the more sterically crowded analogues with 2,6-dimethyl-substituted aryl groups, benzene coordination becomes rate-determining. This switch is manifested in distinctly different isotope scrambling and kinetic deuterium isotope effect patterns. The more electron-rich the ligand is, as assayed by the CO stretching frequency of the corresponding carbonyl cationic complex, the faster the rate of C [bond] H activation. Although at first sight this trend appears to be at odds with the common description of this class of reaction as electrophilic, the fact that the same trend is observed for the two different series of complexes, which have different rate-determining steps, suggests that this finding does not reflect the actual C [bond] H activation process, but rather reflects only the relative ease of benzene displacing a ligand to initiate the reaction; that is, the change in rates is mostly due to a ground-state effect. The stability of the aquo complex ground state in equilibrium with the solvento complex increases as the diimine ligand is made more electron-withdrawing. Several lines of evidence, including the mechanism of degenerate acetonitrile exchange for the methyl

  6. Kinetics and mechanism of reactions of the drug tiopronin with platinum(IV) complexes.

    Science.gov (United States)

    Huo, Shuying; Shi, Hongmei; Liu, Dongzhi; Shen, Shigang; Zhang, Jiong; Song, Changying; Shi, Tiesheng

    2013-08-01

    Tiopronin, a synthetic thiol-containing drug being used in treatments of cystinuria and certain types of rare arthritis, is also a hepatoprotective and a detoxifying agent. Many analytical methods have been developed based on its redox chemistry with metal ions/complexes, but the kinetic and mechanistic aspects are poorly understood. In this work, the oxidation of tiopronin by cisplatin prodrug and a model compound, cis-[Pt(NH3)2Cl4] and trans-[PtCl2(CN)4](2-), was investigated. The oxidation kinetics was followed by a stopped-flow spectrophotometer over a wide pH range under the pseudo first-order conditions of [Tiopronin]≫[Pt(IV)]. Time-resolved spectra were also recorded for both Pt(IV) complexes, enabling to establish an overall second-order rate law: -d[Pt(IV)]/dt=k'[Tiopronin][Pt(IV)], where k' pertains to observed second-order rate constants. Under the kinetic conditions, tiopronin was oxidized to form the tiopronin-disulfide exclusively as identified by mass spectrometry. A reaction mechanism was proposed, involving parallel reductions of the Pt(IV) complexes by the three protolytic tiopronin species as rate-determining steps. The rate constants for the rate-determining steps were derived. The fully deprotonated tiopronin is about 4×10(4) more reactive than its corresponding thiol form for both Pt(IV) complexes; the huge reactivity difference orchestrates closely with the fact that the nucleophilicity of thiolate is much higher than the corresponding thiol. Hence, the attack of the sulfur atom in thiol/thiolate of tiopronin on the axially-coordinated chloride in the Pt(IV) complexes is nucleophilic in nature in the rate-determining steps, resulting in a bridge formation and a subsequent bridged electron-transfer. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Glycosylated Platinum(IV) Complexes as Substrates for Glucose Transporters (GLUTs) and Organic Cation Transporters (OCTs) Exhibited Cancer Targeting and Human Serum Albumin Binding Properties for Drug Delivery.

    Science.gov (United States)

    Ma, Jing; Wang, Qingpeng; Huang, Zhonglv; Yang, Xiande; Nie, Quandeng; Hao, Wenpei; Wang, Peng George; Wang, Xin

    2017-07-13

    Glycosylated platinum(IV) complexes were synthesized as substrates for GLUTs and OCTs for the first time, and the cytotoxicity and detailed mechanism were determined in vitro and in vivo. Galactoside Pt(IV), glucoside Pt(IV), and mannoside Pt(IV) were highly cytotoxic and showed specific cancer-targeting properties in vitro and in vivo. Glycosylated platinum(IV) complexes 5, 6, 7, and 8 (IC50 0.24-3.97 μM) had better antitumor activity of nearly 166-fold higher than the positive controls cisplatin (1a), oxaliplatin (3a), and satraplatin (5a). The presence of a hexadecanoic chain allowed binding with human serum albumin (HSA) for drug delivery, which not only enhanced the stability of the inert platinum(IV) prodrugs but also decreased their reduction by reductants present in human whole blood. Their preferential accumulation in cancer cells compared to noncancerous cells (293T and 3T3 cells) suggested that they were potentially safe for clinical therapeutic use.

  8. Synthesis, Structure, and Reactivity of Arylchlorobis(dialkyl sulfide)platinum(II) Complexes.

    Science.gov (United States)

    Wendt, Ola F.; Oskarsson Å, Åke; Leipoldt, Johann G.; Elding, Lars I.

    1997-09-24

    Complexes trans-[PtRCl(SR'(2))(2)], where R = Ph, mesityl, and p-anisyl and R' = Me or Et, have been synthesized and their crystal and molecular structures determined. Crystals of trans-[PtPhCl(SEt(2))(2)] (2) are triclinic (P&onemacr;) with a = 10.112(6) Å, b = 13.158(2) Å, c = 14.714(5) Å, alpha = 102.48(2) degrees, beta = 94.394(4) degrees, gamma = 90.22(3) degrees, and Z = 4. Crystals of trans-[Pt(mesityl)Cl(SMe(2))(2)] (4) are monoclinic (P2(1)/c) with a = 13.158(2) Å, b = 9.170(1) Å, c = 16.013(3) Å, beta = 120.93(2) degrees, and Z = 4, and crystals of [Pt(p-anisyl)Cl(SMe(2))(2)] (5) are monoclinic (P2(1)/n) with a = 9.879(4) Å, b = 8.128(2) Å, c = 19.460(5) Å, beta = 96.56(3) degrees, and Z = 4. All complexes are square-planar, featuring Pt-Cl distances between 2.40 and 2.42 Å, indicating a large ground-state trans influence of the aryl group. The coordination geometry is maintained in methanol and chloroform solution as shown by (1)H-NMR spectra. The kinetics of substitution of the labile chloride trans to aryl by various nucleophiles has been studied in methanol by variable-temperature and -pressure stopped-flow spectrophotometry. A two-term rate law with a well-developed solvolytic pathway is followed. Negative entropies and volumes of activation indicate an associative mode of activation in all cases, independent of steric blocking of the axial sites and a large Pt-Cl ground-state bond-weakening. Comparison of the reaction rates of the present series of complexes with their bis(phosphine) analogues and with related cyclometalated compounds shows that the triethylphosphine complexes are 2-3 orders of magnitude less reactive than the thioether complexes, which in turn are a factor 10-20 less reactive than the cyclometalated ones. This reactivity increase can be rationalized mainly in terms of a decrease in steric hindrance in the series. There seems to be no inherent differences with regard to trans labilizing ability of the aryl ligands in the

  9. Hexakis (PCP-Platinum and -Ruthenium) Complexes by the Transcyclometalation Reaction and Their Use in Catalysis

    NARCIS (Netherlands)

    Koten, G. van; Dijkstra, H.P.; Albrecht, M.; Medici, S.; Klink, G.P.M. van

    2002-01-01

    Hexakis(PCP-pincer) complexes [C6{PtBr(PCP)}6] (5d) and [C6{RuCl(PCP)(PPh3)}6] (5e) were synthesized via the transcyclometalation (TCM) procedure. Mixing the hexakis(PCHP-arene) ligand 7 with six equivalents of [PtBr(NCN)] (1a) or [RuCl(NCN)(PPh3)] (1b), respectively, resulted in the selective

  10. Preparation of platinum(IV) complexes with dipeptide and diimine. X-ray crystal structure and 195Pt NMR spectra.

    Science.gov (United States)

    Watabe, Masatoshi; Fukuda, Hiroto; Kitsukawa, Koichiro; Nakajima, Hiroshi; Yukawa, Yasuhiko; Igarashi, Satoshi; Fujii, Yuki; Takayama, Toshio

    2006-10-01

    We prepared platinum(IV) complexes containing dipeptide and diimine or diamine, the [PtCl(dipeptide-N,N,O)(diimine or diamine)]Cl complex, where -N,N,O means dipeptide coordinated as a tridentate chelate, dipeptide=glycylglycine (NH(2)CH(2)CON(-)CH(2)COO(-), digly, where two protons of dipeptide are detached when the dipeptide coordinates to metal ion as a tridentate chelate), glycyl-L-alanine (NH(2)CH(2)CON(-)CHCH(3)COO(-), gly-L-ala), L-alanylglycine (NH(2)CH CH(3)CON(-)CH(2)COO(-), L-alagly), or L-alanyl-L-alanine (NH(2)CHCH(3)CON(-)CHCH(3)COO(-), dil-ala), and diimine or diamine=bipyridine (bpy), ethylenediamine (en), N-methylethylenediamine (N-Me-en), or N,N'-dimethylethylenediamine (N,N'-diMe-en). In the complexes containing gly-L-ala or dil-ala, two separate peaks of the (195)Pt NMR spectra of the [PtCl(dipeptide-N,N,O)(diimine or diamine)]Cl complexes appeared in, but in the complexes containing digly or L-alagly, one peak which contained two overlapped signals appeared. One of the two complexes containing gly-L-ala and bpy, [PtCl(gly-L-ala-N,N,O)(bpy)]NO(3), crystallized and was analyzed. This complex has the monoclinic space group P2(1)2(1)2(1) with unit cell dimensions of a=9.7906(3)A, b=11.1847(2)A, c=16.6796(2)A, Z=4. The crystal data revealed that this [PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) complex has the near- (Cl, CH(3)) configuration of two possible isomers. Based on elemental analysis, the other complex must have the near- (Cl, CH(3))-[PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) configuration. The (195)Pt NMR chemical shifts of the near- (Cl, CH(3))-[PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) complex and the far- (Cl, CH(3))-[PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) complex are 0 ppm and -19 ppm, respectively (0 ppm for the Na(2)[PtCl(6)] signal). The additive property of the (195)Pt NMR chemical shift is discussed. The (195)Pt NMR chemical shifts of [PtCl(dipeptide-N,N,O)(bpy)]Cl appeared at a higher field when the H attached to the dipeptide carbon atom was replaced with a

  11. [Synthesis and luminescent spectral characteristics of porphyrin complexes with platinum group metals].

    Science.gov (United States)

    Rumiantseva, V D; Ivanovskaia, N P; Konovalenko, L I; Tsukanov, S V; Mironov, A F; Osin, N S

    2008-01-01

    The synthesis of natural and synthetic porphyrin complexes with Pt, Pd, Rh, and Ru is reported. Their electronic absorption spectra, phosphorescence spectra, and lifetimes at room temperature both in the presence and in the absence of oxygen were studied. It has been shown that the variation of the nature of the central metal atom and of the substituents in pyrrole and phenyl rings allows the obtaining of metalloporphyrins with various phosphorescence excitation and phosphorescing emission spectra at room temperature. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http://www.maik.ru.

  12. DNA-based aptamer fails as a simultaneous cancer targeting agent and drug delivery vehicle for a phenanthroline-based platinum(II) complex.

    Science.gov (United States)

    McGinely, Nicola L; Plumb, Jane A; Wheate, Nial J

    2013-11-01

    The sgc8c aptamer is a 41-base DNA oligonucleotide that binds to leukaemia cells with high affinity and specificity. In this work we examined the utility of this aptamer as both a delivery vehicle and an active targeting agent for an inert platinum complex [(1,10-phenathroline)(ethylenediamine)platinum(II)](2+). The aptamer forms a stem-and-loop confirmation as determined by circular dichroism. This conformation is adopted in both water and phosphate buffered saline solutions. The metal complex binds through intercalation into the aptamer's double helical stem with a binding constant of approximately 4.3 × 10(4) M(-1). Binding of the metal complex to the aptamer had a significant effect on the aptamer's global conformation, and increased its melting temperature by 28°C possibly through lengthening and stiffening of the aptamer stem. The effect of the aptamer on the metal complex's cytotoxicity and cellular uptake was determined using in vitro assays with the target leukaemia cell line CCRF-CEM and the off-target ovarian cancer cell lines A2780 and A2780cp70. The aptamer has little inherent cytotoxicity and when used to deliver the metal complex results in a significant decrease in the metal complex's cytotoxicity and uptake. The reason(s) for the poor uptake and activity may be due to the change in aptamer conformation which affects its ability to recognise leukaemia cells.

  13. Electrospray ionization mass spectrometry for the hydrolysis complexes of cisplatin: implications for the hydrolysis process of platinum complexes.

    Science.gov (United States)

    Feifan, Xie; Pieter, Colin; Jan, Van Bocxlaer

    2017-07-01

    Non-enzyme-dependent hydrolysis of the drug cisplatin is important for its mode of action and toxicity. However, up until today, the hydrolysis process of cisplatin is still not completely understood. In the present study, the hydrolysis of cisplatin in an aqueous solution was systematically investigated by using electrospray ionization mass spectrometry coupled to liquid chromatography. A variety of previously unreported hydrolysis complexes corresponding to monomeric, dimeric and trimeric species were detected and identified. The characteristics of the Pt-containing complexes were investigated by using collision-induced dissociation (CID). The hydrolysis complexes demonstrate distinctive and correlative CID characteristics, which provides tools for an informative identification. The most frequently observed dissociation mechanism was sequential loss of NH3 , H2 O and HCl. Loss of the Pt atom was observed as the final step during the CID process. The formation mechanisms of the observed complexes were explored and experimentally examined. The strongly bound dimeric species, which existed in solution, are assumed to be formed from the clustering of the parent compound and its monohydrated or dihydrated complexes. The role of the electrospray process in the formation of some of the observed ions was also evaluated, and the electrospray ionization-related cold clusters were identified. The previously reported hydrolysis equilibria were tested and subsequently refined via a hydrolysis study resulting in a renewed mechanistic equilibrium system of cisplatin as proposed from our results. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  14. Characteristic effect of an anticancer dinuclear platinum(II) complex on the higher-order structure of DNA.

    Science.gov (United States)

    Kida, Naoko; Katsuda, Yousuke; Yoshikawa, Yuko; Komeda, Seiji; Sato, Takaji; Saito, Yoshihiro; Chikuma, Masahiko; Suzuki, Mari; Imanaka, Tadayuki; Yoshikawa, Kenichi

    2010-06-01

    It is known that a 1,2,3-triazolato-bridged dinuclear platinum(II) complex, [{cis-Pt(NH(3))(2)}(2)(micro-OH)(micro-1,2,3-ta-N (1),N (2))](NO(3))(2) (AMTA), shows high in vitro cytotoxicity against several human tumor cell lines and circumvents cross-resistance to cisplatin. In the present study, we examined a dose- and time-dependent effect of AMTA on the higher-order structure of a large DNA, T4 phage DNA (166 kbp), by adapting single-molecule observation with fluorescence microscopy. It was found that AMTA induces the shrinking of DNA into a compact state with a much higher potency than cisplatin. From a quantitative analysis of the Brownian motion of individual DNA molecules in solution, it became clear that the density of a DNA segment in the compact state is about 2,000 times greater than that in the absence of AMTA. Circular dichroism spectra suggested that AMTA causes a transition from the B to the C form in the secondary structure of DNA, which is characterized by fast and slow processes. Electrophoretic measurements indicated that the binding of AMTA to supercoiled DNA induces unwinding of the double helix. Our results indicate that AMTA acts on DNA through both electrostatic interaction and coordination binding; the former causes a fast change in the secondary structure from the B to the C form, whereas the latter promotes shrinking in the higher-order structure as a relatively slow kinetic process. The shrinking effect of AMTA on DNA is attributable to the possible increase in the number of bridges along a DNA molecule. It is concluded that AMTA interacts with DNA in a manner markedly different from that of cisplatin.

  15. Study on the cytotoxic activity of platinum(II) complexes of (1R,2R)-N(1)-cyclopentyl-1,2-cyclohexanediamine with substituted malonate derivatives.

    Science.gov (United States)

    Zhou, Zhiping; Chen, Feihong; Xu, Gang; Gou, Shaohua

    2016-01-15

    Three platinum(II) complexes of (1R,2R)-N(1)-cyclopentyl-1,2-cyclohexanediamine with malonate derivatives were designed, synthesized and spectrally characterized. MTT assay showed that the complexes possessed positive cytotoxic effect on the four human solid tumor cell lines. Among the complexes, complex 2 demonstrated the strongest cytotoxic activity compared to cisplatin and oxaliplatin against HepG2 cell line (IC50=3.04μM). Furthermore, the results of gel electrophoresis revealed that complex 2 interacted with DNA in a different mode from that of cisplatin. Mechanism studies of cell proliferation inhibition and cellular uptake indicated that complex 2 entered HepG2 cell more efficiently than cisplatin, exhibited massive G2 accumulation and then induced apoptosis.

  16. Kinetics of the methylation of a platinum(II) diimine dithiolate complex

    Energy Technology Data Exchange (ETDEWEB)

    Stace, Justin J.; Ball, P. J.; Shingade, Vikas; Chatterjee, Sayandev; Shiveley, Amber; Fleeman, Wendi L.; Staniszewski, Aaron J.; Krause, Jeanette A.; Connick, William B.

    2016-06-01

    Pt(dbbpy)(bdt) and Pt(tmphen)(bdt) (dbbpy = 4,4'-di-t-butyl-2,2'-bipyridine; tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline; bdt2- = 1,2-benzenedithiolate) are reported. Pt(dbbpy)(bdt) reacts with one equivalent of methyl iodide to give the S-methylated product, [Pt(dbbpy)(CH3bdt)]I. The reaction follows second order kinetics with a rate constant of 1.3×10 2 M-1s-1 at 311 K. The accumulated data are consistent with direct nucleophilic attack by the coordinated bdt2- ligand sulfur atom on the carbon atom of the methyl iodide. Variable-temperature experiments yield an Arrhenius activation energy of 51 ± 3 kJ/mol. Activated complex reaction theory yields an enthalpy and entropy of activation of 48 ± 2 kJ/mol and 125 ± 7 J/(mol K), respectively, consistent with an SN2 reaction mechanism. The structure of the monosulfinate adduct, Pt(dbbpy)(bdtO2), also is reported. The fluid-solution luminescence of Pt(tmphen)(bdt) is concentration dependent and characterized by a 1591 ± 41 ns lifetime and 2.6 ± 0.2% quantum yield at infinite dilution.

  17. Turning-On of Coumarin Phosphorescence in Acetylacetonato Platinum Complexes of Cyclometalated Pyridyl-Substituted Coumarins

    Directory of Open Access Journals (Sweden)

    Andrej Jackel

    2015-04-01

    Full Text Available Two pyridine-functionalized coumarins differing with respect to the site of pyridine attachment to the coumarin dye (3 in L1 or 7 in L2 and with respect to the presence (L1 or absence (L2 of a peripheral NMe2 donor were prepared and used as cyclometalating ligands towards the Pt(acac fragment. X-ray crystal structures of complexes 1 and 2 show strong intermolecular interactions by π-stacking and short Pt∙∙∙Pt or C-H∙∙∙O hydrogen bonding that result in the formation of sheetlike packing patterns. The NMe2 donor substituent has a profound influence on the absorption and emission properties of the free coumarin dyes; L1 emits strongly while L2 is only weakly emissive. On binding to Pt(acac the strong fluorescence of L1 is partially quenched while coumarin phosphorescence is observed from cyclometalated L1 and L2. The ligand-centered nature of the LUMO was confirmed by IR spectroelectrochemistry while the assignment of the phosphorescence emission as ligand-based rests on the vibrational structuring, the negligible solvatochromism, the small temperature-induced Stokes shifts on cooling to 77 K, the emission lifetimes, and strong oxygen quenching. (TD-DFT calculations confirm our experimental results and provide an assignment of the electronic transitions and the spin density distributions in the T1 state.

  18. Synthesis, DFT calculations and cytotoxic investigation of platinum complexes with 3-thiolanespiro-5‧-hydantoin and 4-thio-1H-tetrahydropyranespiro-5‧-hydantoin

    Science.gov (United States)

    Bakalova, Adriana; Buyukliev, Rossen; Momekov, Georgi

    2015-07-01

    Two organic compounds - 3-thiolanespiro-5‧-hydantoin, 4-thio-1H-tetrahydropyranespiro-5‧-hydantoin and four new Pt(II) and Pt(IV) complexes with general formulas cis-[Pt(L)2Cl2] and cis-[Pt(L)2Cl4] were synthesized. The obtained compounds were characterized by elemental analysis, IR, 1H, 13C NMR spectroscopy. The hybrid DFT calculations were used for optimization of the structure geometries of the ligand (L1) and its Pt(II) complex (1). The calculated structural parameters such as bond lengths and angles are in good agreement with the experimental data for similar hydantoins and their platinum complexes. The obtained results showed that the geometry of the complex (1) is plane square and the bounding of the L1 with platinum ion is realized by sulfur atom from thiolane ring. The complexes were tested for cytotoxicity in vitro on four human tumor cell lines. The tested compounds exerted concentration-dependent cytotoxic effects against some of the tumor cell lines.

  19. Platinum-group minerals in the LG and MG chromitites of the eastern Bushveld Complex, South Africa

    Science.gov (United States)

    Oberthür, Thomas; Junge, Malte; Rudashevsky, Nikolay; de Meyer, Eveline; Gutter, Paul

    2016-01-01

    The chromitites of the Bushveld Complex in South Africa contain vast resources of platinum-group elements (PGE); however, except for the economic upper group (UG)-2 chromitite seam, information on the distribution of the PGE in the ores and on the mineralogical nature, assemblages, and proportions of platinum-group minerals (PGM) is essentially missing. In the present geochemical and mineralogical study, PGE concentrates originating from the lower group (LG)-6 and middle group (MG)-1/2 chromitites were investigated with the intention to fill this gap of knowledge. Chondrite-normalized PGE patterns of bulk rock and concentrates are characterized by a positive slope from Os to Rh, a slight drop to Pt, and an increase to Pd again. The pronounced similarities of the PGE patterns indicate similar primary processes of PGE concentration in the chromitites, namely "sulfide control" of the PGE mineralization, i.e., co-precipitation of chromite and sulfide. Further, the primary control of PGE concentration in chromitites appears to be dual in character: (i) base-level concentrations of IPGE (up to ˜500 ppb) hosted within chromite and (ii) co-precipitation of chromite and sulfide, the latter containing virtually the entire remaining PGE budget. Sulfides (chalcopyrite, pentlandite, and pyrite; pyrrhotite is largely missing) are scarce within the chromitites and occur mainly interstitial to chromite grains. Pd and Rh contents in pentlandite are low and erratic. Essentially, the whole PGE inventory of the ores occurs in the form of discrete PGM. The PGM are almost always associated with sulfides. The dominant PGM are various Pt-Pd-Rh sulfides (cooperite/braggite [(Pt,Pd)S] and malanite/cuprorhodsite [CuPt2S4]/[CuRh2S4]), laurite [RuS2], the main carrier of the IPGE (Os, Ir, Ru), sulfarsenides [(Rh,Pt,Ir)AsS], sperrylite [PtAs2], Pt-Fe alloys, and a large variety of mainly Pd-rich PGM. The LG and MG chromitites have many characteristics in common and define a general, "typical

  20. Luminescent platinum complexes with terdentate ligands forming 6-membered chelate rings: advantageous and deleterious effects in N--N--N and N--C--N-coordinated complexes.

    Science.gov (United States)

    Garner, Katherine L; Parkes, Louise F; Piper, Jason D; Williams, J A Gareth

    2010-01-18

    Platinum(II) complexes of the form [PtL(n)Cl](+) are reported, containing the N--N--N-coordinating ligands 2,6-di(8-quinolyl)pyridine (L(1)), 2,6-di(8-quinolyl)-4-methoxypyridine (L(2)), or 2,6-di(7-aza-indolyl)-pyridine (L(3)). Metathesis of the chloride co-ligand in [PtL(1)Cl](+) can be accomplished under mild conditions, as exemplified by the formation of the complexes [PtL(1)OMe](+) and [PtL(1)(C[triple bond]C-tfp)](+), in which L(1) remains bound as a terdentate ligand {HC[triple bond]C-tfp = 3,5-bis(trifluoromethyl)-phenylacetylene}. An N--C--N-coordinated, cyclometalated analogue of [PtL(1)Cl](+) has also been prepared, namely, PtL(4)Cl where HL(4) is 1,3-di(8-quinolyl)benzene. The common feature among the six new complexes described here is that they contain 6-membered chelate rings, rather than the usual 5-membered rings that form when more common N--N--N ligands, such as 2,2':6',2''-terpyridine (tpy), bind to Pt(II). All the quinolyl-based complexes are phosphorescent in solution at room temperature, with quantum yields up to 4%. This contrasts with the well-established lack of emission from [Pt(tpy)Cl](+) under these conditions. Density functional theory calculations suggest that the improvement may stem, at least in part, from the relief of ring strain associated with the larger chelate ring size, leading to a more optimal bite angle at the metal, close to 180 degrees , and hence to a stronger ligand field. Consideration of the luminescence parameters, including data at 77 K, together with absorption and electrochemical data and the results of TD-DFT calculations, suggests that the lowest-lying singlet states have metal-to-ligand charge-transfer (MLCT) character, but that the triplet state from which emission occurs has more predominant ligand-centered character. The azaindolyl complex [PtL(3)Cl](+) is not emissive at room temperature, apparently owing to a particularly small radiative rate constant. The cyclometalated complex PtL(4)Cl emits at lower

  1. Nanocarriers for delivery of platinum anticancer drugs☆

    Science.gov (United States)

    Oberoi, Hardeep S.; Nukolova, Natalia V.; Kabanov, Alexander V.; Bronich, Tatiana K.

    2014-01-01

    Platinum based anticancer drugs have revolutionized cancer chemotherapy, and continue to be in widespread clinical use especially for management of tumors of the ovary, testes, and the head and neck. However, several dose limiting toxicities associated with platinum drug use, partial anti-tumor response in most patients, development of drug resistance, tumor relapse, and many other challenges have severely limited the patient quality of life. These limitations have motivated an extensive research effort towards development of new strategies for improving platinum therapy. Nanocarrier-based delivery of platinum compounds is one such area of intense research effort beginning to provide encouraging preclinical and clinical results and may allow the development of the next generation of platinum chemotherapy. This review highlights current understanding on the pharmacology and limitations of platinum compounds in clinical use, and provides a comprehensive analysis of various platinum–polymer complexes, micelles, dendrimers, liposomes and other nanoparticles currently under investigation for delivery of platinum drugs. PMID:24113520

  2. Arene ruthenium(II) azido complexes incorporating N intersection O chelate ligands: Synthesis, spectral studies and 1,3-dipolar-cycloaddition to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Kaminsky, W.

    Synthesis of (η6-arene) ruthenium (II) complexes has attracted considerable attention owing to their anti-cancer [1-3], antiviral [4] and catalytic properties [5-7]. The catalytic activities of these complexes range from hydrogen transfer to ring closing...

  3. The mononuclear nickel(II) complex bis(azido-κN)bis[2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole-κ(2) N(2) ,N(3) ]nickel(II) protects tomato from Verticillium dahliae by inhibiting fungal growth and activating plant defences.

    Science.gov (United States)

    Zine, Hanane; Rifai, Lalla Aicha; Koussa, Tayeb; Bentiss, Fouad; Guesmi, Salaheddine; Laachir, Abdelhakim; Makroum, Kacem; Belfaiza, Malika; Faize, Mohamed

    2017-01-01

    The antifungal properties of the nickel(II) complex bis(azido-κN)bis[2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole-κ(2) N(2) ,N(3) ]nickel(II) [NiL2 (N3 )2 ] and its parental ligand 2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole were examined to evaluate their ability to protect tomato plants against Verticillium dahliae. Our main objectives were to determine their effects on the in vitro growth of the pathogen, and their aptitude for controlling verticillium wilt and activating plant defence responses in the greenhouse. NiL2 (N3 )2 exhibited in vitro an elevated inhibition of radial growth of three strains of the pathogen. According to the strain, the EC50 values ranged from 10 to 29 µg mL(-1) for NiL2 (N3 )2 . In the greenhouse, it induced an elevated protection against V. dahliae when it was applied twice as foliar sprays at 50 µg mL(-1) . It reduced the leaf alteration index by 85% and vessel browning by 96%. In addition, its protective ability was associated with the accumulation of H2 O2 and the activation of total phenolic content, as well as potentiation of the activity of peroxidase and polyphenol oxidase. These results demonstrated that the coordination of the ligand with Ni associated with the azide as a coligand resulted in an improvement in its biological activity by both inhibiting the growth of V. dahliae and activating plant defence responses. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  4. Study of the interaction between two newly synthesized cyclometallated platinum (II) complexes and human serum albumin: Spectroscopic characterization and docking simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yousefi, Reza, E-mail: ryousefi@shirazu.ac.ir [Protein Chemistry Laboratory (PCL), Department of Biology, College of Sciences, Shiraz University, Shiraz (Iran, Islamic Republic of); Mohammadi, Roghayeh [Protein Chemistry Laboratory (PCL), Department of Biology, College of Sciences, Shiraz University, Shiraz (Iran, Islamic Republic of); Taheri-Kafrani, Asghar [Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Bagher Shahsavani, Mohammad [Protein Chemistry Laboratory (PCL), Department of Biology, College of Sciences, Shiraz University, Shiraz (Iran, Islamic Republic of); Dadkhah Aseman, Marzieh; Masoud Nabavizadeh, S.; Rashidi, Mehdi [Department of Chemistry, College of Sciences, Shiraz University, Shiraz (Iran, Islamic Republic of); Poursasan, Najmeh; Moosavi-Movahedi, Ali-Akbar [Institute of Biochemistry and Biophysics (IBB), the University of Tehran, Tehran (Iran, Islamic Republic of)

    2015-03-15

    This study describes HSA binding properties of two cyclometalated platinum (II) complexes with non-leaving lipophilic ligands; deprotonated 2-phenylpyridine (ppy): C{sub 1} and deprotonated benzo [h]quinolone (bhq): C{sub 2}, using UV–vis, fluorescence and circular dichroism (CD) spectroscopy. The absorption spectra of HSA decreased in the presence of increasing concentration of these complexes, reflecting HSA structural alteration after drug's binding. Also the thermodynamic parameters (ΔG, ΔH and ΔS) that obtained from Trp fluorescence study revealed that the interaction between these complexes and HSA were spontaneous. In addition, C{sub 1} with flexible chemical structure indicated significantly higher fluorescence quenching and binding affinity to HSA than C{sub 2} which possesses a higher structural rigidity. The ANS fluorescence results also indicated that two Pt (II) complexes were competing for binding to the hydrophobic regions of HSA. Moreover, CD results demonstrated that C{sub 2} complex induced alteration of HSA conformation to more significant extent compared to C{sub 1}. The molecular docking results revealed the involvement of π–π stacking and hydrophobic interaction between these complexes and the protein. Overall, this study may highlight the significance of structural flexibility in designing of future anticancer Pt (II) complexes with improved binding affinity for HSA. - Highlights: • HSA is a general transport carrier for a wide variety of ligands such as metabolites and pharmaceutical drugs. • The HSA binding properties of two structurally related cyclometallated platinum (II) complexes (C{sub 1} and C{sub 2}) were studied. • The complexes can bind to HSA and induce structural alteration in this protein. • The thermodynamic parameters revealed that the interactions were spontaneous and mainly hydrophobic driven. • C{sub 1} with flexible chemical structure indicated a higher binding affinity for HSA than C{sub 2}.

  5. Higher fluorescence in platinum(iv) orthometallated complexes of perylene imine compared with their platinum(ii) or palladium(ii) analogues.

    Science.gov (United States)

    Expósito, J Emilio; Álvarez-Paíno, Marta; Aullón, Gabriel; Miguel, Jesús A; Espinet, Pablo

    2015-09-28

    The reaction of 3-perylenylmethylen-4'-ethylaniline () with [Pt2Me4(μ-SMe2)2] (and subsequent addition of PPh3) or with [Pt2(η(3)-C4H7)2(μ-Cl)2] produced cyclometallated Pt(II) complexes [Pt(C^N)Me(PPh3)] () and, respectively, [Pt2(C^N)2(μ-Cl)2] () (HC^N = 3-C20H11CH[double bond, length as m-dash]NC6H4-p-C2H5), with Pt bound to the ortho site of the perylenyl fragment. From the mononuclear complexes [Pt(C^N)L2] (L2 = acac (); S2COMe (); S2CNEt2 () are easily formed. Oxidative addition of methyl iodide to the square-planar Pt(II) complexes , , and gave the corresponding cyclometallated Pt(IV) compounds [Pt(C^N)L2MeI] , and . The X-ray structures of , , and show that the perylenyl fragment remains essentially flat in and and slightly twisted in . Comparison of the optical properties of these Pt(II) complexes with those reported for similar Pd(II) derivatives reveals that the change of metal exerts a notable influence on the UV-vis spectra. In solution at room temperature, all the Pt complexes exhibit fluorescence associated with the perylene fragment with low emission quantum yields for the Pt(II) complexes (IV) complexes: up to 29%, with emission lifetimes of 1-5 ns. Time-dependent density functional theory (TD-DFT) calculations were performed on the perylene imine and on representative complexes [M(C^N)(acac)] (M = Pd, Pt) and [Pt(C^N)(acac)MeI] to analyse the absorption spectra. These calculations support a perylene-dominated intraligand π-π*emissive state based on the HOMO and LUMO orbitals of the perylene chromophore, and a ligand-to-ligand charge-transfer (more intense for the Pt(II) complex) that explains the observed influence of the metal on the absorption properties.

  6. Antimicrobial and antitumor activity of platinum and palladium complexes of novel spherical aramides nanoparticles containing flexibilizing linkages: Structure-property relationship

    Science.gov (United States)

    Elhusseiny, Amel F.; Hassan, Hammed H. A. M.

    2013-02-01

    Square planar Pd (II) and octahedral Pt (IV) complexes with novel spherical aramides nanoparticles containing flexible linkages ligands have been synthesized and characterized using analytical and spectral techniques. The synthesized complexes have been tested for their antimicrobial activity using Kirby-Bauer disc diffusion method. The antitumor activity has been performed using liver carcinoma (HEPG2), breast carcinoma (MCF7) and colon carcinoma (HCT 116) cell lines. Palladium complexes of polyamides containing sulfones showed the highest potency as antibacterial and antifungal agents. Platinum complexes containing sulfone and ether flexible linkages and chloro groups exhibited high potency as antitumor and antimicrobial agents. The uniform sizes of these nanomaterials could find biological uses such as immune assay and other medical purposes.

  7. [1H, 15N] heteronuclear single quantum coherence NMR study of the mechanism of aquation of platinum(IV) ammine complexes.

    Science.gov (United States)

    Davies, Murray S; Hall, Matthew D; Berners-Price, Susan J; Hambley, Trevor W

    2008-09-01

    The aquation and hydrolysis of a series of platinum(IV) complexes of the general form cis, trans, cis-[PtCl 2(X) 2( (15)NH 3) 2] (X = Cl (-), O 2CCH 3 (-), OH (-)) have been followed by [ (1)H, (15)N] Heteronuclear Single Quantum Coherence NMR spectroscopy. Negligible aquation (complexes where X = O 2CCH 3 (-) or OH (-) over 3-4 weeks. Aquation of cis-[PtCl 4( (15)NH 3) 2] ( 1) is observed, and the rate of aquation increases with increasing pH and upon the addition of 0.01 mol equiv of the platinum(II) complex cis-[PtCl 2( (15)NH 3) 2] (cisplatin). The first aquated species formed from cis-[PtCl 4(NH 3) 2] has one of the axial chloro groups (relative to the equatorial NH 3 ligands) replaced by an aqua/hydroxo ligand. The second observed substitution occurs in an equatorial position. Peaks that are consistent with five of the eight possible aquation species were observed in the NMR spectra.

  8. Manganese(II)-azido/thiocyanato complexes of naphthylazoimidazoles: X-ray structures of Mn(β-NaiEt) 2(X) 2 (β-NaiEt = 1-ethyl-2-(naphthyl-β-azo)imidazole; X=N3-, NCS -)

    Science.gov (United States)

    Das, D.; Chand, B. G.; Wu, J. S.; Lu, T.-H.; Sinha, C.

    2007-10-01

    Manganese(II)-naphthylazoimidazole complexes using N3- and NCS - as counter ions are characterized as Mn(β-NaiR) 2(X) 2(β-NaiEt = 1-alkyl-2-(naphthyl-β-azo)imidazole; X=N3-, NCS -). The ligands are unsymmetric N(imidazole), N(azo) chelating agents. The microanalytical, spectral (FT-IR, UV-vis), magnetic (bulk moment and EPR) and electrochemical data establish the structure and composition of the complexes. The single crystal X-ray diffraction studies of Mn(β-NaiEt) 2(N 3) 2 and Mn(β-NaiEt) 2(NCS) 2(β-NaiEt = 1-ethyl-2-(naphthyl-β-azo)imidazole) have confirmed the three dimensional structure of the complexes. Cyclic voltammetry exhibits high potential Mn(III)/Mn(II) couple along with azo reductions. The EPR spectra show usual pattern.

  9. Experimental investigations of the hydrothermal geochemistry of platinum and palladium: V. Equilibria between platinum metal, Pt(II), and Pt(IV) chloride complexes at 25 to 300°C

    Science.gov (United States)

    Gammons, Christopher H.

