Sample records for platinum ii porphyrin

  1. [Formylation of porphyrin platinum complexes]. (United States)

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


    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.

  2. 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


    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.

  3. Platinum(II)-porphyrin as a sensitizer for visible-light driven water oxidation in neutral phosphate buffer

    NARCIS (Netherlands)

    Chen, H.C.; Hetterscheid, D.G.H.; Williams, R.M.; van der Vlugt, J.I.; Reek, J.N.H.; Brouwer, A.M.


    A water-soluble Pt(II)-porphyrin with a high potential for one-electron oxidation (similar to 1.42 V vs. NHE) proves very suitable for visible-light driven water oxidation in neutral phosphate buffer solution in combination with a variety of water oxidation catalysts (WOCs) . Two homogeneous WOCs (i

  4. A Tin(IV) Porphyrin with Two Axial Organometallic NCN-Pincer Platinum Units

    NARCIS (Netherlands)

    Suijkerbuijk, B.M.J.M.; Tooke, D.M.; Spek, A.L.; van Koten, G.; Klein Gebbink, R.J.M.


    A tin(IV) porphyrin was combined with two axial NCN-pincer platinum(II) fragments by utilizing the oxophilicity of the apical positions on the tin atom and the acidic nature of the NCN-pincer platinum derived benzoic acid. The solid-state structure determined by X-ray crystallography revealed some

  5. Platinum porphyrins as ionophores in polymeric membrane electrodes

    DEFF Research Database (Denmark)

    Lvova, Larisa; Verrelli, Giorgio; Nardis, Sara


    porphyrin dimers occurs in the membrane plasticized both with high or low dielectric constant plasticizer, due to a low oxophilicity of central Pt. The computational study of various anion–Pt(IV)TPPCl2 complex formation by means of semi-empirical and density functional theory (DFT) methods revealed a good......A comparative study of Pt(II)- and Pt(IV)-porphyrins as novel ionophores for anion-selective polymeric membrane electrodes is performed. Polymeric membranes of different compositions, prepared by varying plasticizers, cationic and anionic additives and Pt porphyrins, have been examined...... within the electrode membranes, while those based on Pt(IV)TPPCl2 operate via a mixed mode carrier mechanism, evidencing also a partial reduction of the starting ionophore to Pt(II)TPP. Spectrophotometric measurements of thin polymeric films indicate that no spontaneous formation of hydroxide ion bridged...

  6. Nanostructured oxygen sensor--using micelles to incorporate a hydrophobic platinum porphyrin.

    Directory of Open Access Journals (Sweden)

    Fengyu Su

    Full Text Available Hydrophobic platinum(II-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl-porphyrin (PtTFPP was physically incorporated into micelles formed from poly(ε-caprolactone-block-poly(ethylene glycol to enable the application of PtTFPP in aqueous solution. Micelles were characterized using dynamic light scattering (DLS and atomic force microscopy (AFM to show an average diameter of about 140 nm. PtTFPP showed higher quantum efficiency in micellar solution than in tetrahydrofuran (THF and dichloromethane (CH₂Cl₂. PtTFPP in micelles also exhibited higher photostability than that of PtTFPP suspended in water. PtTFPP in micelles exhibited good oxygen sensitivity and response time. This study provided an efficient approach to enable the application of hydrophobic oxygen sensors in a biological environment.

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


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


    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.

  8. Robust optical oxygen sensors based on polymer-bound NIR-emitting platinum(II)-benzoporphyrins

    DEFF Research Database (Denmark)

    Hutter, L.H.; Müller, B.J.; Koren, Klaus


    Several advanced optical oxygen sensor materials are presented. They are based on bright NIR-emitting platinum(II)-benzoporphyrins covalently incorporated into a variety of polymeric matrices. The dye-polymer conjugates are prepared either via Suzuki coupling of the brominated porphyrins to the s......Several advanced optical oxygen sensor materials are presented. They are based on bright NIR-emitting platinum(II)-benzoporphyrins covalently incorporated into a variety of polymeric matrices. The dye-polymer conjugates are prepared either via Suzuki coupling of the brominated porphyrins...... dyes showed significant drift of their calibration. Additionally, we present a new synthetic method for preparation of analytically pure benzoporphyrins via simple 1-step template condensation which a promising alternative to the commonly used Lindsey method. © the Partner Organisations 2014....

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


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


    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 ...

  10. Synthesis and characterization of new platinum(II) and platinum(IV) triphyrin complexes. (United States)

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


    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.

  11. Highly red-shifted NIR emission from a novel anthracene conjugated polymer backbone containing Pt( ii ) porphyrins

    KAUST Repository

    Freeman, D. M. E.


    © The Royal Society of Chemistry 2016. We present the synthesis of a novel diphenylanthracene (DPA) based semiconducting polymer. The polymer is solubilised by alkoxy groups attached directly to a DPA monomer, meaning the choice of co-monomer is not limited to exclusively highly solubilising moieties. Interestingly, the polymer shows a red-shifted elecroluminescence maximum (510 nm) when compared to its photoluminescence maximum (450 nm) which we attribute to excimer formation. The novel polymer was utilised as a host for a covalently-linked platinum(ii) complexed porphyrin dopant. Emission from these polymers was observed in the NIR and again showed almost a 100 nm red shift from photoluminescence to electroluminescence. This work demonstrates that utilising highly aggregating host materials is an effective tool for inducing red-shifted emission in OLEDs.

  12. 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.


    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.

  13. [Synthesis and luminescent spectral characteristics of porphyrin complexes with platinum group metals]. (United States)

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


    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

  14. Cu(II) porphyrins modified TiO{sub 2} photocatalysts: Accumulated patterns of Cu(II) porphyrin molecules on the surface of TiO{sub 2} and influence on photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Su, Xiao-qin [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an, Shaanxi 710069 (China); Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an, Shaanxi 710021 (China); Li, Jun, E-mail: [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an, Shaanxi 710069 (China); Zhang, Zeng-qi; Yu, Mi-mi; Yuan, Lin [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an, Shaanxi 710069 (China)


    Highlights: • Two new crystal structures of copper porphyrins containing meso-tetra(ester and carboxyl) were obtained. • The two copper porphyrins were used to modify TiO{sub 2} for the first time. • The accumulated patterns of copper porphyrin molecules on the TiO{sub 2} surface is an important factor for the photocatalytic activity. • The peripheral groups of copper porphyrins influence their stacking patterns in solid state. - Abstract: The accumulated patterns of porphyrin molecules on the surface of TiO{sub 2} have an important effect on the photoactivity of porphyrin/TiO{sub 2} photocatalysts. Herein, two copper porphyrins containing flexible peripheral functional groups (meso-tetra(ester, carboxy)), Cu(II)5,10,15,20-tetrakis[4-(carboethoxymethyleneoxy)phenyl]porphyrin (CuPp(2a)) and Cu(II)5,10,15,20-tetrakis[4-(carboxymethyleneoxy)phenyl]porphyrin (CuPp(2b)), were synthesized and characterized spectroscopically. Their crystal structures were also determined by single crystal X-ray diffraction. The Cu(II) porphyrin-TiO{sub 2} composites were also prepared and characterized. The accumulated patterns of synthesized copper porphyrins on the surface of TiO{sub 2} were proposed for the first time. The photoactivity of the composites was investigated by carrying out the degradation of 4-nitrophenol (4-NP) in aqueous solution under UV–visible light. The results indicated that the CuPp(2b)-TiO{sub 2} showed the higher photocatalytic activity than that of CuPp(2a)-TiO{sub 2}. Above all, it can be concluded that the accumulated patterns of porphyrins on the surface of TiO{sub 2} is an important factor for the photocatalytic efficiency of porphyrin/TiO{sub 2}.

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


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


    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.

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

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


    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.

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

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


    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.

  18. Photoinduced triplet-state electron transfer of platinum porphyrin: a one-step direct method for sensing iodide with an unprecedented detection limit

    KAUST Repository

    Masih, Dilshad


    Here, we report for the first time a one-step direct method for sensing halides in aqueous solution using phosphorescence quenching of platinum-cationic porphyrin. This method offers an easy, rapid, environmentally friendly, ultra-sensitive (with a previously unattained detection limit of 1 × 10−12 M) and economical method for the determination of iodide. To fully understand the reaction mechanism responsible for the phosphorescence quenching process, we have employed cutting-edge time-resolved laser spectroscopy with broadband capabilities.

  19. Photoinduced triplet-state electron transfer of platinum porphyrin: A one-step direct method for sensing iodide with an unprecedented detection limit

    KAUST Repository

    Masih, Dilshad


    Here, we report for the first time a one-step direct method for sensing halides in aqueous solution using phosphorescence quenching of platinum-cationic porphyrin. This method offers an easy, rapid, environmentally friendly, ultra-sensitive (with a previously unattained detection limit of 1 × 10-12 M) and economical method for the determination of iodide. To fully understand the reaction mechanism responsible for the phosphorescence quenching process, we have employed cutting-edge time-resolved laser spectroscopy with broadband capabilities. This journal is © The Royal Society of Chemistry 2015.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ratilla, E.


    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.

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

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


    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.

  2. Fluorinated Dodecaphenylporphyrins: Synthetic and Electrochemical Studies Including the First Evidence of Intramolecular Electron Transfer Between an Fe(II) Porphyrin -Anion Radical and an Fe(I) Porphyrin

    Energy Technology Data Exchange (ETDEWEB)

    D' Souza, F.; Forsyth, T.P.; Fukuzumi, S.; Kadish, K.M.; Krattinger, B.; Lin, M.; Medforth, C.J.; Nakanishi, I.; Nurco, D.J.; Shelnutt, J.A.; Smith, K.M.; Van Caemelbecke, E.


    Dodecaphenylporphyrins with varying degrees of fluorination of the peripheral phenyl rings (FXDPPS) were synthesized as model compounds for studying electronic effects in nonplan~ porphyrins, and detailed electrochemical studies of the chloroiron(HI) complexes of these compounds were undertaken. The series of porphyrins, represented as FeDPPCl and as FeFXDPPCl where x = 4, 8 (two isomers), 12, 20,28 or 36, could be reversibly oxidized by two electrons in dichloromethane to give n-cation radicals and n-dications. All of the compounds investigated could also be reduced by three electrons in benzonitrile or pyridine. In benzonitrile, three reversible reductions were observed for the unfluorinated compound FeDPPC1, whereas the FeFXDPPCl complexes generally exhibited irreversible first and second reductions which were coupled to chemical reactions. The chemical reaction associated with the first reduction involved a loss of the chloride ion after generation of Fe FXDPPC1. The second chemical reaction involved a novel intramolecular electron transfer between the initially generated Fe(H) porphyrin n-anion radical and the final Fe(I) porphyrin reduction product. In pyridine, three reversible one electron reductions were observed with the second reduction affording stable Fe(II) porphyrin o - anion radicals for ail of the complexes investigated.

  3. New platinum(II complexes with benzothiazole ligands

    Directory of Open Access Journals (Sweden)

    José A. Carmona-Negrón


    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.

  4. 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.


    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).

  5. Multiporphyrin coordination arrays based on complexation of magnesium(II) porphyrins with porphyrinylphosphine oxides. (United States)

    Atefi, Farzad; McMurtrie, John C; Arnold, Dennis P


    Di- and triporphyrin arrays consisting of 5,15-diphenylporphyrinatomagnesium(II) (MgDPP) coordinated to free-base and Ni(II) porphyrinyl mono- and bis-phosphine oxides, as well as the self-coordinating diphenyl[10,20-diphenylporphyrinatomagnesium(II)-5-yl]phosphine oxide [MgDPP(Ph(2)PO)], were synthesised in excellent yields and characterised by various spectroscopic techniques. Phosphine oxides stabilise Mg(II) coordination to porphyrins and the resulting complexes have convenient solubilities, while the Ni(II) complexes exhibit interesting intramolecular fluorescence quenching behaviour. The binding constant of MgDPP to triphenylphosphine oxide (5.3 +/- 0.1 x 10(5) M(-1)) and the very high self-association constant of [MgDPP(Ph(2)PO)] (5.5 +/- 0.5 x 10(8) M(-1)) demonstrate the strong affinity of phosphine oxides towards Mg(II) porphyrins. These complexes are the first strongly bound synthetic Mg(II) multiporphyrin complexes and could potentially mimic the "special pair" in the photosynthetic reaction centre.

  6. Sorption recovery of platinum (II, IV in presence of copper (II and zinc (II from chloride solutions

    Directory of Open Access Journals (Sweden)

    Kononova Olga N.


    Full Text Available The sorption preconcentration of platinum (II, IV ions was investigated in presence of accompanying copper (II and zinc (II ions from chloride solutions on the new ion exchangers CYBBER (Russia, previously unexplored. The initial concentrations of platinum and accompanying ions were 0.25 mmol L-1 and 2.0 mmol L-1, respectively, and the acidity of medium was 0.001 - 4.0 mol L-1. It was shown that the resins investigated - strong and weak basic anion exchangers as well as chelate ion exchangers - possess good sorption and kinetic properties. The simultaneous sorption of investigated ions results in the complete recovery of platinum, while the non-ferrous metal ions are sorbed at less than 20%. Followed by the selective elution of platinum by thiourea (80 g L-1 solution in 0.3 M H2SO4, the quantitative isolation of platinum was achieved (more than 90%. Therefore, the studied ion exchangers can be recommended for recovery and separation of Pt(II,IV, Cu(II and Zn(II ions.

  7. Spontaneous Tl(I)-to-Tl(III) oxidation in dynamic heterobimetallic Hg(II)/Tl(I) porphyrin complexes. (United States)

    Ndoyom, Victoria; Fusaro, Luca; Roisnel, Thierry; Le Gac, Stéphane; Boitrel, Bernard


    Strapped heterobimetallic Hg(II)/Tl(I) porphyrin complexes, with both metal ions bridged by the N-core in a dynamic way, undergo spontaneous Tl(I)-to-Tl(III) oxidation leading to a mono-Tl(III) complex and a mixed valence Tl(I)/Tl(III) bimetallic complex. It provides a new opportunity to tune metal ion translocations in bimetallic porphyrin systems.

  8. A pentanuclear lead(II) complex based on a strapped porphyrin with three different coordination modes. (United States)

    Le Gac, Stéphane; Furet, Eric; Roisnel, Thierry; Hijazi, Ismail; Halet, Jean-François; Boitrel, Bernard


    We have previously described Pb(II) and Bi(III) bimetallic complexes with overhanging carboxylic acid strapped porphyrins in which one metal ion is bound to the N-core ("out-of-plane", OOP), whereas the second one is bound to the strap ("hanging-atop", HAT). In such complexes, the hemidirected coordination sphere of a HAT Pb(II) cation provides sufficient space for an additional binding of a neutral ligand (e.g., DMSO). Interestingly, investigations of the HAT metal coordination mode in a single strap porphyrin show that a HAT Pb(II) can also interact via intermolecular coordination bonds, allowing the self-assembly of two bimetallic complexes. In the pentanuclear Pb(II) complex we are describing in this Article, three different coordination modes were found. The OOP Pb(II) remains inert toward the supramolecular assembling process, whereas the HAT Pb(II) cation, in addition to its intramolecular carboxylate and regular exogenous acetate groups, coordinates an additional exogenous acetate. These two acetates are shared with a third lead(II) cation featuring a holo-directed coordination sphere, from which a centro-symmetric complex is assembled. Density functional theory calculations show some electron-density pockets in the vicinity of the hemidirected HAT Pb(II) atoms, which are associated with the presence of a stereochemically active lone pair of electrons. On the basis of the comparison with other HAT Pb(II) and Bi(III) systems, the "volume" of this lone pair correlates well with the bond distance distributions and the number of the proximal oxygen atoms tethered to the post-transition metal cation. It thus follows the order 6-coordinate Bi(III) > 6-coordinate Pb(II) > 5-coordinate Pb(II).