    1996-05-01

    The solubility of metallic Pt in HCl solutions was determined at 200 to 300°C at oxidation states buffered near the aqueous Pt(II)/Pt(IV) boundary. Equilibrium constants were obtained for the following disproportionation reactions: log K, 200° 250° 300°C 2PtCl 42- = PtCl 42- + Pt(s) + 2Cl - 1.47 1.70 1.54 (a) 2PtCl 3- = PtCl 5- + Pt(s) + Cl - 1.77 1.74 1.37 (b) with experimental uncertainties of approximately ±0.20 log units. These results are found to be in good agreement with previously published estimates for reaction at 60 to 152.5°C. The data indicate that the relative stability of the Pt(II) and Pt(IV) chloride complexes does not change appreciably with temperature. This is in contrast to previous work in the Au(0)/Au(I)/Au(III) system which demonstrates that the Au(I) chloride complexes are unstable with respect to Au (III) at low temperature, but become the dominant aqueous species at 300°C. Pt(IV) chloride complexes are unlikely to be important in high temperature hydrothermal fluids, as unrealistically high aqueous platinum concentrations are required to stabilize these species relative to Pt(II). In contrast, thermodynamic calculations suggest that Pt(IV) chloride or hydroxychloride complexes may be the dominant form of dissolved platinum in low temperature brines that are strongly oxidized (e.g., seawater). In oxygenated, Cl-rich solutions, the solubility of Pt is extremely high at pH < 6, such that the mobility of this metal will most likely be limited by surface adsorption reactions and/ or its abundance and rate of dissolution in the enclosing rock or soil. At neutral to alkaline pH, calculated solubilities are much lower, and saturation with Pt oxide phases may occur, as has recently been described in nature.

  10. computer modeling ter modeling ter modeling of platinum reforming ...

    African Journals Online (AJOL)

    eobe

    naphtha to complex chemical reactions, at h temperature and ... at is leaving any stage of the platinum reforming reactors in terms of ... In this study, only platinum reforming .... IV. Hydrocracking of paraffinic hydrocarbons: +. →. ( +. +. +. +. ) (18).

  11. Precise investigation of the axial ligand substitution mechanism on a hydrogenphosphato-bridged lantern-type platinum(III) binuclear complex in acidic aqueous solution.

    Science.gov (United States)

    Iwatsuki, Satoshi; Mizushima, Chiho; Morimoto, Naoyuki; Muranaka, Shinji; Ishihara, Koji; Matsumoto, Kazuko

    2005-10-31

    Detailed equilibrium and kinetic studies on axial water ligand substitution reactions of the "lantern-type" platinum(III) binuclear complex, [Pt(2)(mu-HPO(4))(4)(H(2)O)(2)](2)(-), with halide and pseudo-halide ions (X(-) = Cl(-), Br(-), and SCN(-)) were carried out in acidic aqueous solution at 25 degrees C with I = 1.0 M. The diaqua Pt(III) dimer complex is in acid dissociation equilibrium in aqueous solution with -log K(h1) = 2.69 +/- 0.04. The consecutive formation constants of the aquahalo complex () and the dihalo complex () were determined spectrophotometrically to be log = 2.36 +/- 0.01 and log = 1.47 +/- 0.01 for the reaction with Cl(-) and log = 2.90 +/- 0.04 and log = 2.28 +/- 0.01 for the reaction with Br(-), respectively. In the kinetic measurements carried out under the pseudo-first-order conditions with a large excess concentration of halide ion compared to that of Pt(III) dimer (C(X)()- > C(Pt)), all of the reactions proceeded via a one-step first-order reaction, which is a contrast to the consecutive two-step reaction for the amidato-bridged platinum(III) binuclear complexes. The conditional first-order rate constant (k(obs)) depended on C(X)()- as well as the acidity of the solution. From kinetic analyses, the rate-limiting step was determined to be the first substitution process that forms the monohalo species, which is in rapid equilibrium with the dihalo complex. The reaction with 4-penten-1-ol was also kinetically investigated to examine the reactivity of the lantern complex with olefin compounds.

  12. Synthesis and assembly with mesoporous silica of platinum (II) porphyrin complexes bearing carbazyl groups: Luminescent and oxygen sensing properties

    Institute of Scientific and Technical Information of China (English)

    HUO Cheng; ZHANG Huidong; GUO Jianhua; ZHANG Hongyu; ZHANG Ping; WANG Yue

    2006-01-01

    A series of platinum meso-tetrakis [3-methoxy-4-(N-carbazyl)n-alkyloxyphenyl]porphyrin (Pt-4Cn-TPP, n = 4, 6 and 8) are synthesized. Pt-4C4-TPP, Pt-4C6-TPP and Pt-4C8-TPP exhibit similar luminescent properties in solution and solid state. Three protonated platinum (II) porphyrins are assembled with mesoporous silica MCM-48, respectively, resulting in assembly materials Pt-4Cn-TPP4+/ MCM-48 (n = 4, 6 and 8). The luminescent intensity of Pt-4Cn-TPP4+/MCM-48 can be extremely quenched by molecular oxygen with high sensitivity (I0/I100>9). The Stern-Volmer plots of these assembly materials display considerable linearity within a wide range of oxygen concentration (0 to 100%). The response time is all ≤ 1 s and recovery time ≤ 22 s for these assembly materials.

  13. Probing the lowest coordination number of dianionic platinum-cyanide complexes in the gas phase: Dynamics of the charge dissociation process

    DEFF Research Database (Denmark)

    Bojesen, G; Hvelplund, P; Jørgensen, Thomas J. D.

    2000-01-01

    Low-energy and high-energy collision induced dissociation techniques are used to study the dissociation behavior of the gaseous Pt(CN)(6)(2-) and Pt(CN)(4)(2-) dianion complexes in order to probe the smallest stable dianion complex. Loss of neutral molecules from Pt(CN)(6)(2-) occurs resulting...... in Pt(CN)(5)(2-) and Pt(CN)(4)(2-), but no indication of the existence of Pt(CN)(3)(2-) was found. This indicates that the lifetime of Pt(CN)(3)(2-) is less than 4 mus (the flight time from the collision region to the detector). In contrast, all monoanion platinum-cyanide complexes were observed, i...

  14. The synthesis and characterization of complexes of zinc(II, cadmium(II, platinum(II and palladium(II with potassium 3-dithiocarboxy-3-aza-5-aminopentanoate

    Directory of Open Access Journals (Sweden)

    SRECKO TRIFUNOVIC

    2004-02-01

    Full Text Available Complexes of zinc(II, cadmium(II, platinum(II and palladium(II with a new polydentate dithiocarbamate ligand, 3-dithiocarboxy-3-aza-5-aminopentanoate (daap-, of the type M(daap2·nH2O (M = Zn(II, Cd(II, n = 2, or M = Pt(II, Pd(II, n = 0, have been prepared and characterized by elemental analysis, IR and UV/VIS spectroscopy, as well as magnetic measurements. The spectra of the complexes suggest a bidentate coordination of the daap- ligand to the metal ions via the sulfur atoms of the deprotonated dithiocarbamato group. The fact that under the same experimental conditions its S-methyl ester does not form complexes could be taken as proof of the suggested coordination mode.

  15. Platinum(II/IV) complexes containing ethylenediamine-N,N'-di-2/3-propionate ester ligands induced caspase-dependent apoptosis in cisplatin-resistant colon cancer cells.

    Science.gov (United States)

    Kaluđerović, Goran N; Mijatović, Sanja A; Zmejkovski, Bojana B; Bulatović, Mirna Z; Gómez-Ruiz, Santiago; Mojić, Marija K; Steinborn, Dirk; Miljković, Djordje M; Schmidt, Harry; Stošić-Grujičić, Stanislava D; Sabo, Tibor J; Maksimović-Ivanić, Danijela D

    2012-08-01

    Several new R(2)eddp (R = i-Pr, i-Bu; eddp = ethylenediamine-N,N'-di-3-propionate) esters and corresponding platinum(ii) and platinum(iv) complexes of the general formula [PtCl(n)(R(2)edda-type)] (n = 2, 4) were synthesized and characterized by spectroscopic methods (IR, (1)H and (13)C NMR) and elemental analysis. The crystal structure of platinum(iv) complex [PtCl(4){(c-Pe)(2)eddip}] (3a) was resolved and is given herein. Ligand precursors, platinum(ii), and platinum(iv) complexes were tested against eight tumor cell lines (CT26CL25, HTC116, SW620, PC3, LNCaP, U251, A375, and B16). Selectivity in the action of those compounds between tumor and two normal primary cells (fibroblasts and keratinocytes) are discussed. A structure-activity relationship of these compounds is discussed. Furthermore, cell cycle distribution, induction of necrosis, apoptosis, autophagy, anoikis, caspase activation, ROS, and RNS are presented on the cisplatin-resistant colon carcinoma HCT116 cell line.

  16. Platinum impact assessment

    OpenAIRE

    Yip, Joyce Pui Yan

    2007-01-01

    This paper presents a comprehensive strategic analysis of Company X's strategies to mitigate its risks from volatile platinum prices, since Platinum is a critical component of fuel cells. It is recommended that Company X consider leasing platinum to lower cash flow requirements to meet its platinum demand over the next 5 years. A shorter platinum leasing period will reduce Company X's platinum market risk. OEMs can set up metal accounts with catalyst suppliers to eliminate Company X from plat...

  17. Novel monofunctional platinum (II) complex Mono-Pt induces apoptosis-independent autophagic cell death in human ovarian carcinoma cells, distinct from cisplatin.

    Science.gov (United States)

    Guo, Wen-Jie; Zhang, Yang-Miao; Zhang, Li; Huang, Bin; Tao, Fei-Fei; Chen, Wei; Guo, Zi-Jian; Xu, Qiang; Sun, Yang

    2013-07-01

    Failure to engage apoptosis appears to be a leading mechanism of resistance to traditional platinum drugs in patients with ovarian cancer. Therefore, an alternative strategy to induce cell death is needed for the chemotherapy of this apoptosis-resistant cancer. Here we report that autophagic cell death, distinct from cisplatin-induced apoptosis, is triggered by a novel monofunctional platinum (II) complex named Mono-Pt in human ovarian carcinoma cells. Mono-Pt-induced cell death has the following features: cytoplasmic vacuolation, caspase-independent, no nuclear fragmentation or chromatin condensation, and no apoptotic bodies. These characteristics integrally indicated that Mono-Pt, rather than cisplatin, initiated a nonapoptotic cell death in Caov-3 ovarian carcinoma cells. Furthermore, incubation of the cells with Mono-Pt but not with cisplatin produced an increasing punctate distribution of microtubule-associated protein 1 light chain 3 (LC3), and an increasing ratio of LC3-II to LC3-I. Mono-Pt also caused the formation of autophagic vacuoles as revealed by monodansylcadaverine staining and transmission electron microscopy. In addition, Mono-Pt-induced cell death was significantly inhibited by the knockdown of either BECN1 or ATG7 gene expression, or by autophagy inhibitors 3-methyladenine, chloroquine and bafilomycin A 1. Moreover, the effect of Mono-Pt involved the AKT1-MTOR-RPS6KB1 pathway and MAPK1 (ERK2)/MAPK3 (ERK1) signaling, since the MTOR inhibitor rapamycin increased, while the MAPK1/3 inhibitor U0126 decreased Mono-Pt-induced autophagic cell death. Taken together, our results suggest that Mono-Pt exerts anticancer effect via autophagic cell death in apoptosis-resistant ovarian cancer. These findings lead to increased options for anticancer platinum drugs to induce cell death in cancer.

  18. Oxidizing behavior of some platinum metal fluorides. [Xe complexes with Pt, Pd fluorides; Chlorine-2 oxidation by transition metal hexafluorides

    Energy Technology Data Exchange (ETDEWEB)

    Graham, L.

    1978-10-01

    The previously known compounds Xe/sub 2/F/sub 3//sup +/PtF/sub 6//sup -/, XeF/sup +/PtF/sub 6//sup -/ and XeF/sub 2/.2PtF/sub 4/(XePt/sub 2/F/sub 10/) were prepared by the interaction of XeF/sub 2/ with PtF/sub 4/. The new compounds XeF/sub 2/.PdF/sub 4/ and XeF/sub 2/.2PdF/sub 4/(XePd/sub 2/F/sub 10/) were produced by interaction of XeF/sub 2/ with either PdF/sub 4/ or Pd/sub 2/F/sub 6/. A weight loss-versus-time curve indicated the presence of 4:1, 3:1 and 2:1 XeF/sub 2//PdF/sub 4/ complexes. The thermal decomposition of XeFPtF/sub 6/ or XePd/sub 2/F/sub 10/ yields highly pure XeF/sub 4/. Thus the interaction of XeF/sub 2/ with platinum fluorides (PtF/sub 4/ or PtF/sub 5/) or palladium fluorides (Pd/sub 2/F/sub 6/ or PdF/sub 4/) provides for the conversion of XeF/sub 2/ to XeF/sub 4/. The compound XePd/sub 2/F/sub 10/ is a close structural relative of XePt/sub 2/F/sub 10/, and spectroscopic evidence suggests that both are salts of XeF/sup +/ and a polymeric (M/sub 2/F/sub 9/)/sub x//sup x-/ ion. A Xe:PtF/sub 6/ material of approximately 1:1 stoichiometry has been prepared and compared with XePdF/sub 6/(XeF/sub 2/.PdF/sub 4/). The interaction of chlorine with the third-series transition metal hexafluorides has been investigated. Gravimetric and tensimetric evidence indicate that the initial product of the Cl/sub 2/ plus IrF/sub 6/ reaction is a solid of composition Cl/sub 2/IrF/sub 6/. Vibrational spectroscopic and other evidence indicates that this solid yields a sequence of products, of which Cl/sub 3//sup +/IrF/sub 6//sup -/, Cl/sub 3//sup +/Ir/sub 2/F/sub 11//sup -/ and Ir/sub 4/F/sub 20/ have been identified, the last being the ultimate solid product of the room temperature decomposition of the adduct. A new chlorine fluoride generated in the room temperature decomposition of Cl/sub 2/IrF/sub 6/ has been tentatively formulated as Cl/sub 3/F from infrared evidence.

  19. Nafion-Induced Metal-Metal Interactions in a Platinum(Ⅱ) Terpyridyl Acetylide Complex:a Luminescent Sensor for Detection of Volatile Organic Compounds

    Institute of Scientific and Technical Information of China (English)

    TONG,Qing-Xiao(佟庆笑); LI,Xiao-Hong(李晓红); WU,Li-Zhu(吴骊珠); YANG,Qing-Zheng(杨清正); ZHANG,Li-Ping(张丽萍); TUNG,Chen-Ho(佟振合)

    2004-01-01

    The platinum(Ⅱ) terpyridyl acetylide complex [Pt(terpy)(C≡CR)]C1O4 (terpy=2,2′: 6′2″-terpyridine, R=CH2CH2CH3) (1) was incorporated into Nafion membranes. At high loading the dry membranes exhibit intense photoluminescence with λmax at 707 nm from the 3MMLCT state, which was not observed in fluid solution. Upon exposure to the vapor of polar volatile organic compounds (VOC), this photoluminescence was significantly red-shifed. This process was fully reversible when the VOC-incorporated membrane was dried in air. The dramatic and reversible changes in the emission spectra made the Nafion-supported complex as an interesting sensor candidate for polar VOC.

  20. A platinum(II) complex of liriodenine from traditional Chinese medicine (TCM): Cell cycle arrest, cell apoptosis induction and telomerase inhibition activity via G-quadruplex DNA stabilization.

    Science.gov (United States)

    Li, Yu-Lan; Qin, Qi-Pin; Liu, Yan-Cheng; Chen, Zhen-Feng; Liang, Hong

    2014-08-01

    Liriodenine (L), an antitumor active ingredient from the traditional Chinese medicine (TCM), Zanthoxylum nitidum, afforded a platinum(II) complex (1) of L, cis-[PtCl2(L)(DMSO)], which previously reported for its in vitro antitumor activity and intercalative binding with DNA. In this study, complex 1 was further discussed for its antitumor mechanism and structure-activity relationship, comparing with L and cisplatin. Towards the most sensitive BEL-7404 human hepatoma cells, complex 1 significantly induced cell cycle arrest at both G2/M phase and S phase. It suggests that double helix DNA is not the simplex intracellular target for 1. On the other hand, the BEL-7404 cells incubated with 1 and stained by Hoechst 33258 and AO/EB showed typical cell apoptosis in dose-dependent manner. The BEL-7404 cells incubated with 1 and stained by JC-1 were also characteristic for cell apoptosis on the loss of mitochondrial membrane potential. Furthermore, the G-quadruplex DNA binding property of complex 1 was also investigated by spectroscopic analyses, fluorescent indicator displacement (FID) assay and fluorescence resonance energy transfer (FRET) assay. The results indicated that 1 stabilized the human telomeric G4-HTG21 DNA better than L. The telomerase inhibition ratio of 1 ((62.50±0.03)%), which was examined by telomerase polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), was much higher than L ((21.77±0.01)%). It can be ascribed to the better G4-HTG21 DNA stabilization of 1 than L. The results suggested that the nuclei, mitochondria and telomerase via G-quadruplex DNA stabilization all should be key targets for the antitumor mechanism of 1, in which the central platinum(II) played a key role.

  1. Platinum(0-1,3-divinyl-1,1,3,3-tetramethyldisiloxane Complex as a Pt Source for Pt/SnO2 Catalyst

    Directory of Open Access Journals (Sweden)

    Agnieszka Martyla

    2014-01-01

    Full Text Available This paper presents new preparation method of Pt/SnO2, an important catalytic system. Besides of its application as a heterogenic industrial catalyst, it is also used as a catalyst in electrochemical processes, especially in fuel cells. Platinum is commonly used as an anode catalyst in low temperature fuel cells, fuelled with alcohols of low molecular weight such as methanol. Platinum(0-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex was used as a precursor of metallic phase. The aim of the research was to obtain a highly active in electrochemical system Pt/SnO2 catalyst with low metal load. Considering small size of Pt crystallites, it should result in high activity of Pt/SnO2 system. The presented method of SnO2 synthesis allows for obtaining support consisting of nanoparticles. The effect of the thermal treatment on activity of Pt/SnO2 gel was demonstrated. The system properties were investigated using TEM, FTIR (ATR, and XRD techniques to describe its thermal structural evolution. The results showed two electrocatalytical activity peaks for drying at a temperature of 430 K and above 650 K.

  2. Finely Tuned Asymmetric Platinum(IV) Anticancer Complexes: Structure-Activity Relationship and Application as Orally Available Prodrugs.

    Science.gov (United States)

    Yap, Siew Qi; Chin, Chee Fei; Hong Thng, Agnes Hwee; Pang, Yi Yun; Ho, Han Kiat; Ang, Wee Han

    2017-02-20

    Platinum(IV) bis-carboxylates are highly versatile prodrug scaffolds with different axial ligands that can be functionalized while keeping the platinum(II) pharmacophore intact. Using a sequential acylation strategy, we developed a class of Pt(IV) prodrugs of cisplatin with contrasting lipophilic and hydrophilic ligands. We investigated their stability, reduction rates, lipophilicity, aqueous solubility, and antiproliferative efficacies, and assessed for correlations among the parameters that could be useful in drug design. We showed that compounds with high lipophilicity result in better antiproliferative effects in vitro and in vivo, with one of the three compounds tested showing better efficacy than satraplatin against an animal model of colorectal cancer, owing to its higher solubility and lower reduction rates. Our asymmetric Pt(IV) prodrugs may pave the way for a highly predictable, fine-tuned class of orally available Pt(IV) prodrugs for the treatment of colorectal cancer. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. DNA interstrand cross-links of an antitumor trinuclear platinum(II) complex: thermodynamic analysis and chemical probing.

    Science.gov (United States)

    Malina, Jaroslav; Farrell, Nicholas P; Brabec, Viktor

    2011-06-06

    The trinuclear platinum compound [{trans-PtCl(NH(3))(2)}(2)(μ-trans-Pt(NH(3))(2){NH(2)(CH(2))(6)NH(2)}(2))](4+) (BBR3464) belongs to the polynuclear class of platinum-based anticancer agents. These agents form in DNA long-range (Pt,Pt) interstrand cross-links, whose role in the antitumor effects of BBR3464 predominates. Our results show for the first time that the interstrand cross-links formed by BBR3464 between two guanine bases in opposite strands separated by two base pairs (1,4-interstrand cross-links) exist as two distinct conformers, which are not interconvertible, not only if these cross-links are formed in the 5'-5', but also in the less-usual 3'-3' direction. Analysis of the conformers by differential scanning calorimetry, chemical probes of DNA conformation, and minor groove binder Hoechst 33258 demonstrate that each of the four conformers affects DNA in a distinctly different way and adopts a different conformation. The results also support the thesis that the molecule of antitumor BBR3464 when forming DNA interstrand cross-links may adopt different global structures, including different configurations of the linker chain of BBR3464 in the minor groove of DNA. Our findings suggest that the multiple DNA interstrand cross-links available to BBR3464 may all contribute substantially to its cytotoxicity.

  4. Recent development in platinum complexes with anticancer activities and the underlying mechanisms%具有抗肿瘤活性的铂类配合物及其作用机制研究进展

    Institute of Scientific and Technical Information of China (English)

    陈填烽; 李林林; 禹莲玲; 杨芳; 郑文杰

    2012-01-01

    顺铂自二十世纪七十年代起被批准并广泛应用于肿瘤的临床治疗,对多肿瘤疗效显著.但水溶性小、毒副作用大及获得性耐药等缺点极大的限制了铂类配合物的发展与应用.为了获得高效低毒的抗肿瘤药物,科学家们合成了数以千计的铂类配合物,并取得了阶段性进展.本文综述了近五年合成的铂类配合物的结构及其抗肿瘤活性与机制,分成:①具有空间位阻的铂(Ⅱ)配合物;②多核铂(Ⅱ)配合物;③含硫、磷酸(盐)配位原子铂(Ⅱ)配合物;④改变配体或离去基团合成的配合物及⑤铂(Ⅳ)配合物等五个类型分别阐述.%Cisplatin has been approved and widely used as anticancer drugs in clinical application since 1970s. Although cisplatin exhibited excellent and broad-spectrum anticancer activities, its low solubility , high toxicity, drug resistance, and other adverse side effects have limited its clinical applications. To obtain anticancer complexes 4with high efficacy and low toxicity, scientists have synthesized thousands of platinum complexes and have acquired gradual improvement. This paper reviews the recent developments in platinum complexes with anticancer activities and the underlying mechanisms. The complexes were classified as (Dsterically hindered platinum (II) complexes; @multinuclear platinum (II) complexes; (§) platinum (II) complexes with P or S as coordination atom; ?other platinum (II) complexes with small ligands; ?platinum (IV) complexes and so on.

  5. Highly fluorescent platinum(II) organometallic complexes of perylene and perylene monoimide, with Pt σ-bonded directly to the perylene core.

    Science.gov (United States)

    Lentijo, Sergio; Miguel, Jesús A; Espinet, Pablo

    2010-10-18

    3-Bromoperylene (BrPer) or N-(2,5-di-tert-butylphenyl)-9-bromo-perylene-3,4-dicarboximide (BrPMI) react with [Pt(PEt(3))(4)] to yield trans-[PtR(PEt(3))(2)Br] (R = Per, 1a; R = PMI, 1b). Neutral and cationic perylenyl complexes containing a Pt(PEt(3))X group have been prepared from 1a,b by substitution of the Br ligand by a variety of other ligands (NCS, CN, NO(3), CN(t)Bu, PyMe). The X-ray structures of trans-[PtR(PEt(3))(2)X] (R = Per, X = NCS (2a); R = PMI, X = NO(3) (4b); R = Per, X = CN(t)Bu (5a)) show that the perylenyl fragment remains nearly planar and is arranged almost orthogonal to the coordination plane: The three molecules appear as individual entities in the solid state, with no π-π stacking of perylenyl rings. Each platinum complex exhibits fluorescence associated to the perylene or PMI fragments with emission quantum yields, in solution at room temperature, in the range 0.30-0.80 and emission lifetimes ∼4 ns, but with significantly different emission maxima, by influence of the X ligands on Pt. The similarity of the overall luminescence spectra of these metalated complexes with the perylene or PMI strongly suggests a perylene-dominated intraligand π-π*emissive state, metal-perturbed by interaction of the platinum fragment mostly via polarization of the Ar-Pt bond.

  6. The synthesis, spectroscopic, X-ray characterization and in vitro cytotoxic testing results of activity of five new trans-platinum(IV) complexes with functionalized pyridines.

    Science.gov (United States)

    Rakić, Gordana M; Grgurić-Šipka, Sanja; Kaluđerović, Goran N; Bette, Martin; Filipović, Lana; Aranđelović, Sandra; Radulović, Siniša; Tešić, Zivoslav Lj

    2012-09-01

    Platinum(IV) complexes with general formulas [Pt(L(1-2))(2)Cl(4)], where L(1-2) are 3-acetylpyridine (1) and 4-acetylpyridine (2) respectively, and [Pt(HL(3-5))(2)Cl(2)], where H(2)L(3-5) are 2,3-pyridinedicarboxylic acid (3), 2,4-pyridinedicarboxylic acid (4) and 2,5-pyridinedicarboxylic acid (5) respectively, were prepared by the reaction of K(2)[PtCl(6)] with the corresponding ligand in 1:2 M ratio in water. The complexes were characterized by elemental analysis and IR and NMR spectroscopy. The structures of complexes 2 and 5 were determined by X-ray crystallography, which revealed the trans orientation of chloride anions around platinum(IV) in the case of both complexes. The antiproliferative activity was investigated in six tumor cell lines (human cervical carcinoma cells (HeLa), murine melanoma cells (B16), human breast carcinoma cells (MDA-MB-453), human colon carcinoma cells (LS-174), transformed human umbilical vein endothelial cells (EA.hy 926) and murine endothelial cells (MS1)) and in one non-tumor cell line-human fetal lung fibroblast cells (MRC-5). Cytotoxicity studies indicated that Pt(IV) complexes with acetyl-substituted pyridine ligands exhibit significantly higher in vitro antiproliferative activity than the complexes with carboxylato-substituted pyridines. Complexes 1 and 2 showed antiproliferative activity in all tested tumor cell lines, with the highest potential in human endothelial cells EA.hy 926, since they had IC(50) values of 13.8 ± 5.8 μM and 23.4 ± 3.3 μM, respectively and were more active than cisplatin. Complexes 1 and 2 exhibited lower toxicity against the non-tumor human lung fibroblast cell line (MRC-5) than against most of the tested tumor cell lines. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  7. Optimized syntheses of Fmoc azido amino acids for the preparation of azidopeptides.

    Science.gov (United States)

    Pícha, Jan; Buděšínský, Miloš; Macháčková, Kateřina; Collinsová, Michaela; Jiráček, Jiří

    2017-03-01

    The rise of CuI-catalyzed click chemistry has initiated an increased demand for azido and alkyne derivatives of amino acid as precursors for the synthesis of clicked peptides. However, the use of azido and alkyne amino acids in peptide chemistry is complicated by their high cost. For this reason, we investigated the possibility of the in-house preparation of a set of five Fmoc azido amino acids: β-azido l-alanine and d-alanine, γ-azido l-homoalanine, δ-azido l-ornithine and ω-azido l-lysine. We investigated several reaction pathways described in the literature, suggested several improvements and proposed several alternative routes for the synthesis of these compounds in high purity. Here, we demonstrate that multigram quantities of these Fmoc azido amino acids can be prepared within a week or two and at user-friendly costs. We also incorporated these azido amino acids into several model tripeptides, and we observed the formation of a new elimination product of the azido moiety upon conditions of prolonged couplings with 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate/DIPEA. We hope that our detailed synthetic protocols will inspire some peptide chemists to prepare these Fmoc azido acids in their laboratories and will assist them in avoiding the too extensive costs of azidopeptide syntheses. Experimental procedures and/or analytical data for compounds 3-5, 20, 25, 26, 30 and 43-47 are provided in the supporting information. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd.

  8. Síntese e reatividade de complexos platina-trifenilestibina: uma revisão bibliográfica Synthesis and reactivity of triphenylstibine-platinum complexes: a bibliographic revision

    Directory of Open Access Journals (Sweden)

    Roberto Santos Barbiéri

    2006-07-01

    Full Text Available This article deals with synthesis and reactivity of complexes with triphenylstibine (SbPh3 as the ligand. A comparative study of analogous complexes of triphenylphosphine (PPh3 and triphenylarsine (AsPh3 with platinum in the oxidation states zero, two and four is included. The bibliographic revision includes publications since 1936, when the first Pt(II complex with triphenylstibine was described.

  9. The crystal structure and absolute configuration of the antitumor platinum complex trans(OH)-Pt(OH)2(malonato)(1R,2R-cyclohexanediamine).

    Science.gov (United States)

    Goto, M; Hirose, J; Noji, M; Lee, K I; Saito, R; Kidani, Y

    1992-04-01

    The absolute configuration of the anti-tumor complex trans(OH)-Pt(OH)2(malonato)(1R,2R-cyclohexanediamine) was determined by X-ray anomalous scattering technique. The final unit cell was monoclinic, space group P2(1) with a = 9.142 A, b = 7.788 A, c = 11.946 A, beta = 96.48 degrees, Z = 2. The crystal structure was determined by direct method and difference Fourier synthesis, and refined to R = 0.025 and Rw = 0.033 based on 2768 independent reflections. The platinum atom has roughly octahedral coordination. The cyclohexane ring has the expected chair configuration, with two amino groups in equatorial positions while the malonato ligand, in contrast, shows a boat conformation for six membered Pt O-C-C-C-O ring.

  10. Mass spectrometric proteomics reveals that nuclear protein positive cofactor PC4 selectively binds to cross-linked DNA by a trans-platinum anticancer complex.

    Science.gov (United States)

    Du, Zhifeng; Luo, Qun; Yang, Liping; Bing, Tao; Li, Xianchan; Guo, Wei; Wu, Kui; Zhao, Yao; Xiong, Shaoxiang; Shangguan, Dihua; Wang, Fuyi

    2014-02-26

    An MS-based proteomic strategy combined with chemically functionalized gold nanoparticles as affinity probes was developed and validated by successful identification and quantification of HMGB1, which is well characterized to interact selectively with 1,2-cross-linked DNA by cisplatin, from whole cell lysates. The subsequent application of this method to identify proteins responding to 1,3-cross-linked DNA by a trans-platinum anticancer complex, trans-PtTz (Tz = thiazole), revealed that the human nuclear protein positive cofactor PC4 selectively binds to the damaged DNA, implying that PC4 may play a role in cellular response to DNA damage by trans-PtTz.

  11. Bulky N(,N)-(di)alkylethane-1,2-diamineplatinum(II) compounds as precursors for generating unsymmetrically substituted platinum(IV) complexes.

    Science.gov (United States)

    Pichler, Verena; Göschl, Simone; Meier, Samuel M; Roller, Alexander; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K

    2013-07-15

    Investigations of the influence of bulky groups in the equatorial ligand sphere of platinum(IV) compounds on the complexes' stability and reaction pattern were performed. Four dihydroxidoplatinum(IV) complexes were reacted with anhydrides, cinnamoyl chloride, and n-propyl isocyanate and yielded the symmetric dicarboxylated products or, if steric hindrance was observed, unsymmetrically substituted monocarboxylated analogues. With the aim of raising the steric demand, the following ligands were chosen: N-cyclohexylethane-1,2-diamine, N,N-dimethylethane-1,2-diamine, N,N-diethylethane-1,2-diamine, and N,N-diisopropylethane-1,2-diamine. All of the novel complexes were characterized by electrospray ionization mass spectrometry (ESI-MS), one- and two-dimensional NMR spectroscopy, elemental analysis, and reversed-phase HPLC; complexes B3, C3, C6, and D4 were also analyzed by X-ray diffraction. Additionally, the cytotoxicities of 10 compounds toward the cisplatin-sensitive cell line CH1 and the intrinsically cisplatin-resistant cell lines A549 and SW480 were investigated, and IC50 values down to the nanomolar range were found. To aid in the interpretation of structure-activity relationships, log k(w) values as a measure for the lipophilicity were determined for all of the new complexes, and the rates of reduction of C1, C3, and C4 relative to satraplatin were determined by means of NMR spectroscopy and ESI-MS.

  12. Platinum(II Complexes with Tetradentate Schiff Bases as Ligands: Synthesis, Characterization and Detection of DNA Interaction by Differential Pulse Voltammetry

    Directory of Open Access Journals (Sweden)

    Lijun Li

    2012-01-01

    Full Text Available Five sterically hindered platinum(II complexes with tetradentate schiff bases as ligands, [Pt(L] (L= N,N′-bisalicylidene-1,2-ethylenediamine (L1, N,N′-bisalicylidene-1,2-cyclohexanediamine (L2, N,N′-bis(5-hydroxyl-salicylidene-1,2-cyclohexanediamine (L3, N,N′-bisalicylidene-1,2-diphenyl-ethylenediamine (L4 and N,N′-bis(3-tert-butyl-5-methyl-salicylidene-1,2-diphenylethylenediamine (L5 have been synthesized and characterized by IR spectroscopy and elemental analysis. The sterical hindrance of antitumor drug candidates potentially makes them less susceptible to deactivation by sulphur containing proteins and helping to overcome resistance mechanisms. The interaction of these metal complexes with fish sperm single-stranded DNA (ssDNA was studied electrochemically based on the oxidation signals of guanine and adenine. Differential pulse voltammetry was employed to monitor the DNA interaction in solution by using renewable pencil graphite electrode. The results indicate that ligands with different groups can strongly affect the interaction between [Pt(L] complexes and ssDNA due to sterical hindrances and complex [Pt(L1] has the best interaction with DNA among the five complexes.

  13. Theoretical Study of Nonclassical Platinum Complexes Bonding to Purine Bases: How the Long-lived Monofunctional Adducts Can Be in Existence?

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The B3LYP/6-31G* level of theory was used for the optimization of nonclassical platinum drugs with planar aromatic heterocycle ligands in addition to their monoaqua species, diaqua species and monofunctional adducts. Single point calculations were performed on optimized geometries using the MP2/6-31G** method, and the Lanl2dz pseudo potential for the Pt atom remained constant in all calculations. It can be easily seen that the trans effect can influence both geometrical structures and bond dissociating energies (BDEs). On the basis of our calculation, we get that the long-lived monofunctional adducts with chloride ligand may be in existence, because they possessed higher stability energies, easily dissociated chloride compared with the monoaqua species dissociating chloride and that replacement of the first chloride by bases became exothermic in solution. Our calculated results also demonstrate that the strongest H-bonds appear in the complexes of q-wG and t-wG using different methods. In comparison with adenine complexes, the corresponding guanine complexes possess larger interaction energies as well as higher stability energies either corrected by basis set superposition error (bsse) of Boys-Bernardi counterpoise method or uncorrected both in gas phase and in solution with one exception that the stability energy of q-ClA complex in solution is larger than that of q-ClG complex. Finally, the nature of bond was analyzed in terms of partial charges distribution based on NBO population.

  14. Platinum-group elements in rocks from the voikar-syninsky ophiolite complex, Polar Urals, U.S.S.R.

    Science.gov (United States)

    Page, N.J.; Aruscavage, P. J.; Haffty, J.

    1983-01-01

    Analyses of platinum-group elements (PGE) in rocks collected from the Voikar-Syninsky ophiolite in the Polar Urals suggest that the distribution and geochemistry of PGE in this Paleozoic ophiolite are similar to those in Mesozoic ophiolites from elsewhere. Chondrite-normalized PGE patterns for chromitite, the tectonite unit, and ultramafic and mafic cumulate unit have negative slopes. These results are similar to those found for chromitites from other ophiolites; stratiform chromities show positive slopes. If the magmas that form both types of chromitite originate from similar mantle source material with respect to PGE content, the processes involved must be quite different. However, the distinct chondrite-normalized PGE patterns may reflect differing source materials. ?? 1983 Springer-Verlag.

  15. Rhomboidal [Cu4] coordination cluster from self-assembly of two asymmetric phenoxido-bridged Cu2 units: Role of 1,1-azido clips

    Indian Academy of Sciences (India)

    Avijit Sarkar; Aloke Kumar Ghosh; Moumita Pait; Haridas Mandal; Tufan Singha Mahapatra; Biswajit Sharangi; Mrinal Sarkar; Debashis Ray

    2012-11-01

    The coordination cluster [Cu2(-OMe)(1,1-N3)(-bcp)(N3)]2 (1; Hbcp = 2,6-bis(2-benzoyl-4-chloro-phenylimino)-methyl)-4-methylphenol, forming a new member within the rapidly growing family of Cu4 cluster complexes, has been synthesized and structurally characterized by X-ray crystallography. The complex crystallizes in the monoclinic system, space group P21/, with unit cell parameters a = 14.620(7) Å, b = 17.923(8) Å, c = 15.008(7) Å, = 115.815(14)° and Z = 2. It is the first example of a rhomboidal [Cu4] compound formed from 1,1-azido clipping of two methoxido bridged [Cu2] complexes showing asymmetric coordination from benzophenone oxygen atoms and terminal azido groups.

  16. Strategy to enhance the anticancer efficacy of X-ray radiotherapy in melanoma cells by platinum complexes, the role of ROS-mediated signaling pathways.

    Science.gov (United States)

    Xie, Qiang; Lan, Guoqiang; Zhou, Yangliang; Huang, Jiamin; Liang, Yuanwei; Zheng, Wenjie; Fu, Xiaoyan; Fan, Cundong; Chen, Tianfeng

    2014-11-01

    Radiotherapy plays an important role in treatment of cancers with low toxicity to the surrounding normal tissues. However, it still fails to eradicate hypoxic tumors due to the occurrence of radioresistance. Therefore, the search for new radiation sensitizers is of great significance. Platinum (Pt) complexes have been identified as potential radiation sensitizers to increase the sensitivity of cancer cells to radiotherapy. In the present study, we have synthesized four Pt complexes containing (2 - benzimidazole [4, 5-f] - [1, 10] phenanthroline) ligand and found that they could effectively enhance the X-ray-induced growth inhibition against A375 human melanoma cells through induction of G2/M cell cycle arrest. In contrast, they showed much lower cytotoxicity toward human normal cells. The complexes also dramatically inhibited the TrxR activity and caused intracellular ROS overproduction, due to the Auger electron effect of heavy metal element under X-ray radiation. Excessive ROS triggered DNA damage and activated downstream signaling pathways, including the phosphorylation of p53 and p38MAPK, and down-regulation of phosphorylated AKT and ERK, finally resulted in increase of radiosensitivity and inhibition of tumor reproduction. Taken together, our results suggest that the synthetic Pt complexes could be further developed as sensitizers of X-ray radiotherapy.

  17. Platinum(IV) complexes with some derivatives of 5-methyl-5-(4-pyridyl) hydantoin. Synthesis, study and comparative pharmacological investigation.

    Science.gov (United States)

    Bakalova, A; Buyukliev, R; Ivanova, Z; Momekov, G; Ivanov, D

    2013-08-01

    3 Pt(IV) complexes with 3-ethyl-5-methyl-5-(4-pyridyl)hydantoin (4), 3-propyl-5-methyl-5-(4-pyridyl)hydantoin (5) and 3-benzyl-5-methyl-5-(4-pyridyl)hydantoin (6) with general formulae cis-[Pt(L)2Cl4] were synthesized. The novel compounds were characterized by elemental analysis, IR, 1H, 13C, NMR spectra in solid state and in solution. The studies showed that the ligands coordinate to the platinum ions in a monodentate manner through the nitrogen atom from the pyridine ring. The cytotoxic activity in vitro of newly synthesized complexes as well as their previously prepared analogous of Pt(IV) with other derivatives like 3-amino-5-methyl-5-(4-pyridyl)hydantoin (1), 5-methyl-5-(4-pyridyl)hydantoin (2), 3,5-dimethyl-5-(4-pyridyl)hydantoin (3) was screened against a panel of human tumor cell lines. The tested compounds displayed cytotoxic activity which was invariably superior with the Pt(IV) complex with 3-benzyl-5-methyl-5-(4-pyridyl)hydantoin (6) causing 50% inhibition of cellular viability at micromolar concentration, though the activity of the other studied Pt(IV) complexes proved to greatly decrease in the order 5-4-3-2-1. © Georg Thieme Verlag KG Stuttgart · New York.

  18. Shedding light on the photophysical properties of newly designed platinum(II) complexes by adding substituents on functionalized ligands as highly efficient OLED emitters from a theoretical viewpoint

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jieqiong [Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Wang, Li, E-mail: chemwangl@henu.edu.cn [Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Wang, Xin [Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); He, Chaozheng, E-mail: hecz2013@nynu.edu.cn [College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061 (China); Zhang, Jinglai, E-mail: zhangjinglai@henu.edu.cn [Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China)

    2015-08-01

    The phosphorescent properties of three synthesized and three new designed platinum(II) complexes are focused on in this work. To reveal their structure–property relationships, a density functional theory/time-dependent density functional theory (DFT/TDDFT) investigation is performed on the geometric and electronic structures, absorption and emission spectra. The electroluminescent (EL) properties are evaluated by the ionization potential (IP), electron affinity (EA), and reorganization energy (λ). Furthermore, the radiative rate constant (k{sub r}) is qualitatively elucidated by various factors including the strength of the SOC interaction between the higher-lying singlet excited states (S{sub n}) and the T{sub 1} state, the oscillator strength (f) of the S{sub n} states that can couple with the T{sub 1} state, and the energy separation between the coupled states. A combined analysis of various elements that could affect the phosphorescent efficiency is beneficial to exploring efficient triplet phosphors in OLEDs. Consequently, complexes Pt-1 and 1 would be more suitable blue-emitting phosphorescent materials with balance of EL properties and acceptable quantum yields. - Graphical abstract: Display Omitted - Highlights: • The absorption and phosphorescence spectra of Pt(II) complexes are investigated. • Their Φ{sub em}, IP, EA, and reorganization energy are compared. • Three new Pt(II) complexes are designed.

  19. DNA studies of newly synthesized heteroleptic platinum(II) complexes [Pt(bpy)(iip)](2+) and [Pt(bpy)(miip)](2.).

    Science.gov (United States)

    Coban, Burak; Tekin, Ishak Ozel; Sengul, Abdurrahman; Yildiz, Ufuk; Kocak, Izzet; Sevinc, Nergis

    2016-04-01

    Two new mono-nuclear heteroleptic platinum(II) complexes, [Pt(bpy)(iip)](PF6)2 (1) and [Pt(bpy)(miip)](PF6)2·2H2O (2) (bpy is 2,2'-bipyridine; iip is 2-(imidazo-4-yl)-1H-imidazo[4,5-f] [1,10] phenanthroline; miip is 2-(1-methylimidazo-2-yl)-1H-imidazo[4,5-f] [1, 10] phenanthroline), have been synthesized and fully characterized by CHN analysis, electrospray ionization and MALDI-TOF mass spectrometry, (1)H NMR, FT-IR (ATR), and UV-Vis spectrophotometer. Cytotoxicity, ability to inhibit DNA transcription and DNAse activity of the complexes were studied. The DNA-binding behaviors of both complexes have also been studied by spectroscopic methods, cyclic voltammetry and viscosity measurements. Both complexes showed cytotoxic properties and 2 was more cytotoxic than 1. DNA transcription was inhibited upon increasing concentrations of both complexes. The complex 2 was found to be a better inhibitor than 1. The same pattern can be seen in the DNAse profile of the complexes. In addition, 2 was found to promote cleavage of pBR322 DNA at a lower concentration than 1. The spectroscopic, electrochemical and viscometric results indicate that both complexes show some degree of binding to DNA in an intercalative mode, resulting in intrinsic binding constants K b = 3.55 ± 0.6 × 10(4) M(-1) and 7.01 ± 0.9 × 10(4) M(-1) for 1 and 2, respectively. The difference in the DNA-binding affinities of 1 and 2 may presumably be explained by the methylated imidazole nitrogen atom that makes the compound more hydrophobic and gives better intercalative binding ability to DNA's hydrophobic environment.

  20. New platinum(II) complexes conjugated at position 7α of 17β-acetyl-testosterone as new combi-molecules against prostate cancer: design, synthesis, structure-activity relationships and biological evaluation.

    Science.gov (United States)

    Fortin, Sébastien; Brasseur, Kevin; Morin, Nathalie; Asselin, Éric; Bérubé, Gervais

    2013-10-01

    Prostate cancer is a major public health problem worldwide and, more specifically, new treatments for hormone-refractory cancers are highly sought by several research groups. Although platinum(II)-based chemotherapy and other strategies grow in interest to treat castration-resistant prostate cancer (CRPC), they still exhibit modest activity on CRPC and overall patient survival. In this study, we designed and prepared new combi-molecules using 17β-acetyl-testosterone and amino acid platinum(II) complexes linked at the position 7α to target and to improve the antiproliferative activity of platinum(II)-based chemotherapy on prostate cancer cells. Twelve chemical intermediates and six new combi-molecules were prepared and characterized. Structure-activity relationships studies show that the platinum complex moiety is essential for an optimal cytocidal activity. Moreover, stereochemistry of the amino acid involved in the platinum complexes had only minor effects on the antiproliferative activity whereas pyridinyl (10a and b) and thiazolyl (10f) complexes exhibited the highest cytocidal activities that are significantly superior to that of cisplatin used as control on human prostate adenocarcinoma LNCaP (AR+), PC3 (AR-) and DU145 (AR-). Compounds 10a, b and f arrested the cell cycle progression in S-phase and induced double strand breaks as confirmed by the phosphorylation of histone H2AX into γH2AX. Compounds 10a and f showed 33 and 30% inhibition, respectively of the growth of HT-1080 tumors grafted onto chick chorioallantoic membranes. Finally, compounds 10a and 10f exhibited low toxicity on the chick embryos (18 and 21% of death, respectively), indicating that these new combi-molecules might be a promising new class of anticancer agents for prostate cancer.

  1. Characterization and properties of monoammine nitroimidazole complexes of platinum (PtCl sub 2 (NH sub 3 )(NO sub 2 Im)). Crystal and molecular structure of cis-Amminedichloro(1-((((2-hydroxyethyl)amino)carbonyl)methyl)-2-nitroimidazole)platinum(II)

    Energy Technology Data Exchange (ETDEWEB)

    Rochon, F.D.; Pichang Kong; Melanson, R. (Univ. du Quebec, Montreal (Canada)); Skov, K.A. (British Columbia Cancer Research Centre, Vancouver (Canada)); Farrell, N. (Univ. of Vermont, Burlington (United States))

    1991-11-27

    The characterization of monoammine(nitroimidazole)platinum(II) complexes of structure (PtCl{sub 2}(NH{sub 3})(NO{sub 2}Im)) (NO{sub 2}Im = 1-((((2-hydroxyethyl)amino)carbonyl)methyl)-2-nitroimidazole, Etanidazole (I), 1-(2-nitro-1-imidazolyl)-3-methoxy2-propanol, Misonidazole (II), and 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole, Metronidazole (III)) is reported. Both is cis and trans isomers may be isolated for II and III. The crystal structure of cis-amminedichloro(1-((((2-hydroxyethyl)amino)carbonyl)methyl)-2-nitroimidazole)platinum(II) has been determined by X-ray diffraction. The crystals are orthorhombic, space group Pnab with cell dimensions a = 14.867 (7) {angstrom}, b = 9.915 (5) {angstrom}, c = 19.015 (9) {angstrom}, and Z = 8. The structure was refined to R = 0.062 and R{sub w} = 0.052. Platinum has the expected square-planar coordination. The Pt-Cl bond trans to the nitroimidazole ligand is shorter (2.269 (3) {angstrom}) than normal. The dihedral angle between the platinum plane and the imidazole ring is 111{degree}, while the nitro group makes an angle of 31{degree} with the imidazole ring plane. Electrochemistry and {sup 195}Pt NMR data are also reported. The relevance of the chemical properties to their biological properties as radiosensitizers and hypoxic cytotoxins is discussed.

  2. Primary cumulus platinum minerals in the Monts de Cristal Complex, Gabon: magmatic microenvironments inferred from high-definition X-ray fluorescence microscopy

    Science.gov (United States)

    Barnes, Stephen J.; Fisher, Louise A.; Godel, Bélinda; Pearce, Mark A.; Maier, Wolfgang D.; Paterson, David; Howard, Daryl L.; Ryan, Christopher G.; Laird, Jamie S.

    2016-03-01

    An unusual occurrence of Pt-enriched pyroxenites in the Monts de Cristal igneous complex is characterized by unusually high ratios of Pt to other platinum-group elements (PGEs) and very low Cu and sulfide contents. Synchrotron X-ray fluorescence microscopy was used to identify over a hundred discrete grains of platinum minerals and relate their occurrence to textural associations in the host heteradcumulate orthopyroxenites. Element associations, backed up by FIB-SEM and PIXE probe observations, indicate that most of the Pt is associated with either As- or trace Cu-Ni-rich sulfides, or both. Some of the Pt-As grains can be identified as sperrylite, and most are likely to be Pt-Fe alloy. The relative abundances and volumes of Pt minerals to sulfide minerals are very large compared with typical magmatic sulfides. Almost all of the grains observed lie at or within a few tens of μm of cumulus orthopyroxene grain boundaries, and there is no significant difference between the populations of grains located inside or outside plagioclase oikocrysts. These oikocrysts are inferred to have crystallized either at the cumulus stage or very shortly thereafter, on the basis of their relationship to Ti enrichment in the margins of pyroxene grains not enclosed in oikocrysts. This relationship precludes a significant role of trapped intercumulus liquid in Pt deposition or mobilization and also allows a confident inference that Pt-rich and Pt-As-enriched phases precipitated directly from the magma at the cumulus stage. These observations lead to the conclusion that fractionation of Pt from other PGEs in this magmatic system is a consequence of a solubility limit for solid Pt metal and/or Pt arsenide.

  3. A comparative study of pharmacokinetics, urinary excretion and tissue distribution of platinum in rats following a single-dose oral administration of two platinum(IV) complexes LA-12 (OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) and satraplatin (OC-6-43)-bis(acetato)amminedichloro(cyclohexylamine)platinum(IV).

    Science.gov (United States)

    Sova, Petr; Mistr, Adolf; Kroutil, Ales; Semerád, Martin; Chlubnová, Hana; Hrusková, Veronika; Chládková, Jirina; Chládek, Jaroslav

    2011-06-01

    This study compared the pharmacokinetics, tissue distribution, and urinary excretion of platinum in rats after single oral doses of LA-12 and satraplatin. Both platinum derivatives were administered to male Wistar rats as suspensions in methylcellulose at four equimolar doses within the range of 37.5-300 mg LA-12/kg body weight. Blood sampling was performed until 72 h, and plasma and plasma ultrafiltrate were separated. Moreover, urine was collected until 72 h, and kidney and liver tissue samples were obtained at several times after administration. Platinum was measured by atomic absorption spectrometry. The pharmacokinetics of platinum was analyzed by population modelling and post hoc Bayesian estimation as well as using non-compartmental pharmacokinetic analysis of the mean concentration-time curves. Platinum was detected in all plasma and ultrafiltrate samples 15 min after oral administration of both compounds and peaked between 3-4 h and 1-3 h, respectively. Similar for LA-12 and satraplatin, the C (max) and AUC values of plasma and ultrafiltrate platinum increased less than in proportion to dose. The mean C (max) and AUC values of plasma platinum observed after administration of LA-12 were from 0.84 to 2.5 mg/l and from 20.2 to 75.9 mg h/l. For ultrafiltrate platinum, the corresponding ranges were 0.16-0.78 mg/l and 0.63-1.8 mg h/l, respectively. The AUC of plasma platinum was higher after satraplatin (P platinum after the doses of 150 mg and 300 mg/kg (P platinum dose was below 5% for both compounds, and it decreased with the dose of satraplatin (P platinum was similar regardless of the dose and compound administered. Platinum concentrations in the liver homogenate exceeded those in the kidney. Distribution of platinum to tissues was higher after LA-12 compared to satraplatin. The difference in kidney platinum increased with dose and was twofold after 350 mg/kg LA-12. Liver platinum was twofold higher after LA-12 across all four doses. In conclusion, this

  4. Zwitterionic and cationic bis(phosphine) platinum(II) complexes: structural, electronic, and mechanistic comparisons relevant to ligand exchange and benzene C-H activation processes.

    Science.gov (United States)

    Thomas, J Christopher; Peters, Jonas C

    2003-07-23

    Structurally similar but charge-differentiated platinum complexes have been prepared using the bidentate phosphine ligands [Ph(2)B(CH(2)PPh(2))(2)], ([Ph(2)BP(2)], [1]), Ph(2)Si(CH(2)PPh(2))(2), (Ph(2)SiP(2), 2), and H(2)C(CH(2)PPh(2))(2), (dppp, 3). The relative electronic impact of each ligand with respect to a coordinated metal center's electron-richness has been examined using comparative molybdenum and platinum model carbonyl and alkyl complexes. Complexes supported by anionic [1] are shown to be more electron-rich than those supported by 2 and 3. A study of the temperature and THF dependence of the rate of THF self-exchange between neutral, formally zwitterionic [Ph(2)BP(2)]Pt(Me)(THF) (13) and its cationic relative [(Ph(2)SiP(2))Pt(Me)(THF)][B(C(6)F(5))(4)] (14) demonstrates that different exchange mechanisms are operative for the two systems. Whereas cationic 14 displays THF-dependent, associative THF exchange in benzene, the mechanism of THF exchange for neutral 13 appears to be a THF independent, ligand-assisted process involving an anchimeric, eta(3)-binding mode of the [Ph(2)BP(2)] ligand. The methyl solvento species 13, 14, and [(dppp)Pt(Me)(THF)][B(C(6)F(5))(4)] (15), each undergo a C-H bond activation reaction with benzene that generates their corresponding phenyl solvento complexes [Ph(2)BP(2)]Pt(Ph)(THF) (16), [(Ph(2)SiP(2))Pt(Ph)(THF)][B(C(6)F(5))(4)] (17), and [(dppp)Pt(Ph)(THF)][B(C(6)F(5))(4)] (18). Examination of the kinetics of each C-H bond activation process shows that neutral 13 reacts faster than both of the cations 14 and 15. The magnitude of the primary kinetic isotope effect measured for the neutral versus the cationic systems also differs markedly (k(C(6)H(6))/k(C(6)D(6)): 13 = 1.26; 14 = 6.52; 15 approximately 6). THF inhibits the rate of the thermolysis reaction in all three cases. Extended thermolysis of 17 and 18 results in an aryl coupling process that produces the dicationic, biphenyl-bridged platinum dimers [[(Ph(2)SiP(2))Pt](2

  5. Singlet and Triplet Excitation Management in a Bichromophoric Near-Infrared-Phosphorescent BODIPY-Benzoporphyrin Platinum Complex

    KAUST Repository

    Whited, Matthew T.

    2011-01-12

    Multichromophoric arrays provide one strategy for assembling molecules with intense absorptions across the visible spectrum but are generally focused on systems that efficiently produce and manipulate singlet excitations and therefore are burdened by the restrictions of (a) unidirectional energy transfer and (b) limited tunability of the lowest molecular excited state. In contrast, we present here a multichromophoric array based on four boron dipyrrins (BODIPY) bound to a platinum benzoporphyrin scaffold that exhibits intense panchromatic absorption and efficiently generates triplets. The spectral complementarity of the BODIPY and porphryin units allows the direct observation of fast bidirectional singlet and triplet energy transfer processes (k ST(1BDP→1Por) = 7.8×1011 s-1, kTT(3Por→3BDP) = 1.0×1010 s-1, kTT(3BDP→ 3Por) = 1.6×1010 s-1), leading to a long-lived equilibrated [3BDP][Por]=[BDP][3Por] state. This equilibrated state contains approximately isoenergetic porphyrin and BODIPY triplets and exhibits efficient near-infrared phosphorescence (λem = 772 nm, φ = 0.26). Taken together, these studies show that appropriately designed triplet-utilizing arrays may overcome fundamental limitations typically associated with core-shell chromophores by tunable redistribution of energy from the core back onto the antennae. © 2010 American Chemical Society.

  6. Anticancer platinum (IV) prodrugs with novel modes of activity.

    Science.gov (United States)

    Chin, Chee Fei; Wong, Daniel Yuan Qiang; Jothibasu, Ramasamy; Ang, Wee Han

    2011-01-01

    Over the past four decades, the search for improved platinum drugs based on the classical platinum (II)-diam(m)ine pharmacophore has yielded only a handful of successful candidates. New methodologies centred on platinum (IV) complexes, with better stability and expanded coordination spheres, offer the possibility of overcoming limitations inherent to platinum (II) drugs. In this review, novel strategies of targeting and killing cancer cells using platinum (IV) constructs are discussed. These approaches exploit the unique electrochemical characteristics and structural attributes of platinum (IV) complexes as a means of developing anticancer prodrugs that can target and selectively destroy cancer cells. Anticancer platinum (IV) prodrugs represent promising new strategies as targeted chemotherapeutic agents in the ongoing battle against cancer.

  7. Synthesis and characterization of electron donor-acceptor platinum(II) complexes composed of N,N-diphenylpyridineamine and triphenylamine ligands.

    Science.gov (United States)

    Dai, Zhi; Metta-Magaña, Alejandro J; Nuñez, Jose E

    2014-07-21

    The synthesis and electronic properties of a series of platinum(II) complexes composed of electron-donor and electron-acceptor components as potential photovoltaic materials is reported. The complexes are composed of triphenylamines (TPA) and pyridine-derivatized TPAs as the electron-donating components, and alkynyl derivatives of 2,1,3-benzothiadiazole and cyclopentadithiophenone as the electron acceptors. The complexes containing the pyridine-derivatized ligands were prepared to examine the effect that direct coordination of a heteroatom-modified TPA may have on the electronic properties of donor-acceptor (D-A) complexes. Four complexes composed of meta- and para- pyridine-derivatized TPAs were prepared, and their electronic properties were compared with three structurally similar complexes composed of TPA, as well as with purely organic D-A compounds. Data collected from UV-vis and cyclic voltammetry show minor differences on the properties of the complexes containing the pyridine-derivatized ligands when compared to the TPA analogs, exhibiting similar highest occupied molecular orbital-lowest unoccupied molecular orbital bandgaps ranging from 2.156 to 2.705 eV for the pyridine-derivatized complexes (6a,b and 7a,b), 2.038-2.320 eV for the TPA complexes (8a,b and 9a), 2.301 eV for organic molecule 10a, and 1.997 eV for 10b. All compounds are stable, exhibiting no decomposition in the solid indefinitely, and only minor decomposition in solution. All compounds were characterized by (1)H and (13)C nuclear magnetic resonance, infrared spectroscopy, and electrospray mass spectrometry. All complexes were also characterized by (31)P nuclear magnetic resonance and elemental analysis of CHN; determination of Ag content for 6a,b and 7a,b (carried through the synthetic steps) was determined by inductively coupled plasma optical emission spectrometry. The para-pyridine-derivatized complex of 2,1,3-benzothiadiazole (6a) was further characterized by X-ray crystallography as a

  8. Solid-state phosphorescence of trans-bis(salicylaldiminato)platinum(II) complexes bearing long alkyl chains: morphology control towards intense emission.

    Science.gov (United States)

    Komiya, Naruyoshi; Itami, Nao; Naota, Takeshi

    2013-07-15

    Morphology control for intense solid-state phosphorescence of non-emissive, but potentially emissive crystals of platinum complexes and the mechanistic rationale are described. A series of trans-bis(salicylaldiminato)platinum(II) complexes bearing linear alkyl chains (1a: n=5; 1b: n=8; 1c: n=12; 1d: n=14; 1e: n=16; 1f: n=18) was synthesized and the solid-state emission properties were examined by using crystals/aggregates prepared under various precipitation conditions. Crystals of 1e, prepared using "kinetic" conditions including rapid cooling, high concentrations, and poor solvents, emit intensive yellow phosphorescence (λ(max)=545 nm) under UV irradiation at 298 K with an absolute quantum efficiency of 0.36, whereas all the crystals of 1a-1f prepared using "thermodynamic" conditions including slow cooling, low concentrations, and good solvents were either non- or less emissive with Φ(298K) values of 0.12 (1a), 0.11 (1b), 0.10 (1c), 0.07 (1d), 0.02 (1e), and 0.02 (1f) under the same measurement conditions. The amorphous solid 1e, prepared by rapid cooling and freeze-drying, was also non-emissive (Φ(298K)=0.02, 0.02). Temperature-dependent emission spectra showed that the kinetic crystals of 1e exhibit high heat-resistance towards emission decay with increasing temperature, whereas the amorphous solid 1e is entirely heat-quenchable. This is a rare example of the change from a non-emissive crystal into a highly emissive crystal by morphology control through crystal engineering. Emission spectra and powder X-ray diffraction (XRD) patterns of the emissive, kinetic crystals of 1e are clearly distinct from those of the less emissive, thermodynamic crystals of 1a-1f. Single-crystal XRD unequivocally establishes that the thermodynamic crystals of 1d have a multilayered lamellar structure supported by highly regulated, consecutive π-stacking interactions between imine moieties, whereas the kinetic crystals of 1e have a face-to-edge lamellar structure with less

  9. Effects of TAT-conjugated platinum nanoparticles on lifespan of mitochondrial electron transport complex I-deficient Caenorhabditis elegans, nuo-1.

    Science.gov (United States)

    Sakaue, Yuri; Kim, Juewon; Miyamoto, Yusei

    2010-09-20

    Platinum nanoparticle (Pt-np) species are superoxide dismutase/catalase mimetics and also have an activity similar to that of mitochondrial electron transport complex I. To examine if this complex I-like activity functions in vivo, we studied the effects of Pt-nps on the lifespan of a mitochondrial complex I-deficient Caenorhabditis elegans mutant, nuo-1 (LB25) compared with wild-type N2. We synthesized a fusion protein of a cell-penetrating peptide, human immunodeficiency virus-1 TAT (48-60), C-terminally linked to a peptide with a high affinity to platinum (GRKKRRQRRRPPQ-DRTSTWR). Pt-nps were functionalized by conjugation with this fusion protein at a 1:1 ratio of TAT-PtBP to Pt atoms. Adult worms were treated with conjugated Pt-nps for 10 days. The mean lifespan of untreated N2 and LB25 was 19.6 ± 0.4 and 11.8 ± 0.3 days, respectively. Using 5 μM of conjugated Pt-nps, the lifespan of N2 and LB25 was maximally extended. This maximal lifespan extension of LB25 was 31.9 ± 2.6%, which was significantly greater than that of N2 (21.1 ± 1.7%, P < 0.05 by Student's t-test). Internalization of Pt into the whole body and mitochondria was similar between these two strains. Excessive accumulation of reactive oxygen species was not observed in the cytosol or mitochondria of untreated LB25. Treatment for five days with 5 μM conjugated Pt-nps decreased cytosolic and mitochondrial reactive oxygen species in N2 and LB25 to a similar extent. The ratio of [NAD(+)]/[NADH] was very low in the whole body and mitochondria of control LB25. After five days of treatment with 5 μM conjugated Pt-nps, the ratio of [NAD(+)]/[NADH] was increased in N2 and LB25. However, the degree of the increase was much higher in LB25 than in N2. Pt-nps function as NADH oxidase and recover the [NAD(+)]/[NADH] ratio in LB25, leading to effective extension of the lifespan of LB25.

  10. Selective turn-off phosphorescent and colorimetric detection of mercury(II) in water by half-lantern platinum(II) complexes.

    Science.gov (United States)

    Sicilia, Violeta; Borja, Pilar; Baya, Miguel; Casas, José M

    2015-04-21

    The platinum(ii) half-lantern dinuclear complexes [{Pt(bzq)(μ-C7H4NS2-κN,S)}2] () and [{Pt(bzq)(μ-C7H4NOS-κN,S)}2] () [bzq = benzo[h]quinolinate, C7H4NS2 = 2-mercaptobenzothiazolate, C7H4NOS = 2-mercaptobenzoxazolate] in solution of DMSO-H2O undergo a dramatic color change from yellowish-orange to purple and turn-off phosphorescence in the presence of a small amount of Hg(2+), being discernible by the naked-eye and by spectroscopic methods. Other metal ions as Ag(+), Li(+), Na(+), K(+), Ca(2+), Mg(2+), Ba(2+), Pb(2+), Cd(2+), Zn(2+) and Tl(+) were tested and, even in a big excess, showed no interference in the selective detection of Hg(2+) in water. Job's plot analysis indicated a 1 : 1 stoichiometry in the complexation mode of Hg(2+) by /. The phosphorescence quenching attributed to the formation of [/ : Hg(2+)] complexes showed binding constants of K = 1.13 × 10(5) M(-1) () and K = 1.99 × 10(4) M(-1) (). The limit of detection has been also evaluated. In addition, dried paper test strips impregnated in DMSO solutions of and can detect concentration of Hg(2+) in water as low as 1 × 10(-5) M for and 5 × 10(-5) M for , making these complexes good candidates to be used as real-time Hg(2+) detectors. The nature of the interaction of the Pt2 half-lantern complex with the Hg(2+) cation, has been investigated by theoretical calculations.

  11. A novel class of bis- and tris-chelate diam(m)inebis(dicarboxylato)platinum(IV) complexes as potential anticancer prodrugs.

    Science.gov (United States)

    Varbanov, Hristo P; Göschl, Simone; Heffeter, Petra; Theiner, Sarah; Roller, Alexander; Jensen, Frank; Jakupec, Michael A; Berger, Walter; Galanski, Markus; Keppler, Bernhard K

    2014-08-14

    A novel class of platinum(IV) complexes of the type [Pt(Am)(R(COO)2)2], where Am is a chelating diamine or two monodentate am(m)ine ligands and R(COO)2 is a chelating dicarboxylato moiety, was synthesized. For this purpose, the reaction between the corresponding tetrahydroxidoplatinum(IV) precursors and various dicarboxylic acids, such as oxalic, malonic, 3-methylmalonic, and cyclobutanedicarboxylic acid, was utilized. All new compounds were characterized in detail, using 1D and 2D NMR techniques, ESI-MS, FTIR spectroscopy, elemental analysis, TGA, and X-ray diffraction. Their in vitro cytotoxicity was determined in a panel of human tumor cell lines (CH1, SW480 and A549) by means of the MTT colorimetric assay. Furthermore, the lipophilicity and redox properties of the novel complexes were evaluated in order to better understand their pharmacological behavior. The most promising drug candidate, 4b (Pt(DACH)(mal)2), demonstrated low in vivo toxicity but profound anticancer activity against both the L1210 leukemia and CT-26 colon carcinoma models.

  12. Core-shell magnetite-silica composite nanoparticles enhancing DNA damage induced by a photoactive platinum-diimine complex in red light.

    Science.gov (United States)

    Zhang, Zhigang; Chai, Aiyun

    2012-12-01

    Lack of solubility under physiological conditions poses an additional risk for toxicity and side effects for intravenous delivery of the photodynamic therapeutic agent in vivo. Employing magnetite-silica composite nanoparticles as carriers of the photodynamic therapeutic agents may be a promising way to solve the problem. In this study, core-shell magnetite-silica composite nanoparticles were prepared by a sol-gel method, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and dynamic light scattering, then they were used as carriers of a photoactive platinum diimine complex. The interactions of the photosensitizer-loaded magnetic composite nanoparticles with DNA in red light were monitored by agarose-gel electrophoresis. The results suggest that high doses of magnetite-silica composite nanoparticles might facilitate the transformation of covalently closed circular (ccc)-DNA band to open circular (oc)-DNA band though they are harmless to DNA at their low concentrations, therefore enhancing the extent of DNA damage caused by the metal complex in red light.

  13. PLATINUM AND FUEL CELLS

    Science.gov (United States)

    Platinum requirements for fuel cell vehicles (FCVS) have been identified as a concern and possible problem with FCV market penetration. Platinum is a necessary component of the electrodes of fuel cell engines that power the vehicles. The platinum is deposited on porous electrodes...

  14. Synthesis and antitumor activity of platinum(II) complexes with trans-3,4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl.

    Science.gov (United States)

    Sen', V D; Golubev, V A; Volkova, L M; Konovalova, N P

    1996-10-01

    Platinum complexes PtII(DAPO)X2 with diaminonitroxyl radical-trans-3,4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl (DAPO)-were synthesized by the direct reaction of DAPO with K2PtX4 (X = Cl, I) or by the replacement of chloro ligands in PtII(DAPO)Cl2 by bromo, nitrato, oxalato, malonato, and 1,1-cyclobutanedicarboxylato ligands. The complexes thus obtained were characterized by elemental analysis, infrared,electronic, electron paramagnetic resonance spectroscopic techniques, and high-performance liquid chromatography. The toxicity of compounds in terms of LD50 strongly depends on the nature of X-ligands, and varies between 11 mg/kg (X = NO3) and 400 mg/kg (X2 = 1,1-cyclobutanedicarboxylate). Up to 66% of mice bearing leukemia L1210 survive after the administration of these complexes. This effect is comparable to the effect of cisplatin (50% survive). An increase in the life span of the rest of the animals ranges from 158 to 383%. Complex PtII(DAPO)Cl2 appears to be more efficient than cisplatin against adenocarcinoma 755. Cisplatin, cis-diamminedichloroplatinum(II); CBDCA, 1,1-cyclobutanedicarboxylic acid; DAPO, trans-3,4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl; Mal, malonic acid; Ox, oxalic acid; IR, infrared; EPR, electron paramagnetic resonance; HPLC, high-performance liquid chromatography; Ca755, adenocarcinoma 755; LD50 and LD100, dose of compounds (mg/kg), causing a death of 50 or 100% or treated animals; ILS, increase in life span of mice.

  15. Pseudo-rotation mechanism for fast olefin exchange and substitution processes at orthometalated C,N-complexes of platinum(II).

    Science.gov (United States)

    Otto, Stefanus; Samuleev, Pavel V; Polyakov, Vladimir A; Ryabov, Alexander D; Elding, Lars I

    2004-11-07

    Bridge splitting in chloroform of the orthometalated chloro-bridged complex [Pt(micro-Cl)(2-Me(2)NCH(2)C(6)H(4))](2)(1), with ethene, cyclooctene, allyl alcohol and phosphine according to 1+ 2L --> 2[PtCl(2-Me(2)NCH(2)C(6)H(4))(L)], where L = C(2)H(4)(3a), C(8)H(14), (3b), CH(2)CHCH(2)OH (3c), and PPh(3)(4a and 4b) gives monomeric species with L coordinated trans or cis to aryl. With olefins the thermodynamically stable isomer with L coordinated cis to aryl is formed directly without an observable intermediate. With phosphine and pyridine, the kinetically controlled trans-product isomerizes slowly to the more stable cis-isomer. Bridge splitting by olefins is slow and first-order in 1 and L, with largely negative DeltaS(++). Substitution of ethene cis to aryl by cyclooctene and allyl alcohol to form 3b and 3c, and substitution of cot from 3b by allyl alcohol to form 3c are first order in olefin and complex, ca. six orders of magnitude faster than bridge cleavage due to a large decrease in DeltaH(++), and with largely negative DeltaS(++). Cyclooctene exchange at 3b is first-order with respect to free cyclooctene and platinum complex. All experimental data for olefin substitution and exchange are compatible with a concerted substitution/isomerization process via a turnstile twist pseudo-rotation in a short-lived labile five-coordinated intermediate, involving initial attack on the labile coordination position trans to the sigma-bonded aryl. Bridge-cleavage reactions of the analogous bridged complexes occur similarly, but are much slower because of their ground-state stabilization and steric hindrance.

  16. High catalytic activity of heteropolynuclear cyanide complexes containing cobalt and platinum ions: visible-light driven water oxidation.

    Science.gov (United States)

    Yamada, Yusuke; Oyama, Kohei; Gates, Rachel; Fukuzumi, Shunichi

    2015-05-04

    A near-stoichiometric amount of O2 was evolved as observed in the visible-light irradiation of an aqueous buffer (pH 8) containing [Ru(II) (2,2'-bipyridine)3 ] as a photosensitizer, Na2 S2 O8 as a sacrificial electron acceptor, and a heteropolynuclear cyanide complex as a water-oxidation catalyst. The heteropolynuclear cyanide complexes exhibited higher catalytic activity than a polynuclear cyanide complex containing only Co(III) or Pt(IV) ions as C-bound metal ions. The origin of the synergistic effect between Co and Pt ions is discussed in relation to electronic and local atomic structures of the complexes.

  17. "Lantern-Shaped" Platinum(III) Complexes with Axially Bound 9-Ethylguanine or 1-Methylcytosine (L) of General Formula [Pt(2){HN=C(Bu)O}(4)L(2)](NO(3))(2).

    Science.gov (United States)

    Pacifico, Concetta; Intini, Francesco Paolo; Nushi, Fiorentin; Natile, Giovanni

    2010-01-01

    The synthesis, NMR characterization, and X-ray crystallography of "lantern-shaped" platinum(III) complexes with four pivaloamidate bridging ligands and two 9-ethylguanines (9-EtG) or 1-methylcytosines (1-MeC) in axial positions are reported: cis-N(2)O(2)-[Pt(2){HN=C(Bu(t))O}(4)(9-EtG)(2)](NO(3))(2) and cis-N(2)O(2)-[Pt(2){HN=C(Bu(t))O}(4)(1-MeC)(2)](NO(3))(2). The last complex is, to the best of our knowledge, the first dinuclear compound of platinum(III) with axially bound 1-MeC.

  18. “Lantern-Shaped” Platinum(III Complexes with Axially Bound 9-Ethylguanine or 1-Methylcytosine (L of General Formula [Pt2{HN=C(ButO}4L2](NO32

    Directory of Open Access Journals (Sweden)

    Concetta Pacifico

    2010-01-01

    Full Text Available The synthesis, NMR characterization, and X-ray crystallography of “lantern-shaped” platinum(III complexes with four pivaloamidate bridging ligands and two 9-ethylguanines (9-EtG or 1-methylcytosines (1-MeC in axial positions are reported: cis-N2O2-[Pt2{HN=C(ButO}4(9-EtG2](NO32 and cis-N2O2-[Pt2{HN=C(ButO}4(1-MeC2](NO32. The last complex is, to the best of our knowledge, the first dinuclear compound of platinum(III with axially bound 1-MeC.