  9. Electronic Configuration of Five-Coordinate High-Spin Pyrazole-Ligated Iron(II) Porphyrinates (United States)

    Hu, Chuanjiang; Noll, Bruce C.; Schulz, Charles E.; Scheidt, W. Robert


    Pyrazole, a neutral nitrogen ligand and an isomer of imidazole, has been used as a fifth ligand to prepare two new species, [Fe(TPP)(Hdmpz)] and [Fe(Tp-OCH3PP)(Hdmpz)] (Hdmpz = 3,5-dimethylpyrazole), the first structurally characterized examples of five-coordinate iron(II) porphyrinates with a nonimidazole neutral ligand. Both complexes are characterized by X-ray crystallography, and structures show common features for five-coordinate iron(II) species, such as an expanded porphinato core, large equatorial Fe–Np bond distances and a significant out-of-plane displacement of the iron(II) atom. The Fe–N(pyrazole) and Fe–Np bond distances are similar to those in imidazole-ligated species. These suggest that the coordination abilities to iron(II) for imidazole and pyrazole are very similar even though pyrazole is less basic than imidazole. Mössbauer studies reveal that [Fe(TPP)(Hdmpz)] has the same behavior as those of imidazole-ligated species, such as negative quadrupole splitting values and relative large asymmetry parameters. Both the structures and Mössbauer spectra suggest pyrazole-ligated five-coordinate iron(II) porphyrinates have the same electronic configuration as imidazole-ligated species. PMID:21047081

  10. Electronic configuration of five-coordinate high-spin pyrazole-ligated iron(II) porphyrinates. (United States)

    Hu, Chuanjiang; Noll, Bruce C; Schulz, Charles E; Scheidt, W Robert


    Pyrazole, a neutral nitrogen ligand and an isomer of imidazole, has been used as a fifth ligand to prepare two new species, [Fe(TPP)(Hdmpz)] and [Fe(Tp-OCH(3)PP)(Hdmpz)] (Hdmpz = 3,5-dimethylpyrazole), the first structurally characterized examples of five-coordinate iron(II) porphyrinates with a nonimidazole neutral ligand. Both complexes are characterized by X-ray crystallography, and structures show common features for five-coordinate iron(II) species, such as an expanded porphyrinato core, large equatorial Fe-N(p) bond distances, and a significant out-of-plane displacement of the iron(II) atom. The Fe-N(pyrazole) and Fe-N(p) bond distances are similar to those in imidazole-ligated species. These suggest that the coordination abilities to iron(II) for imidazole and pyrazole are very similar even though pyrazole is less basic than imidazole. Mössbauer studies reveal that [Fe(TPP)(Hdmpz)] has the same behavior as those of imidazole-ligated species, such as negative quadrupole splitting values and relative large asymmetry parameters. Both the structures and the Mössbauer spectra suggest pyrazole-ligated five-coordinate iron(II) porphyrinates have the same electronic configuration as imidazole-ligated species.

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

    Directory of Open Access Journals (Sweden)

    Fabio Marchetti


    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.

  12. Thermal and photochemical reactions of diphosphine-platinum(II) carboxylates

    Energy Technology Data Exchange (ETDEWEB)

    Siria, J.W.


    Theoretical calculations have been described which suggest that activation in an angular ML[sub 4] species was achieved through a destabilized d[sub yx] molecular orbital. A d[sup 10] PtL[sub 2] system, where L[sub 2] is a chelating phosphine which maintains the fragment in a [open quotes]bent[close quotes] orientation, also has a high-lying d[sub yx] level and should be a viable candidate for such reaction. Platinum phosphine complexes are readily observed using [sup 31]P nuclear magnetic resonance spectroscopy, thus formation of a diphosphineplatinum(II) fragment may demonstrate catalytic activity while providing a convenient means for characterization. The author performed a series of experiments involving photodissociation of the oxalate ligand from [Pt(dppe)(C[sub 2]O[sub 4])]. In the presence of methanol, photolysis led to the formation of [Pt(dppe)(Co[sub 2]Me)[sub 2

  13. Recent Progress on the Photonic Properties of Conjugated Organometallic Polymers Built Upon the trans-Bis(para-ethynylbenzene)bis(phosphine)platinum(II) Chromophore and Related Derivatives. (United States)

    Wong, Wai-Yeung; Harvey, Pierre D


    This review article surveys the electronic and photophysical properties of conjugated organometallic polymers built upon the title compound and its related derivatives focussing primarily on systems investigated in our laboratories. The general structure of the polymers is (trans-bis(para-ethynylbenzene)bis(phosphine)platinum(II)-G)(n) where G is a conjugated group such as thiophene, fluorene, carbazole, substituted silole, quinone derivative, and metalloporphyrin residue, or a non-conjugated main-group moiety. Systems based on substituted phenylene units and other related fused rings are also discussed. The phosphine ligands are generally triethyl- or tri-n-butylphosphine groups. These trans-platinum(II) polymers and the corresponding model compounds are compared to the corresponding ortho-derivatives in the quinone series, and the newly prepared paracyclophane-containing polymers. For the porphyrin series, a comparison of fully conjugated oligomers exhibiting the general structure (trans-bis(para-ethynyl(zinc(porphyrin)))bis(phosphine)platinum(II))(n) (i.e., the C(6) H(4) group is absent from the main chain) will be made. This contribution also includes a description of the properties of the mononuclear chromophore itself, properties that define those of the polymers. Potential applications with regard to electronic and optical devices will be highlighted. These soluble and stable materials feature both the processing advantages of polymers and the functionality provided by the presence of metal centers. These multifunctional organometallic polyyne polymers exhibit convenient structural variability as well as optical and electronic properties, which renders them important for use in different research domains as chemical sensors and sensor protectors, as converters for light/electricity signals, and as patternable precursors to magnetic metal alloy nanoparticles.

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

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


    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.

  15. Influence of Matrices on Oxygen Sensing of Three Sensing Films with Chemically Conjugated Platinum Porphyrin Probes and Preliminary Application for Monitoring of Oxygen Consumption of Escherichia coli (E. coli)


    Tian, Yanqing; Shumway, Bradley R.; Gao, Weimin; Youngbull, Cody; Holl, Mark R.; Johnson, Roger H.; Meldrum, Deirdre R.


    Oxygen sensing films were synthesized by a chemical conjugation of functional platinum porphyrin probes in silica gel, polystyrene (PS), and poly(2-hydroxyethyl methacrylate) (PHEMA) matrices. Responses of the sensing films to gaseous oxygen and dissolved oxygen were studied and the influence of the matrices on the sensing behaviors was investigated. Silica gel films had the highest fluorescence intensity ratio from deoxygenated to oxygenated environments and the fastest response time to oxyg...

  16. 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)


    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.

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

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


    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.

  18. [Simultaneous determination of platinum (IV) and palladium (II) using spectrophotometry method]. (United States)

    Ma, Dong-Lan; Wang, Yun; Ma, Kuang-Biao; Wang, Jin-Ye


    The N-(m-methylphenyl)-N'-(sodium p-aminobenzenesulfonate)-thiourea (MMPT) was good reagent of water solubility. In the medium of an HAc-NaAc buffer solution and hexadecyltrimethylammonium bromide (CTMAB), MMPT can react with platinum (IV) and palladium (II) to form green and brown soluble complex. The maximum absorbance of the complex was at lambdaPt(max) = 754.4 nm and lambdaPD(max) = 304.6 nm. Beer's law was obeyed with the concentration in the range of 0-32.0 microg Pt(IV)/25 mL and 0-25.0 microg Pd(II)/25 mL for platinum (IV) and palladium(II) respectively. The correlated coefficient was r754.4 = 0.999 5 for platinum (IV); and r304.6 = 0.999 9 for palladium (II). Their molar absorption coefficients were epsilonPT(754.4 = 8.6 x 10(4) L x mol(-1) x cm(-1) and epsilonPd(304.6) = 7.4 x 10(4) L x mol(-1) x cm(-1) respectively. The contents of platinum (IV) and palladium (II) were converted by determination of the absorbency of mix solution of platinum (IV) and palladium (II) at 754.4 and 304.6 nm. Only Cu2+ and Co2+ interfered with the determination of palladium (II) among 50 coexistent ions, so the selectivity was good. It can be used for the determination of content of synthesis samples. The relative standard deviation (RSD) was less than 2.0%, and the recovery (%) was in the range of 96%-104%. The results are satisfactory. Because the reagent reacts with platinum (IV) and palladium (II) to form water soluble complex and does not require pre-separation for simultaneous determination of platinum (IV) and palladium (II), the method is easy to operate, rapid and environment-friendly.


    NARCIS (Netherlands)


    The chemical stability of the new anticancer platinum analogue 1,2-diaminomethyl-cyclobutane-platinum(II)-lactate (D19466) in infusion media was studied in an accelerated stability testing experiment with a selective HPLC-UV method. Variables were time, temperature, light, concentration, and

  20. Platinum electrodeposition from a dinitrosulfatoplatinate(II) electrolyte (United States)

    Weiser, Mathias; Schulze, Claudia; Schneider, Michael; Michaelis, Alexander


    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.

  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


    石井, 昭彦


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

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


    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.

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

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


    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.

  4. Design, Synthesis of Novel Platinum(II) Glycoconjugates, and Evaluation of Their Antitumor Effects. (United States)

    Han, Jianbin; Gao, Xiangqian; Liu, Ran; Yang, Jinna; Zhang, Menghua; Mi, Yi; Shi, Ying; Gao, Qingzhi


    A new series of sugar-conjugated (trans-R, R-cyclohexane-1, 2-diamine)-2-halo-malonato-platinum(II) complexes were designed and synthesized to target tumor-specific glucose transporters (GLUTs). The water solubility of the sugar-conjugated platinum (II) complexes was greatly improved by average of 570-fold, 33-fold, and 94-fold, respectively, compared to cisplatin (1.0 mg/mL), carboplatin (17.1 mg/mL), and the newest generation of clinical drug oxaliplatin (6.0 mg/mL). Despite the high water solubility, the platinum(II) glycoconjugates exhibited a notable increase in cytotoxicity by a margin of 1.5- to 6.0-fold in six different human cancer cell lines with respect to oxaliplatin. The potential GLUT1 transportability of the complexes was investigated through a molecular docking study and was confirmed with GLUT1 inhibitor-mediated cytotoxicity dependency evaluation. The results showed that the sugar-conjugated platinum(II) complexes can be recognized by the glucose recognition binding site of GLUT1 and their cell killing effect depends highly on the GLUT1 inhibitor, quercetin. The research presenting a prospective concept for targeted therapy anticancer drug design, and with the analysis of the synthesis, water solubility, antitumor activity, and the transportability of the platinum(II) glycoconjugates, this study provides fundamental data supporting the inherent potential of these designed conjugates as lead compounds for GLUT-mediated tumor targeting.

  5. 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)


    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.

  6. 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


    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.

  7. Study of Interaction Platinum Salts (Ii and Palladium (Ii on the Biologically Active Ligand

    Directory of Open Access Journals (Sweden)

    Asmat Nizami Kyzy Azizova


    Full Text Available Studied complexing ability of platinum (II and palladium (II with a time of personal gray-oxygen and sulfur-containing ligands donor nitrogens in different taniyah. A combination of functional groups. It is found that the complexation unimportant role nature of the starting metal salts, the pH of the medium, the nature of the solvent and the ratio of reactants. Determine the actual denticity tiodiuksusnoy, tiodipro propionic acid, mercaptoethanol, and bis -- hydroxyethyl sulfide. Discovered that a molecule entering the reaction of cysteamine origin walks splitting S–S communication and the resulting deproto-bined mercamine enter into complexation. In non-aqueous medium splitting S–S communication occurs.

  8. Synthesis and Spectroscopic and Biological Activities of Zn(II Porphyrin with Oxygen Donors

    Directory of Open Access Journals (Sweden)

    Gauri Devi Bajju


    Full Text Available Results of investigation of the physicochemical properties of zinc complexes containing substituted phenols as axial ligand having general formula [X-Zn-t(p-CH3 PP] [where X = different phenolates as axial ligand] in impurity-free organic solvent are presented. The four-coordinated zinc porphyrin accepts one axial ligand in 1 : 1 molar ratio to form five-coordinated complex, which is purified by column chromatography and characterized by physicochemical, biological evaluation and TGA/DTA studies. Absorption spectra show two principal effects: a red shift for phenols bearing substituted electron releasing groups (−CH3, −NH2 and blue shift for phenols bearing electron withdrawing groups (−NO2, −Cl relative to Zn-t(p-CH3 PP, respectively. 1H NMR spectra show that the protons of the phenol ring axially attached to the central metal ion are merged with the protons of the porphyrin ring. Fluorescence spectra show two fluorescence peaks in the red region with emission ranging from 550 nm to 700 nm. IR spectra confirm the appearance of Zn-NPor and Zn-O vibrational frequencies, respectively. According to the thermal studies, the complexes have a higher thermal stability and the decomposition temperature of these complexes depends on the axial ligation. The respective complexes of X-ZnII-t(p-CH3 PP were found to possess higher antifungal activity (up to 90% and higher in vitro cytotoxicity against human cancer cells lines.

  9. On Spin Hamiltonian fits to Moessbauer spectra of high-spin Fe(II) porphyrinate systems

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Charles E., E-mail: [Knox College, Department of Physics (United States); Hu Chuanjiang, E-mail:; Scheidt, W. Robert [University of Notre Dame, Department of Chemistry and Biochemistry (United States)


    Fits to Moessbauer spectra of high-spin iron(II) porphyrinates have been applied to the Fe(II) model compounds octaethylporphyrin(1,2-dimethylimidazole) and tetra-paramethoxyporphyrin(1,2-dimethylimidazole). Moessbauer spectra have been measured on these compounds at 4.2 K in large applied fields. Spin Hamiltonians were used for fitting both the electronic and nuclear interactions. The fits are done by adjusting the Hamiltonian parameters to simultaneously minimize the total {chi}{sup 2} for three different applied fields. In order to get best fits, the EFG tensor need to be rotated relative to the ZFS tensor. A comparative sensitivity analysis of their Spin Hamiltonian parameters has also been done on the ZFS parameters D, and the EFG asymmetry parameter {eta}. The best fits suggest that both systems definitely have a negative quadrupole splitting, and that largest EFG component is tilted far from the z-axis of the ZFS tensor, which is likely to be near the heme normal.

  10. The Next Generation of Platinum Drugs: Targeted Pt(II) Agents, Nanoparticle Delivery, and Pt(IV) Prodrugs. (United States)

    Johnstone, Timothy C; Suntharalingam, Kogularamanan; Lippard, Stephen J


    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. Cobalt-Porphyrin-Platinum-Functionalized Reduced Graphene Oxide Hybrid Nanostructures: A Novel Peroxidase Mimetic System For Improved Electrochemical Immunoassay (United States)

    Shu, Jian; Qiu, Zhenli; Wei, Qiaohua; Zhuang, Junyang; Tang, Dianping


    5,10,15,20-Tetraphenyl-21H,23H-porphine cobalt flat stacking on the reduced graphene oxide with platinum nanoparticles (PtNPs/CoTPP/rGO) were first synthesized and functionalized with monoclonal rabbit anti-aflatoxin B1 antibody (anti-AFB1) for highly efficient electrochemical immunoassay of aflatoxin B1 (AFB1) in this work. Transmission electron microscopy (TEM), atomic force microscope (AFM) and spectral techniques were employed to characterize the PtNPs/CoTPP/rGO hybrids. Using anti-AFB1-conjugated PtNPs/CoTPP/rGO as the signal-transduction tag, a novel non-enzymatic electrochemical immunosensing system was designed for detection of target AFB1 on the AFB1-bovine serum albumin-functionalized sensing interface. Experimental results revealed that the designed immunoassay could exhibit good electrochemical responses for target analyte and allowed the detection of AFB1 at a concentration as low as 5.0 pg mL-1 (5.0 ppt). Intra- and inter-assay coefficients of variation were below 10%. Importantly, the methodology was further validated for analyzing naturally contaminated or spiked blank peanut samples with consistent results obtained by AFB1 ELISA kit, thus providing a promising approach for quantitative monitoring of organic pollutants.

  12. 2-Deoxyglucose conjugated platinum (II) complexes for targeted therapy: design, synthesis, and antitumor activity. (United States)

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


    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.

  13. 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)


    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.

  14. Ion exchange equilibria in simultaneous extraction of platinum(II, IV) and rhodium(III) from hydrochloric solutions (United States)

    Mel'nikov, A. M.; Kononova, O. N.; Pavlenko, N. I.; Krylov, A. S.


    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.

  15. A New Composition for Co(II-porphyrin-based Membranes Used in Thiocyanate-selective Electrodes

    Directory of Open Access Journals (Sweden)

    Otilia Bizerea-Spiridon


    Full Text Available In the present paper, the potentiometric response characteristics of ametalloporphyrin-based electrode in o-nitrophenyloctylether (o-NPOE plasticizedpolyvinyl chloride (PVC membrane are presented for a set of monovalent anions. Asmembrane ionophore, 5,10,15,20-tetrakis-(4-methoxyphenyl-porphyrin-Co(II(CoTMeOPP was used. To establish the optimum composition of the membrane, differentmolar percents of cationic derivative (mol.% relative to ionophore were used. Electrodesformulated with membranes containing 1 wt.% ionophore, 66 wt.% o-NPOE, 33 wt.% PVC(plasticizer: PVC = 2:1 and the lipophilic cationic derivative (35 mol% are shown toexhibit high selectivity for thiocyanate with a near-Nernstian slope in the workingconcentration range of 1.0×10−1–1.0×10−5 M, with a good stability in time.

  16. Binding of kinetically inert metal ions to RNA: the case of platinum(II). (United States)

    Chapman, Erich G; Hostetter, Alethia A; Osborn, Maire F; Miller, Amanda L; DeRose, Victoria J


    In this chapter several aspects of Pt(II) are highlighted that focus on the properties of Pt(II)-RNA adducts and the possibility that they influence RNA-based processes in cells. Cellular distribution of Pt(II) complexes results in significant platination of RNA, and localization studies find Pt(II) in the nucleus, nucleolus, and a distribution of other sites in cells. Treatment with Pt(II) compounds disrupts RNA-based processes including enzymatic processing, splicing, and translation, and this disruption may be indicative of structural changes to RNA or RNA-protein complexes. Several RNA-Pt(II) adducts have been characterized in vitro by biochemical and other methods. Evidence for Pt(II) binding in non-helical regions and for Pt(II) cross-linking of internal loops has been found. Although platinated sites have been identified, there currently exists very little in the way of detailed structural characterization of RNA-Pt(II) adducts. Some insight into the details of Pt(II) coordination to RNA, especially RNA helices, can be gained from DNA model systems. Many RNA structures, however, contain complex tertiary folds and common, purine-rich structural elements that present suitable Pt(II) nucleophiles in unique arrangements which may hold the potential for novel types of platinum-RNA adducts. Future research aimed at structural characterization of platinum-RNA adducts may provide further insights into platinum-nucleic acid binding motifs, and perhaps provide a rationale for the observed inhibition by Pt(II) complexes of splicing, translation, and enzymatic processing.