  19. The New Anticancer Platinum Complex Designed on the Basis of Nucleic Acid%基于核酸修饰新策略的抗肿瘤铂配合物设计

    Institute of Scientific and Technical Information of China (English)

    郑小辉; 夏立新; 毛宗万

    2016-01-01

    肿瘤已成为严重威胁人类健康的重大疾病之一.以顺铂为首的铂类抗肿瘤药物一直是化疗首选药物.但是长期用药导致的一系列的毒副作用如肾毒性、耳毒性和耐药性等极大地限制了铂类配合物的发展与应用.本文针对目前铂类药物所处形势重点综述了新一代铂类药物的设计研发方法:(1)研发具有新颖结构的铂类药物,例如经过改造的反式铂类配合物、多核铂类配合物、Pt(Ⅳ)配合物等;(2)发展新的抗肿瘤靶点,例如以G-四螺旋DNA(G4-DNA)为靶点,为寻找更有效的铂类抗肿瘤药物提供新的思路.同时通过列举最新研究成果,分析药物的抗肿瘤机理及在克服顺铂耐药性机理方面的研究进展,提出铂类药物的设计研发方法,让读者了解铂类抗肿瘤药物的发展历程和未来的发展趋势.%Tumor is one of the serious diseases which greatly threaten human's health.Therefore,the large amount of innovative anticancer drugs have been discovered and created.Among these anticancer drugs,cisplatinum and its analogs are some of the most effective chemotherapeutic agents in clinical use,particularly in the treatment of testicular and ovarian cancers.Unfortunately,they have several major drawbacks,such as cumulative toxicities of nephrotoxicity and ototoxicity,inherent or treatment-induced resistance.This has provided the urgency and motivation for developing novel platinum complexes with high antitumor effect and low toxic side effect on normal cells.This review highlights some methods on the development of the novel platinum complexes:(1) developing the platinum complex with new structure,like trans-platinum complex,multinuclear platinum complex,Pt(Ⅳ) complex;(2) developing new anticancer target,such as G-quadruplex (G4) DNA.By consideration of the anticancer mechanism of the drugs and the tolerance of cis-platinum,the prospect provides new ways to develop novel platinum complexes with high

  20. Synthesis of antitumor azolato-bridged dinuclear platinum(ii) complexes with in vivo antitumor efficacy and unique in vitro cytotoxicity profiles.

    Science.gov (United States)

    Komeda, Seiji; Takayama, Hiroshi; Suzuki, Toshihiro; Odani, Akira; Yamori, Takao; Chikuma, Masahiko

    2013-05-01

    We synthesised four tetrazolato-bridged dinuclear Pt(ii) complexes, [{cis-Pt(NH3)2}2(μ-OH)(μ-5-R-tetrazolato-N2,N3)](n+), where R is CH3 (1), C6H5 (2), CH2COOC2H5 (3), or CH2COO(-) (4) and n = 2 (1-3) or 1 (4). Their structures were characterised by (1)H, (13)C, and (195)Pt NMR spectroscopy, mass spectrometry, and elemental analysis, and the crystal structure of 1 was determined by X-ray crystallography. The cytotoxicities of the complexes to human non-small-cell lung cancer (NSCLC) cell lines sensitive and resistant to cisplatin were assayed. Complex 1 was more cytotoxic than cisplatin in both PC-9 and PC-14 NSCLC cell lines, and cross-resistance to 1 in the cisplatin-resistant cells was largely circumvented. Complex 3 was moderately cytotoxic, whereas 2 and 4 were only marginally cytotoxic. We also determined the growth inhibitory activities of 1 and 3, as well as prototype azolato-bridged complexes [{cis-Pt(NH3)2}2(μ-OH)(μ-pyrazolato)](2+) (AMPZ), [{cis-Pt(NH3)2}2(μ-OH)(μ-1,2,3-triazolato-N1,N2)](2+) (AMTA), [{cis-Pt(NH3)2}2(μ-OH)(μ-tetrazolato-N1,N2)](2+) (5-H-X), and [{cis-Pt(NH3)2}2(μ-OH)(μ-tetrazolato-N2,N3)](2+) (5-H-Y), against a panel of 39 human cancer cell lines (JFCR39). The average 50% growth inhibition concentrations of the complexes against the JFCR39 cell lines ranged from 0.933 to 23.4 μM. The cytotoxicity fingerprints of the complexes based on the JFCR39 cytotoxicity data were similar to one another but completely different from the fingerprints of clinical platinum-based anticancer drugs. Complex 3 exhibited marked antitumor efficiency when tested in vivo on xenografts of PANC-1 pancreatic cancer in nude mice. The high potency of 3 confirmed that the tetrazolato-bridged structure exhibits high in vivo antitumor efficacy.

  1. Identification of a (H2O)8 cluster in a supramolecular host of a charge transfer platinum(II) complex

    Indian Academy of Sciences (India)

    Sutanuva Mandal; Ipsita Chatterjee; Alfonso Castiñeirs; Sreebrata Goswami

    2014-09-01

    The chemical reaction of PtII(L1)Cl2 [L1 = 2-(phenylazo)pyridine] with a bidentate N,S-donor atom ligand, 2-phenylthioaniline, (HL2) in alkaline acetonitrile yielded a mixed ligand donor acceptor complex, [PtII(L1)(L2)−]Cl, [1]Cl. The complex has been characterized by using a host of physical methods: X-ray crystallography, nuclear magnetic resonance, cyclic voltammetry, absorption spectroscopy, electron paramagnetic resonance. The complex showed intense interligand charge transfer (ILCT) transition in the long wavelength region of UV-vis spectrum at 785 nm. The single-crystal X-ray structure of complex, [1]Cl·2.6H2O is reported. The cationic complex upon crystallization from aqueous methanol solvent produces an assembly of three dimensional (H2O)8 guest moiety within the host lattice of reference Pt-complex. The water assembly showed a unique type of aggregation of two trigonal pyramids hydrogen bonded with three chloride anions. The complex displayed two reversible responses at −0.34 and −1.05 V along with one irreversible anodic response at 0.91 V versus Ag/AgCl reference electrode. The redox processes are characterized by examination of EPR spectra of the electrogenerated complexes.

  2. Mechanistic studies on the reactions of platinum(II) complexes with nitrogen- and sulfur-donor biomolecules.

    Science.gov (United States)

    Bugarčić, Živadin D; Bogojeski, Jovana; Petrović, Biljana; Hochreuther, Stephanie; van Eldik, Rudi

    2012-10-28

    A brief overview of mechanistic studies on the reactions of different Pt(II) complexes with nitrogen- and sulfur-donor biomolecules is presented. The first part describes the results obtained for substitution reactions of mono-functional Pt(II) complexes with different biomolecules, under various experimental conditions (temperature, pH and ionic strength). In addition, an overview of the results obtained for the substitution reactions of bi-functional Pt(II) complexes, analogous to cisplatin, with biomolecules is given. The last part of this report deals with different polynuclear Pt(II) complexes and their substitution behaviour with different biomolecules. The purpose of this perspective is to improve the understanding of the mechanism of action of Pt(II) complexes as potential anti-tumour drugs in the human body.

  3. Stereospecific ligands and their complexes. Part XII. Synthesis, characterization and in vitro antiproliferative activity of platinum(IV) complexes with some O,O‧-dialkyl esters of (S,S)-ethylenediamine-N,N‧-di-2-propanoic acid against colon cancer (HCT-116) and breast cancer (MDA-MB-231) cell lines

    Science.gov (United States)

    Stojković, Danijela Lj.; Jevtić, Verica V.; Radić, Gordana P.; Đačić, Dragana S.; Ćurčić, Milena G.; Marković, Snežana D.; Ðinović, Vesna M.; Petrović, Vladimir P.; Trifunović, Srećko R.

    2014-03-01

    Synthesis of three new platinum(IV) complexes C1-C3, with bidentate N,N‧-ligand precursors, O,O‧-dialkyl esters (alkyl = propyl, butyl and pentyl), of (S,S)-ethylenediamine-N,N‧-di-2-propanoic acid, H2-S,S-eddp were reported. The reported platinum(IV) complexes characterized by elemental analysis and their structures were discussed on the bases of their infrared, 1H and 13C NMR spectroscopy. In vitro antiproliferative activity was determined on tumor cell lines: human colon carcinoma HCT-116 and human breast carcinoma MDA-MB-231, using MTT test.

  4. Preparation of Platinum(II) Complexes with 1-b-D-Ribofuranosyl-1,2,4-triazole-3-carboxamide and its Deoxy-analogue

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The platinum (II) complexes of the [Pt (N4,N7-Ribavirin) (DMSO) Cl], [Pt (N4,N7-De-oxyribavirin) (DMSO) Cl] were obtained by the reactions of cis-[Pt (DMSO)2 Cl2] and K[Pt (DMSO) Cl3] with 1-b -D-ribofuranosyl-1,2,4-triazole-3-carboxamide (Ribavirin) and its deoxy-analogue (deoxyribavirin). The preparation of 1-(2'-deoxy-b-D-ribofuranosyl) -1,2,4-triazole-3-carboxamide was also performed through a four-step procedure, protection of 3', 5'-dihydroxyl group of Ribavirin with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane (TPDS-Cl), phenoxythio-carbonylation of the 2'-hydroxyl group of 3', 5'-O-TPDS-Ribavirin with phenoxythiocarbonyl-chloride (PTC-Cl), reduction of 2′-O-phenoxythiocarbonyl ester of 3', 5'-O-TPDS-Ribavirin with tri-n-butyltin hydride and AIBN, deprotection of 3', 5'-O-TPDS-Ribavirin with tetrabutylammon-ium fluoride in THF.

  5. Mono-functionalized glycosylated platinum(IV) complexes possessed both pH and redox dual-responsive properties: Exhibited enhanced safety and preferentially accumulated in cancer cells in vitro and in vivo.

    Science.gov (United States)

    Ma, Jing; Yang, Xiande; Hao, Wenpei; Huang, Zhonglv; Wang, Xin; Wang, Peng George

    2017-03-10

    A serious of carbohydrate-conjugated platinum(IV) complexes in the form Pt(L2)(A2)(OH)R based on the clinical drug cisplatin and oxaliplatin were designed, synthesized and evaluated as antitumor agents in vitro and in vivo. The conjugates possessing both pH and redox dual-responsive properties exhibited more potent cytotoxicity in seven different human cancer cell lines and lower toxicity to the normal 3T3 cells than cisplatin, oxaliplatin and even the reported bis-functionalized glycosylated platinum(IV) complexes indicating the enhanced safety of the sugar conjugates. Cellular drug uptake and DNA platination were also superior to cisplatin, oxaliplatin and the reported bis-functionalized ones. Peak current of B7 and B8 with the scan rate of 200mv/s at the concentration of 0.08 mM was 5-fold higher at pH 6.4 than the pH 7.4, indicating that carbohydrate-conjugated mono-functionalized platinum(IV) complexes possessed both pH and redox dual-responsive properties in the cancer cells. The in vivo assays demonstrated that the Pt(IV) compounds could inhibit the growth of MCF-7 tumour and exert more safety than oxaliplatin. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Competitive formation of DNA linkage isomers by a trinuclear platinum complex and the influence of pre-association.

    Science.gov (United States)

    Moniodis, Joseph J; Thomas, Donald S; Davies, Murray S; Berners-Price, Susan J; Farrell, Nicholas P

    2015-02-28

    2D [(1)H, (15)N] HSQC NMR spectroscopy has been used to monitor the reaction of fully (15)N-labelled [{trans-PtCl(NH3)2}2(μ-trans-Pt(NH3)2{NH2(CH2)6NH2}2)](4+) (BBR3464 ((15)N-1)) with the 14-mer duplex (5'-{d(ATACATG(7)G(8)TACATA)}-3'·5'-{d(TATG(18)TACCATG(25)TAT)}-3' or I) at pH 5.4 and 298 K, to examine the possible formation of 1,4 and 1,5-GG adducts in both 5'-5' and 3'-3' directions. In a previous study, the binding of the dinuclear 1,1/t,t to I showed specific formation of the 5'-5' 1,4 G(8)G(18) cross-link, whereas in this case a mixture of adducts were formed. Initial (1)H NMR spectra suggested the presence of two pre-associated states aligned in both directions along the DNA. The pre-association was studied in the absence of covalent binding, by use of the "non-covalent" analog [{trans-Pt(NH3)3}2(μ-trans-Pt(NH3)2{NH2(CH2)6NH2}2)](6+) (AH44, 0). Chemical shift changes of DNA protons combined with NOE connectivities between CH2 and NH3 protons of 0 and the adenine H2 protons on I show that two different molecules of 0 are bound in the minor groove. Molecular dynamic simulations were performed to study the interaction of 0 at the two pre-association sites using charges derived from density functional theory (DFT) calculations. Structures where the central platinum is located in the minor groove and the aliphatic linkers extend into the major groove, in opposite directions, often represent the lowest energy structures of the snapshots selected. In the reaction of (15)N-1 and I, following the pre-association step, aquation occurs to give the mono aqua monochloro species 2, with a rate constant of 3.43 ± 0.03 × 10(-5) s(-1). There was evidence for two monofunctional adducts (3, 4) bound to the 3' (G8) and 5' (G7) residues and the asymmetry of the (1)H,(15)N peak for 3 suggested two conformers of the 3' adduct, aligned in different directions along the DNA. The rate constant for combined monofunctional adduct formation (0.6 ± 0.1 M(-1)) is ca. 2-fold lower

  7. Design, synthesis and biological evaluation of a novel series of glycosylated platinum(iv) complexes as antitumor agents.

    Science.gov (United States)

    Wang, Qingpeng; Huang, Zhonglv; Ma, Jing; Lu, Xiaolin; Zhang, Li; Wang, Xin; George Wang, Peng

    2016-06-21

    A new series of glycosylated Pt(iv) complexes were designed, synthesized and evaluated for antitumor activities in vitro and in vivo. The incorporation of glycosyl groups to the Pt(iv) system has much influence on the antitumor abilities. Four lead compounds with activities comparable or even superior to cisplatin and oxaliplatin are screened out. These Pt(iv) complexes could be reduced to release Pt(ii) complexes and cause the death of tumour cells. The apoptosis-inducing properties of these compounds are similar to cisplatin. The accumulation of the glycosylated Pt(iv) complexes in cells and DNA is higher than cisplatin and oxaliplatin. The in vivo assay demonstrates that the tested compounds inhibit the growth of HepG2 tumors with low toxicity.

  8. TD-DFT Studies on Electronic and Spectral Properties of Platinum(Ⅱ) Complexes with Phenol and Pyridine Groups

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shan-shan; SHI Li-li; SU Zhong-min; GENG Yun; ZHAO Liang

    2013-01-01

    The molecular structures of the ground and the lowest triplet states for a series of Pt(ll) complexes PtLCl(1)[L=6-(2-hydroxyphenyl)-2,2'-bipyridine],Pt(pp)2[pp=2-(2-hydroxyphenyl)pyridine](2),PtbpyC12(bpy=2,2'-bipyridine)(3),and the free tridentate L ligand(4) were optimized by the density functional theory B3LYP and UB3LYP methods,respectively.On the basis of optimized geometries,the spectral properties were investigated with time-dependent density functional theory(TD-DFT).In comparison with those of complexes 2 and 3,the more rigid structure of complex 1 together with its low rate of the radiationless decay via nonemissive d-d state leads to higher photoluminescence quantum efficiency.And the phosphorescence quantum efficiency of complex 1 can be easily controlled by modifying auxiliary ligands.The introduction of fluorine ligand into complexes can effectively increase the radiation transition rate and decrease the radiationless d-d transition rate,and as a result,a novel complex PtLF(5) might be a good phosphorescent material suitable for organic electronic devices.

  9. Influence of Ancillary Ligands and Isomerism on the Luminescence of Bis-cyclometalated Platinum(IV) Complexes.

    Science.gov (United States)

    Juliá, Fabio; García-Legaz, María-Dulce; Bautista, Delia; González-Herrero, Pablo

    2016-08-01

    The synthesis, characterization, and photophysical properties of a wide variety of bis-cyclometalated Pt(IV) complexes featuring a C2-symmetrical or unsymmetrical {Pt(ppy)2} unit (sym or unsym complexes, respectively; ppy = C-deprotonated 2-phenylpyridine) and different ancillary ligands are reported. Complexes sym-[Pt(ppy)2X2] (X = OTf(-), OAc(-)) were obtained by chloride abstraction from sym-[Pt(ppy)2Cl2] using the corresponding AgX salts, and the triflate derivative was employed to obtain homologous complexes with X = F(-), Br(-), I(-), trifluoroacetate (TFA(-)). Complexes unsym-[Pt(ppy)2(Me)X] (X = OTf(-), F(-)) were prepared by reacting unsym-[Pt(ppy)2(Me)Cl] with AgOTf or AgF, respectively, and the triflate derivative was employed as precursor for the synthesis of the homologues with X = Br(-), I(-), or TFA(-) through its reaction with the appropriate anionic ligands. The previously reported complexes unsym-[Pt(ppy)2X2] (X = Cl(-), Br(-), OAc(-), TFA(-)) are included in the photophysical study to assess the influence of the arrangement of the cyclometalated ligands. Density functional theory (DFT) and time-dependent DFT calculations on selected derivatives were performed for a better interpretation of the observed excited-state properties. Complexes sym-[Pt(ppy)2X2] (except X = I(-)) exhibit phosphorescent emissions in fluid solutions at 298 K arising from essentially (3)LC(ppy) excited states, which are very similar in shape and energy. However, their efficiencies are heavily dependent on the nature of the ancillary ligands, which affect the energy of deactivating ligand-to-ligand charge transfer (LLCT) or ligand-to-metal charge transfer (LMCT) states. The fluoride derivative sym-[Pt(ppy)2F2] shows the highest quantum yield of this series (Φ = 0.398), mainly because the relatively high metal-to-ligand charge transfer admixture in its emitting state leads to a high radiative rate constant. Complexes unsym-[Pt(ppy)2X2] emit from (3)LC(ppy) states in frozen

  10. Influence of complexing agents on the preparation of bimetallic platinum-ruthenium catalysts supported on O-functionalized graphite cloths

    Energy Technology Data Exchange (ETDEWEB)

    Sieben, J.M., E-mail: jmsieben@uns.edu.a [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Universidad Nacional del Sur., Av. Alem 1253, (B8000CPB) Bahia Blanca (Argentina); Duarte, M.M.E.; Mayer, C.E. [Instituto de Ingenieria Electroquimica y Corrosion (INIEC), Universidad Nacional del Sur., Av. Alem 1253, (B8000CPB) Bahia Blanca (Argentina)

    2010-02-18

    Electrodeposition of bimetallic Pt-Ru catalysts on O-functionalized graphite cloths from H{sub 2}PtCl{sub 6} and RuCl{sub 3} solutions containing trisodium citrate (Cit) and disodium dihydrogen ethylenediaminetetraacetate (Na{sub 2}H{sub 2}EDTA) was investigated. SEM analysis of the electrode prepared without complexant showed a relatively compact and rough deposit displaying a 'tree cortex' structure, whereas uniform size and globular shape particles regularly distributed over the support surface were obtained using citrate and Na{sub 2}H{sub 2}EDTA as complexants. In addition, XRD diffraction and EDX analysis revealed that the catalysts prepared using the complexants showed smaller size particles and lower Ru content. Electrocatalytic activity measurements indicated that the most active electrode for methanol oxidation was obtained with Na{sub 2}H{sub 2}EDTA as additive.

  11. Palladium(II) and platinum(II) complexes containing benzimidazole ligands: Molecular structures, vibrational frequencies and cytotoxicity

    Science.gov (United States)

    Abdel Ghani, Nour T.; Mansour, Ahmed M.

    2011-04-01

    (1H-benzimidazol-2-ylmethyl)-(4-methoxyl-phenyl)-amine (L 1), (1H-benzimidazol-2-ylmethyl)-(4-methyl-phenyl)-amine (L 2) and their Pd(II) and Pt(II) complexes have been synthesized as potential anticancer compounds and their structures were elucidated using a variety of physico-chemical techniques. Theoretical calculations invoking geometry optimization, vibrational assignments, 1H NMR, charge distribution and molecular orbital description HOMO and LUMO were done using density functional theory. Natural bond orbital analysis (NBO) method was performed to provide details about the type of hybridization and the nature of bonding in the studied complexes. Strong coordination bonds (LP(1)N11 → σ *(M sbnd Cl22)) and (LP(1)N21 → σ *(M sbnd Cl23)) (M = Pd or Pt) result from donation of electron density from a lone pair orbital on the nitrogen atoms to the acceptor metal molecular orbitals. The experimental results and the calculated molecular parameters revealed square-planar geometries around the metallic centre through the pyridine-type nitrogen of the benzimidazole ring and secondary amino group and two chlorine atoms. The activation thermodynamic parameters were calculated using non-isothermal methods. The synthesized ligands, in comparison to their metal complexes were screened for their antibacterial activity. In addition, the studied complexes showed activity against three cell lines of different origin, breast cancer (MCF-7), Colon Carcinoma (HCT) and human heptacellular carcinoma (Hep-G2) comparable to cis-platin.

  12. Synthesis, Characterization, and Interaction with Biomolecules of Platinum(II Complexes with Shikimic Acid-Based Ligands

    Directory of Open Access Journals (Sweden)

    Yan Peng

    2013-01-01

    Full Text Available Starting from the active ingredient shikimic acid (SA of traditional Chinese medicine and NH2(CH2nOH, (n=2–6, we have synthesized a series of new water-soluble Pt(II complexes PtLa–eCl2, where La–e are chelating diamine ligands with carbon chain covalently attached to SA (La–e = SA-NH(CH2nNHCH2CH2NH2; La, n=2; Lb, n=3; Lc, n=4; Ld, n=5; Le, n=6. The results of the elemental analysis, LC-MS, capillary electrophoresis, and 1H, 13C NMR indicated that there was only one product (isomer formed under the present experimental conditions, in which the coordinate mode of PtLa–eCl2 was two-amine bidentate. Their in vitro cytotoxic activities were evaluated by MTT method, where these compounds only exhibited low cytotoxicity towards BEL7404, which should correlate their low lipophilicity. The interactions of the five Pt(II complexes with DNA were investigated by agarose gel electrophoresis, which suggests that the Pt(II complexes could induce DNA alteration. We also studied the interactions of the Pt(II complexes with 5′-GMP with ESI-MS and 1H NMR and found that PtLbCl2, PtLcCl2, and PtLdCl2 could react with 5′-GMP to form mono-GMP and bis-GMP adducts. Furthermore, the cell-cycle analysis revealed that PtLbCl2, PtLcCl2 cause cell G2-phase arrest after incubation for 72 h. Overall, these water-soluble Pt(II complexes interact with DNA mainly through covalent binding, which blocks the DNA synthesis and replication and thus induces cytotoxicity that weakens as the length of carbon chain increases.

  13. Tunable and Efficient White Light Phosphorescent Emission Based on Single Component N-Heterocyclic Carbene Platinum(II) Complexes.

    Science.gov (United States)

    Bachmann, Michael; Suter, Dominik; Blacque, Olivier; Venkatesan, Koushik

    2016-05-16

    A new class of cyclometalated pyridine N-heterocyclic carbene (NHC) Pt(II) complexes with electronically different alkyne derivatives (C≡CR; R = C6H4C(CH3)3 (1), C6H5 (2), C6H4F (3), C6H3(CF3)2 (4)) as ancillary ligands were synthesized, and the consequences of the electronic properties of the different substituted phenylacetylene ligands on the phosphorescent emission efficiencies were studied, where C≡CC6H4C(CH3)3 = 4-tert-butylphenylacetylene, C≡CC6H5 = phenylacetylene, C≡CC6H4F = 4-fluorophenylacetylene, and C≡CC6H3(CF3)2 = 3,5-bis(trifluoromethyl)phenylacetylene. Structural characterization, electrochemistry, and photophysical investigations were performed for all four compounds. Moreover, the emission quantum efficiencies and wavelength emission intensities of the complexes were also recorded in different weight percents in poly(methyl methacrylate) films (PMMA) and evaluated in the CIE-1931 chromaticity diagram. The square planar coordination geometry with the alkynyl ligands was corroborated for complexes 1, 2, and 3 by single crystal X-ray diffraction studies. These complexes show tunable monomeric high energy triplet emission and an additional concentration-dependent low-energy excimer-based phosphorescence. While adopting weight percent concentrations between 15 and 25%, the two emission bands covering the entire visible spectrum were obtained with these particular complexes displaying the properties of an efficient white light triplet emitter with excellent CIE-1931 coordinates (0.31, 0.33). On the basis of the high luminescent quantum efficiency of over 50% for white light emission, these compounds could be potentially useful for white organic light-emitting diodes (WOLEDs) based applications.

  14. Novel palladium(II) and platinum(II) complexes with 1H-benzimidazol-2-ylmethyl-N-(4-bromo-phenyl)-amine: structural studies and anticancer activity.

    Science.gov (United States)

    Abdel Ghani, Nour T; Mansour, Ahmed M

    2012-01-01

    [MLCl(2)] (L = (1H-benzimidazol-2-ylmethyl)-N-(4-bromo-phenyl)-amine; M = Pd & Pt) and [PdL(OH(2))(2)]∙2X∙zH(2)O (X = Br, I, z = 2; X = SCN, z = 1; X = NO(3), z = 0) complexes have been synthesized as potential anticancer compounds and their structures were elucidated using elemental analysis, spectral, thermal analysis and X-ray powder diffraction. The benzimidazole (L) crystallizes in the space group P2(1)/c with a = 8.6660(3) Å, b = 16.6739(7) Å, c = 9.8611(4) Å and β = 113.505(3) ° and forms an infinite chain structure with a trans-zigzag type along the crystallographic axis "a", through the intermolecular H-bond. FT-IR and (1)H NMR studies revealed that the ligand L is coordinated to the metal ion via the pyridine-type nitrogen (N(py)) of the benzimidazole ring and secondary amino group (NH(sec)). Quantum mechanical calculations of energies, geometries, vibrational wavenumbers, and (1)H NMR of the benzimidazole L and its complexes were carried out by DFT/B3LYP method combined with 6-31G(d) and LANL2DZ basis sets. Natural bond orbital (NBO) analysis and frontier molecular orbitals (FMO) were performed at B3LYP/LANL2DZ level of theory. The benzimidazole L, in comparison to its metal complexes was screened for its antibacterial activity. The complexes showed cyctotoxic effects against human breast cancer (MCF7), hepatocarcinoma (HepG(2)) and colon carcinoma cells (HCT). The platinum complex (6) exhibited a moderate antitumor activity against MCF7 with IC(50) = 10.2 μM comparing to that reported for cis-platin 9.91 μM.

  15. Molecular interaction fields vs. quantum-mechanical-based descriptors in the modelling of lipophilicity of platinum(IV) complexes.

    Science.gov (United States)

    Ermondi, Giuseppe; Caron, Giulia; Ravera, Mauro; Gabano, Elisabetta; Bianco, Sabrina; Platts, James A; Osella, Domenico

    2013-03-14

    We report QSAR calculations using VolSurf descriptors to model the lipophilicity of 53 Pt(iv) complexes with a diverse range of axial and equatorial ligands. Lipophilicity is measured using an efficient HPLC method. Previous models based on a subset of these data are shown to be inadequate, due to incompatibility of whole molecule descriptors between carboxylato and hydroxido ligands. Instead, the interaction surfaces of complexes with various probes are used as independent descriptors. Partial least squares modelling using three latent variables results in an accurate (R(2) = 0.92) and robust model (Q(2) = 0.87) of lipophilicity, that moreover highlights the importance of size and hydrophobicity terms and the modest relevance of hydrogen bonding.

  16. Activity of phosphino palladium(II) and platinum(II) complexes against HIV-1 and Mycobacterium tuberculosis.

    Science.gov (United States)

    Gama, Ntombenhle H; Elkhadir, Afag Y F; Gordhan, Bhavna G; Kana, Bavesh D; Darkwa, James; Meyer, Debra

    2016-08-01

    Treatment of human immunodeficiency virus (HIV) is currently complicated by increased prevalence of co-infection with Mycobacterium tuberculosis. The development of drug candidates that offer the simultaneous management of HIV and tuberculosis (TB) would be of great benefit in the holistic treatment of HIV/AIDS, especially in sub-Saharan Africa which has the highest global prevalence of HIV-TB coinfection. Bis(diphenylphosphino)-2-pyridylpalladium(II) chloride (1), bis(diphenylphosphino)-2-pyridylplatinum(II) chloride (2), bis(diphenylphosphino)-2-ethylpyridylpalladium(II) chloride (3) and bis(diphenylphosphino)-2-ethylpyridylplatinum(II) (4) were investigated for the inhibition of HIV-1 through interactions with the viral protease. The complexes were subsequently assessed for biological potency against Mycobacterium tuberculosis H37Rv by determining the minimal inhibitory concentration (MIC) using broth microdilution. Complex (3) showed the most significant and competitive inhibition of HIV-1 protease (p = 0.014 at 100 µM). Further studies on its in vitro effects on whole virus showed reduced viral infectivity by over 80 % at 63 µM (p < 0.05). In addition, the complex inhibited the growth of Mycobacterium tuberculosis at an MIC of 5 µM and was non-toxic to host cells at all active concentrations (assessed by tetrazolium dye and real time cell electronic sensing). In vitro evidence is provided here for the possibility of utilizing a single metal-based compound for the treatment of HIV/AIDS and TB.

  17. Distribution of Platinum-Group Elements in Chromite Ores of the Sorkhband Ultramafic Complex, Kerman, Southeastern Iran

    Science.gov (United States)

    Najafzadeh, Alireza; Arvin, Mohsen; Ahmadipour, Hamid; Pan, Yuanming

    2016-10-01

    The Ordovician Sorkhband ultramafic complex lies in southern Kerman Province of Iran. The wedge shape complex covers an area of more than 100 km2 and is divided into: lower part comprises of dunites, largest podiform chromitite deposits in Iran (Faryab mine), olivine clinopyroxenite dykes and massive's, wehrlite and olivine websterite dykes; and upper part comprises of clinopyroxene bearing harzburgites, with subordinate lenses and dykes of dunite, massive and dyke like olivine clinopyroxenite and minor orthopyroxenite dykes with no significant chromitite mineralization. Chromitite orebodies exhibit variable sizes and shapes, forming pods, lenses, bands, vein-like bodies and rich dissemination. Podiform chromitites in dunite form tabular to lenticular bodies although may occur also as pencil-like masses. The chromitites occur in four distinct textural modes. Massive, disseminated, banded and nodular chromitites are the most common textural types and commonly grade into one other. Massive chromitites have sharp contacts with the enclosing dunite whereas disseminated bodies grade outward into dunite and occasionally pass into interbanded chromitite and dunite. A detailed electron microprobe study reveals very high Cr#, Mg# and very low TiO2 contents for chromian spinels in chromitites. The Sorkhband chromitites contain up to 440 ppb total PGE, and display a systematic enrichment in IPGE relative to PPGE, with a steep negative slope in the PGE spidergrams and very low PPGE/IPGE ratios, a feature typical of ophiolitic podiform chromitites worldwide. The mineral chemistry data and PGE geochemistry of the chromitites indicates that the Sorkhband ultramafic complex was generated from an arc-related magma with boninitic affinity in a supra-subduction zone setting.

  18. A relativistic DFT methodology for calculating the structures and NMR chemical shifts of octahedral platinum and iridium complexes.

    Science.gov (United States)

    Vícha, Jan; Patzschke, Michael; Marek, Radek

    2013-05-28

    A methodology for optimizing the geometry and calculating the NMR shielding constants is calibrated for octahedral complexes of Pt(IV) and Ir(III) with modified nucleic acid bases. The performance of seven different functionals (BLYP, B3LYP, BHLYP, BP86, TPSS, PBE, and PBE0) in optimizing the geometry of transition-metal complexes is evaluated using supramolecular clusters derived from X-ray data. The effects of the size of the basis set (ranging from SVP to QZVPP) and the dispersion correction (D3) on the interatomic distances are analyzed. When structural deviations and computational demands are employed as criteria for evaluating the optimizations of these clusters, the PBE0/def2-TZVPP/D3 approach provides excellent results. In the next step, the PBE0/def2-TZVPP approach is used with the continuum-like screening model (COSMO) to optimize the geometry of single molecules for the subsequent calculation of the NMR shielding constants in solution. The two-component zeroth-order regular approximation (SO-ZORA) is used to calculate the NMR shielding constants (PBE0/TZP/COSMO). The amount of exact exchange in the PBE0 functional is validated for the nuclear magnetic shieldings of atoms in the vicinity of heavy transition metals. For the PBE0/TZP/COSMO setup, an exact exchange of 40% is found to accurately reproduce the experimental NMR shielding constants for both types of complexes. Finally, the effect of the amount of exact exchange on the NMR shielding calculations (which is capable of compensating for the structural deficiencies) is analyzed for various molecular geometries (SCS-MP2, BHLYP, and PBE0) and the influence of a trans-substituent on the NMR chemical shift of nitrogen is discussed. The observed dependencies for an iridium complex cannot be rationalized by visualizing the Fermi-contact (FC) induced spin density and probably originate from changes in the d-d transitions that modulate the spin-orbit (SO) part of the SO/FC term.

  19. Blue-emitting platinum(II) complexes bearing both pyridylpyrazolate chelate and bridging pyrazolate ligands: synthesis, structures, and photophysical properties.

    Science.gov (United States)

    Chang, Sheng-Yuan; Chen, Jing-Lin; Chi, Yun; Cheng, Yi-Ming; Lee, Gene-Hsiang; Jiang, Chang-Ming; Chou, Pi-Tai

    2007-12-24

    A new Pt(II) dichloride complex [Pt(fppzH)Cl2] (1), in which fppzH = 3-(trifluoromethyl)-5-(2-pyridyl)pyrazole, was prepared by the treatment of a pyridylpyrazole chelate fppzH with K2PtCl4 in aqueous HCl solution. Complex 1 could further react with its parent pyrazole (pzH), 3,5-dimethylpyrazole (dmpzH), or 3,5-di-tert-butylpyrazole (dbpzH) to afford the monometallic [Pt(fppz)(pzH)Cl] (2), [Pt(fppz)(dmpzH)Cl] (3), [Pt(fppz)(dmpzH)2]Cl (4), or two structural isomers with formula [Pt(fppz)(dbpzH)Cl] (5a,b). Single-crystal X-ray diffraction studies of 2, 4, and 5a,b revealed a square planar Pt(II) framework, among which a strong interligand hydrogen bonding occurred between fppz and pzH ligands in 2. This interligand H-bonding is replaced by dual N-H...Cl interaction in 4 and both intermolecular N-H...O (with THF solvate) and N-H...Cl interaction in 5a,b, respectively; the latter are attributed to the bulky tert-butyl substituents that force the dbpzH ligand to adopt the perpendicular arrangement. Furthermore, complex 2 underwent rapid deprotonation in basic media to afford two isomeric complexes with formula [Pt(fppz)(mu-pz)]2 (6a,b), which are related to each other according to the spatial orientation of the fppz chelates, i.e., trans- and cis-isomerism. Similar reaction exerted on 3 afforded isomers 7a,b. Both 6a,b (7a,b) are essentially nonemissive in room-temperature fluid state but afford strong blue phosphorescence in solid state prepared via either vacuum-deposited thin film or 77 K CH2Cl2 matrix. As also supported by the computational approaches, the nature of emission has been assigned to be ligand-centered triplet pipi* mixed with certain metal-to-ligand charge-transfer character.

  20. Lithium ion intercalation in partially crystalline TiO 2 electrodeposited on platinum from aqueous solution of titanium(IV) oxalate complexes

    Science.gov (United States)

    Dziewoński, Paweł Marek; Grzeszczuk, Maria

    Starting from the aqueous solution of titanium(IV) oxalate complexes and controlling electrochemical conditions using a cyclic voltammetry (CV) method, the thin layers of TiO 2 on platinum were obtained, which after additional heat treatment, at 450 °C, were still of amorphous nature. The amorphous state of the samples, containing an admixture of crystalline anatase, was confirmed by Raman spectroscopy and by a variety of electrochemical techniques. The new electrochemical procedure allows preparing the oxide with different morphologies. By the comparison with the peroxotitanium route, the oxalate precursor method offers the possibility of the synthesis of amorphous TiO 2 at higher temperatures that is the essential key for the cycling stability of the oxide if one is used as an anode material in lithium ion batteries. The results from cycling voltammetry revealed that electrodeposited TiO 2 reversibly and fast intercalates lithium ions due to its high internal surface area. Therefore, the nanostructural morphology facilitates lithium ion intercalation which was monitored and confirmed in all electrochemical testing. The specific capacity of the TiO 2 approaches the value of 145 mAh g -1 at 8 C-rate in the best case. From the electrochemical impedance spectroscopy (EIS) measurements in connection with SEM investigations, it was concluded that Li + diffusion is the finite space process and its rate is depending on the size of the crystallites building the oxide films. Evaluated values of the D-coefficients are of the order of 10 -14 cm 2 s -1.

  1. Galactose conjugated platinum(II) complex targeting the Warburg effect for treatment of non-small cell lung cancer and colon cancer.