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

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


    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.

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


    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.

  19. 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.


    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 =

  20. Potentiometric Polymeric Film Sensors Based on 5,10,15-tris(4-aminophenyl Porphyrinates of Co(II and Cu(II for Analysis of Biological Liquids

    Directory of Open Access Journals (Sweden)

    Larisa Lvova


    Full Text Available Novel carbonate-selective potentiometric sensors based on 5,10,15-tris(4-aminophenyl-20-phenyl porphyrinates of Cu(II and Co(II have been developed. Ionophore functioning mechanism and possible source of carbonate sensitivity have been evolved. Potentiometric properties of Co(II- and Cu(IITATPP-based sensors were compared with common carbonate-ISEs containing trifluoroacetophenone derivatives. The analytical utility of newly developed sensors has been demonstrated by measuring the bicarbonate content in human blood plasma.

  1. 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)



    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.

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

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


    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

  3. 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.


    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

  4. Synthesis, characterization, and biological activity of platinum II, III, and IV pivaloamidine complexes. (United States)

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


    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.

  5. 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.


    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

  6. Synthesis, molecular docking and evaluation of antifungal activity of Ni(II), Co(II) and Cu(II) complexes of porphyrin core macromolecular ligand. (United States)

    Singh, Urvashi; Malla, Ali Mohammad; Bhat, Imtiyaz Ahmad; Ahmad, Ajaz; Bukhari, Mohd Nadeem; Bhat, Sneha; Anayutullah, Syed; Hashmi, Athar Adil


    Porphyrin core dendrimeric ligand (L) was synthesized by Rothemund synthetic route in which p-hydroxy benzaldehyde and pyrrole were fused together. The prepared ligand was complexed with Ni(II), Cu(II) and Co(II) ions, separately. Both the ligand and its complexes were characterized by elemental analysis and spectroscopic studies (FT-IR, UV-Vis, (1)HNMR). Square planar geometries were proposed for Cu(II), Ni(II) and Co(II) ions in cobalt, Nickel and copper complexes, respectively on the basis of UV-Vis spectroscopic data. The ligand and its complex were screened on Candida albicans (ATCC 10231), Aspergillus fumigatus (ATCC 1022), Trichophyton mentagrophytes (ATCC 9533) and Pencillium marneffei by determining MICs and inhibition zones. The activity of the ligand and its complexes was found to be in the order: CuL ˃ CoL ≈ NiL ˃ L. Detection of DNA damage at the level of the individual eukaryotic cell was observed by commet assay. Molecular docking technique was used to understand the ligand-DNA interactions. From docking experiment, we conclude that copper complex interacts more strongly than rest two.

  7. Characterization of vanadium compounds in selected crudes. II. Electron paramagnetic resonance studies of the first coordination spheres in porphyrin and non-porphyrin fractions

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, J.G.; Biggs, W.R.; Fetzer, J.C.


    The authors applied electron paramagnetic resonance spectroscopy (EPR) to heavy petroleum fractions to characterize the first coordination sphere around the vanadyl +2 ion. The fractions were generated using a modified porphyrin extraction procedure. For the residual oil from the extraction, which contains the non-porphyrin metals, the first coordination sphere was dominated by 4N and N O 2S for Boscan, Beta, Morichal, and Arabian Heavy crudes. Maya had distinctively different parameters. These findings are significant for determining the overall structure of metal-containing compounds in heavy crude oils. They discuss the difference between the porphyrin and non-porphyrin behavior, possible biogenic precursors, and some process implications. 59 references, 1 figure, 2 tables.

  8. Cholesterol-tethered platinum II-based supramolecular nanoparticle increases antitumor efficacy and reduces nephrotoxicity. (United States)

    Sengupta, Poulomi; Basu, Sudipta; Soni, Shivani; Pandey, Ambarish; Roy, Bhaskar; Oh, Michael S; Chin, Kenneth T; Paraskar, Abhimanyu S; Sarangi, Sasmit; Connor, Yamicia; Sabbisetti, Venkata S; Kopparam, Jawahar; Kulkarni, Ashish; Muto, Katherine; Amarasiriwardena, Chitra; Jayawardene, Innocent; Lupoli, Nicola; Dinulescu, Daniela M; Bonventre, Joseph V; Mashelkar, Raghunath A; Sengupta, Shiladitya


    Nanoscale drug delivery vehicles have been harnessed extensively as carriers for cancer chemotherapeutics. However, traditional pharmaceutical approaches for nanoformulation have been a challenge with molecules that exhibit incompatible physicochemical properties, such as platinum-based chemotherapeutics. Here we propose a paradigm based on rational design of active molecules that facilitate supramolecular assembly in the nanoscale dimension. Using cisplatin as a template, we describe the synthesis of a unique platinum (II) tethered to a cholesterol backbone via a unique monocarboxylato and O→Pt coordination environment that facilitates nanoparticle assembly with a fixed ratio of phosphatidylcholine and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino (polyethylene glycol)-2000]. The nanoparticles formed exhibit lower IC(50) values compared with carboplatin or cisplatin in vitro, and are active in cisplatin-resistant conditions. Additionally, the nanoparticles exhibit significantly enhanced in vivo antitumor efficacy in murine 4T1 breast cancer and in K-Ras(LSL/+)/Pten(fl/fl) ovarian cancer models with decreased systemic- and nephro-toxicity. Our results indicate that integrating rational drug design and supramolecular nanochemistry can emerge as a powerful strategy for drug development. Furthermore, given that platinum-based chemotherapeutics form the frontline therapy for a broad range of cancers, the increased efficacy and toxicity profile indicate the constructed nanostructure could translate into a next-generation platinum-based agent in the clinics.

  9. Platinum (II) azatetrabenzoporphyrins for near-infrared organic light emitting diodes (United States)

    Huang, L.; Park, C. D.; Fleetham, T.; Li, J.


    This article describes a series of platinum (II) azatetrabenzoporphyrin emitters for near-infrared (NIR) organic light emitting diode (OLED) applications. Platinum (II) aza-triphenyltetrabenzoporphyrin (PtNTBP) results in a 72 nm shift in the photoluminescent (PL) emission spectrum to 842 nm compared to 770 nm of the platinum (II) tetraphenyltetrabenzoporphyrin (PtTPTBP). Also, the full width at half maximum of the emission spectrum of PtNTBP was significantly narrowed to 27 nm compared to 40 nm for PtTPTBP. The multilayer devices fabricated by thermal vacuum evaporation process employing PtTPTBP, PtNTBP, and cis-PtN2TBP exhibit electroluminescent (EL) emission peak at 770 nm, 848 nm, and 846 nm with the peak external quantum efficiency (EQE) of 8.0%, 2.8%, and 1.5%, respectively. Even with the decrease in EQE of devices employing PtNTBP and cis-PtN2TBP compared with those employing PtTPTBP, the combination of the spectral narrowing and the bathochromic shift to lower energy EL emission demonstrates the promise of PtNTBP for NIR applications. In the meanwhile, the solution-processed single-layer device using PtNTBP demonstrates the EQE of 0.33% and the peak EL emission at 844 nm.

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

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


    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.

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

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


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

    Maeda, Yuri; Hashimoto, Hideki; Nishioka, Takanori


    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.

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

    Directory of Open Access Journals (Sweden)

    Malinowska Katarzyna


    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. Biological evaluation of a novel Herceptin-platinum (II) conjugate for efficient and cancer cell specific delivery. (United States)

    Huang, Rong; Sun, Yu; Zhang, Xiang-yang; Sun, Bai-wang; Wang, Qiu-cui; Zhu, Jin


    Platinum-based drugs have been widely used for the treatment of malignant tumors. However, their applications are limited by severe side effects for their lack of selectivity for cancer cells. The development of antibody drug conjugates (ADCs) have provided a platform to reduce drug toxicity and improve drug efficacy. Here we describe a nover conjugate comprising of Herceptin (an anti-HER2 antibody) and platinum drug via a cathepsin B cleavable dipetide for enhancing drug accumulation and HER2-positive cancer cell specific delivery. This conjugate is believed to be cleaved by cathepsin B, leading to a 1,6-elimination reaction and activation of drug release. Herceptin-Pt(II) is evaluated to have approximately loaded with 6.4 moles platinum drugs per mole of antibody. We demonstrate that Herceptin-Pt(II) retain high and selective binding affinity for HER2 protein and HER2-positive SK-BR-3 cancer cells. The in vitro cytotoxicity tests indicate that Herceptin-Pt(II) exhibits much higher cytotoxicity than oxaliplatin against SK-BR-3 cells. More importantly, Herceptin-Pt(II) shows no obvious inhibition against the growth of both MCF-7 and MDA-MB-231 cells, which express lower levels of HER2. Furthermore, compared with free oxaliplatin, Herceptin significantly improved the cellular uptake of platinum drugs in SK-BR-3 cells. In summary, Herceptin-platinum (II) conjugate is a remarkable and potent platform for efficient and cancer cell specific delivery.

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

    Wendt, Ola F.; Elding, Lars I.


    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.

  16. Visible-light-induced water oxidation by a hybrid photocatalyst consisting of bismuth vanadate and copper(II) meso-tetra(4-carboxyphenyl)porphyrin. (United States)

    Nakashima, Shu; Negishi, Ryo; Tada, Hiroaki


    Copper(II) meso-tetra(4-carboxyphenyl)porphyrin surface-modified monoclinic scheelite bismuth vanadate (CuTCPP/BiVO4) has been synthesized via a two-step route involving chemisorption of TCPP on BiVO4 and successive Cu(II) ion incorporation into the TCPP, and the surface modification drastically enhances the water oxidation to oxygen (O2) under visible-light irradiation (λ > 430 nm).

  17. GLUT1-mediated selective tumor targeting with fluorine containing platinum(II) glycoconjugates. (United States)

    Liu, Ran; Fu, Zheng; Zhao, Meng; Gao, Xiangqian; Li, Hong; Mi, Qian; Liu, Pengxing; Yang, Jinna; Yao, Zhi; Gao, Qingzhi


    Increased glycolysis and overexpression of glucose transporters (GLUTs) are physiological characteristics of human malignancies. Based on the so-called Warburg effect, 18flurodeoxyglucose-positron emission tomography (FDG-PET) has successfully developed as clinical modality for the diagnosis and staging of many cancers. To leverage this glucose transporter mediated metabolic disparity between normal and malignant cells, in the current report, we focus on the fluorine substituted series of glucose, mannose and galactose-conjugated (trans-R,R-cyclohexane-1,2-diamine)-2-flouromalonato-platinum(II) complexes for a comprehensive evaluation on their selective tumor targeting. Besides highly improved water solubility, these sugar-conjugates presented improved cytotoxicity than oxaliplatin in glucose tranporters (GLUTs) overexpressing cancer cell lines and exhibited no cross-resistance to cisplatin. For the highly water soluble glucose-conjugated complex (5a), two novel in vivo assessments were conducted and the results revealed that 5a was more efficacious at a lower equitoxic dose (70% MTD) than oxaliplatin (100% MTD) in HT29 xenograft model, and it was significantly more potent than oxaliplatin in leukemia-bearing DBA/2 mice as well even at equimolar dose levels (18% vs 90% MTD). GLUT inhibitor mediated cell viability analysis, GLUT1 knockdown cell line-based cytotoxicity evaluation, and platinum accumulation study demonstrated that the cellular uptake of the sugar-conjugates was regulated by GLUT1. The higher intrinsic DNA reactivity of the sugar-conjugates was confirmed by kinetic study of platinum(II)-guanosine adduct formation. The mechanistic origin of the antitumor effect of the fluorine complexes was found to be forming the bifunctional Pt-guanine-guanine (Pt-GG) intrastrand cross-links with DNA. The results provide a rationale for Warburg effect targeted anticancer drug design.

  18. Diarylplatinum(II Compounds as Versatile Metallating Agents in the Synthesis of Cyclometallated Platinum Compounds with N-Donor Ligands

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    Margarita Crespo


    Full Text Available This review deals with the reactions of diarylplatinum(II complexes with N-donor ligands to produce a variety of cycloplatinated compounds including endo-five-, endo-seven-, endo-six- or exo-five-membered platinacycles. The observed reactions result from a series of oxidative addition/reductive elimination processes taking place at platinum(II/platinum(IV species and involving C–X (X = H, Cl, Br bond activation, arene elimination, and, in some cases, Caryl–Caryl bond formation.

  19. Infinite dilution partial molar volumes of platinum(II) 2,4-pentanedionate in supercritical carbon dioxide. (United States)

    Kong, Chang Yi; Siratori, Tomoya; Funazukuri, Toshitaka; Wang, Guosheng


    The effects of temperature and density on retention of platinum(II) 2,4-pentanedionate in supercritical fluid chromatography were investigated at temperatures of 308.15-343.15K and pressure range from 8 to 40MPa by the chromatographic impulse response method with curve fitting. The retention factors were utilized to derive the infinite dilution partial molar volumes of platinum(II) 2,4-pentanedionate in supercritical carbon dioxide. The determined partial molar volumes were small and positive at high pressures but exhibited very large and negative values in the highly compressible near critical region of carbon dioxide.

  20. Platinum(II), palladium(II), rhodium(III) and lead(II) voltammetric determination in sites differently influenced by vehicle traffic. (United States)

    Melucci, Dora; Locatelli, Clinio


    The present work reports analytical results relevant to voltammetric determination of Pt(II), Pd(II), Rh(III) [Platinum Group Metals (PGMs)] and Pb(II) in superficial water sampled in sites differently influenced by vehicle traffic, especially considering their temporal behaviour. For all the elements, in addition to detection limits, precision, expressed as relative standard deviation (s(r) %) and accuracy, expressed as percentage recovery (R %) are also reported. In all cases they show to be good, being the former lower than 6% and the latter in the range 94-105%. A critical comparison with spectroscopic measurements is also discussed.

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

    Kidani, Y; Noji, M; Tashiro, T


    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.

  2. The oxidation of Ni(II) N-confused porphyrins (NCPs) with azo radical initiators and an unexpected intramolecular nucleophilic substitution reaction via a proposed Ni(III) NCP intermediate. (United States)

    Jiang, Hua-Wei; Chen, Qing-Yun; Xiao, Ji-Chang; Gu, Yu-Cheng


    The oxidation of Ni(II) N-confused porphyrins (NCPs) with azo radical initiators resulted in an unexpected intramolecular nucleophilic substitution reaction via a proposed Ni(III) NCP intermediate, which could be detected by HRMS.

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


    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.

  4. Quantum chemical topology study of the water-platinum(II) interaction. (United States)

    Bergès, Jacqueline; Fourré, Isabelle; Pilmé, Julien; Kozelka, Jiri


    The "inverse hydration" of neutral complexes of Pt(II) by an axial water molecule, whose one OH-bond is oriented toward Pt, has been the subject of recent works, theoretical as well as experimental. To study the influence of the ligands on this non-conventional H-bond, we extend here our previous energy calculations, using the second-order Moeller-Plesset perturbation theory (MP2) method together with the Dolg-Pélissier pseudopotential for platinum, to various neutral complexes including the well-known chemotherapeutic agent "cisplatin". The stabilization energy, depending on the nature and the configuration of platinum ligands, is dominated by the same important dispersive component, for all the investigated complexes. For a further characterization of this particular H-bond, we used the atoms in molecules theory (AIM) and the topological analysis of the electron localization function (ELF). The charge transfer occurring from the complex to the water molecule and the Laplacian of the density at the bond critical point between water and Pt are identified as interesting AIM descriptors of this non-conventional H-bond. Beyond this AIM analysis, we show that the polarization of the ELF bonding O-H basin involved in the non-conventional H-bond is enhanced during the approach of the water molecule to the Pt complexes. When the water medium, treated in an implicit solvation model, is taken into account, the interaction energies become independent on the nature and configuration of platinum ligands. However, the topological descriptors remain qualitatively unchanged.

  5. Post-column reaction detector for platinum(II) antieoplastic agents

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, K.C.; Sternson, L.A.; Repta, A.J.


    The development and evaluation of a post-column reaction detector sensitive to platinum(II) complexes is presented in which sodium bisulfite is used as the derivatizing agent with potassium dichromate as an activating agent. The influences of mobile phase changes (i.e., pH, organic modifiers, electrolytes), oxygen, metal ions, and order of reagent addition on reaction kinetics and product yield are defined and used in optimization of detector response. Detection at lambda/sub max/ 290 nm results in an on-line post-column sensitivity of 40-60 ng/mL for selected cis-dichloroplatinum complexes and a sensitivity of 300-1200 ng/mL for four (substituted)-malonato-platinum complexes. The reaction detector is used to monitor the kinetics of aquation of cisplatin (CDDP) and to quantitate CDDP degradation in plasma. As the sensitivity for CDDP in plasma is comparable to that achieved from high pressure liquid chromatography (HPLC) effluent fractionation/off-line flameless atomic absorption (AAS) quantitation, significant utilitiy for this time-efficient post-column reactor in clinical analysis is suggested. 33 references, 8 figures, 2 tables.

  6. Novel dinuclear platinum(II) complexes containing mixed nitrogen-sulfur donor ligands. (United States)

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


    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

  7. 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


    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

  8. Kinetics of metal exchange in Cd(II) octa(4-bromophenyl)porphyrinate with d-metal salts in organic solvents (United States)

    Zvezdina, S. V.; Chizhova, N. V.; Mamardashvili, N. Zh.


    The reaction of metal exchange between Cd(II) octa(4-bromophenyl)porphyrinate with CuCl2 and ZnCl2 in DMFA and DMSO is studied by means of spectrophotometry. The kinetic parameters of the metal exchange reaction are calculated, a stoichiometric reaction mechanism is proposed. The effect the natures of the solvent, salt solvate, and the chemical modification of tetrapyrrole macrocycle have on the kinetic parameters of the metal exchange reaction are revealed.

  9. 4D-π-1A type β-substituted Zn(II)-porphyrins: ideal green sensitizers for building-integrated photovoltaics. (United States)

    Covezzi, A; Orbelli Biroli, A; Tessore, F; Forni, A; Marinotto, D; Biagini, P; Di Carlo, G; Pizzotti, M


    Two novel green β-substituted Zn(II)-porphyrins, G1 and G2, based on a 4D-π-1A type substitution pattern have been synthesized. Their enhanced push-pull character, by reduction of H-L energy gaps, promotes broadening and red-shifting of absorption bands. The effective synthetic pathway and the remarkable spectroscopic properties make G2 ideal for BIPV application.

  10. Effects of cis-malonato-diammino platinum (II) on P-388 lymphocytic leukemia cell metabolism. (United States)

    Hall, I H; Holshouser, M H; Loeffler, L J


    cis-Malonato-diammino platinum(II) significantly inhibited P-388 lymphocytic leukemia cell proliferation at 10 mg/kg/day. Incorporation studies showed that DNA synthesis was inhibited following in vivo drug therapy. The major inhibitory effects appeared to be on thymidine kinase and dihydrofolate reductase activities and on overall purine synthesis, with marginal effects on DNA polymerase and ribonucleotide reductase activities. In addition to the DNA inhibition, a marked increase in cyclic adenosine 3',5'-monophosphate levels was noted, which correlated with a rapid decrease in histone phosphorylation. Other minor effects of the drug included significant reduction of proteolytic activity, suppression of States 4 and 3 respiration, and an increase in adenosine triphosphatase and acid phosphatase activities of P-388 cells.

  11. Cyclometalated platinum(II) with ethynyl-linked azobenzene ligands: an original switching mode. (United States)

    Savel, Paul; Latouche, Camille; Roisnel, Thierry; Akdas-Kilig, Huriye; Boucekkine, Abdou; Fillaut, Jean-Luc


    The photophysical properties of 6-phenyl-2,2'-bipyridyl platinum(ii) complexes bearing different σ-alkynyl-linked azobenzene ancillary ligands were investigated. These complexes exhibited strong, broad, structureless charge-transfer bands in the visible region, which were red-shifted when the electron-donating ability of the para substituent on the azo-acetylide ligand increased. When excited at the charge-transfer absorption band, the complexes exhibited weak green emission, which was assigned to a triplet metal-to-ligand charge transfer/interligand charge transfer emission ((3)MLCT/(3)L'LCT). The presence of an amino substituent in the azobenzene moiety opened the possibility of protonation, which led to the formation of an azonium based derivative and resulted in drastic perturbations of the molecular orbitals and photophysical properties of the Pt-acetylide complex. These studies are fully supported by DFT and TD-DFT calculations.

  12. Binary Diffusion Coefficients of Platinum(II) Acetylacetonate in Supercritical Carbon Dioxide. (United States)

    Kong, Chang Yi; Siratori, Tomoya; Wang, Guosheng; Sako, Takeshi; Funazukuri, Toshitaka


    Binary diffusion coefficients (D12) and retention factors (k) of platinum(II) acetylacetonate at infinitesimal concentration in supercritical (sc) carbon dioxide (CO2) were measured by the chromatographic impulse response method with a poly(ethylene glycol) coated capillary column at temperatures from (308.15 to 343.15) K and pressures from (8.5 to 40.0) MPa, and D12 in liquid ethanol at temperatures from (298.15 to 333.15) K and atmospheric pressure by the Taylor dispersion method. As has been seen for our previously reported data on other metal complexes measured in sc CO2 and organic solvents, the D12 data in sc CO2 and liquid ethanol were represented by a function of temperature and solvent viscosity. The D12 values for metal complexes were not related to the solute molecular weights. The k values in sc CO2 were expressed by a function of temperature and CO2 density.

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

    Directory of Open Access Journals (Sweden)

    Ha Phuong Thu


    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.

  14. Iron(III) and copper(II) complexes of trans-bis(ferrocenyl)porphyrin: Effect of metal ions on long-range electronic communication

    Indian Academy of Sciences (India)

    Dipankar Sahoo; Sankar Prasad Rath


    A series of complex with a general formula of M(Fc2Ph2P) [Fc2Ph2P = 5, 10-bisferrocenyl-15,20-bisphenylporphyrin (2−); M = Fe(III)Cl Fe(III)(ClO4) and Cu(II)] have been synthesized and characterized. The single crystal X-ray structure of CuII(Fc2Ph2P) has been reported in which two ferrocene moieties are in anti form with respect to each other. The ferrocenyl groups of CuII(Fc2Ph2P) are more easily oxidized via a single two-electron quasi-reversible process compared to the free base ligand in which two 1e-oxidative response separated by 0.23 V are observed. Electrochemical study of FeIII(Fc2Ph2P)Cl revealed ferrocenebased two-electron quasi-reversible oxidation at 0.72 V indicating no observable coupling of the ferrocene moieties. The higher oxidation state of Fe(III) reduces the electron releasing tendency of the porphyrin ring and thus make the ferrocene oxidation difficult. The porphyrin, however, lack substituents at the -pyrrolic positions, and the ferrocenyl moieties are therefore free to rotate. The observed electrochemical analyses thus demonstrate that the oxidation of the ferrocene subunit is strongly affected by porphyrin ring as well as the central metal through extended -conjugation.

  15. 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


    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.

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

    Directory of Open Access Journals (Sweden)

    Ján Vančo


    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.

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

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


    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.

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

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


    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.

  19. Cobalt-Porphyrin Catalyzed Electrochemical Reduction of Carbon Dioxide in Water II: Mechanism from First Principles

    CERN Document Server

    Leung, Kevin; Sai, Na; Medforth, Craig J; Shelnutt, J A; 10.1021/jp1012335


    We apply first principles computational techniques to analyze the two-electron, multi-step, electrochemical reduction of CO2 to CO in water using cobalt porphyrin as a catalyst. Density Functional Theory calculations with hybrid functionals and dielectric continuum solvation are used to determine the steps at which electrons are added. This information is corroborated with ab initio molecular dynamics simulations in an explicit aqueous environment which reveal the critical role of water in stabilizing a key intermediate formed by CO2 bound to cobalt. Using potential of mean force calculations, the intermediate is found to spontaneously accept a proton to form a carboxylate acid group at pH<9.0, and the subsequent cleavage of a C-OH bond to form CO is exothermic and associated with a small free energy barrier. These predictions suggest that the proposed reaction mechanism is viable if electron transfer to the catalyst is sufficiently fast. The variation in cobalt ion charge and spin states during bond break...

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

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


    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.

  1. Porphyrin Tests (United States)

    ... Blood Cell Porphyrins Acute intermittent porphyria Increased Increased URO* Normal Normal Variegate porphyria Increased Increased COPRO Increased ... COPRO Increased PROTO Porphyria cutanea tarda Normal Increased URO, 7-carboxyl Increased Isocoproporphyrin Normal Erythropoietic Protoporphyria Normal ...

  2. Novel platinum(II) compounds with O,S bidentate ligands: synthesis, characterization, antiproliferative properties and biomolecular interactions. (United States)

    Mügge, Carolin; Liu, Ruiqi; Görls, Helmar; Gabbiani, Chiara; Michelucci, Elena; Rüdiger, Nadine; Clement, Joachim H; Messori, Luigi; Weigand, Wolfgang


    Cisplatin and its analogues are first-line chemotherapeutic agents for the treatment of numerous human cancers. A major inconvenience in their clinical use is their strong tendency to link to sulfur compounds, especially in kidney, ultimately leading to severe nephrotoxicity. To overcome this drawback we prepared a variety of platinum complexes with sulfur ligands and analyzed their biological profiles. Here, a series of six platinum(II) compounds bearing a conserved O,S binding moiety have been synthesized and characterized as experimental anticancer agents. The six compounds differ in the nature of the O,S bidentate β-hydroxydithiocinnamic alkyl ester ligand where both the substituents on the aromatic ring and the length of the alkyl chain may be varied. The two remaining coordination positions at the square-planar platinum(II) center are occupied by a chloride ion and a DMSO molecule. These novel platinum compounds showed an acceptable solubility profile in mixed DMSO-buffer solutions and an appreciable stability at physiological pH as judged from analysis of their time-course UV-visible absorption spectra. Their anti-proliferative and pro-apoptotic activities were tested against the cisplatin-resistant lung cancer cell line A549. Assays revealed significant effects of the sample drugs at low concentrations (in the μmolar range); initial structure-activity-relationships are proposed. The activity of the apoptosis-promoting protein caspase 3/7 was determined; results proved that these novel platinum compounds, under the chosen experimental conditions, preferentially induce apoptosis over necrosis. Reactions with the model proteins cytochrome c, lysozyme and albumin were studied by ESI MS and ICP-OES to gain preliminary mechanistic information. The tested compounds turned out to metalate the mentioned proteins to a large extent. In view of the obtained results these novel platinum complexes qualify themselves as promising cytotoxic agents and merit, in our

  3. Quinoxaline-2-carboxamide as a carrier ligand in two new platinum(ii) compounds: Synthesis, crystal structure, cytotoxic activity and DNA interaction

    NARCIS (Netherlands)

    Marques Gallego, P.; Amparo Gamiz-Gonzalez, M.; Fortea-Pérez, F. R.; Lutz, M.; Spek, A.L.; Pevec, A.; Kozlevar, B.; Reedijk, J.


    The search for platinum compounds structurally different from cisplatin has led to two new platinum(II) compounds containing quinoxaline-2-carboxamide as a carrier ligand, i.e. cis-[Pt(qnxca)(MeCN)Cl2] (1) and the [Pt(qnxca−H)(dmso)Cl] (2). Both compounds have been synthesized and characterized usin

  4. Binding of Cationic Bis-porphyrins Linked with p- or m-Xylylenediamine and Their Zinc(II Complexes to Duplex DNA

    Directory of Open Access Journals (Sweden)

    Tadayuki Uno


    Full Text Available Spectroscopic, viscometric, and molecular docking analysis of binding of cationic bis-porphyrins linked with p- or m-xylylenediamine (H2pXy and H2mXy and their zinc(II complexes (ZnpXy and ZnmXy to duplex DNA are described. H2pXy and H2mXy bound to calf thymus DNA (CTDNA stronger than unichromophoric H2TMPyP, and showed exciton-type induced circular dichroism spectra of their Soret bands. The H2TMPyP-like units of the metal-free bis-porphyrins did not intercalate into CTDNA, and thus the binding mode is outside binding with intramolecular stacking. ZnpXy showed favorable binding to A·T over G·C region, and should lie in the major groove of A·T region.

  5. Platinum (II) and (IV) spermidine complexes. Synthesis, characterization, and biological studies. (United States)

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


    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.

  6. Platinum(II)-Based Metallo-Supramolecular Polymer with Controlled Unidirectional Dipoles for Tunable Rectification. (United States)

    Chakraborty, Chanchal; Pandey, Rakesh K; Hossain, Md Delwar; Futera, Zdenek; Moriyama, Satoshi; Higuchi, Masayoshi


    A platinum(II)-based, luminescent, metallo-supramolecular polymer (PolyPtL1) having an inherent dipole moment was synthesized via complexation of Pt(II) ions with an asymmetric ligand L1, containing terpyridyl and pyridyl moieties. The synthesized ligand and polymer were well characterized by various NMR techniques, optical spectroscopy, and cyclic voltammetry studies. The morphological study by atomic force microscopy revealed the individual and assembled polymer chains of 1-4 nm height. The polymer was specifically attached on Au-electrodes to produce two types of film (films 1 and 2) in which the polymer chains were aligned with their dipoles in opposite directions. The Au-surface bounded films were characterized by UV-vis, Raman spectroscopy, cyclic voltammetry, and atomic force microscopy study. The quantum mechanical calculation determined the average dipole moment for each monomer unit in PolyPtL1 to be about 5.8 D. The precise surface derivatization permitted effective tuning of the direction dipole moment, as well as the direction of rectification of the resulting polymer-attached molecular diodes. Film 1 was more conductive in positive bias region with an average rectification ratio (RR = I(+4 V)/I(-4 V)) ≈ 20, whereas film 2 was more conducting in negative bias with an average rectification ratio (RR = I(-4 V)/I(+4 V)) ≈ 18.

  7. Optical oxygen-sensing properties of porphyrin derivatives anchored on ordered porous aluminium oxide plates. (United States)

    Araki, Naoko; Amao, Yutaka; Funabiki, Takuzo; Kamitakahara, Masanobu; Ohtsuki, Chikara; Mitsuo, Kazunori; Asai, Keisuke; Obata, Makoto; Yano, Shigenobu


    An optical oxygen-sensing activity of anchored porphyrin derivatives on ordered porous aluminium oxide plates was studied in relevance to development of new oxygen-sensing systems. Porphyrin derivatives, 5,10,15,20-tetrakis(4-carboxylundecane-1-oxy)porphyrin, 5-[4-(11-carboxylundecane-1-oxy)-10,15,20-triphenyl]porphyrin, 5-(4-carboxylphenyl)-10,15,20-triphenylporphyrin, and their platinum complexes, 5,10,15,20-tetrakis(4-carboxylundecane-1-oxy)porphyrinatoplatinum(II), 5-[4-(11-carboxylundecane-1-oxy)-10,15,20-triphenyl]porphyrinatoplatinum(II), 5-(4-carboxylphenyl)-10,15,20-triphenylporphyrinatoplatinum(II), were synthesized and anchored by an equilibrium adsorption method on aluminium oxide plates, which were prepared by an anodic oxidation. The excitation spectra of the porphyrin-anchored layers showed a broadened and blue-shifted Soret band compared with the corresponding porphyrins in DMSO. The luminescence intensity decreased with increasing oxygen concentrations. The oxygen-sensing ability estimated from I(0)/I(100) (I(0) and I(100) denote the luminescence intensity in 0 and 100% oxygen) was 9.08, 6.78, 8.71, 81.9, 35.5, and 39.1, which are greater than those of corresponding porphyrin derivatives in DMSO under the measured conditions, and indicates the remarkable enhancement effect of platinum(II). Non-linear Stern-Volmer plots were well fitted by the two component system to give the oxygen-sensitive constant (K(SV1)/%(-1)), the oxygen-insensitive constant (K(SV2)/%(-1)), and the former contribution (f(1)): 0.232, 3.32 x 10(-2), and 0.642; 0.141, 2.05 x 10(-2), and 0.687; 0.143, 1.05 x 10(-2), and 0.882; 17.3, 7.04 x 10(-3), and 0.980; 10.2, 1.43 x 10(-2), and 0.935; 16.3, 8.35 x 10(-3), and 0.954. The response time for the change of the atmospheric gas from argon to oxygen was 9.4 s, 12.5 s, 9.6 s, 5.0 s, 8.9 s, and 4.6 s, indicating the shortening effect of platinum. The reverse effect of platinum was observed in the change from oxygen to argon: 15.5 s

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

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


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


    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.

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

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


    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.

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

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


    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.

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


    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.

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

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


    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.

  14. Chemical and cellular investigations of trans-ammine-pyridine-dichlorido-platinum(II), the likely metabolite of the antitumor active cis-diammine-pyridine-chorido-platinum(II). (United States)

    Xu, Dechen; Min, Yuanzeng; Cheng, Qinqin; Shi, Hongdong; Wei, Kaiju; Arnesano, Fabio; Natile, Giovanni; Liu, Yangzhong


    It has been proposed that the well-studied monofunctional platinum complex cis-[PtCl(NH3)2(py)](+) (cDPCP) forms DNA adducts similar to those of the trans platinum complex trans-[PtCl2(NH3)(py)] (ampyplatin, py=pyridine). Thus this latter could be the active form of cDPCP. Detailed studies on the mechanism of ampyplatin action were performed in this work. Results indicate that ampyplatin has significantly higher antiproliferative activity than cDPCP and is comparable to cisplatin. Cellular uptake experiments indicate that ampyplatin can be efficiently accumulated in A549 cancer cells. Binding of ampyplatin to DNA mainly produces monofunctional adducts; remarkably, these adducts can be recognized by the HMGB1 protein. Kinetic studies on the reaction with GMP indicate that the reactivity of ampyplatin is much lower than that of transplatin and is more similar to that of trans-[PtCl2{E-HN=C(Me)OMe}2] (trans-EE), a widely investigated antitumor active trans-oriented platinum complex. In addition, the hydrolysis of ampyplatin is significantly suppressed, whereas the hydrolysis of the mono-GMP adduct is highly enhanced. These results indicate that the mechanism of ampyplatin differs not only from that of antitumor inactive transplatin but also from that of antitumor active trans-EE and this could account for the remarkable activity of parent cDPCP.