    Science.gov (United States)

    Wu, Meng; Li, Hong; Liu, Ran; Gao, Xiangqian; Zhang, Menghua; Liu, Pengxing; Fu, Zheng; Yang, Jinna; Zhang-Negrerie, Daisy; Gao, Qingzhi

    2016-03-03

    Malignant neoplasms exhibit a higher rate of glycolysis than normal cells; this is known as the Warburg effect. To target it, a galactose-conjugated (trans-R,R-cyclohexane-1,2-diamine)-2-chloromalonato-platinum(II) complex (Gal-Pt) was designed, synthesized, and evaluated in five human cancer cell lines and against two different xenograft tumour models. Gal-Pt exhibits much higher aqueous solubility (over 25 times) and improved cytotoxicity than oxaliplatin, especially in human colon (HT29) and lung (H460) cancer cell lines. The safety profile of Gal-Pt was investigated in vivo by exploring the maximum tolerated dose (MTD) and animal mortality rate. The ratios of the animal lethal dosage values to the cytotoxicity in HT29 (LD50/IC50) showed that Gal-Pt was associated with an increased therapeutic index by over 30-fold compared to cisplatin and oxaliplatin. We evaluated in vivo antitumor activity by single agent intravenous treatment comparison studies of Gal-Pt (50 mg/kg as 65% MTD) and cisplatin (3 mg/kg, as 80% MTD) in a H460 lung cancer xenograft model, and with oxaliplatin (7 mg/kg, as 90% MTD) in a HT29 colon cancer xenograft model. The results show that Gal-Pt was more efficacious against H460 than cisplatin, and had superior potency in HT29 cells compared to oxaliplatin under nontoxic dosage conditions. The dependency between cytotoxicity of Gal-Pt and glucose transporters (GLUTs) was investigated by using quercetin as an inhibitor of GLUTs in HT29 cells. The cytotoxic potency of Gal-Pt was highly reduced by the inhibitor, suggesting that the uptake of Gal-Pt was regulated by glucose transporters. The GLUT mediated transportability and cellular uptake of Gal-Pt was also demonstrated using a fluorescent glucose bioprobe in HT29 competition assay.

  2. Synthesis and Crystal Structure of a One-dimensional Azido-bridged Manganese (II) Compound [Mn(N3)2(H2O)3·C6H12N4]n

    Institute of Scientific and Technical Information of China (English)

    CHEN Hui; WANG Wen-Guo; ZHANG Xiao-Feng; CHEN Chang-Neng; LIU Qiu-Tian

    2006-01-01

    A new one-dimensional azido-bridged manganese compound has been prepared and structurally characterized by X-ray diffraction. The complex [Mn(N3)2(H2O)3·C6H12N4]n crystallizes in space group Pnma with a = 6.5252 (5), b = 9.3226(7), c = 22.2070(15)(A), V = 1350.89(17)(A)3, Z = 4, Mr = 333.24, Dc = 1.639 g/cm3, μ= 1.005 mm-1 and F(000) = 692. The final refinement gave R = 0.0328 and wR = 0.0777 for 1085 observed reflections with I > 2σ(I). The structure contains [Mn- (N3)2(H2O)3]n polymeric chains and uncoordinated hexamethylenetetramine (HMTA) molecules with Mn/HMTA molar ratio of 1:1. The Mn atoms are bridged by end-to-end azido ligands to construct one-dimensional zig-zag infinite chains. Each Mn atom is six-coordinated by three N atoms of three azido ligands and three water O atoms, resulting in an octahedral geometry. Extending hydrogen- bonding interactions involving water O atoms, azido and HMTA N atoms link the chains and HMTA molecules into a three-dimensional network.

  3. Studying the interactions of a platinum(II) 9-aminoacridine complex with proteins and oligonucleotides by ESI-TOF MS.

    Science.gov (United States)

    Samper, Katia G; Vicente, Consuelo; Rodríguez, Venancio; Atrian, Sílvia; Cutillas, Natalia; Capdevila, Mercè; Ruiz, José; Palacios, Òscar

    2012-01-07

    The interaction of a novel Pt complex, [Pt(dmba)(N9-9AA)(PPh(3))](+)1 (dmba = N,N-dimethylbenzylamine-κN,κC; 9AA = 9-aminoacridine), which exhibits anti-tumor activity, with certain key proteins has been monitored by ESI-MS. Also, the interaction of 1 with a designed double-stranded oligonucleotide containing the GG motif has been followed by mass spectrometry as well as by fluorimetry. The results obtained show the low interaction of 1 with the considered proteins and the absence of covalent interaction with the oligonucleotides, but the fluorimetric data confirm the π-π interaction of 1 with the double-stranded DNA, which is probably the reason of the previously reported activity of 1 in several tumor cell lines.

  4. trans-Platinum(II) complex of 3-aminoflavone - synthesis, X-ray crystal structure and biological activities in vitro.

    Science.gov (United States)

    Fabijańska, Małgorzata; Studzian, Kazimierz; Szmigiero, Leszek; Rybarczyk-Pirek, Agnieszka J; Pfitzner, Arno; Cebula-Obrzut, Barbara; Smolewski, Piotr; Zyner, Elżbieta; Ochocki, Justyn

    2015-01-21

    This paper describes the synthesis of trans-bis-(3-aminoflavone)dichloridoplatinum(ii) (trans-Pt(3-af)2Cl2; TCAP) for use as a potential anticancer compound, and the evaluation of its structure by elemental and spectral analyses, and X-ray crystallography. The complex demonstrated a significant cytotoxic effect against human and murine cancer cell lines, as well as weaker toxicity towards healthy cells (human peripheral blood lymphocytes) in comparison with cisplatin. Various biochemical and morphological methods confirm that the proapoptotic activity of trans-Pt(3-af)2Cl2 is markedly higher than the reference cisplatin. Our results suggest that trans-Pt(3-af)2Cl2 may have a different antitumour specificity from that of cisplatin.

  5. Platinum complexes having redox-active PPh2C[triple bond]CFc and/or C[triple bond]CFc as terminal or bridging ligands.

    Science.gov (United States)

    Díez, Alvaro; Lalinde, Elena; Teresa Moreno, M; Sánchez, Sergio

    2009-05-14

    A series of heteronuclear-Pt(ii) complexes containing ferrocenylethynyl units linked directly (Pt-C[triple bond]CFc) or through a phosphorous atom (Pt-PPh(2)C[triple bond]CFc) to the platinum center is reported. The reaction of derivative [cis-Pt(R(F))(2)(PPh(2)C[triple bond]CFc)(2)] (R(F) = C(6)F(5)) with the solvate complex [cis-Pt(R(F))(2)(thf)(2)] leads to the formation of an asymmetrical heteronuclear diplatinum complex [{Pt(R(F))(2)(mu-1kappaP:2eta(2)-PPh(2)C[triple bond]CFc)(2)}Pt(R(F))(2)] having the "cis-Pt(R(F))(2)" fragment coordinated to the triple bonds of both ferrocenylethynylphosphine units, while treatment of [cis-Pt(C[triple bond]CFc)(2)(PPh(2)C[triple bond]CR)(2)] (R = Fc , Ph , tBu ) with the same solvate [cis-Pt(R(F))(2)(thf)(2)], affords double ferrocenylacetylide-bridged diplatinum systems [{Pt(PPh(2)C[triple bond]CR)(2)(mu-eta(1):eta(2)-C[triple bond]CFc)(2)}Pt(R(F))(2)] . The solid-state structures of [cis/trans-Pt(R(F))(2)(PPh(2)C[triple bond]CFc)(2)] /, [cis-Pt(R(F))(2)(PPh(2)C[triple bond]CFc)(tht)] (tht = tetrahydrothiophene), [{Pt(R(F))(2)(mu-1kappaP:2eta(2)-PPh(2)C[triple bond]CFc)(2)}Pt(R(F))(2)] and [{Pt(PPh(2)C[triple bond]CtBu)(2)(mu-eta(1):eta(2)-C[triple bond]CFc)(2)}Pt(R(F))(2)] have been determined by X-ray diffraction methods. The electronic spectra and the electrochemical behaviour of all monoplatinum derivatives are discussed, showing a different extent of interaction between the remote ferrocenyl groups when they belong to PPh(2)C[triple bond]CFc or C[triple bond]CFc ligands. For the diplatinum systems and , containing bridging (kappaP:eta(2)-PPh(2)C[triple bond]CFc ) or (eta(1):eta(2)-C[triple bond, length as m-dash]CFc ) ligands, their electrochemical properties were also compared with the parent precursors.

  6. Computational studies on the photophysical properties and NMR fluxionality of dinuclear platinum(II) A-frame alkynyl diphosphine complexes.

    Science.gov (United States)

    Lam, Wai Han; Yam, Vivian Wing-Wah

    2010-12-06

    The structural geometry, electronic structure, photophysical properties, and the fluxional behavior of a series of A-frame diplatinum alkynyl complexes, [Pt(2)(μ-dppm)(2)(μ-C≡CR)(C≡CR)(2)](+) [R = (t)Bu (1), C(6)H(5) (2), C(6)H(4)Ph-p (3), C(6)H(4)Et-p (4), C(6)H(4)OMe-p (5); dppm = bis(diphenylphosphino)methane], have been studied by density functional theory (DFT) and time-dependent TD-DFT associated with conductor-like polarizable continuum model (CPCM) calculations. The results show that the Pt···Pt distance strongly depends on the binding mode of the alkynyl ligands. A significantly shorter Pt···Pt distance is found in the symmetrical form, in which the bridging alkynyl ligand is σ-bound to the two metal centers, than in the unsymmetrical form where the alkynyl ligand is σ-bound to one metal and π-bound to another. For the two structural forms in 1-5, both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels show a dependence on the nature of the substituents attached to the alkynyl ligand. The energies of the HOMO and LUMO are found to increase and decrease, respectively, from R = (t)Bu to R = Ph and to R = C(6)H(4)Ph-p, because of the increase of the π- conjugation of the alkynyl ligand. On the basis of the TDDFT/CPCM calculations, the low-energy absorption band consists of two types of transitions, which are ligand-to-ligand charge-transfer (LLCT) [π(alkynyl) → σ*(dppm)]/metal-centered MC [dσ*(Pt(2)) → pσ(Pt(2))] transitions as well as interligand π → π* transition from the terminal alkynyl ligands to the bridging alkynyl ligand mixed with metal-metal-to-ligand charge transfer MMLCT [dσ*(Pt(2)) → π*(bridging alkynyl)] transition. The latter transition is lower in energy than the former. The calculation also indicates that the emission for the complexes originates from the triplet interligand π(terminal alkynyls) → π*(bridging alkynyl)/MMLCT [dσ*(Pt(2)) →

  7. Highly trifluoromethylated platinum compounds.

    Science.gov (United States)

    Martínez-Salvador, Sonia; Forniés, Juan; Martín, Antonio; Menjón, Babil

    2011-07-11

    The homoleptic, square-planar organoplatinum(II) compound [NBu(4)](2) [Pt(CF(3))(4)] (1) undergoes oxidative addition of CF(3) I under mild conditions to give rise to the octahedral organoplatinum(IV) complex [NBu(4)](2) [Pt(CF(3))(5)I] (2). This highly trifluoromethylated species reacts with Ag(+) salts of weakly coordinating anions in Me(2)CO under a wet-air stream to afford the aquo derivative [NBu(4)][Pt(CF(3))(5) (OH(2))] (4) in around 75% yield. When the reaction of 2 with the same Ag(+) salts is carried out in MeCN, the solvento compound [NBu(4) ][Pt(CF(3))(5)(NCMe)] (5) is obtained in around 80% yield. The aquo ligand in 4 as well as the MeCN ligand in 5 are labile and can be cleanly replaced by neutral and anionic ligands to furnish a series of pentakis(trifluoromethyl)platinate(IV) compounds with formulae [NBu(4)][Pt(CF(3))(5) (L)] (L=CO (6), pyridine (py; 7), tetrahydrothiophene (tht; 8)) and [NBu(4)](2) [Pt(CF(3))(5)X] (X=Cl (9), Br (10)). The unusual carbonyl-platinum(IV) derivative [NBu(4)][Pt(CF(3))(5) (CO)] (6) is thermally stable and has a ν(CO) of 2194 cm(-1). The crystal structures of 2⋅CH(2)Cl(2), 5, [PPh(4) ][Pt(CF(3))(5)(CO)] (6'), and 7 have been established by X-ray diffraction methods. Compound 2 has shown itself to be a convenient entry to the chemistry of highly trifluoromethylated platinum compounds. To the best of our knowledge, compounds 2 and 4-10 are the organoelement compounds with the highest CF(3) content to have been isolated and adequately characterized to date.

  8. The azido oxide N{sub 3}O

    Energy Technology Data Exchange (ETDEWEB)

    Petris, Giulia de [Dipartimento di Chimica e Tecnologie del Farmaco, Universita ' La Sapienza' , P.le Aldo Moro 5, 00185 Roma (Italy); Troiani, Anna, E-mail: anna.troiani@uniroma1.it [Dipartimento di Chimica e Tecnologie del Farmaco, Universita ' La Sapienza' , P.le Aldo Moro 5, 00185 Roma (Italy); Rosi, Marzio [Dipartimento di Ingegneria Civile e Ambientale, Universita di Perugia and ISTM-CNR, Perugia (Italy); Sgamellotti, Antonio [Dipartimento di Chimica, Universita di Perugia and ISTM-CNR, Perugia (Italy); Cipollini, Romano [Dipartimento di Chimica e Tecnologie del Farmaco, Universita ' La Sapienza' , P.le Aldo Moro 5, 00185 Roma (Italy)

    2012-04-04

    Graphical abstract: N{sub 3}O{sup +} ions prepared in the source of a mass spectrometer under low-pressure conditions are submitted to neutralization by collisional electron transfer, leading to the observation of the novel N{sub 3}O oxide. Highlights: Black-Right-Pointing-Pointer The study reports the positive detection in the gas phase of the novel azido oxide N{sub 3}O. Black-Right-Pointing-Pointer It has been prepared by collisional electron transfer to the N{sub 3}O{sup +} ion and observed on a microsecond time scale. Black-Right-Pointing-Pointer The oxide has been assigned a minimum lifetime of 0.7 {mu}s and an open-chain structure of NNNO connectivity. Black-Right-Pointing-Pointer The study examines the role of excited species in the formation of covalently bound ions suitable to neutralization. - Abstract: The new nitrogen-rich oxide N{sub 3}O has been detected in the gas phase by mass spectrometric experiments. The radical has been assigned a minimum lifetime of 0.7 {mu}s and an open-chain NNNO structure in the quartet state. Structures and energies of the N{sub 3}O{sup +} precursor ion and the N{sub 3}O radical have been investigated by ab initio calculations.

  9. The conformation effect of the diamine bridge on the stability of dinuclear platinum(II) complexes and their hydrolysis.

    Science.gov (United States)

    Esteves, Lucas F; Dos Santos, Hélio F; Costa, Luiz Antônio S

    2015-09-01

    In this paper, the hydrolysis process of a bisplatinum complex containing the flexible chain 1,6-hexanediamine between the two metal centers was investigated through the use of density functional theory (DFT) with the analysis of the role of the spacing group arrangement on the values of free energy activation barrier. All structures were fully optimized in aqueous solution using implicit model for solvent at DFT level. The energy profiles for the hydrolysis reaction were determined by using the supermolecule approach. Five transition states were proposed differing by the conformation of the bridge group, and the activation free energy calculated as a weighted average within the selected forms. The Gibbs population for reactant was used as a statistical weight leading to the predicted value of 23.1kcalmol(-1), in good accordance with experiment, 23.8kcalmol(-1). Our results suggests that for 1,6-hexanediamine bridge ligand, the extend forms with average torsional angle over the carbon chain larger than 130° have the greatest contribution to the hydrolysis kinetics. The results presented here point out that the hydrolysis mechanism might follow different paths for each conformation and each of these contributes to the observed energy barrier.

  10. Diversity of azido magnetic chains constructed with flexible ligand 2,2'-dipyridylamine.

    Science.gov (United States)

    Wang, Xiu-Teng; Wang, Xiao-Hua; Wang, Zhe-Ming; Gao, Song

    2009-02-16

    By employing a flexible molecule, 2,2'-dipyridylamine (dpa), as a bidentate coligand, three azide-bridged one-dimensional coordination polymers, [M(dpa)(N(3))(2)](n) (M = Cu, 1.Cu; Co, 2.Co) and [Ni(dpa)(OAc)(0.5)(N(3))(1.5)(H(2)O)](n) (3.Ni), have been successfully synthesized and structurally and magnetically characterized. They show versatile one-dimensional chain structures. 1.Cu is an EO-N(3) bridged uniform chain; 2.Co is an alternative chain linked by two EO-N(3) and two EE-N(3) bridges. Interestingly, 3.Ni is a zigzag chain linked alternatively by one EE-N(3) and a novel 3-fold bridge, which is composed of two EO-N(3) and one acetate group. This series of azido complexes demonstrates that the flexibility of the dpa ligand plays an important role in directing the structures of the final products. Magnetic studies reveal dominant intrachain antiferromagnetic couplings in compound 1.Cu. Compounds 2.Co and 3.Ni are weak ferromagnets due to the spin canting, with critical temperatures of 12.4 and 32.5 K, respectively.

  11. Synthesis, structural, spectral, thermal and antimicrobial studies of palladium(II), platinum(II), ruthenium(III) and iridium(III) complexes derived from N,N,N,N-tetradentate macrocyclic ligand.

    Science.gov (United States)

    Rani, Soni; Kumar, Sumit; Chandra, Sulekh

    2011-05-01

    Palladium(II), platinum(II), ruthenium(III) and iridium(III) complexes of general stoichiometry [PdL]Cl(2), [PtL]Cl(2), [Ru(L)Cl(2)]Cl and [Ir(L)Cl(2)]Cl are synthesized with a tetradentate macrocyclic ligand, derived from 2,6-diaminopyridine with 3-ethyl 2,4-pentanedione. Ligand was characterized on the basis of elemental analyses, IR, mass, and (1)H NMR and (13)C NMR spectral studies. All the complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, mass, electronic spectral techniques and thermal studies. The value of magnetic moments indicates that all the complexes are diamagnetic except Ru(III) complex which shows magnetic moments corresponding its one unpaired electron. The macrocyclic ligand and all its metal complexes were also evaluated in vitro against some plant pathogenic fungi and bacteria to assess their biocidal properties.

  12. Platinum compounds with anti-tumour activity

    NARCIS (Netherlands)

    Plooy, A.C.M.; Lohman, P.H.M.

    1980-01-01

    Ten platinum (Pt) coordination complexes with different ligands, comprising both Pt(II) and Pt(IV) complexes of which the cis-compounds all possessed at least some anti-tumour activity and the trans-compounds were inactive, were tested as to their effect on cell survival and the induction and repair

  13. Behind platinum's sparkle.

    Science.gov (United States)

    Yam, Vivian W W

    2010-09-01

    As a rare and precious metal that is also resistant to wear and tarnish, platinum is known to be particularly well-suited to jewellery. Vivian Yam reflects on how, beyond its prestigious image, platinum has also found its way into a variety of fields ranging from the petrochemical to the pharmaceutical industry.

  14. Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))platinum(II)].

    Science.gov (United States)

    Nguyen Thi Thanh, Chi; Pham Van, Thong; Le Thi Hong, Hai; Van Meervelt, Luc

    2016-10-01

    Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))platinum(II)], [Pt2(C15H19O4)2Cl2], containing a derivative of the natural compound eugenol as ligand, have been performed. Using five different sets of crystallization conditions resulted in four different complexes which can be further used as starting compounds for the synthesis of Pt complexes with promising anticancer activities. In the case of vapour diffusion with the binary chloroform-diethyl ether or methylene chloride-diethyl ether systems, no change of the molecular structure was observed. Using evaporation from acetonitrile (at room temperature), dimethylformamide (DMF, at 313 K) or dimethyl sulfoxide (DMSO, at 313 K), however, resulted in the displacement of a chloride ligand by the solvent, giving, respectively, the mononuclear complexes (acetonitrile-κN)(η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))chloridoplatinum(II) monohydrate, [Pt(C15H19O4)Cl(CH3CN)]·H2O, (η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))chlorido(dimethylformamide-κO)platinum(II), [Pt(C15H19O4)Cl(C2H7NO)], and (η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))chlorido(dimethyl sulfoxide-κS)platinum(II), determined as the analogue {η(2)-2-allyl-4-methoxy-5-[(ethoxycarbonyl)methoxy]phenyl-κC(1)}chlorido(dimethyl sulfoxide-κS)platinum(II), [Pt(C14H17O4)Cl(C2H6OS)]. The crystal structures confirm that acetonitrile interacts with the Pt(II) atom via its N atom, while for DMSO, the S atom is the coordinating atom. For the replacement, the longest of the two Pt-Cl bonds is cleaved, leading to a cis position of the solvent ligand with respect to the allyl group. The crystal packing of the complexes is characterized by dimer formation via C-H...O and C-H...π interactions, but no π-π interactions are observed despite the presence of

  15. Substituted 4,4′-stilbenoid NCN-pincer platinum(II) complexes : luminescence and tuning of the electronic and NLO properties and the application in an OLED

    NARCIS (Netherlands)

    Batema, G.D.; Lutz, M.; van Walree, C.A.; de Mello Donega, C.; Meijerink, A.; Havenith, R.W.A.; Pérez-Moreno, J.; Clays, K.; Büchel, M.; van Dijken, A.; Bryce, D.L.; van Klink, G.P.M.; van Koten, G.

    2008-01-01

    A series of 4,4′-disubstituted organic−organometallic stilbenes, i.e., the 4′-substituted stilbenoid-NCN-pincer platinum(II) complexes [PtCl(NCN-R-4)] (NCN-R-4 = [C6H2(CH2NMe2)2-2,6-R-4]− in which R = C2H2C6H4-R′-4′ with R′ = NPh2, NMe2, OMe, SiMe3 H, I, CN, NO2) (1−8), were studied for their

  16. Linear homobimetallic 4-thioacetyl-substituted NCN pincer palladium(II) and platinum(II) complexes with N-bidentate connecting units (NCN = [C6H2(CH2NMe2)2-2,6-R-4]−)

    NARCIS (Netherlands)

    Döring, K.; Taher, D.; Walfort, B.; Lutz, M.; Spek, A.L.; van Klink, G.P.M.; van Koten, G.; Lang, H.

    2008-01-01

    The synthesis and characterization of homobimetallic palladium and platinum complexes of type [(Me(O)CS-4-NCN–M ← N∩N → M–NCN-4-SC(O)Me](OTf)2 (Me(O)CS-4-NCN = [C6H2(CH2NMe2)2-2,6-SC(O)Me-4]−; N∩N = 4,4′-bipyridine (bipy); M = Pd, 12; M = Pt, 13) is reported. The required bifunctional thio-acetyl NC

  17. Substituted 4,4′-stilbenoid NCN-pincer platinum(II) complexes : luminescence and tuning of the electronic and NLO properties and the application in an OLED

    NARCIS (Netherlands)

    Batema, G.D.; Lutz, M.; van Walree, C.A.; de Mello Donega, C.; Meijerink, A.; Havenith, R.W.A.; Pérez-Moreno, J.; Clays, K.; Büchel, M.; van Dijken, A.; Bryce, D.L.; van Klink, G.P.M.; van Koten, G.

    2008-01-01

    A series of 4,4′-disubstituted organic−organometallic stilbenes, i.e., the 4′-substituted stilbenoid-NCN-pincer platinum(II) complexes [PtCl(NCN-R-4)] (NCN-R-4 = [C6H2(CH2NMe2)2-2,6-R-4]− in which R = C2H2C6H4-R′-4′ with R′ = NPh2, NMe2, OMe, SiMe3 H, I, CN, NO2) (1−8), were studied for their electr

  18. Oxidation of 3,6-dioxa-1,8-octanedithiol by platinum(IV) anticancer prodrug and model complex: kinetic and mechanistic studies.

    Science.gov (United States)

    Huo, Shuying; Shen, Shigang; Liu, Dongzhi; Shi, Tiesheng

    2012-06-07

    Thioredoxins are small redox proteins and have the active sites of Cys-Xaa-Yaa-Cys; they are overexpressed by many different cancer cells. Cisplatin and Pt(II) analogues could bind to the active sites and inhibit the activities of the proteins, as demonstrated by other researchers. Platinum(IV) anticancer drugs are often regarded as prodrugs, but their interactions with thioredoxins have not been studied. In this work, 3,6-dioxa-1,8-octanedithiol (dithiol) was chosen as a model compound for the active sites of thioredoxins, and its reactions with cis-[Pt(NH(3))(2)Cl(4)] and trans-[PtCl(2)(CN)(4)](2-) (cisplatin prodrug and a model complex) were studied. The pK(a) values for the dithiol were characterized to be 8.7 ± 0.2 and 9.6 ± 0.2 at 25.0 °C and an ionic strength of 1.0 M. The reaction kinetics was followed by a stopped-flow spectrophotometer over a wide pH range. An overall second-order rate law was established, -d[Pt(IV)]/dt = k'[Pt(IV)][dithiol], where k' stands for the observed second-order rate constants. Values of k' increased several orders of magnitude when the solution pH was increased from 3 to 9. A stoichiometry of Δ[Pt(IV)]/Δ[dithiol] = 1:1 derived for the reduction process and product analysis by mass spectrometry indicated that the dithiol was oxidized to form an intramolecular disulfide, coinciding with the nature of thioredoxin proteins. All of the reaction features are rationalized in terms of a reaction mechanism, involving three parallel rate-determining steps depending on the pH of the reaction medium. Rate constants for the rate-determining steps were evaluated. It can be concluded that Pt(IV) anticancer prodrugs can oxidize the reduced thioredoxins, and the oxidation mechanism is similar to those of the oxidations of biologically important reductants by some reactive oxygen species (ROS) such as hypochlorous acid/hypochlorite and chloramines.

  19. 三联吡啶铂(II)配合物的合成及其自组装性质研究%Synthesis and Self-Assembly Behavior of Terpyridine-Platinum(II)Complex

    Institute of Scientific and Technical Information of China (English)

    何红波; 田玉敬; 姚日生

    2013-01-01

    铂金属配合物因其卓著的疗效已迅速发展为临床治疗癌症的重要药物,本文设计并合成了三联吡啶铂(II)配合物1,通过核磁及质谱等实验表征了目标分子的结构,通过温度依赖性核磁、溶剂依赖性紫外可见光谱等实验证明了酰胺分子间的氢键、π-π堆积以及Pt-Pt金属-金属相互作用是配合物1在自组装过程中的主要驱动力,通过透射电镜观测到组装体的形貌为单分子纳米纤维结构,该研究有利于阐明铂类化合物的自组装行为与其抗癌活性的联系性。%Platinum(II) ligand complexes have become one of the important drugs for anti-cancer therapy. In this paper,terpyridine-platinum(II) complex 1 was successfully designed and synthesized, which was proved by NMR and mass spectrometry. By means of temperature dependent 1H NMR and UV-vis absorption measurements, it is evident that hydrogen bonds between intermolecular amide groups, π-π stacking and Pt-Pt metal-metal interactions were the main driving forces during self-assembly. Moreover, nanofibers were clearly observed by TEM measurement. The current study is helpful to identify the relationships between the structure and anti-cancer properties of platinum drugs.

  20. In vitro antitumor activity of a new platinum complex, cis-malonato [(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane] platinum (II) (SKI 2053R), against human lung and stomach cancer cell lines.

    Science.gov (United States)

    Hong, W S; Kim, H T; Kim, K H; Kim, D K

    1995-01-01

    The in vitro antitumor activity of a new platinum complex, cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolan e] platinum(II) (SKI 2053R, NSC D644591), cisplatin (CDDP) and carboplatin (CBDCA) was determined against two human lung cancer (PC-9 and PC-14) and two human stomach cancer (MKN-45 and KATO III) cell lines by human tumor clonogenic assay. The activity of SKI 2053R was compared with those of CDDP and CBDCA in terms of relative antitumor activity (RAA, peak plasma concentration/IC50). Mean IC50 values (microgram/ml) of SKI 2053R, CDDP and CBDCA were 6.4 +/- 0.8, 1.8 +/- 0.7 and 20.6 +/- 12.2, respectively. The RAAs of SKI 2053R, CDDP and CBDCA were 1.6 +/- 0.4, 2.0 +/- 0.8 and 1.2 +/- 0.6, respectively. The differences in these values were not statistically significant. The results, demonstrating that antitumor activity of SKI 2053R is similar to those of CDDP and CBDCA, suggest that SKI 2053R is an interesting candidate for further development as a new anticancer drug.

  1. Platinum hypersensitivity and desensitization.

    Science.gov (United States)

    Miyamoto, Shingo; Okada, Rika; Ando, Kazumichi

    2015-09-01

    Platinum agents are drugs used for various types of cancer. With increased frequency of administration of platinum agents, hypersensitivity reactions appear more frequently, occurring in over 25% of cases from the seventh cycle or second line onward. It then becomes difficult to conduct treatment using these agents. Various approaches have been investigated to address hypersensitivity reactions to platinum agents. Desensitization, which gradually increases the concentration of the anticancer drug considered to be the antigen until the target dosage, has been reported as being particularly effective, with a success rate of 80-100%. The aims of this paper are to present the current findings regarding hypersensitivity reactions to platinum agents and to discuss attempts of using desensitization against hypersensitivity reactions worldwide. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de

    2000-01-01

    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported.

  3. Targeting Platinum Compounds: synthesis and biological activity

    OpenAIRE

    VAN ZUTPHEN, Steven

    2005-01-01

    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of novel (solid-phase) synthetic methods and to the discovery of several compounds with promising biological properties.

  4. Targeting Platinum Compounds : synthesis and biological activity

    NARCIS (Netherlands)

    Zutphen, Steven van

    2005-01-01

    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of

  5. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de

    2000-01-01

    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported. Is

  6. Synthesis and reactivity towards diiodine of palladium(II) and platinum(II) complexes with non-cyclic and cyclic ligands (C6H3{CH=NR1R2}2-2,6)-. End-on diiodine-platinum(II) bonding in macrocyclic [PtI(C6H3{CH2NMe(CH2)7MeNCH2}-2,6)(h1-I2)

    NARCIS (Netherlands)

    Koten, G. van; Beek, J.A.M. van; Dekker, G.P.C.M.; Wissing, E.; Zoutberg, M.C.; Stam, C.H.

    1990-01-01

    Several new organo-platinum(II) and -palladium(II) complexes [MX(C{6}H{3}{CH{2}NR}1{R}2{}{2}-2, 6)] (X = halide, M = Pt, Pd; R}1{ = R}2{ = Et; R}2{ = Me, R}1{ = }t{Bu, M = Pt: R}2{ = Me, R}1{ = Ph) have been synthesized from [PtCl{2}(SEt{2}){2}] or [PdCl{2}(COD)] (COD = 1, 5-cyclooctadiene) by react

  7. Synthesis and reactivity towards diiodine of palladium(II) and platinum(II) complexes with non-cyclic and cyclic ligands (C6H3{CH=NR1R2}2-2,6)-. End-on diiodine-platinum(II) bonding in macrocyclic [PtI(C6H3{CH2NMe(CH2)7MeNCH2}-2,6)(h1-I2)

    NARCIS (Netherlands)

    Koten, G. van; Beek, J.A.M. van; Dekker, G.P.C.M.; Wissing, E.; Zoutberg, M.C.; Stam, C.H.

    1990-01-01

    Several new organo-platinum(II) and -palladium(II) complexes [MX(C{6}H{3}{CH{2}NR}1{R}2{}{2}-2, 6)] (X = halide, M = Pt, Pd; R}1{ = R}2{ = Et; R}2{ = Me, R}1{ = }t{Bu, M = Pt: R}2{ = Me, R}1{ = Ph) have been synthesized from [PtCl{2}(SEt{2}){2}] or [PdCl{2}(COD)] (COD = 1, 5-cyclooctadiene) by

  8. Synthesis and reactivity towards diiodine of palladium(II) and platinum(II) complexes with non-cyclic and cyclic ligands (C6H3{CH=NR1R2}2-2,6)-. End-on diiodine-platinum(II) bonding in macrocyclic [PtI(C6H3{CH2NMe(CH2)7MeNCH2}-2,6)(h1-I2)

    NARCIS (Netherlands)

    Koten, G. van; Beek, J.A.M. van; Dekker, G.P.C.M.; Wissing, E.; Zoutberg, M.C.; Stam, C.H.

    1990-01-01

    Several new organo-platinum(II) and -palladium(II) complexes [MX(C{6}H{3}{CH{2}NR}1{R}2{}{2}-2, 6)] (X = halide, M = Pt, Pd; R}1{ = R}2{ = Et; R}2{ = Me, R}1{ = }t{Bu, M = Pt: R}2{ = Me, R}1{ = Ph) have been synthesized from [PtCl{2}(SEt{2}){2}] or [PdCl{2}(COD)] (COD = 1, 5-cyclooctadiene) by react

  9. Synthesis and Photochromic Properties of Azido Analogues of Spiropyran and Spirooxazine as Nucleic Acid Labeling Reagent

    Institute of Scientific and Technical Information of China (English)

    Hui GUO; Wu Xin ZOU; Qi JI; Ji Ben MENG

    2005-01-01

    A series of photo active azido analogues have been synthesized and their photochromic properties have also been investigated by UV-Vis spectrum. It will be used for the rapid and reliable preparation of large amounts of stable, non-radioactive labeled DNA and RNA hybridization probes. And it is supposed to be easily detected for its photochromic properties.

  10. Synthesis of azido-functionalized carbohydrates for the design of glycoconjugates.

    Science.gov (United States)

    Cecioni, Samy; Goyard, David; Praly, Jean-Pierre; Vidal, Sébastien

    2012-01-01

    As carbohydrates play a major role in numerous biological processes through their interactions with lectins and also appear as one of the most crucial post-translational modifications of proteins, chemists have developed several approaches for the design of glycoconjugates based on a series of conjugation methodologies. The recent development of copper(I)-catalyzed azide-alkyne cycloaddition (CuACC) paved the way to a novel conjugation strategy in which azido-functionalized carbohydrate derivatives can be readily connected to alkyne-functionalized (bio)molecules. This so-called "click chemistry" methodology has now found numerous applications both in chemistry and biology. The azido moiety can be introduced either directly at the anomeric carbon of the carbohydrate derivative, or attached to a spacer arm. We describe here the syntheses of 2,3,4,6-tetra-O-acetyl-β-D: -glucopyranosyl azide as well as 1-azido-3,6-dioxaoct-8-yl 2,3,4,6-tetra-O-acetyl-β-D: -galactopyranoside and 1-azido-3,6-dioxaoct-8-yl 2,3,6,2',3',4',6'-hepta-O-acetyl-β-D: -lactoside. These molecules can then be used in the construction of glycoconjugates to find applications in chemical biology.

  11. A Pyrazole to Furan Rearrangement. Thermolysis of 5-Azido-4-formylpyrazoles

    DEFF Research Database (Denmark)

    Svenstrup, Niels; Simonsen, Klaus B.; Thorup, Niels

    1999-01-01

    5-Azido-3-benzyl-4-formyl-1-phenylpyrazoles 1a-c extrude dinitrogen upon heating in toluene to give the corresponding nitrenes, which immediately rearrange via a new ring-opening ring-closure reaction to produce an equimolar mixture of 4-cyano-2-phenyl-3-phenylazofurans 2a-c and 3-benzyl-4-cyano-1...

  12. Azido--meconine-`high ortho’ Novolak resin-based negative photoresists for deep UV lithography

    Indian Academy of Sciences (India)

    Maneesh Sharma; Anant A Naik; Manoj Gaur; P Raghunathan; S V Eswaran

    2009-07-01

    Photoactive chemicals blended with polymers, solvents and certain other additives serve as photoresists. A new photoactive compound (PAC), azido--meconine absorbing in the deep UV region has been blended with `alternating’ and `semi-alternating’ and `high ortho’ alternating novolak resins, based on /-cresol. The new photoresists have been evaluated as a negative tone deep UV photoresist for mircolithography.

  13. N(4)-tolyl-2-acetylpyridine thiosemicarbazones and their platinum(II,IV) and gold(III) complexes: cytotoxicity against human glioma cells and studies on the mode of action.

    Science.gov (United States)

    Ferraz, Karina S O; Da Silva, Jeferson G; Costa, Flávia M; Mendes, Bruno M; Rodrigues, Bernardo L; dos Santos, Raquel G; Beraldo, Heloisa

    2013-10-01

    Complexes [Au(2Ac4oT)Cl][AuCl2] (1), [Au(Hpy2Ac4mT)Cl2]Cl·H2O (2), [Au(Hpy2Ac4pT)Cl2]Cl (3), [Pt(H2Ac4oT)Cl]Cl (4), [Pt(2Ac4mT)Cl]·H2O (5), [Pt(2Ac4pT)Cl] (6) and [Pt(L)Cl2OH], L = 2Ac4mT (7), 2Ac4oT (8), 2Ac4pT (9) were prepared with N(4)-ortho- (H2Ac4oT), N(4)-meta- (H2Ac4mT) and N(4)-para- (H2Ac4pT) tolyl-2-acetylpyridine thiosemicarbazone. The cytotoxic activities of all compounds were assayed against U-87 and T-98 human malignant glioma cell lines. Upon coordination cytotoxicity improved in 2, 5 and 8. In general, the gold(III) complexes were more cytotoxic than those with platinum(II,IV). Several of these compounds proved to be more active than cisplatin and auranofin used as controls. The gold(III) complexes probably act by inhibiting the activity of thioredoxin reductase enzyme whereas the mode of action of the platinum(II,IV) complexes involves binding to DNA. Cells treated with the studied compounds presented morphological changes such as cell shrinkage and blebs formation, which indicate cell death by apoptosis induction.

  14. Platinum Group Organometallics Based on "Pincer" Complexes: Sensors, Switches, and Catalysts In memory of Prof. Dr. Luigi M. Venanzi and his pioneering work in organometallic chemistry, particularly in PCP pincer chemistry.