  15. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    KAUST Repository

    Chinnusamy, Tamilselvi R.


    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Cobalt(II) Porphyrin-Catalyzed Intramolecular Cyclopropanation of N-Alkyl Indoles/Pyrroles with Alkylcarbene: Efficient Synthesis of Polycyclic N-Heterocycles. (United States)

    Reddy, Annapureddy Rajasekar; Hao, Fei; Wu, Kai; Zhou, Cong-Ying; Che, Chi-Ming


    A protocol on chemoselective cobalt(II) porphyrin-catalyzed intramolecular cyclopropanation of N-alkyl indoles/pyrroles with alkylcarbenes has been developed. The reaction enables the rapid construction of a range of nitrogen-containing polycyclic compounds in moderate to high yields from readily accessible materials. These N-containing polycyclic compounds can be converted into a variety of N-heterocycles with potential synthetic and biological interest. Compared to their N-tosylhydrazone counterparts, the use of bulky N-2,4,6-triisopropylbenzenesulfonyl hydrazones as carbene precursors allows cyclopropanation to occur under milder reaction conditions.

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

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


    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.

  18. Targeting cytochrome C oxidase in mitochondria with Pt(II)-porphyrins for photodynamic therapy (United States)

    Börsch, Michael


    Mitochondria are the power house of living cells, where the synthesis of the chemical "energy currency" adenosine triphosphate (ATP) occurs. Oxidative phosphorylation by a series of membrane protein complexes I to IV, that is, the electron transport chain, is the source of the electrochemical potential difference or proton motive force (PMF) of protons across the inner mitochondrial membrane. The PMF is required for ATP production by complex V of the electron transport chain, i.e. by FoF1-ATP synthase. Destroying cytochrome C oxidase (COX; complex IV) in Photodynamic Therapy (PDT) is achieved by the cationic photosensitizer Pt(II)-TMPyP. Electron microscopy revealed the disruption of the mitochondrial christae as a primary step of PDT. Time resolved phosphorescence measurements identified COX as the binding site for Pt(II)-TMPyP in living HeLa cells. As this photosensitizer competed with cytochrome C in binding to COX, destruction of COX might not only disturb ATP synthesis but could expedite the release of cytochrome C to the cytosol inducing apoptosis.

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


    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.

  20. Synthesis and Characterization of Phenothiazine-Based Platinum(II)-Acetylide Photosensitizers for Efficient Dye-Sensitized Solar Cells. (United States)

    Siu, Chi-Ho; Lee, Lawrence Tien Lin; Yiu, Sze-Chun; Ho, Po-Yu; Zhou, Panwang; Ho, Cheuk-Lam; Chen, Tao; Liu, Jianyong; Han, Keli; Wong, Wai-Yeung


    Three new unsymmetrical phenothiazine-based platinum(II) bis(acetylide) complexes PT1-PT3 with different electron-donating arylacetylide ligands were synthesized and characterized. Their photophysical, electrochemical, and photovoltaic properties have been fully investigated and the density functional theory (DFT) calculations have been carried out. Under AM 1.5 irradiation (100 mW cm(-2)), the PT1-based dye-sensitized solar cell (DSSC) device exhibited an attractive power conversion efficiency (η) up to 5.78 %, with a short-circuit photocurrent density (J(sc)) of 10.98 mA cm(-2), an open-circuit photovoltage (V(oc)) of 0.738 V, and a fill factor (ff) of 0.713. These findings provide strong evidence that platinum-acetylide complexes have great potential as promising photosensitizers in DSSC applications.

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

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


    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.

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

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


    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

  3. Photophysics of organometallic platinum(II) derivatives of the diketopyrrolopyrrole chromophore

    KAUST Repository

    Goswami, Subhadip


    A pair of diketopyrrolopyrrole (DPP) chromophores that are end-functionalized with platinum containing "auxochromes" were subjected to electrochemical and photophysical study. The chromophores contain either platinum acetylide or ortho-metalated 2-thienylpyridinyl(platinum) end-groups (DPP-Pt(CC) and DPP-Pt(acac), respectively). The ground state redox potentials of the chromophores were determined by solution electrochemistry, and the HOMO and LUMO levels were estimated. The chromophores\\' photophysical properties were characterized by absorption, photoluminescence, and time-resolved absorption spectroscopy on time scales from sub-picoseconds to microseconds. Density functional theory (DFT) computations were performed to understand the molecular orbitals involved in both the singlet and triplet excited state photophysics. The results reveal that in both platinum DPP derivatives the organometallic auxochromes have a significant effect on the chromophores\\' photophysics. The most profound effect is a reduction in the fluorescence yields accompanied by enhanced triplet yields due to spin-orbit coupling induced by the metal centers. The effects are most pronounced in DPP-Pt(acac), indicating that the orthometalated platinum auxochrome is able to induce spin-orbital coupling to a greater extent compared to the platinum acetylide units. (Figure Presented).

  4. Spectroscopic investigation on porphyrins nano-assemblies onto gold nanorods (United States)

    Trapani, Mariachiara; De Luca, Giovanna; Romeo, Andrea; Castriciano, Maria Angela; Scolaro, Luigi Monsù


    The interaction between gold nanorods (Au NRs), synthesized by a conventional seeded growth protocol, and the anionic tetrakis-(4-sulfonatophenyl)porphyrin (TPPS4) has been investigated through various spectroscopic techniques. At neutral pH, the formation of H-aggregates and the inclusion of porphyrin monomers in CTAB micelles covering the nanorods have been evidenced. Under mild acidic conditions (pH = 3) a nano-hybrid assembly of porphyrin J-aggregates and Au NRs has been revealed. For the sake of comparison, Cu(II) and Zn(II) metal porphyrin derivatives as well as a cationic porphyrin have been studied in the same experimental conditions, showing that: i) CuTPPS4 forms porphyrin H-dimers onto the Au NRs; ii) ZnTPPS4 undergoes to demetallation, followed by acidification of the central core and eventually aggregation onto Au NRs; iii) cationic porphyrin does not interact with Au NRs.

  5. cis-Diammine[3-(3-chloro-7-methoxy-9,10-dihydroacridin-9-ylideneaminopropan-1-amine-κ2N,N′]platinum(II dinitrate

    Directory of Open Access Journals (Sweden)

    Young Cheun


    Full Text Available The title complex salt, [Pt(C16H17N3(NH32](NO32, is of interest with respect to anticancer activity. The secondary amine of 9-aminoacridine coordinates with the platinum(II atom, leading to imine–platinum complex cation formation. The crystal structure displays extensive N—H...O and N—H...N hydrogen bonding and weak C—H...Cl and C—H...O hydrogen bonding.

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

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


    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.

  7. 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


    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.

  8. Quantitative and qualitative aspects of topoisomerase I and II alpha and beta in untreated and platinum/cyclophosphamide treated malignant ovarian tumors

    NARCIS (Netherlands)

    van der Zee, A G; de Jong, Steven; Keith, W N; Hollema, H; Boonstra, H; de Vries, Liesbeth


    Quantitative and qualitative aspects of topoisomerase (Topo) I and II were studied in 17 malignant ovarian tumors [eight untreated and nine after platinum/cyclophosphamide (Pt/Cy) chemotherapy]. Median Topo II catalytic activity was lower (P <0.05) in tumors after Pt/Cv chemotherapy in comparison to

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

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


    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.

  10. Electroanalytical method for determination of lead(II) in orange and apple using kaolin modified platinum electrode. (United States)

    El Mhammedi, M A; Achak, M; Bakasse, M; Chtaini, A


    This paper reports on the use of platinum electrode modified with kaolin (K/Pt) and square wave voltammetry for analytical detection of trace lead(II) in pure water, orange and apple samples. The electroanalytical procedure for determination of the Pb(II) comprises two steps: the chemical accumulation of the analyte under open-circuit conditions followed by the electrochemical detection of the preconcentrated species using square wave voltammetry. The analytical performances of the extraction method has been explored by studying the incubating time, and effect of interferences due to other ions. During the preconcentration step, Pb(II) was accumulated on the surface of the kaolin. The observed detection and quantification limits in pure water were 3.6x10(-9)molL(-1) and 1.2x10(-8)molL(-1), respectively. The precision of the method was also determined; the results was 2.35% (n=5).

  11. Building-up novel coordination polymer with Zn(II) porphyrin dimer: Synthesis, structures, surface morphology and effect of axial ligands

    Indian Academy of Sciences (India)

    Sk Asif Ikbal; Sanfaori Brahma; Avinash Dhamija; Sankar Prasad Rath


    Highly flexible Zn(II)1,2-bis(meso-octaethylporphyrin)ethane (1) has been used as host in which two porphyrin rings are found to be face-to-face in non-coordinating solvents. Upon addition of one relatively smaller 4,4′-dipyridine (L1) and one extended N,N′-bispyridine-4-yl-methylene ethylenediamine (L2) guest ligands, the syn conformation of 1 is switched to the anti complexes 1·(L1)2 and 1·L2, respectively. Single crystal X-ray structures of all the complexes are reported in which a stable one-dimensional coordination polymer is produced only in 1·L2 that is, to the best of our knowledge, the first structural report of 1D-coordination polymer with porphyrin dimer. Solution structures of the complexes along with binding studies in solution between 1 and L have also been investigated. The morphology of the polymeric complex 1·L2 on silicon wafer surface was examined by Atomic Force Microscopy (AFM) in which the crystalline islands of well defined facets of size ranging from 200-550 nm perimeter and a height of 20-40 nm have been observed.

  12. Synthesis, characterization and cytotoxic activity of novel platinum(II) iodido complexes. (United States)

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


    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).

  13. Reaction Mechanism for Olefin Exchange at Chloro Ethene Complexes of Platinum(II). (United States)

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


    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).

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


    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

  15. Electrochemical studies of tetraphenylporphyrin and vanadyl porphyrin

    Institute of Scientific and Technical Information of China (English)

    庄乾坤; 高小霞


    The electrochemical reductions and oxidations of tetraphenylporphyrin (TPP) and vanadyl por-phyrin (TPP-VO) were investigated in dimethylformamide at platinum,glass carbon and microdisk electrodes.A new eleetrode reaction mechanism of TPP and TPP-VO is proposed.The kinetic parameters have also been determined.In addition,the theory of molecular hybrid orbitals is used to explain the reduction and oxidation regularity of the transition metal porphyrms

  16. Theoretical investigation of hydrogen bonding between water and platinum(II): an atom in molecule (AIM) study (United States)

    Li, Yan; Zhang, Guiqiu; Chen, Dezhan


    Recently, Rizzato et al. [Angew. Chem. Int. Ed. 49, 7440 (2010)] [1] reported a hydrogen-bonding-like interaction between a water molecule and a d8 metal ion (PtII) based on neutron diffraction, and provided the first crystallographic evidence for this interaction. We studied the hydrogen bonding of the O-H ... Pt interaction theoretically using atoms in molecule (AIM) and natural bond orbital analysis (NBO) in the crystallographic geometries. The method used density functional theory (DFT) with the hybrid B3LYP function. For platinum atoms, we used the Los Alamos National Laboratory 2-Double-Zeta (LANL2DZ) basis set, and for the other atoms we used 6-311++G(d,p) basis sets. Criteria based on a topological analysis of the electron density were used in order to characterize the nature of interactions in the complexes. The main purpose of the present work is to provide an answer to the following questions: Why can a filled d orbital of square-planar d8 metal ions such as platinum(II) also act as hydrogen-bond acceptors? Can a study based on the electron charge density answer this question? A good correlation between the density at the intermolecular bond critical point and the energy interaction was found. The interaction is mainly closed-shell and there is some charge transfer in this system.

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

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


    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

  18. Metal migration processes in homo- and heterobimetallic bismuth(III)-lead(II) porphyrin complexes: emergence of allosteric Newton's cradle-like devices. (United States)

    Najjari, Btissam; Le Gac, Stéphane; Roisnel, Thierry; Dorcet, Vincent; Boitrel, Bernard


    Metal ion migration in a bis-strapped porphyrin ligand with overhanging carboxylate groups has been investigated in solution. Two types of homobimetallic complexes are generated with Pb(II) and Bi(III) cations, which stand on both sides of the macrocycle: (i) a dissymmetric complex with one cation bound to the porphyrin N core and the other cation hung over the N core through bonding with a carboxylate of a strap; (ii) a C(2)-symmetric complex with both cations coordinated to the N core and to the carboxylate groups of the straps. Variable-temperature NMR studies and 2D rotational Overhauser effect spectroscopy NMR experiments have shown that in the former dissymmetric complexes, the two cations undergo a coupled intramolecular migration resulting in exchange of their coordination modes. Such complexes constitute active states of Newton's cradle-like devices (NCDs), with the ion migration rate depending on the lability of the metal-ligand interactions [Pb(II) faster than Bi(III) NCDs]. On the other hand, the C(2)-symmetric complexes constitute either an inactive state [with Pb(II)] or a resting state [with Bi(III)] of an NCD, since they correspond respectively to a precursor or an intermediate in the motion of the cations. The NCDs are under both allosteric and acid-base control: (i) with Pb(II), the addition of an allosteric effector such as an acetate anion to the medium allows the conversion of the symmetric form to the dissymmetric one, thus triggering the Newton's cradle-like motion of the cations; (ii) with Bi(III), a lifted state was converted to a resting one by the addition of protons and then restored by the addition of a base. As an extension to nondegenerate systems, a heterobimetallic Bi(III)-Pb(II) complex was selectively obtained, and it constitutes a frozen lifted state of a dissymmetric NCD. All of these homo- and hetero-NCDs could be successively formed by selective metal ion exchange. These unique findings open the way to novel tristable devices.

  19. 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. (United States)

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


    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.

  20. Three Short Stories about Hexaarylbenzene-Porphyrin Scaffolds. (United States)

    Lungerich, Dominik; Hitzenberger, Jakob F; Donaubauer, Wolfgang; Drewello, Thomas; Jux, Norbert


    A feasible two-step synthesis and characterization of a full series of hexaarylbenzene (HAB) substituted porphyrins and tetrabenzoporphyrins is presented. Key steps represent the microwave-assisted porphyrin condensation and the statistical Diels-Alder reaction to the desired HAB-porphyrins. Regarding their applications, they proved to be easily accessible and effective high molecular mass calibrants for (MA)LDI mass spectrometry. The free-base and zinc(II) porphyrin systems, as well as the respective tetrabenzoporphyrins, demonstrate in solid state experiments strong red- and near-infrared-light emission and are potentially interesting for the application in "truly organic" light-emitting devices. Lastly, they represent facile precursors to large polycyclic aromatic hydrocarbon (PAH) substituted porphyrins. We prepared the first tetra-hexa-peri-hexabenzocoronene substituted porphyrin, which represents the largest prepared PAH-porphyrin conjugate to date. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Porphyrin amino acids-amide coupling, redox and photophysical properties of bis(porphyrin) amides. (United States)

    Melomedov, Jascha; Wünsche von Leupoldt, Anica; Meister, Michael; Laquai, Frédéric; Heinze, Katja


    New trans-AB2C meso-substituted porphyrin amino acid esters with meso-substituents of tunable electron withdrawing power (B = mesityl, 4-C6H4F, 4-C6H4CF3, C6F5) were prepared as free amines 3a-3d, as N-acetylated derivatives Ac-3a-Ac-3d and corresponding zinc(II) complexes Zn-Ac-3a-Zn-Ac-3d. Several amide-linked bis(porphyrins) with a tunable electron density at each porphyrin site were obtained from the amino porphyrin precursors by condensation reactions (4a-4d) and mono- and bis(zinc(II)) complexes Zn(2)-4d and Zn(1)Zn(2)-4d were prepared. The electronic interaction between individual porphyrin units in bis(porphyrins) 4 is probed by electrochemical experiments (CV, EPR), electronic absorption spectroscopy, steady-state and time-resolved fluorescence spectroscopy in combination with DFT/PCM calculations on diamagnetic neutral bis(porphyrins) 4 and on respective charged mixed-valent radicals 4(+/-). The interaction via the -C6H4-NHCO-C6H4- bridge, the site of oxidation and reduction and the lowest excited singlet state S1, is tuned by the substituents on the individual porphyrins and the metalation state.

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

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


    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.


    NARCIS (Netherlands)


    A phase I trial was conducted with lobaplatin (D-19466; 1,2-diamminomethyl-cyclobutane-platinum (II)-lactate) i.v. bolus daily for 5 days every 4 weeks. After entering five patients toxicity appeared to be related to renal function, therefore the individual dose (total dose 20-100 mg m-2 over 5

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

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


    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.

  5. Solid-state materials for anion sensing in aqueous solution: highly selective colorimetric and luminescence-based detection of perchlorate using a platinum(II) salt. (United States)

    Taylor, Stephen D; Howard, Whitney; Kaval, Necati; Hart, Robert; Krause, Jeanette A; Connick, William B


    The PF(6)(-) salt of a platinum(II) complex changes from yellow to red and becomes intensely luminescent upon exposure to aqueous ClO(4)(-). The response is remarkably selective. Spectroscopic changes are consistent with anion exchange resulting in shortening of the intramolecular PtPt distances between the square planar cations.

  6. Solid-state materials for anion sensing in aqueous solution: highly selective colorimetric and luminescence-based detection of perchlorate using a platinum(II) salt

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Stephen D.; Howard, Whitney; Kaval, Necati; Hart, Robert; Krause, Jeanette A.; Connick, William B. (UCIN); (Shepherd)


    The PF{sub 6}{sup -} salt of a platinum(II) complex changes from yellow to red and becomes intensely luminescent upon exposure to aqueous ClO{sub 4}{sup -}. The response is remarkably selective. Spectroscopic changes are consistent with anion exchange resulting in shortening of the intramolecular Pt***Pt distances between the square planar cations.

  7. Crystal structure of μ-fluorido-bis{(η4-cyclooctadiene[hexafluoridoantimonato(V]platinum(II} hexafluoridoantimonate(V hydrogen fluoride 0.75-solvate

    Directory of Open Access Journals (Sweden)

    Konrad Seppelt


    Full Text Available In the complex cation of the binuclear solvated title salt, [Pt2F(SbF62(C8H122]SbF6·0.75HF, an F atom bridges the two platinum(II atoms with a bond angle of 123.3 (2°. The corresponding Pt—F bond lengths are in the range of other fluorine-bridged binuclear platinum(II complexes. Two of the three SbF6− anions each coordinate with one F atom to one platinum(II atom. Including the η4-bound cyclooctadiene (COD ligands, the overall coordination sphere of each platinum(II atom is square-planar. The third SbF6− anion is not bound to the complex. Hydrogen fluoride is present in the crystal structure as a solvent disordered over three positions, each with an occupancy of 0.25. F...F distances of 2.5512 (7, 2.6076 (8 and 3.2215 (10 Å to surrounding SbF6− anions are indicative of F—H...F hydrogen-bonding interactions although no H atoms could be localized for the disordered solvent molecules. The resulting hydrogen-bonded network is three-dimensional.

  8. Phosphorescence parameters for platinum (II) organometallic chromophores: A study at the non-collinear four-component Kohn–Sham level of theory

    DEFF Research Database (Denmark)

    Norman, Patrick; Jensen, Hans Jørgen Aagaard


    A theoretical characterization of the phosphorescence decay traces of a prototypical platinum (II) organic chromophore has been conducted. The phosphorescence wavelength and radiative lifetime are predicted to equal 544 nm and 160 μs, respectively. The third triplet state is assigned as participa...

  9. Higher fluorescence in platinum(iv) orthometallated complexes of perylene imine compared with their platinum(ii) or palladium(ii) analogues. (United States)

    Expósito, J Emilio; Álvarez-Paíno, Marta; Aullón, Gabriel; Miguel, Jesús A; Espinet, Pablo


    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.

  10. Crystal structure of [5-bromo-2-(pyridin-2-yl-κNphenyl-κC1](pentane-2,4-dionato-κ2O,O′platinum(II

    Directory of Open Access Journals (Sweden)

    Keito Fukuda


    Full Text Available The title cyclometalated platinum(II complex with 2-(4-bromophenylpyridinato and acetylacetonato ligands, [Pt(C11H7BrN(C5H7O2], consists of two crystallographically non-equivalent dimers, each stacked by π–π interactions with distances of ≃ 3.4 Å. In both dimers, the platinum(II complexes are arranged antiparallel to each other. Each complex exhibits a slightly distorted square-planar coordination environment around the central Pt(II atom. The dihedral angles between two chelate rings including the PtII atom in these complexes are 0.08 (12 and 1.54 (9°.

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

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


    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.

  12. Antileukemic properties of combinations of radiation and malonato(1,2-diaminocyclohexane) platinum(ii) (NSC-224964). (United States)

    Morris, C R; Blackwell, L H; Loveless, V S


    Mean survival times were increased an average of 23, 53 and 61%, when 10, 15, and 20 mg/kg, respectively, of the organoplatinum congener, malonato(1,2-diaminocyclohexane) platinum(II)(NSC-224964), was given as the only treatment modality to BDF1 mice bearing 1-day-old L1210 leukemia. When a single dose of 10 mg/kg was combined with either 300 or 100 R on day 1 only, the anticipated response (ILS = 30 and 38%, respectively) based on the additive effects of the single modalities was surpassed by 26 and 21%, respectively (i.e. extent of therapeutic synergism). When divided doses of radiation (200 R/day x 3 days) were combined with 15 or 20 mg/kg of NSC-224964, survival times were enhanced an average of 15% (extent of synergism) greater than would be expected if these modalities were acting through an additive process(es).

  13. 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


    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.

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


    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

  15. Activation volume measurement for C[bond]H activation. Evidence for associative benzene substitution at a platinum(II) center. (United States)

    Procelewska, Joanna; Zahl, Achim; van Eldik, Rudi; Zhong, H Annita; Labinger, Jay A; Bercaw, John E


    The reaction of the platinum(II) methyl cation [(N-N)Pt(CH(3))(solv)](+) (N-N = ArN[double bond]C(Me)C(Me)[double bond]NAr, Ar = 2,6-(CH(3))(2)C(6)H(3), solv = H(2)O (1a) or TFE = CF(3)CH(2)OH (1b)) with benzene in TFE/H(2)O solutions cleanly affords the platinum(II) phenyl cation [(N-N)Pt(C(6)H(5))(solv)](+) (2). High-pressure kinetic studies were performed to resolve the mechanism for the entrance of benzene into the coordination sphere. The pressure dependence of the overall second-order rate constant for the reaction resulted in Delta V(++) = -(14.3 +/- 0.6) cm(3) mol(-1). Since the overall second order rate constant k = K(eq)k(2), Delta V(++) = Delta V degrees (K(eq)) + Delta V(++)(k(2)). The thermodynamic parameters for the equilibrium constant between 1a and 1b, K(eq) = [1b][H(2)O]/[1a][TFE] = 8.4 x 10(-4) at 25 degrees C, were found to be Delta H degrees = 13.6 +/- 0.5 kJ mol(-1), Delta S degrees = -10.4 +/- 1.4 J K(-1) mol(-1), and Delta V degrees = -4.8 +/- 0.7 cm(3) mol(-1). Thus DeltaV(++)(k(2)) for the activation of benzene by the TFE solvento complex equals -9.5 +/- 1.3 cm(3) mol(-1). This significantly negative activation volume, along with the negative activation entropy for the coordination of benzene, clearly supports the operation of an associative mechanism.

  16. Inverted porphyrins and expanded porphyrins: An overview

    Indian Academy of Sciences (India)

    S K Pushpan; S Venkatraman; V G Anand; J Sankar; H Rath; T K Chandrashekar


    Porphyrins and metallopophyrins have attracted the attention of chemists for the past 100 years or more owing to their widespread involvement in biology. More recently, synthetic porphyrins and porphyrin-like macrocycles have attracted the attention of researchers due to their diverse applications as sensitizers for photodynamic therapy, MRI contrasting agents, and complexing agents for larger metal ions and also for their anion binding abilities. The number of -electrons in the porphyrin ring can be increased either by increasing the number of conjugated double bonds between the pyrrole rings or by increasing the number of heterocyclic rings. Thus, 22 sapphyrins, 26 rubyrins, 30 heptaphyrins, 34 octaphyrins and higher cyclic polypyrrole analogues containing 40, 48, 64, 80 and 96 systems have recently been reported in the literature. These macrocycles show rich structural diversity where normal and different kinds of inverted structures have been identified. In this review, an attempt has been made to collect the literature of the inverted porphyrins and expanded porphyrins reported until December 2001. Since the meso aryl expanded porphyrins have tendency to form both inverted and non-inverted structures more emphasis has been given to meso aryl expanded porphyrins.

  17. 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


    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)

  18. Enhanced Conversion Efficiencies in Dye-Sensitized Solar Cells Achieved through Self-Assembled Platinum(II) Metallacages (United States)

    He, Zuoli; Hou, Zhiqiang; Xing, Yonglei; Liu, Xiaobin; Yin, Xingtian; Que, Meidan; Shao, Jinyou; Que, Wenxiu; Stang, Peter J.


    Two-component self-assembly supramolecular coordination complexes with particular photo-physical property, wherein unique donors are combined with a single metal acceptor, can be utilized for many applications including in photo-devices. In this communication, we described the synthesis and characterization of two-component self-assembly supramolecular coordination complexes (SCCs) bearing triazine and porphyrin faces with promising light-harvesting properties. These complexes were obtained from the self-assembly of a 90° Pt(II) acceptor with 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPyT) or 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (TPyP). The greatly improved conversion efficiencies of the dye-sensitized TiO2 solar cells were 6.79 and 6.08 respectively, while these SCCs were introduced into the TiO2 nanoparticle film photoanodes. In addition, the open circuit voltage (Voc) of dye-sensitized solar cells was also increased to 0.769 and 0.768 V, which could be ascribed to the inhibited interfacial charge recombination due to the addition of SCCs.

  19. 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. (United States)

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


    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

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

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


    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

  1. Linker design for the modular assembly of multifunctional and targeted platinum(ii)-containing anticancer agents. (United States)

    Ding, S; Bierbach, U


    A versatile and efficient modular synthetic platform was developed for assembling multifunctional conjugates and targeted forms of platinum-(benz)acridines, a class of highly cytotoxic DNA-targeted hybrid agents. The synthetic strategy involved amide coupling between succinyl ester-modified platinum compounds (P1, P2) and a set of 11 biologically relevant primary and secondary amines (N1-N11). To demonstrate the feasibility and versatility of the approach, a structurally and functionally diverse range of amines was introduced. These include biologically active molecules, such as rucaparib (a PARP inhibitor), E/Z-endoxifen (an estrogen receptor antagonist), and a quinazoline-based tyrosine kinase inhibitor. Micro-scale reactions in Eppendorf tubes or on 96-well plates were used to screen for optimal coupling conditions in DMF solution with carbodiimide-, uronium-, and phosphonium-based compounds, as well as other common coupling reagents. Reactions with the phosphonium-based coupling reagent PyBOP produced the highest yields and gave the cleanest conversions. Furthermore, it was demonstrated that the chemistry can also be performed in aqueous media and is amenable to parallel synthesis based on multiple consecutive reactions in DMF in a "one-tube" format. In-line LC-MS was used to assess the stability of the conjugates in physiologically relevant buffers. Hydrolysis of the conjugates occurs at the ester moiety and is facilitated by the aquated metal moiety under low-chloride ion conditions. The rate of ester cleavage greatly depends on the nature of the amine component. Potential applications of the linker technology are discussed.

  2. Intriguing Influence of -COOH-Driven Intermolecular Aggregation and Acid-Base Interactions with N,N-Dimethylformamide on the Second-Order Nonlinear-Optical Response of 5,15 Push-Pull Diarylzinc(II) Porphyrinates. (United States)

    Orbelli Biroli, Alessio; Tessore, Francesca; Righetto, Stefania; Forni, Alessandra; Macchioni, Alceo; Rocchigiani, Luca; Pizzotti, Maddalena; Di Carlo, Gabriele


    A series of 5,15 push-pull meso-diarylzinc(II) porphyrinates, carrying one or two -COOH or -COOCH3 acceptor groups and a -OCH3 or a -N(CH3)2 donor group, show in N,N-dimethylformamide and CHCl3 solutions a negative and solvent-dependent second-order nonlinear-optical (NLO) response measured by the electric-field-induced second-harmonic generation (EFISH) technique, different from the structurally related zinc(II) porphyrinate carrying a -N(CH3)2 donor group and a -NO2 acceptor group, where a still solvent-dependent but positive EFISH second-order response was previously reported. Moreover, when a -N(CH3)2 donor group and a -COOH acceptor group are part of a sterically hindered 2,12 push-pull β-pyrrolic-substituted tetraarylzinc(II) porphyrinate, the EFISH response is positive and solvent-independent. In order to rationalize these rather intriguing series of observations, EFISH measurements have been integrated by electronic absorption and IR spectroscopic investigations and by density functional theory (DFT) and coupled-perturbed DFT theoretical and (1)H pulsed-gradient spin-echo NMR investigations, which prompt that the significant concentration effects and the strong influence of the solvent nature on the NLO response are originated by a complex whole of different aggregation processes induced by the -COOH group.

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

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


    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.

  4. N -annulated perylene as an efficient electron donor for porphyrin-based dyes: Enhanced light-harvesting ability and high-efficiency Co(II/III)-based dye-sensitized solar cells

    KAUST Repository

    Luo, Jie


    Porphyrin-based dyes recently have become good candidates for dye-sensitized solar cells (DSCs). However, the bottleneck is how to further improve their light-harvesting ability. In this work, N-annulated perylene (NP) was used to functionalize the Zn-porphyrin, and four "push-pull"-type NP-substituted and fused porphyrin dyes with intense absorption in the visible and even in the near-infrared (NIR) region were synthesized. Co(II/III)-based DSC device characterizations revealed that dyes WW-5 and WW-6, in which an ethynylene spacer is incorporated between the NP and porphyrin core, showed pantochromatic photon-to-current conversion efficiency action spectra in the visible and NIR region, with a further red-shift of about 90 and 60 nm, respectively, compared to the benchmark molecule YD2-o-C8. As a result, the short-circuit current density was largely increased, and the devices displayed power conversion efficiencies as high as 10.3% and 10.5%, respectively, which is comparable to that of the YD2-o-C8 cell (η = 10.5%) under the same conditions. On the other hand, the dye WW-3 in which the NP unit is directly attached to the porphyrin core showed a moderate power conversion efficiency (η = 5.6%) due to the inefficient π-conjugation, and the NP-fused dye WW-4 exhibited even poorer performance due to its low-lying LUMO energy level and nondisjointed HOMO/LUMO profile. Our detailed physical measurements (optical and electrochemical), density functional theory calculations, and photovoltaic characterizations disclosed that the energy level alignment, the molecular orbital profile, and dye aggregation all played very important roles on the interface electron transfer and charge recombination kinetics. © 2013 American Chemical Society.

  5. N-annulated perylene as an efficient electron donor for porphyrin-based dyes: enhanced light-harvesting ability and high-efficiency Co(II/III)-based dye-sensitized solar cells. (United States)

    Luo, Jie; Xu, Mingfei; Li, Renzhi; Huang, Kuo-Wei; Jiang, Changyun; Qi, Qingbiao; Zeng, Wangdong; Zhang, Jie; Chi, Chunyan; Wang, Peng; Wu, Jishan


    Porphyrin-based dyes recently have become good candidates for dye-sensitized solar cells (DSCs). However, the bottleneck is how to further improve their light-harvesting ability. In this work, N-annulated perylene (NP) was used to functionalize the Zn-porphyrin, and four "push-pull"-type NP-substituted and fused porphyrin dyes with intense absorption in the visible and even in the near-infrared (NIR) region were synthesized. Co(II/III)-based DSC device characterizations revealed that dyes WW-5 and WW-6, in which an ethynylene spacer is incorporated between the NP and porphyrin core, showed pantochromatic photon-to-current conversion efficiency action spectra in the visible and NIR region, with a further red-shift of about 90 and 60 nm, respectively, compared to the benchmark molecule YD2-o-C8. As a result, the short-circuit current density was largely increased, and the devices displayed power conversion efficiencies as high as 10.3% and 10.5%, respectively, which is comparable to that of the YD2-o-C8 cell (η = 10.5%) under the same conditions. On the other hand, the dye WW-3 in which the NP unit is directly attached to the porphyrin core showed a moderate power conversion efficiency (η = 5.6%) due to the inefficient π-conjugation, and the NP-fused dye WW-4 exhibited even poorer performance due to its low-lying LUMO energy level and nondisjointed HOMO/LUMO profile. Our detailed physical measurements (optical and electrochemical), density functional theory calculations, and photovoltaic characterizations disclosed that the energy level alignment, the molecular orbital profile, and dye aggregation all played very important roles on the interface electron transfer and charge recombination kinetics.