    Science.gov (United States)

    Albrecht, Martin; van Koten, Gerard

    2001-10-15

    Since the first reports in the late 1970s on transition metal complexes containing pincer-type ligands-named after the particular coordination mode of these ligands-these systems have attracted increasing interest owing to the unusual properties of the metal centers imparted by the pincer ligand. Typically, such a ligand comprises an anionic aryl ring which is ortho,ortho-disubstituted with heteroatom substituents, for example, CH(2)NR(2), CH(2)PR(2) or CH(2)SR, which generally coordinate to the metal center, and therefore support the M-C sigma bond. This commonly results in a terdentate and meridional coordination mode consisting of two metallacycles which share the M-C bond. Detailed studies of the formation and the properties of a large variety of pincers containing platinum group metal complexes have provided direct access to both a fundamental understanding of a variety of reactions in organometallic chemistry and to a range of new applications of these complexes. The discovery of alkane dehydrogenation catalysts, the mechanistic elucidation of fundamental transformations (for example, C-C bond activation), the construction of the first metallodendrimers for sustainable homogeneous catalysis, and the engineering of crystalline switches for materials processing represent only a few of the many highlights which have emanated from these numerous investigations. This review discusses the synthetic methodologies that are currently available for the preparation of platinum group metal complexes containing pincer ligands and especially emphasizes different applications that have been realized in materials science such as the development and engineering of sensors, switches, and catalysts.

  15. Cyclometalated platinum(Ⅱ) complexes with sterically bulky camphor-derived groups as β-diketonate ancillary ligand:a new route to efficiently reducing π-π interactions and Pt-Pt interactions

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new series of mono-cyclometalated square planar platinum(Ⅱ) complexes have been synthesized and the single-crystal X-ray structures of complex 1 and 2 have been determined.The complexes have the general formula ppyPt(OO),where ppy is 2-phenylpyridyl,and OO is β-diketonate ancillary ligands with the acyl substituent group in position 3 of(D)-(+)-camphor.Although,like the many Pt(Ⅱ) complexes with square-planar geometry,these complexes have plane stacking modes in crystal structure,the sterically bulky camphor-derived groups compel extensive slipping of the molecular stacking planes,resulting in the negligible overlapping of the aromatic ring fragments between molecules and the considerable Pt-Pt distance.The resolved spectra and a little shifted emission in solid state of complexes show that there is significant reduction of π-π interactions and Pt-Pt interactions,and suggest these complexes may be good candidates for doped phosphorescent organic light emitting diodes(PhOLEDs) and even for nondoped PhOLEDs.

  16. New palladium(II) and platinum(II) 5,5-diethylbarbiturate complexes with 2-phenylpyridine, 2,2'-bipyridine and 2,2'-dipyridylamine: synthesis, structures, DNA binding, molecular docking, cellular uptake, antioxidant activity and cytotoxicity.

    Science.gov (United States)

    Icsel, Ceyda; Yilmaz, Veysel T; Kaya, Yunus; Samli, Hale; Harrison, William T A; Buyukgungor, Orhan

    2015-04-21

    Novel palladium(ii) and platinum(ii) complexes of 5,5-diethylbarbiturate (barb) with 2-phenylpyridine (Hppy), 2,2'-bipyridine (bpy) and 2,2'-dipyridylamine (dpya) have been prepared and characterized by elemental analysis, IR, UV-Vis, NMR and ESI-MS. Single-crystal diffraction measurements show that complex consists of binuclear [Pd2(μ-barb-κN,O)2(ppy-κN,C)2] moieties, while complexes are mononuclear, [M(barb-κN)2(L-κN,N')] (L = bpy or dpya). has a composition of [Pt(dpya-κN,N')2][Ag(barb-κN)2]2·4H2O and was assumed to have a structure of [Pt(barb-κN)(Hppy-κN)(ppy-κN,C)]·3H2O. The complexes were found to exhibit significant DNA binding affinity by a non-covalent binding mode, in accordance with molecular docking studies. In addition, complexes and displayed strong binding with supercoiled pUC19 plasmid DNA. Cellular uptake studies were performed to assess the subcellular localization of the selected complexes. A moderate radical scavenging activity of and was confirmed by DPPH and ABTS tests. Complexes , , and showed selectivity against HT-29 (colon) cell line.

  17. Toxicity of platinum compounds.

    Science.gov (United States)

    Hartmann, Jörg Thomas; Lipp, Hans-Peter

    2003-06-01

    Since the introduction of platinum-based combination chemotherapy, particularly cisplatin, the outcome of the treatment of many solid tumours has changed. The leading platinum compounds in cancer chemotherapy are cisplatin, carboplatin and oxaliplatin. They share some structural similarities; however, there are marked differences between them in therapeutic use, pharmacokinetics and adverse effects profiles [1-4]. Compared to cisplatin, carboplatin has inferior efficacy in germ-cell tumour, head and neck cancer and bladder and oesophageal carcinoma, whereas both drugs seem to have comparable efficacy in advanced non-small cell and small cell lung cancer as well as ovarian cancer [5-7]. Oxaliplatin belongs to the group of diaminocyclohexane platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid [8,9]. Other platinum compounds such as oral JM216, ZD0473, BBR3464 and SPI-77, which is a pegylated liposomal formulation of cisplatin, are still under investigation [10-13], whereas nedaplatin has been approved in Japan for the treatment of non-small cell lung cancer and other solid tumours. This review focuses on cisplatin, carboplatin and oxaliplatin.

  18. Two and 8-azido photoaffinity probes. 1. Enzymatic synthesis, characterization, and biological properties of 2- and 8-azido photoprobes of 2-5A and photolabeling of 2-5A binding proteins

    Energy Technology Data Exchange (ETDEWEB)

    Suhadolnik, R.J.; Kariko, K.; Sobol, R.W. Jr.; Li, S.W.; Reichenbach, N.L.; Haley, B.E.

    1988-11-29

    The 2- and 8-azido trimer 5'-triphosphate photoprobes of 2-5A have been enzymatically synthesized from (..gamma..-/sup 32/P)2-azidoATP and (..cap alpha..-/sup 32/P)8-azidoAPT by 2-5A synthetase from rabbit reticulocyte lysates. Identification and structural determination of the 2- and 8-azido adenylate trimer 5'-triphosphates were accomplished by enzymatic hydrolyses with T2 RNase, snake venom phosphodiesterase, and bacterial alkaline phosphatase. Hydrolysis products were identified by HPLC and PEI-cellulose TLC analyses. The 8-azido photoprobe of 2-5A displaces p/sub 3/A/sub 4/(/sup 32/P)pCp from RNase L with affinity equivalent to p/sub 3/A/sub 3/. The 8-azido photoprobe also activates RNase L to hydrolyze poly(U)(/sup 32/P)pCp 50% at 7 /times/ 10/sup /minus/9/ M in core-cellulose assays. The 2- and 8-azido photoprobes and authentic p/sub 3/A/sub 3/ activate RNase L to cleave 28S and 18S rRNA to specific cleavage products at 10/sup /minus/9/ M in rRNA cleavage assays. The nucleotide binding site(s) of RNase L and/or other 2-5A binding proteins in extracts of interferon-treated L929 cells were investigated by photoaffinity labeling. Dramatically different photolabeling patterns were observed with the 2- and 8-azido photoprobes. The (..gamma..-/sup 32/P)2-azido adenylate trimer 5'-triphosphate photolabels only one polypeptide with a molecular weight of 185,000 as determined by SDS gel electrophoresis, whereas the (..cap alpha..-/sup 32/P)8-azido adenylate trimer 5'-triphosphate covalently photolabels six polypeptides with molecular weights of 46,000, 63,000, 80,000, 89,000, 109,000, and 158,000. Evidence that the photolabeling by 2- and 8-azido 2-5A photoprobes was highly specific for the p/sub 3/A/sub 3/ allosteric binding site was obtained.

  19. Oxygen Reduction on Platinum

    DEFF Research Database (Denmark)

    Nesselberger, Markus

    This thesis investigates the electro reduction of oxygen on platinum nanoparticles, which serve as catalyst in low temperature fuel cells. Kinetic studies on model catalysts as well as commercially used systems are presented in order to investigate the particle size effect, the particle proximity...... carbon (HSAC) supported Pt nanoparticle (Pt/C) catalysts (of various size between 1 and 5 nm). The difference in SA between the individual Pt/C catalysts (1 to 5 nm) is very small and within the error of the measurements. The factor four of loss in SA when comparing platinum bulk and Pt/C can largely...

  20. Direct imaging of glycans in Arabidopsis roots via click labeling of metabolically incorporated azido-monosaccharides.

    Science.gov (United States)

    Hoogenboom, Jorin; Berghuis, Nathalja; Cramer, Dario; Geurts, Rene; Zuilhof, Han; Wennekes, Tom

    2016-10-10

    Carbohydrates, also called glycans, play a crucial but not fully understood role in plant health and development. The non-template driven formation of glycans makes it impossible to image them in vivo with genetically encoded fluorescent tags and related molecular biology approaches. A solution to this problem is the use of tailor-made glycan analogs that are metabolically incorporated by the plant into its glycans. These metabolically incorporated probes can be visualized, but techniques documented so far use toxic copper-catalyzed labeling. To further expand our knowledge of plant glycobiology by direct imaging of its glycans via this method, there is need for novel click-compatible glycan analogs for plants that can be bioorthogonally labelled via copper-free techniques. Arabidopsis seedlings were incubated with azido-containing monosaccharide analogs of N-acetylglucosamine, N-acetylgalactosamine, L-fucose, and L-arabinofuranose. These azido-monosaccharides were metabolically incorporated in plant cell wall glycans of Arabidopsis seedlings. Control experiments indicated active metabolic incorporation of the azido-monosaccharide analogs into glycans rather than through non-specific absorption of the glycan analogs onto the plant cell wall. Successful copper-free labeling reactions were performed, namely an inverse-electron demand Diels-Alder cycloaddition reaction using an incorporated N-acetylglucosamine analog, and a strain-promoted azide-alkyne click reaction. All evaluated azido-monosaccharide analogs were observed to be non-toxic at the used concentrations under normal growth conditions. Our results for the metabolic incorporation and fluorescent labeling of these azido-monosaccharide analogs expand the possibilities for studying plant glycans by direct imaging. Overall we successfully evaluated five azido-monosaccharide analogs for their ability to be metabolically incorporated in Arabidopsis roots and their imaging after fluorescent labeling. This expands

  1. Biomineralization of platinum by microorganisms

    Science.gov (United States)

    Pavlova, L. M.; Radomskaya, V. I.; Shumilova, L. P.; Ionov, A. M.; Sorokin, P.

    2017-04-01

    The mechanism of platinum biomineralization by microscopic fungi is displayed based on data of electron microscopy, infrared and X-ray photoelectronic spectroscopy. It was suggested the platinum sorption process by microscopic fungi has some stages. The initial interaction is carried out by the mechanisms of physical and chemical sorption. Hereafter the reduction process of adsorbed platinum ions up to zero state is performed, probably, for account of organic compounds, which are produced by fungi biomass as metabolism result, and the process terminates by nulvalent particles aggregating up to nanosize forms. Obtained data on the platinum biomineralization extends the concept concerning the character of forming platinum nanoparticles in carbonous paleobasin.

  2. Experimental partitioning of Zr, Ti, and Nb between silicate liquid and a complex noble metal alloy and the partitioning of Ti between perovskite and platinum metal

    Science.gov (United States)

    Jurewicz, Stephen R.; Jones, John H.

    1993-01-01

    El Goresy et al.'s observation of Nb, Zr, and Ta in refractory platinum metal nuggets (RPMN's) from Ca-Al-rich inclusions (CAI's) in the Allende meteorite led them to propose that these lithophile elements alloyed in the metallic state with noble metals in the early solar nebula. However, Grossman pointed out that the thermodynamic stability of Zr in the oxide phase is vastly greater than metallic Zr at estimated solar nebula conditions. Jones and Burnett suggested this discrepancy may be explained by the very non-ideal behavior of some lithophile transition elements in noble metal solutions and/or intermetallic compounds. Subsequently, Fegley and Kornacki used thermodynamic data taken from the literature to predict the stability of several of these intermetallic compounds at estimated solar nebula conditions. Palme and Schmitt and Treiman et al. conducted experiments to quantify the partitioning behavior of certain lithophile elements between silicate liquid and Pt-metal. Although their results were somewhat variable, they did suggest that Zr partition coefficients were too small to explain the observed 'percent' levels in some RPMN's. Palme and Schmitt also observed large partition coefficients for Nb and Ta. No intermetallic phases were identified. Following the work of Treiman et al., Jurewicz and Jones performed experiments to examine Zr, Nb, and Ti partitioning near solar nebula conditions. Their results showed that Zr, Nb, and Ti all have an affinity for the platinum metal, with Nb and Ti having a very strong preference for the metal. The intermetallic phases (Zr,Fe)Pt3, (Nb,Fe)Pt3, and (Ti,Fe)Pt3 were identified. Curiously, although both experiments and calculations indicate that Ti should partition strongly into Pt-metal (possibly as TiPt3), no Ti has ever been observed in any RPMN's. Fegley and Kornacki also noticed this discrepancy and hypothesized that the Ti was stabilized in perovskite which is a common phase in Allende CAI's.

  3. Platinum electrodeposition from a dinitrosulfatoplatinate(II) electrolyte

    Science.gov (United States)

    Weiser, Mathias; Schulze, Claudia; Schneider, Michael; Michaelis, Alexander

    2016-12-01

    In this work a halogen-free electrolyte to deposit platinum nanoparticle is studied. The investigated [Pt(NO2)2SO4]2--complex is suitable for electrochemical deposition on halogen sensitive substrates. The mechanism and kinetic of particle deposition is investigated using a glassy carbon rotating disk electrode. Nano sized platinum particles are deposited by using pulse plating technique. The size of the smallest platinum nanoparticle is 5 nm. The shape of the particle distribution strictly depends on the plating time. The platinum deposition is usually superimposed with hydrogen evolution. A diffusion coefficient of the [Pt(NO2)2SO4]2--complex is determined to 5.4 × 10-6 cm2s-1. The current efficiency depends on the deposition parameters and amounts to 37% under the chosen pulse plating conditions.

  4. Mechanistic and conformational studies on the interaction of a platinum(II) complex containing an antiepileptic drug, levetiracetam, with bovine serum albumin by optical spectroscopic techniques in aqueous solution.

    Science.gov (United States)

    Shahabadi, Nahid; Hadidi, Saba

    2015-02-01

    Fluorescence spectroscopy in combination with circular dichroism (CD) and ultraviolet-visible (UV-vis) absorption spectroscopy were employed to investigate the binding of a new platinum(II) complex containing an antiepileptic drug "Levetiracetam" to bovine serum albumin (BSA) under the physiological conditions. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by Pt(II) complex is a result of the formation of Pt(II) complex-BSA complex. The thermodynamic parameters ΔG, ΔH, and ΔS at different temperatures (283, 298, and 310 K) were calculated, and the negative value for ΔH and ΔS indicate that the hydrogen bonds and van der Waals interactions play major roles in Pt(II) complex-BSA association. Binding studies concerning the number of binding sites (n~1) and apparent binding constant K b were performed by fluorescence quenching method. The site marker competitive experiments indicated that the binding of Pt(II) complex to BSA primarily took place in site II. Based on the Förster's theory, the average binding distance between Pt(II) complex and BSA was obtained (r = 5.29 nm). Furthermore, UV-vis, CD, and synchronous fluorescence spectrum were used to investigate the structural change of BSA molecules with addition of Pt(II) complex. These results indicate that the binding of Pt(II) complex to BSA causes apparent change in the secondary structure of BSA and do affect the microenvironment around the tryptophan residue.

  5. Cisplatin and platinum drugs at the molecular level. (Review).

    Science.gov (United States)

    Boulikas, Teni; Vougiouka, Maria

    2003-01-01

    Over twenty years of intensive work toward improvement of cisplatin, and with hundreds of platinum drugs tested, has resulted in the introduction of the widely used carboplatin and of oxaliplatin used only for a very narrow spectrum of cancers. A number of interesting platinum compounds including the orally administered platinum drug JM216, nedaplatin, the sterically hindered platinum(II) complex ZD0473, the trinuclear platinum complex BBR3464, and the liposomal forms Lipoplatin and SPI-77 are under clinical evaluation. This review summarizes the molecular mechanisms of platinum compounds for DNA damage, DNA repair and induction of apoptosis via activation or modulation of signaling pathways and explores the basis of platinum resistance. Cisplatin, carboplatin, oxaliplatin and most other platinum compounds induce damage to tumors via induction of apoptosis; this is mediated by activation of signal transduction leading to the death receptor mechanisms as well as mitochondrial pathways. Apoptosis is responsible for the characteristic nephrotoxicity, ototoxicity and most other toxicities of the drugs. The major limitation in the clinical applications of cisplatin has been the development of cisplatin resistance by tumors. Mechanisms explaining cisplatin resistance include the reduction in cisplatin accumulation inside cancer cells because of barriers across the cell membrane, the faster repair of cisplatin adducts, the modulation of apoptotic pathways in various cells, the upregulation in transcription factors, the loss of p53 and other protein functions and a higher concentration of glutathione and metallothioneins in some type of tumors. A number of experimental strategies to overcome cisplatin resistance are at the preclinical or clinical level such as introduction of the bax gene, inhibition of the JNK pathway, introduction of a functional p53 gene, treatment of tumors with aldose reductase inhibitors and others. Particularly important are combinations of platinum

  6. Synthesis of polyhydroxylated 2H-azirines and 2-halo-2H-azirines from 3-azido-2,3-dideoxyhexopyranoses by alkoxyl radical fragmentation.

    Science.gov (United States)

    Alonso-Cruz, Carmen R; Kennedy, Alan R; Rodríguez, María S; Suárez, Ernesto

    2008-06-06

    The reaction of 3-azido-2,3-dideoxypyranose and 3-azido-2,3-dideoxy-2-halohexopyranose compounds with (diacetoxyiodo)benzene and iodine generated 2-azido-1,2-dideoxy-1-iodoalditols and 2-azido-1,2-dideoxy-1-halo-1-iodoalditols, respectively. These beta-iodo azides could be transformed by chemoselective dehydroiodination into 2-azido-1,2-dideoxy-4- O-formyl-pent-1-enitols and (Z, E)-2-azido-1,2-dideoxy-1-halo-4- O-formyl-pent-1-enitols in good yields. Thermolysis and photochemical studies of these vinyl azides and 1-halovinyl azides for the synthesis of polyhydroxylated 3-alkyl-2 H-azirines and the hitherto unknown 2-halo-3-alkyl-2 H-azirines have also been accomplished.

  7. An in vivo highly antitumor-active tetrazolato-bridged dinuclear platinum(II) complex largely circumvents in vitro cisplatin resistance: two linkage isomers yield the same product upon reaction with 9-ethylguanine but exhibit different cytotoxic profiles.

    Science.gov (United States)

    Uemura, Masako; Suzuki, Toshihiro; Nishio, Kazuto; Chikuma, Masahiko; Komeda, Seiji

    2012-07-01

    Cytotoxicity assays of azolato-bridged dinuclear Pt(II) complexes, [{cis-Pt(NH(3))(2)}(2)(μ-OH)(μ-azolato)](2+), where the azolato was pyrazolato (1), 1,2,3-triazolato-N1,N2 (2), tetrazolato-N1,N2 (3), or tetrazolato-N2,N3 (4), were performed in cisplatin-sensitive and -resistant human non-small-cell lung cancer cell lines (PC-9 and PC-14). These complexes largely circumvented the cisplatin resistance in both cell lines, with resistance factors for 1-4 in the range of 0.5-0.8 and 0.9-2.0 for PC-9 and PC-14 cells, respectively. Complex 4 exhibited approximately 10 times the cytotoxicity of 3. When 3 and 4 were reacted with 2 molar equiv. of 9-ethylguanine (9EtG), they yielded an identical product, [{cis-Pt(NH(3))(2)(9EtG-N7)}(2)(μ-tetrazolato-N1,N3)](3+), that had N1,N3 platinum coordination through a Pt(II) migration process on the tetrazolate ring. The second-order rate kinetics of these isomers were almost the same as each other and faster than those of 1 and 2. The cytotoxicity of azolato-bridged complexes, except for 3, increases as their kinetic rates in the 9EtG reaction increase.

  8. Unexpected cleavage of 2-azido-2-(hydroxymethyl)oxetanes: conformation determines reaction pathway?

    Science.gov (United States)

    Farber, Elisa; Herget, Jackson; Gascón, José A; Howell, Amy R

    2010-11-19

    An unanticipated cleavage of 2-azido-2-(hydroxymethyl)oxetanes is reported. In attempts to oxidize the title oxetanyl alcohols to the corresponding carboxylic acids with RuO4, cleaved nitriles were formed as the sole isolable products, while a closely related tetrahydrofuran gave solely the expected carboxylic acid. Quantum chemical calculations suggest that the divergent outcomes are governed by conformational differences in the azidoalcohols.

  9. Monofunctional and Higher-Valent Platinum Anticancer Agents

    Science.gov (United States)

    Johnstone, Timothy C.; Wilson, Justin J.

    2013-01-01

    Platinum compounds represent one of the great success stories of metals in medicine. Following the serendipitous discovery of the anticancer activity of cisplatin by Rosenberg, a large number of cisplatin variants have been prepared and tested for their ability to kill cancer cells and inhibit tumor growth. These efforts continue today with increased realization that new strategies are needed to overcome issues of toxicity and resistance inherent to treatment by the approved platinum anticancer agents. One approach has been the use of so-called “non-traditional” platinum(II) and platinum(IV) compounds that violate the structure-activity relationships that governed platinum drug-development research for many years. Another is the use of specialized drug delivery strategies. Here we describe recent developments from our laboratory involving monofunctional platinum(II) complexes together with an historical account of the manner by which we came to investigate these compounds and their relationship to previously studied molecules. We also discuss work carried out using platinum(IV) prodrugs and the development of nanoconstructs designed to deliver them in vivo. PMID:23738524

  10. Interaction of DNA with Bis(diiminosuccinonitrilo)platinum(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-Gang; SUN Yuan-Yuan; JIANG Xiao-Ming

    2008-01-01

    Interaction of DNA with bis(diiminosuccinonitrilo)platinum(Ⅱ) has been studied by UV-visible absorbance spectra, fluorescence spectra and viscosity measurements. The UV-visible absorption spectra of the metal complex exhibit hypochromism with a small blue shift on interaction with DNA. Scatchard plot analyses indicate that the binding sites of the metal complex on DNA are different from those of ethidium bromide. Viscosity experiments reveal that the binding of the metal complex decreases the relative viscosity of DNA. These results suggest that the platinum diimine complex interact with DNA by surface binding. These studies are helpful for us to understand the action mechanism of bis(diiminosuccinonitrilo)platinum(Ⅱ) as a potential photodynamic therapeutic agent, and further to develop it.

  11. Biological activity of palladium(II) and platinum(II) complexes of the acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate and the X-ray crystal structure of the [Pd(asme)2] (asme=anionic form of the acetone Schiff base of S-methyldithiocarbazate) complex.

    Science.gov (United States)

    Akbar Ali, Mohammad; Mirza, Aminul Huq; Butcher, Raymond J; Tarafder, M T H; Keat, Tan Boon; Ali, A Manaf

    2002-11-25

    Palladium(II) and platinum(II) complexes of general empirical formula, [M(NS)(2)] (NS=uninegatively charged acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate; M=Pt(II) and Pd(II)) have been prepared and characterized by a variety of physicochemical techniques. Based on conductance, IR and electronic spectral evidence, a square-planar structure is assigned to these complexes. The crystal and molecular structure of the [Pd(asme)(2)] complex (asme=anionic form of the acetone Schiff base of S-methyldithiocarbazate) has been determined by X-ray diffraction. The complex has a distorted cis-square planar structure with the ligands coordinated to the palladium(II) ions as uninegatively charged bidentate NS chelating agents via the azomethine nitrogen and the mercaptide sulfur atoms. The distortion from a regular square-planar geometry is attributed to the restricted bite angles of the ligands. Antimicrobial tests indicate that the Schiff bases exhibit strong activities against the pathogenic bacteria, Bacillus subtilis (mutant defective DNA repair), methicillin-resistant Staphylococcus aureus, B. subtilis (wild type) and Pseudomonas aeruginosa and the fungi, Candida albicans (CA), Candida lypotica (2075), Saccharomyces cerevisiae (20341) and Aspergillus ochraceous (398)-the activities exhibited by these compounds being greater than that of the standard antibacterial and antifungal drugs, streptomycin and nystatin, respectively. The palladium(II) and platinum(II) complexes are inactive against most of these organisms but, the microbe, Pseudomonas aeruginosa shows strong sensitivity to the platinum(II) complexes. Screening of the compounds for their cytotoxicities against T-lymphoblastic leukemia cancer cells has shown that the acetone Schiff base of S-methyldithiocarbazate (Hasme) exhibits a very weak activity, whereas the S-benzyl derivative (Hasbz) is inactive. However, the palladium(II) complexes exhibit strong cytotoxicities against this cancer; their

  12. Optimizing treatment of the partially platinum-sensitive ovarian cancer patient.

    Science.gov (United States)

    Colombo, Nicoletta

    2013-12-01

    Ovarian cancer is the leading cause of gynecological cancer deaths worldwide. Despite primary treatment with platinum-containing regimens, the majority of women will experience recurrent disease and subsequent death. Recurrent ovarian cancer remains a challenge for successful management, and the choice of second-line chemotherapy is complex due to the range of different factors that need to be considered. One of the main considerations is the platinum-free interval and, specifically, the optimal treatment for patients who are partially platinum-sensitive (platinum-free interval: 6-12 months). Data from the large, multicenter, randomized OVA-301 study have shown that combined trabectedin-pegylated liposomal doxorubicin (PLD) significantly prolonged median overall survival compared with PLD alone (p = 0.0027) in 214 patients with partially platinum-sensitive advanced relapsed ovarian cancer. Furthermore, in OVA-301 patients with partially platinum-sensitive disease who received platinum therapy immediately after disease progression (n = 94), final median overall survival was improved by 9 months (p = 0.0153) in trabectedin-PLD patients compared with PLD alone. In addition to demonstrating a survival advantage, trabectedin-PLD may also allow the treatment of patients having not yet recovered from previous platinum toxicity. In summary, the data suggest the use of combined trabectedin-PLD as a second-line treatment option in patients with partially platinum-sensitive recurrent ovarian cancer, followed by a third-line platinum-containing regimen.

  13. Synthesis of platinum(II) and palladium(II) complexes with 9,9-dihexyl-4,5-diazafluorene and their in vivo antitumour activity against Hep3B xenografted mice.

    Science.gov (United States)

    Wang, Q-W; Lam, P-L; Wong, R S-M; Cheng, G Y-M; Lam, K-H; Bian, Z-X; Ho, C-L; Feng, Y-H; Gambari, R; Lo, Y-H; Wong, W-Y; Chui, C-H

    2016-11-29

    Two complexes dichloro(9,9-dihexyl-4,5-diazafluorene)platinum(II) (Pt-DHF) and dichloro(9,9-dihexyl-4,5-diazafluorene)palladium(II) (Pd-DHF) were synthesized and their in vivo antitumour activity was investigated using an athymic nude mice model xenografted with human Hep3B carcinoma cells. Pt-DHF- and Pd-DHF-treated groups showed significant tumour growth inhibition (with about 9-fold and 3-fold tumour growth retardation) when compared with the vehicle control group. The liver toxicology effects on the animals of the two compounds were investigated. Pt-DHF and Pd-DHF-treated groups had a lower alanine transaminase and aspartate transaminase values than those of the vehicle treated group as the animals from the vehicle control group had very heavy hepatoma burden. We assume that both complexes could be further investigated as effective antitumour agents and it is worthwhile to study their underlying working mechanism.

  14. Cytotoxic malonate platinum(II) complexes with 1,2,4-triazolo[1,5-a]pyrimidine derivatives: structural characterization and mechanism of the suppression of tumor cell growth.

    Science.gov (United States)

    Łakomska, Iwona; Hoffmann, Kamil; Wojtczak, Andrzej; Sitkowski, Jerzy; Maj, Ewa; Wietrzyk, Joanna

    2014-12-01

    A series of malonate (mal) platinum(II) complexes of the general formula [Pt(mal)(L)2], where L=5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) (1), 7-isobutyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp) (2) or 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) (3), has been prepared and characterized using multinuclear ((1)H, (13)C, (15)N, (195)Pt) NMR, IR and electrospray ionization mass spectrometry (ESIMS). Furthermore, the crystal structures of [Pt(mal)(dmtp)2]∙4H2O (1a) and [Pt(mal)(dbtp)2]∙CHCl3 (3a) have been determined using single-crystal X-ray diffraction. The spectroscopic characterization unambiguously confirmed the square-planar geometry of Pt(II) with two monodentate N3-bonded 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidines and one O-chelating malonate. The antiproliferative activities of the compounds against the human cell lines T47D (cisplatin-resistant human ductal breast epithelial tumor cell line) and A549 (lung adenocarcinoma epithelial cell line) and the mouse cell line 4T1 (mouse breast tumor model) were assessed using an in vitro screening assay. Compounds (2) and (3) exhibited substantial antigrowth properties against T47D cells, whereas only (3) exhibited an IC50 value that was lower than cisplatin and carboplatin against the 4T1 cell line. Additionally, compounds (2, 3) are capable of arresting the cell cycle of A549 cells at the G0/G1 phase, whereas cisplatin and carboplatin arrested the cells at the G2/M phase, indicating differences in the mechanism of the suppression of tumor cell growth. Finally, in the quest for low toxicity platinum drugs, the in vitro antiproliferative activity against normal mouse fibroblast cells (BALB/3T3) was evaluated. The inhibition of BALB/3T3 cell proliferation by the evaluated Pt(II) complexes increased in the order (1)<(2)

  15. Synthesis, characterization and antimicrobial activity of novel platinum(IV) and palladium(II) complexes with meso-1,2-diphenyl-ethylenediamine-N,N‧-di-3-propanoic acid - Crystal structure of H2-1,2-dpheddp·2HCl·H2O

    Science.gov (United States)

    Radić, Gordana P.; Glođović, Verica V.; Ratković, Zoran R.; Novaković, Slađana B.; Garcia-Granda, Santiago; Roces, Laura; Menéndez-Taboada, Laura; Radojević, Ivana D.; Stefanović, Olgica D.; Čomić, Ljiljana R.; Trifunović, Srećko R.

    2012-12-01

    In the reaction of meso-1,2-diphenyl-ethylenediamine (1,2-dphen) with neutralized 3-chlor-propanoic acid, the new linear tetradentate edda-like ligand (edda = ethylenediamine-N,N'-diacetic ion) meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoic acid dihydrochloride monohydrate (H2-1,2-dpheddp·2HCl·H2O) was prepared. The corresponding platinum(IV) complex, s-cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoate)-platinum(IV) ([PtCl2(1,2-dpheddp)]) was synthesized by heating potassium-hexachloridoplatinate(IV) and H2-1,2-dpheddp·2HCl·H2O on steam bath for 12 h with neutralization by means of lithium-hydroxide. The palladium(II) complex, cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoate)-palladium(II) ([PdCl2(1,2-dpheddp)]) was obtained in the similar way using potassium-tetrachloridopalladate(II), H2-1,2-dpheddp·2HCl·H2O and lithium-hydroxide. The compounds were characterized by elemental analysis and infrared spectroscopy. The spectroscopically predicted structure of the synthesized tetradentate ligand was confirmed by X-ray analysis of the H2-1,2-dpheddp·2HCl·H2O. Antimicrobial activity of the ligand and corresponding palladium(II) and platinum(IV) complexes is investigated against 25 species of microorganisms. Testing is preformed by microdilution method and minimum inhibitory concentrations (MIC) and minimum microbicidal concentration (MMC) have been determined. The difference between antimicrobial activity of the ligand and corresponding platinum(IV) and palladium(II) complex is noticed and, in general, palladium(II) complex was the most active.

  16. Platinum nitride with fluorite structure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Rong; Zhang, Xiao-Feng

    2005-01-31

    The mechanical stability of platinum nitride has been studied using first-principles calculations. By calculating the single-crystal elastic constants, we show that platinum nitride can be stabilized in the fluorite structure, in which the nitrogen atoms occupy all the tetrahedral interstitial sites of the metal lattice. The stability is attributed to the pseudogap effect from analysis of the electronic structure.

  17. Structure of matrix metalloproteinase-3 with a platinum-based inhibitor.

    Science.gov (United States)

    Belviso, Benny Danilo; Caliandro, Rocco; Siliqi, Dritan; Calderone, Vito; Arnesano, Fabio; Natile, Giovanni

    2013-06-18

    An X-ray investigation has been performed with the aim of characterizing the binding sites of a platinum-based inhibitor (K[PtCl3(DMSO)]) of matrix metalloproteinase-3 (stromelysin-1). The platinum complex targets His224 in the S1' specificity loop, representing the first step in the selective inhibition process (PDB ID code 4JA1).

  18. Advances in the synthesis mulitmetallic systems: hydroxyl group protection in aryldiamine platinum species

    NARCIS (Netherlands)

    Koten, G. van; Davies, P.J.; Grove, D.M.

    1997-01-01

    A multimetallic system containing three platinum atoms has been synthesized through use of an (aryldiamine)platinum complex with a protected hydroxyl group which, after deprotection, is coupled with the trisubstituted aryl molecule 1,3,5-tris(chlorocarbonyl)benzene that provides the core moiety. The

  19. The interaction of platinum-based drugs with native biologically relevant proteins

    NARCIS (Netherlands)

    Brauckmann, Christine; Wehe, Christoph A.; Kieshauer, Michael; Lanvers-Kaminsky, Claudia; Sperling, Michael; Karst, Uwe

    2013-01-01

    This study focuses on the identification of the products that are formed upon binding of therapeutically relevant platinum complexes to proteins like beta-lactoglobulin A (LGA), human serum albumin (HSA), or human hemoglobin (HB). The respective proteins were incubated with the platinum-based antica

  20. Ion exchange equilibria in simultaneous extraction of platinum(II, IV) and rhodium(III) from hydrochloric solutions

    Science.gov (United States)

    Mel'nikov, A. M.; Kononova, O. N.; Pavlenko, N. I.; Krylov, A. S.

    2012-06-01

    Regularities of sorption extraction of platinum(II, IV) and rhodium(III) by anion exchangers of various physical and chemical structure in the presence of hydrochloric media were studied. It is established that AM-2B, Purolite A 500, and Purolite S 985 ionites adsorb complex anions of platinum metals employing mixed mechanism. A high affinity of the studied anionites for the studied complex anions of platinum and rhodium is established.

  1. 5-Azido-4-dimethylamino-1-methyl-1,2,4-triazolium Hexafluoridophosphate and Derivatives

    Directory of Open Access Journals (Sweden)

    Gerhard Laus

    2016-02-01

    Full Text Available 5-Azido-4-(dimethylamino-1-methyl-1,2,4-triazolium hexafluoridophosphate was synthesized from the corresponding 5-bromo compound with NaN3. Reaction with bicyclo[2.2.1]hept-2-ene yielded a tricyclic aziridine, addition of an N-heterocyclic carbene resulted in a triazatrimethine cyanine, and reduction with triphenylphosphane gave the 5-amino derivative. The crystal structures of three nitrogen-rich salts were determined. Thermoanalysis of the cationic azide and triazene showed exothermal decomposition. The triazene exhibited negative solvatochromism in polar solvents involving the dipolarity π* and hydrogen-bond donor acidity α of the solvent.

  2. An unusual (H(2)O)(20) discrete water cluster in the supramolecular host of a charge transfer platinum(ii) complex: cytotoxicity and DNA cleavage activities.

    Science.gov (United States)

    Mandal, Sutanuva; Castiñeiras, Alfonso; Mondal, Tapan K; Mondal, Arindam; Chattopadhyay, Dhrubajyoti; Goswami, Sreebrata

    2010-10-28

    The chemical reaction of Pt(II)(L(1))Cl(2) [L(1) = N-4-tolylpyridine-2-aldimine] with a bidentate N,S-donor atom ligand, 2-methylthioaniline, (HL(2)) in alkaline methanolic medium yielded a mixed ligand donor-acceptor complex, [Pt(II)(L(1))(L(2))]Cl, [1]Cl. The complex has been characterized by different spectroscopic and electrochemical techniques. The complex showed intense interligand charge transfer (ILCT) transition in the long wavelength region of UV-vis spectrum (>600 nm). The single-crystal X-ray structure of complex, [1]Cl·3.3H(2)O is reported. The cationic complex upon crystallization from aqueous methanol solvent produces an assembly of discrete, three dimensional (H(2)O)(20) guest moiety within the reference Pt-complex host lattice. The water assembly showed a unique type of aggregation of a distorted cube encapsulated by hydrogen bonded network of a twelve-water ring. The complex displayed one reversible cathodic response at -0.75 V and two irreversible anodic responses at 0.42 and 0.79 V versus Ag/AgCl reference electrode. The redox processes are characterized by EPR and spectroelectrochemistry. Density-functional theory calculations were employed to confirm the structural features and to support the spectral and redox properties of the complex. The square-planar complex has been found to intercalate DNA. Fluorescence spectroscopy, circular dichroism, cyclic voltammetry, viscosity measurements, together with DNA melting studies have been employed to characterize the binding of [1]Cl with calf thymus DNA. Agarose gel electrophoresis indicates that the complex cleaves supercoiled (SC) pUC19 plasmid DNA to its nicked circular (NC) form via singlet oxygen. As determined by a MTT assay, [1]Cl exhibits significant cytotoxicity with IC(50) value 58 μM.