  6. In vitro cytotoxicity, pharmacokinetics and ex vivo pharmacodynamics of a new platinum compound, cis-malonato [(4R,5R-4,5-bis(aminomethyl)-1,3-dioxolane-2-spiro-1'-cyclopentane] platinum (II). (United States)

    Kim, D K; Kim, H T; Cho, Y B; Kim, T S; Kim, K H; Hong, W S


    The in vitro cytotoxicity of a new platinum complex, cis-malonato [(4R, 5R)-4,5-bis(aminomethyl)-1,3-dioxolane 2- spiro 1' cyclo-pentane]platinum(II) (SKI 2054R) and cisplatin (CDDP) was evaluated against two human stomach adenocarcinoma cell lines (MKN-45 and KATO III) and a human lung adenocarcinoma cell line (PC-14). The in vitro 50% inhibitory concentration (IC50) values of SKI 2054R and CDDP against MKN-45, KATO III, and PC-14 were 1.21 and 0.51, 2.11 and 0.83, and 2.90 and 0.77 micrograms/ml, respectively. The pharma-cokinetic and ex vivo pharmacodynamic studies on SKI 2054R and CDDP were performed in beagle dogs. Equitoxic doses of SKI 2054R and CDDP (7.0 and 3.0 mg/kg, respectively) were administered i.v. bolus to beagle dose in a randomized crossover study. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for the two drugs declined in a biexponential fashion. The mean area under the concentration-tine curve (AUC(0)--> infinity) determined for ultrafiltrable platinum derived from SKI 2054R, as an active component was 6.61 +/- 2.34 micrograms . h/ml (mean +/- S.D.), with an initial half-life of 0.26 +/- 0.14 h, a terminal half-life of 1.57 +/- 0.71 hour, a total clearance of 17.65 +/- 4.99 ml/min/kg, and a steady-state volume of distribution of 1.46 +/- 0.11 l/kg. The ex vivo antitumor activity of SKI 2054R was assessed using the ultrafiltrable plasma against MKN-45, KATO III, and PC-14 by tetrazolium-dye (MTT) assay and was compared with that of CDDP using the antitumor index (ATI) determined from the ex vivo pharmacodynamic results of inhibition rates (%) versus time curves. The mean ATI value recorded for SKI 2054R was higher than that noted for CDDP; however, statistical difference was not observed between SKI 2054R and CDDP, suggesting that the antitumor activity of SKI 2054R is comparable to that of CDDP. These results suggest that SKI 2054R is a new



    Ducommun, Y.; Nichols, P; Helm, L.; Elding, L.; Merbach, A.


    The very slow water exchange on Pt(H2O)2+4 was studied in the temperature range 273 to 334 K and pressure range 0.1 to 228 MPa by 17O FTNMR, following the increase in height of the signal from bound water observed when platinum(II) solutions are mixed with 170 enriched water. The much faster water exchange on Pd(H2O)2+4 studied in the temperature range 240 to 345 K and pressure range 0.1 to 260 MPa, by measuring the 17O FTNMR linewidths of the bound water resonance at 27.1 and 48.7 MHz. Compl...

  8. Interactions of porphyrins and transfer RNA. (United States)

    Foster, N; Singhal, A K; Smith, M W; Marcos, N G; Schray, K J


    The interactions of the free base porphyrin, tetra-(4N-methylpyridyl)porphyrin and its copper(II), manganese(III) and zinc(II) complexes with brewer's yeast type V phenylalaninyl tRNA were evaluated by UV-visible spectroscopy, circular dichroism and melting temperature studies over a range of magnesium ion concentrations and ionic strengths. Scatchard analysis of absorption spectra of the porphyrins in the presence of tRNA showed the free base, copper and zinc porphyrins to have binding constants of 7.3 X 10(7), 1.7 X 10(6) and 2.3 X 10(8), respectively; the manganese(III) complex did not demonstrate changes in its electronic spectra that enable the calculation of a binding constant. The results of the spectroscopic studies indicate a mode of binding for the free base, copper(II) and zinc(II) complexes that is neither intercalative nor simply outside electrostatic. The magnitude of the binding constants and the UV-visible results support intercalation, but the analyses of the thermal denaturation studies and the circular dichroism evaluations suggest that the porphyrins are associating at a single site in a fold of the tertiary structure of the tRNA close to several crucial hydrogen bonds, perhaps in the vicinity of the P10 loop. That the manganese(III) complex does not bind in this site points to constraints on the axial thickness of a molecule that may be accommodated in this locus.

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

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


    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.

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

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


    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.

  11. Magnesium(II) polyporphine: The first electron-conducting polymer with directly linked unsubstituted porphyrin units obtained by electrooxidation at a very low potential

    Energy Technology Data Exchange (ETDEWEB)

    Vorotyntsev, Mikhail A., E-mail: mv@u-bourgogne.f [Institut de Chimie Moleculaire de l' Universite de Bourgogne, Universite de Bourgogne, CNRS UMR 5260, 21078 Dijon (France); Konev, Dmitry V. [Institut de Chimie Moleculaire de l' Universite de Bourgogne, Universite de Bourgogne, CNRS UMR 5260, 21078 Dijon (France); Devillers, Charles H., E-mail: charles.devillers@u-bourgogne.f [Institut de Chimie Moleculaire de l' Universite de Bourgogne, Universite de Bourgogne, CNRS UMR 5260, 21078 Dijon (France); Bezverkhyy, Igor; Heintz, Olivier [Institut Carnot de Bourgogne, Universite de Bourgogne, CNRS UMR 5209, 21078 Dijon (France)


    Electrooxidation of magnesium(II) porphine, a totally unsubstituted porphyrin, in acetonitrile solution under potentiostatic or potentiodynamic regime leads to a polymer film at the electrode surface. Polymer deposition takes place at extremely low potential, several hundred mV less positive even compared to the deposition potential for pyrrole or EDOT (at identical monomer concentrations) in the same solvent. Film thickness can be controlled by the passed deposition charge. This material and its THF-soluble fraction have been characterized by various electrochemical methods as well as by UV-visible and IR spectroscopies, XPS, XRD and MALDI-TOF techniques. This analysis has allowed us to conclude that the polymer film is composed by chains of Mg porphine building blocks, with single bonds between the neighboring units. In the course of the potential sweep, this polymer film demonstrates a redox response resembling that of polythiophene-coated electrodes. Namely, the film is electroactive and electronically conducting in two potential ranges (p- and n-doping), which are separated by a broad interval where the film possesses a much higher resistance. The polymer may be switched between all these redox states repeatedly by the change of the potential. The film capacitance in the electroactive potential intervals is proportional to the deposition charge.

  12. Enhanced photocatalytic degradation activity over TiO2 nanotubes co-sensitized by reduced graphene oxide and copper(II) meso-tetra(4-carboxyphenyl)porphyrin (United States)

    Wei, Meng; Wan, Junmin; Hu, Zhiwen; Peng, Zhiqin; Wang, Bing


    In this paper, TiO2 nanotubes (TNT) co-sensitized with copper(II) meso-tetra(4-carboxyphenyl)porphyrin (CuTCPP) and reduced graphene oxide nanosheets (rGO), which was fabricated through two-step improved hydrothermal method and heating reflux process. The effect of rGO and CuTCPP on the co-photocatalytic behavior of TNT for the degradation of Methylene Blue (MB) were measured under visible light irradiation. The photocatalysts have been characterized and analyzed by high-resolution transmission electron microscopy (TEM), selected area electronic diffraction (SAED), elemental mapping by energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and electron paramagnetic resonance (EPR). The results provide a deeper insight into the co-photocatalytic mechanism of CuTCPP/rGO-TNT nanocomposites. The degradation results showed a purification of more than 95% MB in wastewater, which is about 5 times higher than that of the pure TNT. The results also confirm the prepared CuTCPP/rGO-TNT nanocomposites possess superior co-photocatalytic activities.

  13. In situ FT-IR and UV-vis spectroscopy of the low-temperature NO disproportionation mediated by solid state manganese(II) porphyrinates. (United States)

    Martirosyan, Garik G; Azizyan, Arsen S; Kurtikyan, Tigran S; Ford, Peter C


    The heterogeneous reaction between NO gas and sublimed layers of manganese(II) porphyrinato complexes Mn(Por) (Por = TPP (tetraphenylporphyrinato dianion), TMP (tetramesitylporphyrinato dianion), or TPP(d20) (perdeuterated tetraphenylporphyrinato dianion)) has been monitored by IR and optical spectroscopy over the temperature range of 77 K to room temperature. These manganese porphyrins promote NO disproportionation to NO2 species and N2O, and the reaction proceeds via several distinct stages. At 90 K, the principal species observed spectrally are the nitric oxide dimer, cis-ONNO, two manganese nitrosyls, the simple NO adduct Mn(Por)(NO), and another intermediate (1) that is apparently critical to the disproportionation mechanism. This key intermediate is formed prior to N2O evolution, and proposals regarding its likely structure are offered. When the system is warmed to 130 K, the disproportionation products, N2O and the O-coordinated nitrito complex Mn(Por)(NO)(ONO) (2), are formed. IR spectral changes show that, upon further warming to 200 K, 2 isomerizes into the N-bonded nitro linkage isomer Mn(Por)(NO)(NO2) (3). After it is warmed to room temperature, the latter species loses NO and converts to the known 5-coordinate nitrito complex Mn(Por)(ONO) (4).

  14. Synthesis of porphyrin nanostructures (United States)

    Fan, Hongyou; Bai, Feng


    The present disclosure generally relates to self-assembly methods for generating porphyrin nanostructures. For example, in one embodiment a method is provided that includes preparing a porphyrin solution and a surfactant solution. The porphyrin solution is then mixed with the surfactant solution at a concentration sufficient for confinement of the porphyrin molecules by the surfactant molecules. In some embodiments, the concentration of the surfactant is at or above its critical micelle concentration (CMC), which allows the surfactant to template the growth of the nanostructure over time. The size and morphology of the nanostructures may be affected by the type of porphyrin molecules used, the type of surfactant used, the concentration of the porphyrin and surfactant the pH of the mixture of the solutions, and the order of adding the reagents to the mixture, to name a few variables.

  15. 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)


    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.

  16. 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:; Karczmarczyk, Urszula; Maurin, Michal [Department of Radiopharmaceuticals, National Medicines Institute, 00-725 Warsaw (Poland)


    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

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

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    Violeta Sicilia


    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.

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

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


    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.

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

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


    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.

  20. Comparative Study on the Efficiency of the Photodynamic Inactivation of Candida albicans Using CdTe Quantum Dots, Zn(II Porphyrin and Their Conjugates as Photosensitizers

    Directory of Open Access Journals (Sweden)

    Osnir S. Viana


    Full Text Available The application of fluorescent II-VI semiconductor quantum dots (QDs as active photosensitizers in photodymanic inactivation (PDI is still being evaluated. In the present study, we prepared 3 nm size CdTe QDs coated with mercaptosuccinic acid and conjugated them electrostatically with Zn(II meso-tetrakis (N-ethyl-2-pyridinium-2-yl porphyrin (ZnTE-2-PyP or ZnP, thus producing QDs-ZnP conjugates. We evaluated the capability of the systems, bare QDs and conjugates, to produce reactive oxygen species (ROS and applied them in photodynamic inactivation in cultures of Candida albicans by irradiating the QDs and testing the hypothesis of a possible combined contribution of the PDI action. Tests of in vitro cytotoxicity and phototoxicity in fibroblasts were also performed in the presence and absence of light irradiation. The overall results showed an efficient ROS production for all tested systems and a low cytotoxicity (cell viability >90% in the absence of radiation. Fibroblasts incubated with the QDs-ZnP and subjected to irradiation showed a higher cytotoxicity (cell viability <90% depending on QD concentration compared to the bare groups. The PDI effects of bare CdTe QD on Candida albicans demonstrated a lower reduction of the cell viability (~1 log10 compared to bare ZnP which showed a high microbicidal activity (~3 log10 when photoactivated. The QD-ZnP conjugates also showed reduced photodynamic activity against C. albicans compared to bare ZnP and we suggest that the conjugation with QDs prevents the transmembrane cellular uptake of the ZnP molecules, reducing their photoactivity.

  1. 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


    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.

  2. Novel Platinum(II) compounds modulate insulin-degrading enzyme activity and induce cell death in neuroblastoma cells. (United States)

    Tundo, Grazia R; Sbardella, Diego; De Pascali, Sandra A; Ciaccio, Chiara; Coletta, Massimo; Fanizzi, Francesco P; Marini, Stefano


    The properties of three novel Platinum(II) compounds toward the insulin-degrading enzyme (IDE) enzymatic activity have been investigated under physiological conditions. The rationale of this study resides on previous observations that these compounds, specifically designed and synthesized by some of us, induce apoptosis in various cancer cell lines, whereas IDE has been proposed as a putative oncogene involved in neuroblastoma onset and progression. Two of these compounds, namely [PtCl(O,O'-acac)(DMSO)] and [Pt(O,O'-acac)(γ-acac)(DMS)], display a modulatory behavior, wherefore activation or inhibition of IDE activity occurs over different concentration ranges (suggesting the existence of two binding sites on the enzyme). On the other hand, [Pt(O,O'-acac)(γ-acac)(DMSO)] shows a typical competitive inhibitory pattern, characterized by a meaningful affinity constant (K i  = 0.95 ± 0.21 μM). Although all three compounds induce cell death in neuroblastoma SHSY5Y cells at concentrations exceeding 2 μM, the two modulators facilitate cells' proliferation at concentrations ≤ 1.5 μM, whereas the competitive inhibitor [Pt(O,O'-acac)(γ-acac)(DMSO)] only shows a pro-apoptotic activity at all investigated concentrations. These features render the [Pt(O,O'-acac)(γ-acac)(DMSO)] a promising "lead compound" for the synthesis of IDE-specific inhibitors (not characterized yet) with therapeutic potentiality.

  3. Inorganic nanocarriers for platinum drug delivery

    Directory of Open Access Journals (Sweden)

    Ping’an Ma


    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.

  4. Dichlorido[N-(N,N-dimethylcarbamimidoyl-N′,N′,4-trimethylbenzohydrazonamide]platinum(II nitromethane hemisolvate

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    Dmitrii S. Bolotin


    Full Text Available In the title compound, [PtCl2(C13H21N5]·0.5CH3NO2, the PtII atom is coordinated in a slightly distorted square-planar geometry by two Cl atoms and two N atoms of the bidentate ligand. The (1,3,5-triazapentadienePtII metalla ring is slightly bent and does not conjugate with the aromatic ring. In the crystal, N—H...Cl hydrogen bonds link the complex molecules, forming chains along [001]. The nitromethane solvent molecule shows half-occupancy and is disordered over two sets of sites about an inversion centre.

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

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


    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

  6. Unassisted eta2-coordination of polycyclic aromatic hydrocarbons to platinum(II). (United States)

    Berenguer, Jesús R; Forniés, Juan; Martín, L Francisco; Martín, Antonio; Menjón, Babil


    The coordination of phenanthrene to the d8 Pt(II) center in (SP-4-2)-[Pt(C6F5)2(CO)(eta2-C14H10)] causes a slight pyramidalization at the metal-bound C atoms (C9 and C10), but no perceptible elongation of the corresponding C-C bond [C(13)-C(14) 132.0(5) vs. 133.8(5) pm in the free ligand].

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


    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.

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

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


    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.

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

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


    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.

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

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


    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

  11. Chloridocyclohexyl[(1,2,5,6-η-cycloocta-1,5-diene]platinum(II

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    Kwang Ha


    Full Text Available In the title complex, [Pt(C6H11Cl(C8H12], the PtII ion lies in a distorted square-planar environment defined by the Cl and cyclohexyl C atoms and the mid-points of the two π-coordinated double bonds of cycloocta-1,5-diene. As a result of the different trans influences of the Cl atom and the cyclohexyl group, the Pt—C bonds trans to the cyclohexyl group are longer than those trans to the Cl atom.

  12. Activity of phosphino palladium(II) and platinum(II) complexes against HIV-1 and Mycobacterium tuberculosis. (United States)

    Gama, Ntombenhle H; Elkhadir, Afag Y F; Gordhan, Bhavna G; Kana, Bavesh D; Darkwa, James; Meyer, Debra


    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.

  13. Platinum(II) phenanthroimidazole G-quadruplex ligand induces selective telomere shortening in A549 cancer cells. (United States)

    Mancini, Johanna; Rousseau, Philippe; Castor, Katherine J; Sleiman, Hanadi F; Autexier, Chantal


    Telomere maintenance, achieved by the binding of protective shelterin capping proteins to telomeres and by either telomerase or a recombination-based alternative lengthening of telomere (ALT) mechanism, is critical for cell proliferation and survival. Extensive telomere shortening or loss of telomere integrity activates DNA damage checkpoints, leading to cell senescence or death. Although telomerase upregulation is an attractive target for anti-cancer therapy, the lag associated with telomere shortening and the potential activation of ALT pose a challenge. An alternative approach is to modify telomere interactions with binding proteins (telomere uncapping). G-quadruplex ligands stabilize structures generated from single-stranded G-rich 3'-telomere end (G-quadruplex) folding, which in principle, cannot be elongated by telomerase, thus leading to telomere shortening. Ligands can also mediate rapid anti-proliferative effects by telomere uncapping. We previously reported that the G-quadruplex ligand, phenylphenanthroimidazole ethylenediamine platinum(II) (PIP), inhibits telomerase activity in vitro[47]. In the current study, a long-term seeding assay showed that PIP significantly inhibited the seeding capacity of A549 lung cancer cells and to a lesser extent primary MRC5 fibroblast cells. Importantly, treatment with PIP caused a significant dose- and time-dependent decrease in average telomere length of A549 but not MRC5 cells. Moreover, cell cycle analysis revealed a significant increase in G1 arrest upon treatment of A549 cells, but not MRC5 cells. Both apoptosis and cellular senescence may contribute to the anti-proliferative effects of PIP. Our studies validate the development of novel and specific therapeutic ligands targeting telomeric G-quadruplex structures in cancer cells.