  3. Platinum in Earth surface environments

    Science.gov (United States)

    Reith, F.; Campbell, S. G.; Ball, A. S.; Pring, A.; Southam, G.

    2014-04-01

    Platinum (Pt) is a rare precious metal that is a strategic commodity for industries in many countries. The demand for Pt has more than doubled in the last 30 years due to its role in the catalytic conversion of CO, hydrocarbons and NOx in modern automobiles. To explore for new Pt deposits, process ores and deal with ecotoxicological effects of Pt mining and usage, the fundamental processes and pathways of Pt dispersion and re-concentration in surface environments need to be understood. Hence, the aim of this review is to develop a synergistic model for the cycling of Pt in Earth surface environments. This is achieved by integrating the geological/(biogeo)chemical literature, which focuses on naturally occurring Pt mobility around ore deposits, with the environmental/ecotoxicological literature dealing with anthropogenic Pt dispersion. In Pt deposits, Pt occurs as sulfide-, telluride- and arsenide, native metal and alloyed to other PGEs and iron (Fe). Increased mining and utilization of Pt combined with the burning of fossil fuels have led to the dispersion of Pt-containing nano- and micro-particles. Hence, soils and sediments in industrialized areas, urban environments and along major roads are now commonly Pt enriched. Platinum minerals, nuggets and anthropogenic particles are transformed by physical and (bio)geochemical processes. Complexation of Pt ions with chloride, thiosulfate, ammonium, cyanide, low- and high molecular weight organic acids (LMWOAs and HMWOAs) and siderophores can facilitate Pt mobilization. Iron-oxides, clays, organic matter and (micro)biota are known to sequester Pt-complexes and -particles. Microbes and plants are capable of bioaccumulating and reductively precipitating mobile Pt complexes. Bioaccumulation can lead to toxic effects on plants and animals, including humans. (Bio)mineralization in organic matter-rich sediments can lead to the formation of secondary Pt particles and -grains. Ultimately, Pt is enriched in oceanic sediments

  4. Multi-Nuclear NMR Investigation of Nickel(II), Palladium(II), Platinum(II) and Ruthenium(II) Complexes of an Asymmetrical Ditertiary Phosphine

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Joe Gerald Jesu [Institut National de la Recherche Scientifique, Quebec (China); Pathak, Devendra Deo [Indian School of Mines, Dhanbad (India); Kapoor, Pramesh N. [Univ. of Delhi, Delhi (India)

    2013-12-15

    Complexes synthesized by reacting alkyl and aryl phosphines with different transition metals are of great interest due to their catalytic properties. Many of the phosphine complexes are soluble in polar solvents as a result they find applications in homogeneous catalysis. In our present work we report, four transition metal complexes of Ni(II), Pd(II), Pt(II) and Ru(II) with an asymmetrical ditertiaryphosphine ligand. The synthesized ligand bears a less electronegative substituent such as methyl group on the aromatic nucleus hence makes it a strong σ-donor to form stable complexes and thus could effectively used in catalytic reactions. The complexes have been completely characterized by elemental analyses, FTIR, {sup 1}HNMR, {sup 31}PNMR and FAB Mass Spectrometry methods. Based on the spectroscopic evidences it has been confirmed that Ni(II), Pd(II) and Pt(II) complexes with the ditertiaryphosphine ligand showed cis whereas the Ru(II) complex showed trans geometry in their molecular structure.

  5. Influence of reducing agents on the cytotoxic activity of platinum(IV) complexes: induction of G2/M arrest, apoptosis and oxidative stress in A2780 and cisplatin resistant A2780cis cell lines.

    Science.gov (United States)

    Pichler, Verena; Göschl, Simone; Schreiber-Brynzak, Ekaterina; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K

    2015-07-01

    The concept of Pt(IV) prodrug design is one advanced strategy to increase the selectivity for cancer cells and to reduce systemic toxicity in comparison to established platinum-based chemotherapy. Pt(IV) complexes are thought to be activated by reduction via physiological reductants, such as ascorbic acid or glutathione. Nevertheless, only few investigations on the link between the reduction rate, which is influenced by the reductant, and the ligand sphere of the Pt(IV) metal centre have been performed so far. Herein, we investigated a set of Pt(IV) compounds with varying rates of reduction with respect to their cytotoxicity and drug accumulation in A2780 and A2780cis ovarian cancer cell lines, their influence on the cell cycle, efficiency of triggering apoptosis, and ability to interfere with plasmid DNA (pUC19). The effects caused by Pt(IV) compounds were compared without or with extracellularly added ascorbic acid and glutathione (or its precursor N-acetylcysteine) to gain understanding of the impact of increased levels of the reductant on the activity of such complexes. Our results demonstrate that reduction is required prior to plasmid interaction. Furthermore, the rate of reduction is crucial for the efficiency of this set of Pt(IV) compounds. The substances that are reduced least likely showed similar performances, whereas the fastest reducing substance was negatively affected by an increased extracellular level of reducing agents, with reduced cytotoxicity and lower efficiency in inducing apoptosis and G2/M arrest. These results confirm the connection between reduction and activity, and prove the strong impact of the reduction site on the activity of Pt(IV) complexes.

  6. Coordination Chemistry in Water of a Free and a Lipase-Embedded Cationic NCN-Pincer Platinum Center with Neutral and Ionic Triarylphosphines

    NARCIS (Netherlands)

    Wieczorek, B.; Snelders, D.J.M.; Dijkstra, H.P.; Versluis, C.; Lutz, M.; Spek, A.L.; Egmond, M.R.; Klein Gebbink, R.J.M.; van Koten, G.

    2012-01-01

    The coordination chemistry in aqueous media was studied for the platinum center of low-molecular-weight cationic NCN-pincer platinum complexes [RC6H2(CH2NMe2)2-3,5-Pt(H2O)-4]+ (R = −(CH2)3P(═O)(OEt)(OC6H4NO2-4) (1(OH2)), H (2(OH2))) as well as of the platinum center of the NCN-pincer platinum cation

  7. Coordination Chemistry in Water of a Free and a Lipase-Embedded Cationic NCN-Pincer Platinum Center with Neutral and Ionic Triarylphosphines

    NARCIS (Netherlands)

    Wieczorek, B.; Snelders, D.J.M.; Dijkstra, H.P.; Versluis, C.; Lutz, M.; Spek, A.L.; Egmond, M.R.; Klein Gebbink, R.J.M.; van Koten, G.

    2012-01-01

    The coordination chemistry in aqueous media was studied for the platinum center of low-molecular-weight cationic NCN-pincer platinum complexes [RC6H2(CH2NMe2)2-3,5-Pt(H2O)-4]+ (R = −(CH2)3P(═O)(OEt)(OC6H4NO2-4) (1(OH2)), H (2(OH2))) as well as of the platinum center of the NCN-pincer platinum cation

  8. Electronic spectra and photophysics of platinum(II) complexes with alpha-diimine ligands - Solid-state effects. I - Monomers and ligand pi dimers

    Science.gov (United States)

    Miskowski, Vincent M.; Houlding, Virginia H.

    1989-01-01

    Two types of emission behavior for Pt(II) complexes containing alpha-diimine ligands have been observed in dilute solution. If the complex also has weak field ligands such as chloride, ligand field (d-d) excited states become the lowest energy excited states. If only strong field ligands are present, a diimine 3(pi-pi/asterisk/) state becomes the lowest. In none of the cases studied did metal-to-ligand charge transfer excited state lie lowest.

  9. Crystal structures of μ-oxalato-bis[azido(histaminecopper(II] and μ-oxalato-bis[(dicyanamido(histaminecopper(II

    Directory of Open Access Journals (Sweden)

    Chen Liu

    2015-11-01

    Full Text Available The title compounds, μ-oxalato-κ4O1,O2:O1′,O2′-bis[[4-(2-aminoethyl-1H-imidazole-κ2N3,N4](azido-κN1copper(II], [Cu2(C2O4(N32(C5H9N32], (I, and μ-oxalato-κ4O1,O2:O1′,O2′-bis[[4-(2-aminoethyl-1H-imidazole-κ2N3,N4](dicyanamido-κN1copper(II], [Cu2(C2O4(C2N32(C5H9N32], (II, are two oxalate-bridged dinuclear copper complexes. Each CuII ion adopts a five-coordinate square-pyramidal coordination sphere where the basal N2O2 plane is formed by two O atoms of the oxalate ligand and two N atoms of a bidentate chelating histamine molecule. The apical coordination site in compound (I is occupied by a monodentate azide anion through one of its terminal N atoms. The apical coordination site in compound (II is occupied by a monodentate dicyanamide anion through one of its terminal N atoms. The molecules in both structures are centrosymmetric. In the crystals of compounds (I and (II, the dinuclear complexes are linked through N—H...X and C—H...X (X = N, O hydrogen bonds where the donors are provided by the histamine ligand and the acceptor atoms are provided by the azide, dicyanamide, and oxalate ligands. In compound (I, the coordinatively unsaturated copper ions interact with the histamine ligand via a C—H...Cu interaction. The coordinatively unsaturated copper ions in compound (II interact via a weak N...Cu interaction with the dicyanamide ligand of a neighboring molecule. The side chain of the histamine ligand is disordered over three sets of sites in (II.

  10. The Next Generation of Platinum Drugs: Targeted Pt(II) Agents, Nanoparticle Delivery, and Pt(IV) Prodrugs.

    Science.gov (United States)

    Johnstone, Timothy C; Suntharalingam, Kogularamanan; Lippard, Stephen J

    2016-03-09

    The platinum drugs, cisplatin, carboplatin, and oxaliplatin, prevail in the treatment of cancer, but new platinum agents have been very slow to enter the clinic. Recently, however, there has been a surge of activity, based on a great deal of mechanistic information, aimed at developing nonclassical platinum complexes that operate via mechanisms of action distinct from those of the approved drugs. The use of nanodelivery devices has also grown, and many different strategies have been explored to incorporate platinum warheads into nanomedicine constructs. In this Review, we discuss these efforts to create the next generation of platinum anticancer drugs. The introduction provides the reader with a brief overview of the use, development, and mechanism of action of the approved platinum drugs to provide the context in which more recent research has flourished. We then describe approaches that explore nonclassical platinum(II) complexes with trans geometry or with a monofunctional coordination mode, polynuclear platinum(II) compounds, platinum(IV) prodrugs, dual-threat agents, and photoactivatable platinum(IV) complexes. Nanoparticles designed to deliver platinum(IV) complexes will also be discussed, including carbon nanotubes, carbon nanoparticles, gold nanoparticles, quantum dots, upconversion nanoparticles, and polymeric micelles. Additional nanoformulations, including supramolecular self-assembled structures, proteins, peptides, metal-organic frameworks, and coordination polymers, will then be described. Finally, the significant clinical progress made by nanoparticle formulations of platinum(II) agents will be reviewed. We anticipate that such a synthesis of disparate research efforts will not only help to generate new drug development ideas and strategies, but also will reflect our optimism that the next generation of approved platinum cancer drugs is about to arrive.

  11. C-H Bond Activation of Bisimines by Palladium (Ⅱ) and Platinum (Ⅱ).Synthesis,Characterization of Bis (imino) aryl-palladium (Ⅱ) Pincer Complexes and Their Application in Carbon-Carbon Cross Coupling Reactions%C-H Bond Activation of Bisimines by Palladium (Ⅱ) and Platinum (Ⅱ).Synthesis, Characterization of Bis (imino) aryl-palladium (Ⅱ) Pincer Complexes and Their Application in Carbon-Carbon Cross Coupling Reactions

    Institute of Scientific and Technical Information of China (English)

    CHEN Rong; CHEN Ying; LIU Fang; LI Ping; HU Zhao-xia; WANG Hong-xing

    2013-01-01

    Abstract:The reactions of a variety of 4,6-dimethyl-1,3-bis (imino) benzenes 2a-g derived from 4,6-dimethylisophthalaldehyde and anilines or benzylamine with palladium (Ⅱ) acetate in anhydrous acetic acid under nitrogen were investigated.Experiment results demonstrate that cyclopalladations in such condition are applicable not only to the present system under study but also to the 5-substituted bis(imino)benzenes 6,7.The molecular structure of 3 b was further confirmed by X-Ray single-crystal diffraction.3b Crystallizes in orthorhombic,space groupP2 (1) 2 (1) 2 (1) with a =0.734 53 (8),b =1.683 8 (3),c =1.691 7(2) nm,α =β =γ =90°.Treatment of 2b with K2PtCl4 in anhydrous acetic acid affords the corresponding NCN-platinum pincer.Carbon-carbon cross coupling reactions catalyzed with 3b were investigated.These palladium complexes have been proved to be high effective catalysts for Suzuki coupling reaction.

  12. Stereospecific ligands and their complexes. Part XVII. Synthesis and characterization of ethylenediamine-N,N‧-di-S,S-2-(3-methyl)butanoic acid and its platinum(IV) complex with bromido ligands. Crystal structure of s-cis-[PtBr2(S,S-eddv)]·H2O

    Science.gov (United States)

    Stojković, Danijela Lj.; Jevtić, Verica V.; Radić, Gordana P.; Potočňák, Ivan; Trifunović, Srećko R.

    2014-05-01

    The synthesis of novel platinum(IV) complex of formula [PtBr2(S,S-eddv)]·H2O (S,S-eddv = ethylenediamine-N,N‧-di-S,S-2-(3-methyl)butanoate ion) is reported. The complex has been obtained by direct reaction of potassium-hexabromidoplatinate(IV) with neutralized ethylenediamine-N,N‧-di-S,S-2-(3-methyl)butanoic acid (H2-S,S-eddv). The ligand and complex were characterized by elemental analysis, infrared, 1H and 13C NMR spectroscopy. The spectroscopically predicted geometrical configuration of the obtained complex was confirmed by X-ray analyses of the crystal structure of the s-cis-[PtBr2(S,S-eddv)]·H2O. The asymmetric unit of the complex contains three crystallographically independent s-cis-[PtBr2(S,S-eddv)] and water molecules. The Pt(IV) atom in each complex molecule exhibits a distorted octahedral coordination geometry, built up by two cis-coordinated bromido ligands and one cis-N,N‧ and trans-O,O‧ coordinated S,S-eddv ligand (configuration index: OC-6-33). In the crystal structure, intermolecular N-H⋯O hydrogen bonds are found between the complex and water molecules.

  13. Selective formation of triplet alkyl nitrenes from photolysis of beta-azido-propiophenone and their reactivity.

    Science.gov (United States)

    Singh, Pradeep N D; Mandel, Sarah M; Sankaranarayanan, Jagadis; Muthukrishnan, Sivaramakrishnan; Chang, Mingxin; Robinson, Rachel M; Lahti, Paul M; Ault, Bruce S; Gudmundsdóttir, Anna D

    2007-12-26

    Photolysis of beta-azido propiophenone derivatives, 1, with built-in sensitizer units, leads to selective formation of triplet alkyl nitrenes 2 that were detected directly with laser flash photolysis (lambdamax = 325 nm, tau = 27 ms) and ESR spectroscopy (|D/hc| = 1.64 cm-1, |E/hc| = 0.004 cm-1). Nitrenes 2 were further characterized with argon matrix isolation, isotope labeling, and molecular modeling. The triplet alkyl nitrenes are persistent intermediates that do not abstract H-atoms from the solvent but do decay by dimerizing with another triplet nitrene to form azo products, rather than reacting with an azide precursor. The azo dimer tautomerizes and rearranges to form heterocyclic compound 3. Nitrene 2a, with an n,pi* configuration as the lowest triplet excited state of the its ketone sensitizer moiety, undergoes intramolecular 1,4-H-atom abstraction to form biradical 6, which was identified by argon matrix isolation, isotope labeling, and molecular modeling. beta-Azido-p-methoxy-propiophenone, with a pi,pi* lowest excited state of its triplet sensitizer moiety, does not undergo any secondary photoreactions but selectively yields only triplet alkyl nitrene intermediates that dimerize to form 3b.

  14. Exploring excited-state tunability in luminescent tris-cyclometalated platinum(IV) complexes: synthesis of heteroleptic derivatives and computational calculations.

    Science.gov (United States)

    Juliá, Fabio; Aullón, Gabriel; Bautista, Delia; González-Herrero, Pablo

    2014-12-22

    The synthesis, structure, electrochemistry, and photophysical properties of a series of heteroleptic tris- cyclometalated Pt(IV) complexes are reported. The complexes mer-[Pt(C^N)2 (C'^N')]OTf, with C^N=C-deprotonated 2-(2,4-difluorophenyl)pyridine (dfppy) or 2-phenylpyridine (ppy), and C'^N'=C-deprotonated 2-(2-thienyl)pyridine (thpy) or 1-phenylisoquinoline (piq), were obtained by reacting bis- cyclometalated precursors [Pt(C^N)2 Cl2] with AgOTf (2 equiv) and an excess of the N'^C'H pro-ligand. The complex mer-[Pt(dfppy)2 (ppy)]OTf was obtained analogously and photoisomerized to its fac counterpart. The new complexes display long-lived luminescence at room temperature in the blue to orange color range. The emitting states involve electronic transitions almost exclusively localized on the ligand with the lowest π-π* energy gap and have very little metal character. DFT and time-dependent DFT (TD-DFT) calculations on mer-[Pt(ppy)2 (C'^N')](+) (C'^N'=thpy, piq) and mer/fac-[Pt(ppy)3](+) support this assignment and provide a basis for the understanding of the luminescence of tris-cyclometalated Pt(IV) complexes. Excited states of LMCT character may become thermally accessible from the emitting state in the mer isomers containing dfppy or ppy as chromophoric ligands, leading to strong nonradiative deactivation. This effect does not operate in the fac isomers or the mer complexes containing thpy or piq, for which nonradiative deactivation originates mainly from vibrational coupling to the ground state. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Microwave synthesis of mono- and bis-tetrazolato complexes via 1,3-dipolar cycloaddition of organonitriles with platinum(II)-bound azides.

    Science.gov (United States)

    Mukhopadhyay, Suman; Lasri, Jamal; Charmier, M Adília Januário; da Silva, M Fátima C Guedes; Pombeiro, Armando J L

    2007-12-07

    [2 + 3] Cycloaddition reactions of the diazidoplatinum(II) complexes cis-[Pt(N3)2(PPh3)2] 1 and cis-[Pt(N3)2(2,2'-bipy)] 4 with organonitriles NCR 2 give the bis(tetrazolato) complexes trans-[Pt(N4CR)2(PPh3)2] 3 [R = Me (3a), Et (3b), Pr (3c), Ph (3d), 4-ClC6H4 (3e)] and cis-[Pt(N4CR)2(2,2'-bipy)] 5 [R = Me (5a), Et (5b), Pr (5c), Ph (5d)]. The reaction of cis-[Pt(N3)2(PPh3)2] I with propionitrile also affords, apart from 3b, the unexpected mixed cyano-tetrazolato complex trans-[Pt(CN)(5-ethyltetrazolato)(PPh3)2] 3b' which is derived from the reaction of the bis(tetrazolato) 3b with propionitrile, with concomitant formation of 5-ethyl-1H-tetrazole, via a suggested unusual oxidative addition of the nitrile to PtII. All these reactions are greatly accelerated by microwave irradiation and this method also shows a higher selectivity in the case of the reaction of propionitrile with 1, leading only to the formation of 3b. All the complexes obtained were characterized by IR, 1H, 13C and 31P[1H] (for complexes 3) NMR spectroscopies, FAB-MS and elemental analyses. Complexes 3b', 3d, 3e and 5d were also characterized by X-ray structural analyses.

  16. Comparison of Intracellular Stress Response of NCI-H526 Small Cell Lung Cancer (SCLC) Cells to Platinum(II) Cisplatin and Platinum(IV) Oxoplatin

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Gerhard [Ludwig Boltzmann Cluster of Translational Oncology, A-1090 Vienna (Austria)

    2014-07-08

    In attempts to develop an orally applicable platinum-based drug, platinum(IV) drugs which exhibit higher in vivo stability compared to the platinum(II) drug cisplatin were formulated. The first such chemotherapeutic agent, namely satraplatin, failed to receive approval. In the present work, we checked the initial cellular stress response of the chemosensitive NCI-H526 small cell lung cancer (SCLC) cells by determination of the relative phosphorylation of 46 specific phosphorylation sites of 38 selected proteins in a six hours response to cisplatin (platinum(II)) or oxoplatin (platinum(IV)), respectively. Oxoplatin is considered as prodrug of cisplatin, although several findings point to differences in intracellular effects. Cisplatin induced hyperphosphorylation of p38α MAPK and AMPKα1, whereas oxoplatin treatment resulted in increased phosphorylation of a large number of signaling proteins involved in stress response/drug resistance, including JNK, GSK-3α, AMPKα1, src kinases, STATs, CHK-2 and especially focal adhesion kinase (FAK). Cisplatin exerts markedly higher cytotoxicity upon four hours short-term exposure in comparison to oxoplatin and, correspondingly, the extended initial stress response to the platinum(IV) drug oxoplatin thus is expected to increase clinical drug resistance. Induction of a substantial stress response to any prodrug of a platinum-based compound may likewise limit the effectivity of its active metabolite(s), such contributing to the failure of selected derivatized platinum complexes.

  17. Comparison of Intracellular Stress Response of NCI-H526 Small Cell Lung Cancer (SCLC Cells to Platinum(II Cisplatin and Platinum(IV Oxoplatin

    Directory of Open Access Journals (Sweden)

    Gerhard Hamilton

    2014-07-01

    Full Text Available In attempts to develop an orally applicable platinum-based drug, platinum(IV drugs which exhibit higher in vivo stability compared to the platinum(II drug cisplatin were formulated. The first such chemotherapeutic agent, namely satraplatin, failed to receive approval. In the present work, we checked the initial cellular stress response of the chemosensitive NCI-H526 small cell lung cancer (SCLC cells by determination of the relative phosphorylation of 46 specific phosphorylation sites of 38 selected proteins in a six hours response to cisplatin (platinum(II or oxoplatin (platinum(IV, respectively. Oxoplatin is considered as prodrug of cisplatin, although several findings point to differences in intracellular effects. Cisplatin induced hyperphosphorylation of p38α MAPK and AMPKα1, whereas oxoplatin treatment resulted in increased phosphorylation of a large number of signaling proteins involved in stress response/drug resistance, including JNK, GSK-3α, AMPKα1, src kinases, STATs, CHK-2 and especially focal adhesion kinase (FAK. Cisplatin exerts markedly higher cytotoxicity upon four hours short-term exposure in comparison to oxoplatin and, correspondingly, the extended initial stress response to the platinum(IV drug oxoplatin thus is expected to increase clinical drug resistance. Induction of a substantial stress response to any prodrug of a platinum-based compound may likewise limit the effectivity of its active metabolite(s, such contributing to the failure of selected derivatized platinum complexes.

  18. In vitro antitumor activity and targeted sites of two novel platinum-based (Ⅱ) complexes on SW620 colon cancer cell line%新型铂(Ⅱ)类配合物对大肠癌SW620细胞株的体外抑癌作用及药物作用靶点研究

    Institute of Scientific and Technical Information of China (English)

    Rui Li; Baolin Liu; Hongzhuan Yin; Feng Xu; Qi Su

    2011-01-01

    Objective:The aim of our study was to evaluate the in vitro antitumor activity of two novel platinum-based (Ⅱ) complexes (2.3-pyridinedicarboxylic acid dehydrate platinum and 2.3-pyrazinedicarboxylic acid dehydrate platinum),which were concurrently provided with hydrophilic carboxyl group and lipophilic pyrazinyl or pyridyl group,on SW620 colorectal cancer cell line and the impact of the two compounds on the cell cycle and apoptosis of the cells when compared with the oxaliplatin,desiring the new ligand combined with hydrophilic and lipophilic properties would facilitate the transportation and transmembrane of the drugs,showing a better antitumor activity.Methods:After SW620 cells were treated with different doses of the three platinum-based agents for 24,48 and 72 h,the cell proliferation inhibition rate was determined using methyl thiazolyl tetrazolium (MTT) assay; the morphology of cells were evaluated under inverted microscope; the changes in cell cycle were determined using flow cytometry; the percent apoptosis was measured using Annexin V/PI double staining and the micromorphology of the cells after drug exposure was evaluated using scanning electron microscopy.Results:The evaluation on the proliferation inhibition rate revealed that the three platinum-based agents inhibited the SW620 cells in a time- and dosedependent manner and showed different strengths as pyridine > pyrazine > Oxa.Under optical microscope,the morphological changes such as cell shrinkage,round cells and dead cells were frequently observed after drug exposure.Cell cycle determination showed that all of the three agents could function to block the cells converting from phase S to phase G2M.Apoptosis evaluation revealed that the three agents promoted the apoptosis of SW620 cells in a time- and dose-dependent manner and showed different strengths as pyridine > pyrazine > Oxa.Typical early and late apoptotic morphological changes could be detected during electron microscopy.Conclusion:The two

  19. Synthesis and in vitro anticancer activity of octahedral platinum(IV) complexes with cyclohexyl-functionalized ethylenediamine-N,N'-diacetate-type ligands.

    Science.gov (United States)

    Lazić, Jelena M; Vucićević, Ljubica; Grgurić-Sipka, Sanja; Janjetović, Kristina; Kaluderović, Goran N; Misirkić, Maja; Gruden-Pavlović, Maja; Popadić, Dusan; Paschke, Reinhard; Trajković, Vladimir; Sabo, Tibor J

    2010-06-07

    The present study describes the synthesis and anticancer activity of novel octahedral Pt(IV) complexes with cyclohexyl functionalized ethylenediamine-N,N'-diacetate-type ligands. Molecular mechanics calculations and density functional theory analysis revealed that s-cis is the preferred geometry of these Pt(IV) complexes with tetradentate-coordinated (S,S)-ethylenediamine-N,N'-di-2-(3-cyclohexyl)propanoate. The viability of cancer cell lines (U251 human glioma, C6 rat glioma, L929 mouse fibrosarcoma, and B16 human melanoma) was assessed by measuring mitochondrial dehydrogenase activity and lactate dehydrogenase release. Cell-cycle distribution, oxidative stress, caspase activation, and induction of autophagy were analyzed by flow cytometry using appropriate fluorescent reporter dyes. The cytotoxic activity of novel Pt(IV) complexes against various cancer cell lines (IC(50) range: 1.9-8.7 microM) was higher than that of cisplatin (IC(50) range: 10.9-67.0 microM) and proceeded through completely different mechanisms. Cisplatin induced caspase-dependent apoptosis associated with the cytoprotective autophagic response. In contrast, the new Pt(IV) complexes caused rapid, caspase-independent, oxidative stress-mediated non-apoptotic cell death characterized by massive cytoplasmic vacuolization, cell membrane damage, and the absence of protective autophagy.

  20. Inhibition of Aβ42 peptide aggregation by a binuclear ruthenium(II)-platinum(II) complex: Potential for multi-metal organometallics as anti-amyloid agents.

    Science.gov (United States)

    Kumar, Amit; Moody, Lamaryet; Olaivar, Jason F; Lewis, Nerissa A; Khade, Rahul L; Holder, Alvin A; Zhang, Yong; Rangachari, Vijayaraghavan

    2010-08-23

    Design of inhibitors for amyloid-β (Aβ) peptide aggregation has been widely investigated over the years towards developing viable therapeutic agents for Alzheimer's disease (AD). The biggest challenge seems to be inhibiting Aβ aggregation at the early stages of aggregation possibly at the monomeric level, as oligomers are known to be neurotoxic. In this regard, exploiting the metal chelating property of Aβ to generate molecules that can overcome this impediment presents some promise. Recently, one such metal complex containing Pt(II) ([Pt(BPS)Cl(2)]) was reported to effectively inhibit Aβ42 aggregation and toxicity (1). This complex was able bind to Aβ42 at the N-terminal part of the peptide and triggered a conformational change resulting in effective inhibition. In the current report, we have generated a mixed-binuclear metal complex containing Pt(II) and Ru(II) that inhibited Aβ42 aggregation at an early stage of aggregation and seemed to have different modes of interaction than the previously reported Pt(II) complex, suggesting an important role of the second metal center. This 'proof-of-concept' compound will help in developing more effective molecules against Aβ aggregation by modifying the two metal centers as well as their ligands, which will open doors to new rationale for Aβ inhibition.

  1. Luminescent pincer platinum(II) complexes with emission quantum yields up to almost unity: photophysics, photoreductive C-C bond formation, and materials applications.

    Science.gov (United States)

    Chow, Pui-Keong; Cheng, Gang; Tong, Glenna So Ming; To, Wai-Pong; Kwong, Wai-Lun; Low, Kam-Hung; Kwok, Chi-Chung; Ma, Chensheng; Che, Chi-Ming

    2015-02-09

    Luminescent pincer-type Pt(II)  complexes supported by C-deprotonated π-extended tridentate RC^N^NR' ligands and pentafluorophenylacetylide ligands show emission quantum yields up to almost unity. Femtosecond time-resolved fluorescence measurements and time-dependent DFT calculations together reveal the dependence of excited-state structural distortions of [Pt(RC^N^NR')(CC-C6 F5 )] on the positional isomers of the tridentate ligand. Pt complexes [Pt(R-C^N^NR')(CC-Ar)] are efficient photocatalysts for visible-light-induced reductive CC bond formation. The [Pt(R-C^N^NR')(CC-C6 F5 )] complexes perform strongly as phosphorescent dopants for green- and red-emitting organic light-emitting diodes (OLEDs) with external quantum efficiency values over 22.1 %. These complexes are also applied in two-photon cellular imaging when incorporated into mesoporous silica nanoparticles (MSNs).

  2. Resonant X-ray emission spectroscopy reveals d-d ligand-field states involved in the self-assembly of a square-planar platinum complex.

    Science.gov (United States)

    Garino, Claudio; Gallo, Erik; Smolentsev, Nikolay; Glatzel, Pieter; Gobetto, Roberto; Lamberti, Carlo; Sadler, Peter J; Salassa, Luca

    2012-11-28

    Resonant X-ray Emission Spectroscopy (RXES) is used to characterize the ligand field states of the prototypic self-assembled square-planar complex, [Pt(tpy)Cl]Cl (tpy=2,2':6',2''-terpyridine), and determine the effect of weak metal-metal and π-π interactions on their energy.

  3. Comparison of platinum, palladium, and rhodium distributions in some layered intrusions with special reference to the late differentiates (upper zone) of the Bushveld complex, South Africa.

    Science.gov (United States)

    Page, N.J.; Von Gruenewaldt, G.; Haffty, J.; Aruscavage, P. J.

    1982-01-01

    The Stillwater, Fiskenaesset and Bushveld complexes have many similarities. The trends of the Pt/(Pt + Pd) and its correlation with Mg/(Mg + Fe2+) are presented. Presumably the Pt/(Pt + Pd) variations are related to changes in major mineral compositions. -K.A.R.

  4. Mixed cerium-platinum oxides: Electronic structure of [CeO]Ptn (n = 1, 2) and [CeO2]Pt complex anions and neutrals

    Science.gov (United States)

    Ray, Manisha; Kafader, Jared O.; Topolski, Josey E.; Jarrold, Caroline Chick

    2016-07-01

    The electronic structures of several small Ce-Pt oxide complexes were explored using a combination of anion photoelectron (PE) spectroscopy and density functional theory calculations. Pt and Pt2 both accept electron density from CeO diatomic molecules, in which the cerium atom is in a lower-than-bulk oxidation state (+2 versus bulk +4). Neutral [CeO]Pt and [CeO]Pt2 complexes are therefore ionic, with electronic structures described qualitatively as [CeO+2]Pt-2 and [CeO+]Pt2-, respectively. The associated anions are described qualitatively as [CeO+]Pt-2 and [CeO+]Pt2-2, respectively. In both neutrals and anions, the most stable molecular structures determined by calculations feature a distinct CeO moiety, with the positively charged Ce center pointing toward the electron rich Pt or Pt2 moiety. Spectral simulations based on calculated spectroscopic parameters are in fair agreement with the spectra, validating the computationally determined structures. In contrast, when Pt is coupled with CeO2, which has no Ce-localized electrons that can readily be donated to Pt, the anion is described as [CeO2]Pt-. The molecular structure predicted computationally suggests that it is governed by charge-dipole interactions. The neutral [CeO2]Pt complex lacks charge-dipole stabilizing interactions, and is predicted to be structurally very different from the anion, featuring a single Pt-O-Ce bridge bond. The PE spectra of several of the complexes exhibit evidence of photodissociation with Pt- daughter ion formation. The electronic structures of these complexes are related to local interactions in Pt-ceria catalyst-support systems.

  5. Blocks of Archean material in the structure of the Uralian Platinum Belt: insights from in situ U-Pb (SHRIMP-II) data on zircon from the Nizhny Tagil clinopyroxenite-dunite complex

    Science.gov (United States)

    Malitch, K. N.; Efimov, A. A.; Ronkin, Yu. L.

    2009-04-01

    The Nizhny Tagil massif forms part of the 900-km-long Uralian Platinum Belt (UPB) and represents an undisputable example of a zoned Uralian-type clinopyroxenite-dunite complex (Efimov 1998; Auge et al. 2005). The 47 km2 Nizhny Tagil massif is almond-shape, shear bounded and enclosed by Riphean and Devonian metasediments to the west and late Paleozoic to Mesozoic predominantly mafic igneous rocks to the east. It consists of a platiniferrous dunite core (Fo92-90), surrounded by a clinopyroxenite rim. Recently obtained U-Pb and Sm-Nd isotope ages defined the range for UPB complexes between 540 and 425 Ma. Geochronological data for dunite remains scarce being restricted to the Kytlym dunite block (Bea et al. 2001). To fill this gap, we present the first results of uranium-lead ages for 10 grains of zircon, which were extracted by conventional techniques from course-grained dunite sampled at Alexandrovsky Log in the central part of the Nizhny Tagil massif. Most of zircons are subeuhedral, prismatic (80-170 microns long), with an elongation between 1.3 and 1.6, and oscillatory zoning characteristic of igneous rocks. Majority of zircons yield secondary inclusions; some grains show tracers of subdivision and recrystallization, whereas several grains are characterized by curved external counters pointing to specific condition of their evolution. U-Pb analyses were performed with secondary ion mass spectrometer SHRIMP II at VSEGEI, following the procedure described by Williams (1998). Concentrations of U vary from 34 to 520 ppm, Th from 18 to 358 ppm. Three age clusters have been determined. Two subordinate groups are characterized by concordant ages of 585±29 Ma (MSWD=1.07, probability (P) =0.30) and 1608±56 Ma (MSWD=0.07, P=0.79), whereas the main data set cluster around 2781±56 Ma. We assume, therefore, that the Late Archean age testifies the timing of dunite generation in subcontinental mantle, whereas the "youngest" U-Pb age might be linked with timing of formation

  6. Dimerization of propargyl and homopropargyl 6-azido-6-deoxy-glycosides upon 1,3-dipolar cycloaddition

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Copper-catalyzed, thermal or microwave promoted 1,3-dipolar cycloaddition (Click Reaction of 2-propynyl and 3-butynyl 2,3,4-tri-O-acetyl-6-azido-6-deoxy-glycopyranosides in the D-gluco, D-galacto and D-manno series afford the corresponding dimeric cycloaddition products.

  7. NETWORK CROWN ETHER POLYMERS WITH CENTRIC FUNCTIONAL GROUPS.Ⅱ.SYNTHESIS OF NETROWK CROWN ETHER POLYMER WITH PENDANT SULFIDE SIDE CHAIN AND ITS PLATINUM COMPLEX

    Institute of Scientific and Technical Information of China (English)

    CHENYuanyin; MENGLingzhi; 等

    1995-01-01

    Network crown ether polymer with pendant sulfide side chain in the network structure units has been synthesized via ring-opening copolymerization of β-ethylthioethyl glycidyl ether and diethylene glycol bisglycidyl ether.A kind of active catalyst suitable for this reaction was suggested.The title polymer was found to be a good ligand for platinous chloride,and the platinous complex could catalyze the hydrosilylation of ole fins with triethoxysilane efficiently.

  8. Platinum(II) complexes with 5,7-disubstituted-1,2,4-triazolo [1,5-a]pyrimidines: Spectroscopical characterization and cytotoxic activity in vitro

    Science.gov (United States)

    Łakomska, Iwona; Fandzloch, Marzena; Popławska, Beata; Sitkowski, Jerzy

    2012-06-01

    Complexes of the types: cis-[PtI2(dptp)2] (1), cis-[PtI2(NH3)(dptp)] (2), trans-[PtI2(dptp)(dmso)] (3) and trans-[PtI2(dbtp)(dmso)] (4), where dptp = 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (dptp), dbtp = 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine have been synthesized and characterized by infrared and multinuclear magnetic resonance spectroscopic techniques (1H, 13C, 15N, 195Pt). In 195Pt NMR, the cis-diiodo complexes were observed between -2601 ppm and -3261 ppm, while the trans coordination compounds were found at higher field (ca. -4389 ppm). In all cases significant 15N NMR shielding (92-95 ppm) were observed for N(3) atom indicating this nitrogen atom as a coordination site. The cis complexes have been assayed for antitumor activity in vitro against two human cell lines: A549 (non-small cell lung carcinoma) and T47D (breast cancer). The results indicate a moderate antiproliferative activity of (2) against human cancer lines.

  9. Study of half-sandwich mono and dinuclear complexes of platinum group metals containing pyrazolyl pyridine analogues: Synthesis and spectral characterization

    Indian Academy of Sciences (India)

    Venkateswara Rao Anna; Kota Thirumala Prasad; Peng Wang; Kollipara Mohan Rao

    2012-05-01

    The chelating ligands 3-chloro-6-(3-pyridyl-1-pyrazolyl)pyridazine (-Cl) and 3,6-bis(3-pyridyl-1-pyrazolyl)pyridazine (bppp), were prepared by the condensation of pyridylpyrazole and 3,6-dichloropyridazine. The mononuclear complexes [(6-arene)Ru(-Cl)Cl]+ {6-arene = C6H6 (1); -iPrC6H4Me (2)}, [(5-C5Me5)M(-Cl)]+ {M = Rh (3); Ir (4)}, [(6-arene)Ru()Cl]+ {6-arene = C6H6 (5); -iPrC6H4Me (6)}, [(5-C5Me5)M(bppp)]+ {M =Rh (7); Ir (8)} as well as the binuclear complexes [{(6-arene)RuCl}2(bppp)]2+ {6 -arene =C6H6 (9); -iPrC6H4Me (10)} and [{(5-C5Me5)MCl}2(bppp)]2+ {M = Rh (11); Ir (12)} have been synthesized from 3-chloro-6-(3-pyridyl-1-pyrazolyl)pyridazine (-Cl) or 3,6-bis(3-pyridyl-1-pyrazolyl)pyridazine (bppp) and the corresponding dimers [(6-arene)Ru(-Cl)Cl]2 and [Cp∗M(-Cl)Cl]2, respectively. All complexes were isolated as their hexafluorophosphate salts and characterized by IR, NMR, mass spectrometry and UV-visible spectroscopy. The molecular structures of [2]PF6 and [7]PF6 have been established by single crystal X-ray structure analysis.

  10. Recent Approaches to Platinum(IV) Prodrugs: A Variety of Strategies for Enhanced Delivery and Efficacy.

    Science.gov (United States)

    Najjar, Anas; Rajabi, Naeema; Karaman, Rafik

    2017-01-01

    Intensive efforts have been implemented to improve the efficacy of platinum complexes especially with emerging cisplatin resistance and elevated cancer deaths. Platinum(IV) agents show better pharmacokinetics and decreased side effects compared to Platinum(II) agents. This review aims to summarize and categorize the strategies being employed to improve the efficacy of Platinum-based anticancer agents in recent years. Nanoparticles and nanoplatforms offer a vast variety of strategies in targeting specific tumor types and delivering one or two lethal drugs simultaneously. Theranostic agents are being developed to achieve enhanced imaging and provide further insight into the activity of platinum containing chemotherapy. Moreover, photoactivation of Pt(IV) prodrugs specifically at the tumor site is gaining attention due to a controlled activity. A platinum agent formulated as large multi-activity complex is the most common strategy being employed. Platinum(IV) agents offer great potential in targeting, increasing efficacy, and decreasing toxicity of Platinum-based anticancer agents. The strategies being employed are aiming to increase specificity and targeting as well as provide more potent agents. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Understanding platinum-induced ototoxicity.

    Science.gov (United States)

    Langer, Thorsten; am Zehnhoff-Dinnesen, Antoinette; Radtke, Susanne; Meitert, Johannes; Zolk, Oliver

    2013-08-01

    Childhood cancer survival rates are now nearly 80% in more developed European countries because of improved therapies and better supportive care. Platinum chemotherapy drugs, such as cisplatin and carboplatin, are the cornerstone of many effective therapeutic protocols for childhood cancer. However, the antitumor efficacy of cisplatin and carboplatin comes at the cost of ototoxicity, which affects at least 60% of pediatric patients. Although ototoxicity is not life threatening, it can have debilitating effects on patients' quality of life. Recently, many initiatives have been launched with the ultimate goal of reducing cisplatin and high-dose carboplatin ototoxicity without compromising antitumor efficacy. This review addresses the incidence of platinum ototoxicity and its clinical presentation, time course, and early diagnostic evaluation. Genetic and non-genetic risk factors for platinum-associated ototoxicity, and their predictive value, are discussed. Recent developments in the prevention of platinum ototoxicity are also summarized. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Clinical pharmacology and pharmacokinetics of cis-platinum and analogs.

    Science.gov (United States)

    Ribaud, P; Gouveia, J; Bonnay, M; Mathe, G

    1981-01-01

    cis-Platinum (DDP), the first metal coordination complex introduced into clinical trials, is remarkable for its therapeutic index. A short review of the numerator of this index, ie, the clinical activities of DDP given as a single agent or in combination therapy is presented. Toxicity of DDP, the denominator of the index, is given more attention, particularly nephrotoxicity, whose cumulative character and molecular mechanism are still in question and which can most often be prevented by following certain safety rules that are detailed in this paper. Pharmacokinetics data of free and filterable platinum are reviewed and discussed according to the different modalities of administration of DDP, and to what is known about its toxicity and its mechanism of cell kill. The rationale for using DDP in combination treatment is presented and the question of possible long-term toxicities is raised. cis-platinum analogs are sought for the purpose of enlarging the spectrum of activity, increasing selectivity and diminishing toxicity. Malonato-platinum has been shown not to be cross-resistant with DDP and to be clinically effective in adult acute leukemia. In a phase I study, malonato-platinum, which is poorly soluble, was administered in 6-24-hour infusions to 49 patients in doses ranging from 3 to 32 mg/kg. GI toxicity was universal. Hematological toxicity appeared to be mild and not clearly dose-related (the 3-32 mg/kg patients were not yet evaluable). Platinum pharmacokinetics in urine and plasma were performed using flameless absorption spectrophotometry. Preliminary results have suggested that malonato-platinum presented several pharmacokinetic features in common with DDP. Minor responses were seen in four solid tumor patients, three of whom were refractory to DDP. Other analogs soon to be introduced into clinical trials are listed.

  13. Inorganic nanocarriers for platinum drug delivery

    Directory of Open Access Journals (Sweden)

    Ping’an Ma

    2015-12-01

    Full Text Available Nowadays platinum drugs take up almost 50% of all the clinically used anticancer drugs. Besides cisplatin, novel platinum agents including sterically hindered platinum (II drugs, chemically reductive platinum (IV drugs, photosensitive platinum (IV drugs, and multinuclear platinum drugs have been developed recently, with a few entering clinic trials. Rapid development of nanobiotechnology makes targeted delivery of anticancer platinum agents to the tumor site possible, while simultaneously minimizing toxicity and maximizing the drug efficacy. Being versatile drug carriers to deliver platinum drugs, inorganic nanovehicles such as gold nanoparticles, iron oxide nanomaterials, carbon nanotubes, mesoporous nanosilica, metal-organic frameworks (MOFs, have been extensively studied over the past decades. In contrast to conventional polymeric and lipid nanoparticles, inorganic nanoparticles based drug carriers are peculiar as they have shown excellent theranostic effects, revealing themselves an indispensable part of future nanomedicine. Here, we will elaborate recent research advances on fabrication of inorganic nanoparticles for platinum drug delivery.

  14. Oxidation of 5'-dGMP, 5'-dGDP, and 5'-dGTP by a platinum(IV) complex.

    Science.gov (United States)

    Kipouros, Ioannis; Fica-Contreras, Sebastian Matias; Bowe, Gregory Joon Kee; Choi, Sunhee

    2015-12-01

    We previously reported that a Pt(IV) complex, [Pt(IV)(dach)Cl4] [trans-d,l-1,2-diaminocyclohexanetetrachloroplatinum(IV)] binds to the N7 of 5'-dGMP (deoxyguanosine-5'-monophosphate) at a relatively fast rate and oxidizes it to 8-oxo-5'-dGMP. Here, we further studied the kinetics of the oxidation of 5'-dGMP by the Pt(IV) complex. The electron transfer rate constants between 5'-dGMP and Pt(IV) in [H8-5'-dGMP-Pt(IV)] and [D8-5'-dGMP-Pt(IV)] were similar, giving a small value of the kinetic isotope effect (KIE: 1.2 ± 0.2). This small KIE indicates that the deprotonation of H8 in [H8-5'-dGMP-Pt(IV)] is not involved in the rate-determining step in the electron transfer between guanine (G) and Pt(IV). We also studied the reaction of 5'-dGDP (deoxyguanosine-5'-diphosphate) and 5'-dGTP (deoxyguanosine-5'-triphosphate) with the Pt(IV) complex. Our results showed that [Pt(IV)(dach)Cl4] oxidized 5'-dGDP and 5'-dGTP to 8-oxo-5'-dGDP and 8-oxo-5'-dGTP, respectively, by the same mechanism and kinetics as for 5'-dGMP. The Pt(IV) complex binds to N7 followed by a two-electron inner sphere electron transfer from G to Pt(IV). The reaction was catalyzed by Pt(II) and occurred faster at higher pH. The electron transfer was initiated by either an intramolecular nucleophilic attack by any of the phosphate groups or an intermolecular nucleophilic attack by free OH(-) in the solution. The rates of reactions for the three nucleotides followed the order: 5'-dGMP > 5'-dGDP > 5'-dGTP, indicating that the bulkier the phosphate groups are, the slower the reaction is, due to the larger steric hindrance and rotational barrier of the phosphate groups.

  15. Platinum availability for future automotive technologies.

    Science.gov (United States)

    Alonso, Elisa; Field, Frank R; Kirchain, Randolph E

    2012-12-04

    Platinum is an excellent catalyst, can be used at high temperatures, and is stable in many aggressive chemical environments. Consequently, platinum is used in many current industrial applications, notably automotive catalytic converters, and prospective vehicle fuel cells are expected to rely upon it. Between 2005 and 2010, the automotive industry used approximately 40% of mined platinum. Future automotive industry growth and automotive sales shifts toward new technologies could significantly alter platinum demand. The potential risks for decreased platinum availability are evaluated, using an analysis of platinum market characteristics that describes platinum's geophysical constraints, institutional efficiency, and dynamic responsiveness. Results show that platinum demand for an automotive fleet that meets 450 ppm greenhouse gas stabilization goals would require within 10% of historical growth rates of platinum supply before 2025. However, such a fleet, due largely to sales growth in fuel cell vehicles, will more strongly constrain platinum supply in the 2050 time period. While current platinum reserves are sufficient to satisfy this increased demand, decreasing platinum ore grade and continued concentration of platinum supply in a single geographic area are availability risk factors to platinum end-users.

  16. Specific labelling of the (Ca2+ + Mg2+)-ATPase of Escherichia coli with 8-azido-ATP and 4-chloro-7-nitrobenzofurazan.

    Science.gov (United States)

    Verheijen, J H; Postma, P W; van Dam, K

    1978-05-10

    1. 8-Azido-ATP is a substrate for Escherichia coli (Ca2+ + Mg2+)-ATPase (E. coli F1). 2. Illumination of E. coli F1 in the presence of 8-azido-ATP causes inhibition of ATPase activity. The presence of ATP during illumination prevents inhibition. 3. 8-Azido-ATP and 4-chloro-7-nitrobenzofurazan (NbfCl) bind predominantly to the alpha subunit of the enzyme, but also significantly to the beta subunit. 4. The alpha subunit of E. coli F1 seems to have some properties that in other F1-ATPases are associated with the beta subunit.

  17. Highly Selective Colorimetric and Luminescence Response of a Square-Planar Platinum(II) Terpyridyl Complex to Aqueous TcO4-

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Sayandev; Norton, Amie E.; Edwards, Matthew K.; Peterson, James M.; Taylor, Stephen D.; Bryan, Samuel A.; Andersen, Amity; Govind, Niranjan; Albrecht-Schmitt, Thomas E.; Connick, William; Levitskaia, Tatiana G.

    2015-10-08

    In an effort to address the need for a rapid, selective and economical detection technique for aqueous pertechnetate (TcO4-) anion based on recognition at the molecular level, simple salts of transition metal complexes that undergo a distinct spectroscopic change upon exposure to aqueous anions were explored. The Pt(II) complex [Pt(tpy)Br]SbF6 (tpy=2,2';6',2"-terpyridine) undergoes a dramatic color change and intense luminescence response upon TcO4- uptake due to concomitant enhancement of Pt•••Pt interactions. The spectroscopic response was highly selective and quantitative for aqueous TcO4- among other competing anions. Complimentary Raman spectroscopy and microscopy techniques, structural determination and theoretical methods were employed to achieve molecular-level understanding of the mechanism of the response to aqueous TcO4-.

  18. Monofunctional platinum(II) complexes with potent tumor cell growth inhibitory activity: the effect of a hydrogen-bond donor/acceptor N-heterocyclic ligand.

    Science.gov (United States)

    Margiotta, Nicola; Savino, Salvatore; Gandin, Valentina; Marzano, Christine; Natile, Giovanni

    2014-06-01

    In this paper we investigate the possibility of further increase the role of the N-donor aromatic base in antitumor Hollis-type compounds by conferring the possibility to act as a hydrogen-bond donor/acceptor. Therefore, we synthesized the Pt(II) complex cis-[PtCl(NH3 )2 (naph)]NO3 (1) containing the 1,8-naphthyridine (naph) ligand. The naphthyridine ligand is generally monodentate, and the second nitrogen atom can act as H-bond donor/acceptor depending upon its protonation state. The possibility of forming such an H-bond could be crucial in the interaction of the drug with DNA or proteins. Apart from the synthesis of the compound, in this study we evaluated its in vitro antitumor activity in a wide panel of tumor cell lines, also including cells selected for their sensitivity/resistance to oxaliplatin, which was compared with that of previously reported complex 2 ([PtI(2,9-dimethyl-1,10-phenanthroline)(1-methyl-cytosine)]I) and oxaliplatin and cisplatin as reference compounds. The cytotoxicity data were correlated with the cellular uptake and the DNA platination levels. Finally, the reactivity of 1 towards guanosine 5'-monophosphate (5'-GMP) and glutathione was investigated to provide insights into its mechanism of action.

  19. Synthesis,Antibacterial and DNA-Binding of Platinum(Ⅳ)Complexes with Compounds Containing N Group%含氮杂环铂(Ⅳ)配合物的合成、抑菌性及其与DNA作用研究

    Institute of Scientific and Technical Information of China (English)

    李清萍; 宋玉民; 马新贤; 张玉梅

    2011-01-01

    New binary complexes of potassium platinum(IV ) chloride with imidazole, 2,2'-biimidazole and phenanthroline were synthesized in ethanol aqueous solution. Their composition was characterized by elemental analysis, IR, UV-Vis and TG-DTA. The composition of complexes were confirmed to be Pt( im)2C14 · H2O( I ) , PtH2biimCl4· H2O ( II) and Pt( Phen) Cl4 · H2O ( III ) , respectively. The antibacterial activity of the complexes against B. Subtitis, E. Coli and Staphyloccocus aureus was also studied, which indicated that the complexes had certain antibacterial activity. In order to further investigate the antibacterial mechanism, the interaction between platinum (IV) complexes and ct-DNA was studied with ethidium bromide (EB) probe by electronic absorption and fluorescence spectroscopy. Stem-Volmer plots showed that the quenching of fluorescence by platinum ( IV) complexes was a combined quenching process. And the binding site number n, apparent binding constant K and the corresponding thermodynamic parameters AG, AH, AS were also obtained. AH>0, AS >0 suggested that hydrophobic force played a major role in the binding of platinum (IV) complexes to DNA. Furthermore, It was also found that ionic strength had little or no effect on the binding of platinum(IV ) complexes and DNA. The values of melting temperature ( Tm ) of DNA-EB and complex-DNA-EB were determined, respectively. The experimental results indicated that platinum (IV) complexes could bind to DNA and the major binding mode was intercalative interactions.%分别以咪唑(imidazole)、2,2'-联咪唑(2,2'-biimidazole)和邻菲咯啉(phenanthroline)为配体与氯铂酸钾作用合成了三种铂(Ⅳ)二元配合物并进行了表征,确定其化学组成分别为Pt(im)2Cl4·H2O(Ⅰ),PtH2biimCl4·H2O(Ⅱ)和PtPhenCl4·H2O(Ⅲ)(im=imidazole,H2biim=2,2'-biimidazole,Phen=phenanthroline).抑菌实验结果表明这3种配合物都具有一定的抑菌作用,并以溴化乙锭为荧光探针,研究了配合物与小

  20. Extraction of gold, palladium, and platinum from acidic media with cyclic sulfoxide derivative

    Institute of Scientific and Technical Information of China (English)

    Songping Wu; Guobang Gu

    2007-01-01

    The extraction of gold (Ⅲ), palladium (Ⅱ), and platinum (Ⅳ) from the acidic media with the cyclic sulfoxide derivative of a-dodecyl-tetrahydrothiophene 1-oxide (dtmso) was investigated. Gold (Ⅲ), palladium (Ⅱ), and platinum (Ⅳ) could be separated from the acidic media with suitable sulfoxide concentration and acidity. The extraction reaction of gold (Ⅲ), palladium (Ⅱ) or platinum (Ⅳ) is exothermic when dtmso is used as an extracting reagent. The coordination number was studied by the slope method. The results indicate that, in high acidity, the dtmso coordination number for extracting gold (Ⅲ) or palladium (Ⅱ) is 3, and that for platinum (Ⅳ) is 2. UV and FT-IR spectra were used to analyze the structure of the complex. Gold (Ⅲ) is coordinated with the oxygen atom in S=O group in dtmso, and palladium (Ⅱ) or platinum (Ⅳ) is coordinated with the sulfur atom in S=O group in dtmso.

  1. Polymorph control of luminescence properties in molecular crystals of a platinum and organoarsenic complex and formation of stable one-dimensional nanochannel.

    Science.gov (United States)

    Unesaki, Hikaru; Kato, Takuji; Watase, Seiji; Matsukawa, Kimihiro; Naka, Kensuke

    2014-08-18

    The mononuclear diiodoplatinum(II) complex (trans-PtI2(cis-DHDAMe)2), where cis-DHDAMe = cis-1,4-dihydro-1,4-dimethyl-2,3,5,6-tetrakis(methoxycarbonyl)-1,4-diarsinine, forms three different crystalline polymorphs that can be either concomitantly or separately obtained on varying the recrystallization conditions. Cubic red crystals (α-phase) and red-orange needles (β-phase) exhibit solid-state red emissions at room temperature. Cubic red crystals of the γ-phase show no solid-state emission at room temperature. All crystalline structures were confirmed by X-ray crystallography. Room-temperature strongly luminescent crystals (α-phase) (λem = 657 nm, Φ = 0.52) have a triclinic P1 (No. 2) structure and no voids in the crystal structure. Red-orange needle-shaped crystals of the β-phase exhibit moderate red luminescence (λem = 695 nm, Φ = 0.09) at room temperature and have a trigonal, R3 (No. 148), structure. In the needlelike crystals of the β-phase, stable hexagonal arrays of nanoporous channels, 5.0 Å in diameter, are formed. Room-temperature nonluminescent crystals (γ-phase) have an orthorhombic, Pbca (No. 61), structure with a void volume that is 4.9% of the total crystal volume. After heating the α-phase crystals at 150 °C for 2 min, a powder XRD pattern different from the original crystal is obtained, and its solid-state emission at room temperature decreased. After heating the β-phase crystals at 150 °C for 2 min, the emission wavelength and the quantum yield of the solid-state emission at room temperature and the powder XRD pattern are the same as those of the α-phase after heating at 150 °C. A crystal-to-crystal transition triggered by the thermal stimulus produces a different stable polymorph of the mononuclear diiodoplatinum(II) complex. The one-dimensional nanoporous crystals encapsulated iodine without distorting the crystal packing.

  2. In vivo toxicity of 3 prime -azido-3 prime -deoxythymidine (AZT) on CBA/Ca mice

    Energy Technology Data Exchange (ETDEWEB)

    Cronkite, E.P.; Bullis, J. (Brookhaven National Laboratory, Upton, NY (USA))

    1990-09-01

    CBA/Ca male mice were given 3'-azido-3'-deoxythymidine (AZT) in drinking water (1 mg/ml) for up to 7 weeks. Water consumption and body weight decreased significantly. Neutropenia and lymphopenia were observed during and after exposure. Significant macrocytic anemia developed and disappeared as a function of red cell life span after stopping AZT intake. A microthrombocytosis was seen. Bone marrow cellularity and spleen colony-forming unit (CFU-s) content fell, but recovered completely and quickly after terminating AZT intake. Hemopoietic stem cell function measured by 2 different methods of rescuing fatally irradiated mice was normal 4 weeks after AZT exposure, suggesting that AZT treatment does not induce a long-lasting effect in genetic control of mitotic potential of stem cells. This is in marked contrast to exposure of CBA/Ca mice to benzene and ionizing radiation.

  3. Synthesis and structural study of platinum group metal complexes containing pyrimidine bridged pyrazolyl-pyridine ligand and 5 and 6 - cyclic hydrocarbons

    Indian Academy of Sciences (India)

    Thirumala Prasad Kota; Mohan Rao Kollipara

    2014-07-01

    The mononuclear compounds [(6-arene)Ru(bppm)Cl]PF6{bppm = 4,6-bis3-(2-pyridyl)-1Hpyrazol-1-yl}pyrimidine; arene = C6H6, [1]; -$^i$PrC6H4Me, [2]; C6Me6, [3]}, [CpRu(bppm)(PPh3)]PF6{Cp = 5-C5H5, [4]; 5-C5Me5, [5]; 5-C9H7, [6]} and [Cp∗M(bppm)Cl]PF6 {M = Rh [7]; Ir [8]} have been synthesized from the reaction of 4,6-bis{3-(2-pyridyl)-1H-pyrazol-1-yl}pyrimidine (bppm) and the corresponding precursor metal complexes [(6-arene)Ru(-Cl)Cl]2, [CpRu(PPh3)2Cl] and [Cp∗M(-Cl)Cl]2, respectively, in the presence of NH4PF6. They were characterized by the following techniques viz. IR, NMR, mass spectrometry and UV-visible spectroscopy. The molecular structures of [2] and [7] have been established by single crystal X-ray structure analyses.

  4. Specific photoaffinity labeling of two plasma membrane polypeptides with an azido auxin

    Science.gov (United States)

    Hicks, G. R.; Rayle, D. L.; Jones, A. M.; Lomax, T. L.

    1989-01-01

    Plasma membrane vesicles were isolated from zucchini (Cucurbita pepo) hypocotyl tissue by aqueous phase partitioning and assessed for homogeneity by the use of membrane-specific enzyme assays. The highly pure (ca. 95%) plasma membrane vesicles maintained a pH differential across the membrane and accumulated a tritiated azido analogue of 3-indoleacetic acid (IAA), 5-azido-[7-3H]IAA ([3H]N3IAA), in a manner similar to the accumulation of [3H]IAA. The association of the [3H]N3IAA with membrane vesicles was saturable and subject to competition by IAA and auxin analogues. Auxin-binding proteins were photoaffinity labeled by addition of [3H]N3IAA to plasma membrane vesicles prior to exposure to UV light (15 sec; 300 nm) and detected by subsequent NaDodSO4/PAGE and fluorography. When the reaction temperature was lowered to -196 degrees C, high-specific-activity labeling of a 40-kDa and a 42-kDa polypeptide was observed. Triton X-100 (0.1%) increased the specific activity of labeling and reduced the background, which suggests that the labeled polypeptides are intrinsic membrane proteins. The labeled polypeptides are of low abundance, as expected for auxin receptors. Further, the addition of IAA and auxin analogues to the photoaffinity reaction mixture resulted in reduced labeling that was qualitatively similar to their effects on the accumulation of radiolabeled IAA in membrane vesicles. Collectively, these results suggest that the radiolabeled polypeptides are auxin receptors. The covalent nature of the label should facilitate purification and further characterization of the receptors.

  5. A Cytostatic Ruthenium(II)-Platinum(II) Bis(terpyridyl) Anticancer Complex That Blocks Entry into S Phase by Up-regulating p27(KIP1).

    Science.gov (United States)

    Ramu, Vadde; Gill, Martin R; Jarman, Paul J; Turton, David; Thomas, Jim A; Das, Amitava; Smythe, Carl

    2015-06-15

    Cytostatic agents that interfere with specific cellular components to prevent cancer cell growth offer an attractive alternative, or complement, to traditional cytotoxic chemotherapy. Here, we describe the synthesis and characterization of a new binuclear Ru(II) -Pt(II) complex [Ru(tpy)(tpypma)Pt(Cl)(DMSO)](3+) (tpy=2,2':6',2''-terpyridine and tpypma=4-([2,2':6',2''-terpyridine]-4'-yl)-N-(pyridin-2-ylmethyl)aniline), VR54, which employs the extended terpyridine tpypma ligand to link the two metal centres. In cell-free conditions, VR54 binds DNA by non-intercalative reversible mechanisms (Kb =1.3×10(5)  M(-1) ) and does not irreversibly bind guanosine. Cellular studies reveal that VR54 suppresses proliferation of A2780 ovarian cancer cells with no cross-resistance in the A2780CIS cisplatin-resistant cell line. Through the preparation of mononuclear Ru(II) and Pt(II) structural derivatives it was determined that both metal centres are required for this anti-proliferative activity. In stark contrast to cisplatin, VR54 neither activates the DNA-damage response network nor induces significant levels of cell death. Instead, VR54 is cytostatic and inhibits cell proliferation by up-regulating the cyclin-dependent kinase inhibitor p27(KIP1) and inhibiting retinoblastoma protein phosphorylation, which blocks entry into S phase and results in G1 cell cycle arrest. Thus, VR54 inhibits cancer cell growth by a gain of function at the G1 restriction point. This is the first metal-coordination compound to demonstrate such activity.

  6. Harnessing chemoselective imine ligation for tethering bioactive molecules to platinum(IV) prodrugs.

    Science.gov (United States)

    Wong, Daniel Yuan Qiang; Lau, Jia Yi; Ang, Wee Han

    2012-05-28

    Platinum(II) anticancer drugs are among the most effective and often used chemotherapeutic drugs. In recent years, there has been increasing interest in exploiting inert platinum(IV) scaffolds as a prodrug strategy to mitigate the limitations of platinum(II) anticancer complexes. In this prodrug strategy, the axial ligands are released concomitantly upon intracellular reduction to the active platinum(II) congener, offering the possibility of conjugating bioactive co-drugs which may synergistically enhance cytotoxicity on cancer cells. Existing techniques of tethering bioactive molecules to the axial positions of platinum(IV) prodrugs suffer from limited scope, poor yields and low reliability. This report explores the applications of current chemoselective ligation chemistries to platinum(IV) anticancer complexes with the aim of addressing the aforementioned limitations. Here, we describe the synthesis of a platinum(IV) complex bearing an aromatic aldehyde functionality and explored the scope of imine ligation with various hydrazide and aminooxy functionalized substrates. As a proof of concept, we tethered a six sequence long peptide mimetic (AMVSEF) of the anti-inflammatory protein, ANXA1.

  7. Cross-reactivity of Halogenated Platinum Salts

    Science.gov (United States)

    Halogenated platinum (Pt) salts are well-known respiratory sensitizers associated with the development of asthma. People may be exposed to a variety of platinum compounds in different contexts (e.g. occupationally, automobile exhaust). Published reports suggest that sensitizati...

  8. Synthesis of ferrocene-labeled steroids via copper-catalyzed azide-alkyne cycloaddition. Reactivity difference between 2β-, 6β- and 16β-azido-androstanes.

    Science.gov (United States)

    Fehér, Klaudia; Balogh, János; Csók, Zsolt; Kégl, Tamás; Kollár, László; Skoda-Földes, Rita

    2012-06-01

    Copper-catalyzed cycloaddition of steroidal azides and ferrocenyl-alkynes were found to be an efficient methodology for the synthesis of ferrocene-labeled steroids. At the same time, a great difference between the reactivity of 2β- or 16β-azido-androstanes and a sterically hindered 6β-azido steroid toward both ferrocenyl-alkynes and simple alkynes, such as phenylacetylene, 1-octyne, propargyl acetate and methyl propiolate, was observed.

  9. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

  10. Meeting report on 8th International Symposium on Platinum and Other Metal Coordination Compounds in Cancer Chemotherapy.

    Science.gov (United States)

    Kelland, L R

    1999-10-01

    The platinum-based drugs, cisplatin and carboplatin, represent major agents in the chemotherapeutic treatment of a variety of types of cancer. Novel, "third-generation" agents aimed at broadening the clinical activity of this class of drug are currently undergoing clinical evaluation. These include oxaliplatin, ZD0473 and BBR3464. Clinical trials and preclinical studies are also being conducted with liposomal (SPI-077 and L-NDDP) and polymeric platinum complexes (linked to HPMA or albumin). Combination studies of cisplatin/carboplatin with other anticancer drugs such as gemcitabine and UCN-01 (7-hydroxystaurosporine) and agents designed to reduce platinum drug toxicities (e.g., BNP-7787, DIMESNA) are ongoing. Preclinically, there is interest in trans platinum complexes, terpyridine platinum(II) complexes and other metal-containing agents (ruthenium and gold).

  11. Synthesis and Opto-electronic Properties of a Red-Emitting Heteroleptic Platinum Complex Using Pyrazol-based Diketone Derivative as Ancillary Ligand%Synthesis and Opto-electronic Properties of a Red-Emitting Heteroleptic Platinum Complex Using Pyrazol-based Diketone Derivative as Ancillary Ligand

    Institute of Scientific and Technical Information of China (English)

    邓继勇; 王亚飞; 李小双; 倪美君; 刘明; 刘煜; 雷钢铁; 朱美香; 朱卫国

    2011-01-01

    A red-emitting heteroleptic cyclometalated platinum(II) complex containing an ancillary ligand of pyra- zol-based diketone derivative was synthesized. Its optophysical and electroluminescent properties were studied. Compared to the reported (piq)Pt(acac) complex, this platinum(II) complex exhibited a blue-shifted UV absorption band at 300--450 nm, a low LUMO energy level and improved electroluminescent property. Using this platinum(II) complex as a single doping emitter and a blend of ploy(9,9-dioctylfluorene) and 2-tert-butylphenyl-5-phenyl- 1,3,4-oxadiazole as a host matrix, the fabricated polymer light-emitting devices displayed saturated red emission with a peak at 648 um and a shoulder at 601 nm. Furthermore, the emission quenching of the platinum(II) complex was significantly suppressed in these devices at high current density due to an introduction of the non-planar pyra- zol group into the ancillary ligand.

  12. Coating Carbon Fibers With Platinum

    Science.gov (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  13. Decomposition of the Precursor [Pt(NH3)4](OH)2, Genesis and Structure of the Metal-Support Interface of Alumina Supported Platinum Particles: A Structural Study Using TPR, MS and XAFS Spectroscopy.

    NARCIS (Netherlands)

    Koningsberger, D.C.; Muñoz-Paez, A.

    1995-01-01

    During the preparation of alumina supported platinum catalysts, the precursor [Pt(NH3)4](OH)2 decomposes to a neutral Pt(NH3)zO species during the drying process at 120 'C. Treatment in flowing hydrogen at 180 'C leads to partial reduction of the platinum ammine complex and formation of platinum met

  14. Platinum Group Metals New Material

    Institute of Scientific and Technical Information of China (English)

    XIE Ming; ZHANG Jiankang; WANG Saibei; HU Jieqiong; LIU Manmen; CHEN Yongtai; ZHANG Jiming; YANG Youcai; YANG Yunfeng; ZHANG Guoquan

    2012-01-01

    Platinum group metals (PGM) include six elements,namely Pt,Pd,Rh,Ir,Os and Ru.PGM and their alloys are the important fundamental materials for modern industry and national defense construction,they have special physical and chemical properties,widely used in metallurgy,chemical,electric,electronic,information,energy,environmental protection,aviation,aerospace,navigation and other high technology industry.Platinum group metals and their alloys,which have good plasticity and processability,can be processed to electrical contact materials,resistance materials,solder,electronic paste,temperature-measurement materials,elastic materials,magnetic materials and high temperature structural materials.

  15. Studies on the inhibition of sphingosine-1-phosphate lyase by stabilized reaction intermediates and stereodefined azido phosphates.

    Science.gov (United States)

    Sanllehí, Pol; Abad, José-Luís; Bujons, Jordi; Casas, Josefina; Delgado, Antonio

    2016-11-10

    Two kinds of inhibitors of the PLP-dependent enzyme sphingosine-1-phosphate lyase have been designed and tested on the bacterial (StS1PL) and the human (hS1PL) enzymes. Amino phosphates 1, 12, and 32, mimicking the intermediate aldimines of the catalytic process, were weak inhibitors on both enzyme sources. On the other hand, a series of stereodefined azido phosphates, resulting from the replacement of the amino group of the natural substrates with an azido group, afforded competitive inhibitors in the low micromolar range on both enzyme sources. This similar behavior represents an experimental evidence of the reported structural similarities for both enzymes at their active site level. Interestingly, the anti-isomers of the non-natural enantiomeric series where the most potent inhibitors on hS1PL.

  16. Studies on yeast nucleoside triphosphate-nucleoside diphosphate transphosphorylase (nucleoside diphosphokinase). IV. Steady-state kinetic properties with thymidine nucleotides (including 3'-azido-3'-deoxythymidine analogues).

    Science.gov (United States)

    Kuby, S A; Fleming, G; Alber, T; Richardson, D; Takenaka, H; Hamada, M

    1991-01-01

    A study of the steady-state kinetics of the crystalline brewer's yeast (Saccharomyces carlsbergensis) nucleoside diphosphokinase, with the magnesium complexes of the adenine and thymidine nucleotides as reactants, has led to a postulated kinetic mechanism which proceeds through a substituted enzyme. This agrees with the earlier conclusions of Garces and Cleland [Biochemistry 1969; 8:633-640] who characterized a reaction between the magnesium complexes of the adenine and uridine nucleotides. An advantage of using thymidine nucleotides as reactants is that they permit accurate, rapid and continuous assays of the enzymatic activity in coupled-enzymatic tests. Through measurements of the initial velocities and product inhibition studies, the Michaelis constants, maximum velocities, and inhibition constants could be evaluated for the individual substrates. Competitive substrate inhibition was encountered at relatively high substrate concentrations, which also permitted an evaluation of their ability to act as 'dead-end' inhibitors. The Michaelis constants for the 3'-azido-3'-deoxythymidine (AzT) analogues were also evaluated and, although these values were only somewhat higher than those of their natural substrates, the Km's for the adenine nucleotides as paired substrates were lower and the Vmax's were drastically reduced. The pharmacological implications of these observations are touched upon and extrapolated to the cases where therapeutic doses of AzT may be employed.

  17. Synthesis and Crystal Structure of catena-Poly[[[2,4-dibromo-6-[(3-dimethylaminopropylimino)-methyl]phenolato]copper(Ⅱ)]-μ-azido

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A novel end-to-end azido-bridged polynuclear Schiff-base copper(H) complex,[Cu(C12H15Br2N2O)(N3)]n, was prepared and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction.The crystal belongs to the orthorhombic system, space group Pbcn with a = 24.588(5), b = 10.377(2), c = 13.022(3)(A),V= 3322.6(12)(A)3, Z = 8, Dc = 1.874 g/cm3, Mr= 468.65, λ(MoKα) = 0.71073 (A),μ= 6.130 mm-1, F(000) = 1832, R = 0.0637 and wR = 0.1176.The Cu atom in the complex is five-coordinated in a square pyramidal geometry by three donoratoms of the Schiff-base ligand, and two N atoms from two bridging azide ligands.The [2,4-dibromo-6-[(3-dimethylaminopropylimino)methyl]phenolato]copper(Ⅱ) units are linked by the bridging azide ligands, giving zigzag polymeric chains with backbones of the [-Cu-N-N-N-Cu]n type running along the b axis.

  18. Sensitive Photoacoustic IR Spectroscopy for the Characterization of Amino/Azido Mixed-Linker Metal-Organic Frameworks.

    Science.gov (United States)

    Canivet, Jerome; Lysenko, Vladimir; Lehtinen, Jaakko; Legrand, Alexandre; Wisser, Florian M; Quadrelli, Elsje Alessandra; Farrusseng, David

    2017-08-23

    Photoacoustic Fourier-transform infrared spectroscopy makes it possible to determine the organic composition of mixed-linker metal-organic frameworks. The sound produced upon IR irradiation enables the discrimination of azido and amino linkers in three different MOF platforms with a sensitivity that is two orders of magnitude higher than that achieved using classic IR analysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Quarternization of 3-azido-1-propyne oligomers obtained by copper(I-catalyzed azide–alkyne cycloaddition polymerization

    Directory of Open Access Journals (Sweden)

    Shun Nakano

    2015-06-01

    Full Text Available 3-Azido-1-propyne oligomer (oligoAP samples, prepared by copper(I-catalyzed azide–alkyne cycloaddition (CuAAC polymerization, were quarternized quantitatively with methyl iodide in sulfolane at 60 °C to obtain soluble oligomers. The conformation of the quarternized oligoAP in dilute DMSO-d6 solution was examined by pulse-field-gradient spin-echo NMR based on the touched bead model.

  20. Reactivity of monofunctional cis-platinum adducts as a function of DNA sequence.

    OpenAIRE

    Malinge, J M; Leng, M

    1988-01-01

    The purpose of this work was to study the chemical reactivity of monofunctional cis-platinum-nucleic acid adducts as a function of nucleic acid sequence. The first part of the paper deals with the formation of these adducts. It is shown that the ternary nucleic acid-cis-platinum-ethidium bromide complexes in which ethidium bromide and nucleotide residues are cross-linked by cis-platinum, are relatively unstable at 37 degrees C. In the presence of acridine, ethidium bromide (but not cis-platin...