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

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


    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.

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

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


    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.

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

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


    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.

  17. Pharmacokinetics and antitumor activity of a new platinum compound, cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3- dioxolane]platinum(II), as determined by ex vivo pharmacodynamics. (United States)

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


    The pharmacokinetics and ex vivo pharmacodynamics studies on cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3- dioxolane]platinum(II) (SKI 2053R, NSC D644591), cisplatin (CDDP), and carboplatin (CBDCA) were performed in beagle dogs. Equitoxic doses of SKI 2053R, CDDP, and CBDCA (7.5, 2.5, and 15.0 mg/kg, respectively) were given by i.v. bolus to three beagle dogs in a randomized crossover study. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for the three drugs declined in a biexponential fashion. The mean area under the concentration-time curve (AUC0-->infinity) determined for ultrafiltrable platinum derived from SKI 2053R, as an active component, was 7.72 +/- 2.74 micrograms h ml-1 (mean +/- SD), with an initial half-life of 0.37 +/- 0.20 h, a terminal half-life of 2.19 +/- 0.93 h, a total clearance of 16.83 +/- 4.76 ml min-1 kg-1, and a steady-state volume of distribution of 1.57 +/- 0.30 l/kg. The ex vivo antitumor activity of SKI 2053R was assessed using the ultrafiltrable plasma against two human lung-adenocarcinoma cell lines (PC-9 and PC-14) and five stomach-adenocarcinoma cell lines (MKN-45, KATO III, SNU-1, SNU-5, and SNU-16) by tetrazolium-dye (MTT) assay and was compared with that of CDDP and CBDCA using an antitumor index (ATI) determined from the ex vivo pharmacodynamic results of inhibition rates (%) versus time curves. The mean ATI value was shown to be ranked in the following order: SKI 2053R > CBDCA > CDDP. The mean ATI values recorded for SKI 2053R and CBDCA were significantly (P < 0.05) higher than that noted for CDDP; however, no statistically significant difference was observed between SKI 2053R and CBDCA, suggesting that the antitumor activity of SKI 2053R is superior to that of CDDP and is equivalent to that of CBDCA. These results suggest that SKI 2053R is a promising candidate for further development as a clinically useful

  18. Crystal structure of cis-diamminebis(nitrito-κN)platinum(II). (United States)

    Kahlenberg, Volker; Gelbrich, Thomas; Tessadri, Richard; Klauser, Frederik


    Single crystals of cis-[Pt(NO2)2(NH3)2], were obtained by means of hyper-saturation directly out of a plating electrolyte. The square-planar coordination environment of the divalent Pt(II) atom is formed by four N atoms belonging to two ammine and two monodentate nitrite ligands. The ligands adopt a cis configuration. The crystal structure contains stacks of close-packed mol-ecules which run parallel to [001]. There are nine crystallographically independent inter-molecular N-H⋯O hydrogen bonds, resulting in a hydrogen-bonded hxl-type framework in which each mol-ecule serves as an eight-connected node. Four of the nine distinct hydrogen bonds connect complexes which belong to the same close-packed column parallel to [001]. In contrast to the previously reported crystal structure of the trans isomer, the title structure does not display intra-molecular hydrogen bonding.

  19. Palladium(II) and platinum(II) complexes containing benzimidazole ligands: Molecular structures, vibrational frequencies and cytotoxicity (United States)

    Abdel Ghani, Nour T.; Mansour, Ahmed M.


    (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.

  20. Involvement of both Type I and Type II mechanisms in Gram-positive and Gram-negative bacteria photosensitization by a meso-substituted cationic porphyrin

    Energy Technology Data Exchange (ETDEWEB)

    Ergaieg, Karim; Seux, Rene [Laboratoire d' Etude et de Recherche en Environnement et Sante, National School of Public Health, Av. Pr. Leon Bernard, CS 74312, Rennes 35043 (France); Chevanne, Martine; Cillard, Josiane [Laboratoire de Biologie Cellulaire et Vegetale, UPRES 3891, UFR des Sciences Pharmaceutiques et Biologiques, University of Rennes 1, 2 Av. Pr. Leon Bernard, CS 34317, Rennes 35043 (France)


    A meso-substituted cationic porphyrin (TMPyP) showed a photocytotoxicity against Gram-positive and Gram-negative bacteria. In order to determine the mechanism involved in the phototoxicity of this photosensitizer, electron paramagnetic resonance (EPR) experiments with 2,2,6,6-tetramethyl-4-piperidone (TEMP), a specific probe for singlet oxygen, and the spin-trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) were carried out with illuminated TMPyP. An EPR signal characteristic of TEMP-singlet oxygen (TEMPO) adduct formation was observed, which could be ascribed to singlet oxygen ({sup 1}O{sub 2}) generated by TMPyP photosensitization. The signal for the DMPO spin adduct of superoxide anion (DMPO-OOH) was observed in DMSO solution but not in aqueous conditions. However, an EPR spectrum characteristic of the DMPO-hydroxyl radical spin adduct (DMPO-OH) was observed in aqueous conditions. The obtained results testify a primary hydroxyl radical ({sup .}OH) generation probably from superoxide anion (O{sub 2} {sup x} {sup -})via the Fenton reaction and/or via Haber-Weiss reaction. Gram-positive and Gram-negative bacteria inactivation by TMPyP photosensitization predominantly involved Type II reactions mediated by the formation of {sup 1}O{sub 2}, as demonstrated by the effect of quenchers for {sup 1}O{sub 2} and scavengers for {sup .}OH (sodium azide, thiourea, and dimethylsulphoxide). Participation of other active oxygen species cannot however be neglected since Type I reactions also had a significant effect, particularly for Gram-negative bacteria. For Gram-negative bacteria the photoinactivation rate was lower in the presence of superoxide dismutase, a specific O{sub 2} {sup x} {sup -} scavenger, and/or catalase, an enzyme which specifically eliminates H{sub 2}O{sub 2}, but was unchanged for Gram-positive bacteria. The generation of {sup 1}O{sub 2}, O{sub 2} {sup x} {sup -} and {sup .}OH by TMPyP photosensitization indicated that TMPyP maintained a photodynamic activity in

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

    Shahabadi, Nahid; Mohammadi, Somaye; Alizadeh, Robabeh


    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.

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

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


    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.

  3. PEGylated dendritic diaminocyclohexyl-platinum (II) conjugates as pH-responsive drug delivery vehicles with enhanced tumor accumulation and antitumor efficacy. (United States)

    Pan, Dayi; She, Wenchuan; Guo, Chunhua; Luo, Kui; Yi, Qiangying; Gu, Zhongwei


    Environmentally responsive peptide dendrimers loaded with drugs are suitable candidates for cancer therapy. In this study, we report the preparation and characterization of mPEGylated peptide dendrimer-linked diaminocyclohexyl platinum (II) (dendrimer-DACHPt) conjugates as pH-responsive drug delivery vehicles for tumor suppression in mice. The DACHPt has a molecular structure, is and activity closely related to oxaliplatin and was linked to dendrimer via N,O-chelate coordination. The products were pH-responsive and released drug significantly faster in acidic environments (pH 5.0) than pH 7.4. Consequently, the conjugates suppressed tumor growth better than clinical oxaliplatin(®) without inducing toxicity in an SKOV-3 human ovarian cancer xenograft. Through the systemic delivery of conjugates, 25-fold higher tumor platinum uptake at 36 h post-injection was seen observed due to the enhanced permeability and retention (EPR) effect thereby remarkably enhancing the therapeutic indexes of this small-molecule drug. Thus, the mPEGylated peptide dendrimer-linked DACH-platinum conjugates are novel potential drug delivery systems with implications in future ovarian cancer therapy.

  4. Soluble porphyrin polymers (United States)

    Gust, Jr., John Devens; Liddell, Paul Anthony


    Porphyrin polymers of Structure 1, where n is an integer (e.g., 1, 2, 3, 4, 5, or greater) ##STR00001## are synthesized by the method shown in FIGS. 2A and 2B. The porphyrin polymers of Structure 1 are soluble in organic solvents such as 2-MeTHF and the like, and can be synthesized in bulk (i.e., in processes other than electropolymerization). These porphyrin polymers have long excited state lifetimes, making the material suitable as an organic semiconductor for organic electronic devices including transistors and memories, as well as solar cells, sensors, light-emitting devices, and other opto-electronic devices.

  5. Oxidative addition of halogens to homoleptic perfluoromethyl or perfluorophenyl derivatives of platinum(II): a comparative study. (United States)

    Menjón, Babil; Martínez-Salvador, Sonia; Gómez-Saso, Miguel A; Forniés, Juan; Falvello, Larry R; Martín, Antonio; Tsipis, Athanassios


    Chlorocarbon solvents (solv=CH(2)Cl(2), CHCl(3)) are suggested to play an active role in the oxidative addition of halogens, X(2) (X=Cl, Br, I), to homoleptic d(8) perfluoromethyl and -phenyl platinum(II) species [Pt(R(F))(4)](2-) (R(F)=CF(3), C(6)F(5)). The perfluoromethyl group, CF(3), has been found to be considerably less prone to undergo reductive elimination processes, and is, therefore, more suitable for stabilizing organoplatinum(IV) derivatives (see scheme).The equilibrium geometries of the homoleptic perfluorinated organoplatinate(II) anions [Pt(CF(3))(4)](2-) and [Pt(C(6)F(5))(4)](2-) have been computed at the B3P86/LANL2DZ level of theory. Remarkably good agreement with the experimentally determined structures has been obtained by X-ray diffraction methods. The reactivity of [NBu(4)](2)[Pt(CF(3))(4)] (1) towards halogens (Cl(2), Br(2), and I(2)) has been investigated by using a combined experimental and theoretical approach. The perfluoromethyl derivative 1 has been found to undergo clean oxidative addition of the three halogens under investigation, giving rise to [NBu(4)](2)[trans-Pt(CF(3))(4)X(2)] (X=Cl (7), Br (10), I (13)) in a quantitative and stereoselective way. In the low-temperature reaction of the perfluorophenyl derivative [NBu(4)](2)[Pt(C(6)F(5))(4)] (3) with Cl(2) or Br(2), the corresponding oxidative-addition products [NBu(4)](2)[trans-Pt(C(6)F(5))(4)X(2)] (X=Cl (14), Br (15)) can also be obtained. In the case in which X=Br and working in CHCl(3) at -55 degrees C, it has been possible to detect the formation of an intermediate species to which we assign the formula [trans-Pt(C(6)F(5))(4)Br(ClCHCl(2))](-) (16). The solvento complex 16 is thermally unstable and prone to undergo reductive elimination of C(6)F(5)--C(6)F(5). In the presence of PhCN, complex [NBu(4)][trans-Pt(C(6)F(5))(4)Br(NCPh)] (17) was isolated and structurally characterized. The reaction of 3 with I(2) gave no organoplatinum(IV) compound. Our comparative study reveals that

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

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


    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.

  7. Interpreting effects of structure variations induced by temperature and pressure on luminescence spectra of platinum(II) bis(dithiocarbamate) compounds. (United States)

    Poirier, Stéphanie; Roberts, Ryan J; Le, Debbie; Leznoff, Daniel B; Reber, Christian


    Luminescence spectra of two square-planar dithiocarbamate complexes of platinum(II) with different steric bulk, platinum(II) bis(dimethyldithiocarbamate) (Pt(MeDTC)2) and platinum(II) bis(di(o-pyridyl)dithiocarbamate) (Pt(dopDTC)2), are presented at variable temperature and pressure. The spectra show broad d-d luminescence transitions with maxima at approximately 13500 cm(-1) (740 nm). Variations of the solid-state spectra with temperature and pressure reveal intrinsic differences due to subtle variations of molecular and crystal structures, reported at 100 and 296 K for Pt(dopDTC)2. Luminescence maxima of Pt(MeDTC)2 shift to higher energy as temperature increases by +320 cm(-1) for an increase by 200 K, mainly caused by a bandwidth increase from 3065 to 4000 cm(-1) on the high-energy side of the band over the same temperature range. Luminescence maxima of Pt(dopDTC)2 shift in the opposite direction by -460 cm(-1) for a temperature increase by 200 K. The bandwidth of approximately 2900 cm(-1) does not vary with temperature. Both ground and emitting-state properties and subtle structural differences between the two compounds lead to this different behavior. Luminescence maxima measured at variable pressure show shifts to higher energy by +47 ± 3 and +11 ± 1 cm(-1)/kbar, for Pt(MeDTC)2 and Pt(dopDTC)2, respectively, a surprising difference by a factor of 4. The crystal structures indicate that decreasing intermolecular interactions with increasing pressure are likely to contribute to the exceptionally high shift for Pt(MeDTC)2.

  8. Porphyrins - blood test (United States)

    ... Blood test References Chernecky CC, Berger BJ. Porphyrins, quantitative - blood. In: Chernecky CC, Berger BJ, eds. Laboratory ... Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare ...

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


    Thomas, Christine M.; Peters, Jonas C.


    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)...

  10. 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.


    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

  11. 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.


    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

  12. 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.


    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

  13. Selective turn-off phosphorescent and colorimetric detection of mercury(II) in water by half-lantern platinum(II) complexes. (United States)

    Sicilia, Violeta; Borja, Pilar; Baya, Miguel; Casas, José M


    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.

  14. Novel monofunctional platinum (II) complex Mono-Pt induces apoptosis-independent autophagic cell death in human ovarian carcinoma cells, distinct from cisplatin. (United States)

    Guo, Wen-Jie; Zhang, Yang-Miao; Zhang, Li; Huang, Bin; Tao, Fei-Fei; Chen, Wei; Guo, Zi-Jian; Xu, Qiang; Sun, Yang


    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.

  15. A randomized phase II study of carboplatin plus pegylated liposomal doxorubicin versus carboplatin plus paclitaxel in platinum sensitive ovarian cancer patients: a Hellenic Cooperative Oncology Group study

    Directory of Open Access Journals (Sweden)

    Briasoulis Evangelos


    Full Text Available Abstract Background Platinum-based combinations are the standard second-line treatment for platinum-sensitive ovarian cancer (OC. This randomized phase II study was undertaken in order to compare the combination of carboplatin and pegylated liposomal doxorubicin (LD with carboplatin and paclitaxel (CP in this setting. Methods Patients with histologically confirmed recurrent OC, at the time of or more than 6 months after platinum-based chemotherapy, were randomized to six cycles of CP (carboplatin AUC5 + paclitaxel 175 mg/m2, d1q21 or CLD (carboplatin AUC5 + pegylated LD 45 mg/m2, d1q28. Results A total of 189 eligible patients (CP 96, CLD 93, with a median age of 63 years, median Performance Status (PS 0 and a median platinum free interval (PFI of 16.5 months, entered the study. Discontinuation due to toxicity was higher in the CP patients (13.5% versus 3%, P = 0.016. The overall response rate was similar: CP 58% versus CLD 51%, P = 0.309 (Complete Response; CR 34% versus 23% and there was no statistical difference in time-to-progression (TTP or overall survival (OS; TTP 10.8 months CP versus 11.8 CLD, P = 0.904; OS 29.4 months CP versus 24.7 CLD, P = 0.454. No toxic deaths were recorded. Neutropenia was the most commonly seen severe toxicity (CP 30% versus CLD 35%. More frequent in CLD were severe thrombocytopenia (11% versus 2%, P = 0.016, skin toxicity and Palmar-plantar erythrodysesthesia (PPE grade 1-2 (38% versus 9%, PP = 0.029, 20% versus 5%, P = 0.003. PS and PFI were independent prognostic factors for TTP and OS. Conclusions The combination of pegylated LD with carboplatin is effective, showing less neurotoxicity and alopecia than paclitaxel-carboplatin. It thus warrants a further phase III evaluation as an alternative treatment option for platinum-sensitive OC patients. Trial Registration Australian New Zealand Clinical Trials Registry: ACTRN12609000436279

  16. Quinoxaline-2-carboxamide as a carrier ligand in two new platinum(II) compounds: Synthesis, crystal structure, cytotoxic activity and DNA interaction. (United States)

    Marqués-Gallego, Patricia; Gamiz-Gonzalez, M Amparo; Fortea-Pérez, Francisco R; Lutz, Martin; Spek, Anthony L; Pevec, Andrej; Kozlevčar, Bojan; Reedijk, Jan


    The search for platinum compounds structurally different from cisplatin has led to two new platinum(II) compounds containing quinoxaline-2-carboxamide as a carrier ligand, i.e. cis-[Pt(qnxca)(MeCN)Cl2] (1) and the [Pt(qnxca-H)(dmso)Cl] (2). Both compounds have been synthesized and characterized using different spectroscopic methods. In addition, single-crystal structures have been determined by X-Ray diffraction for both compounds. In each case a square planar Pt(II) is present; in (1) the qnxca is monodentate and neutral, whereas in (2) the ligand has lost a hydrogen, to form the anionic chelating ligand abbreviated as qnxca-H. The biological activity of both compounds has been investigated in a panel of seven human tumour cells, displaying poor cytotoxic activity, compared to cisplatin. The interaction of the new compounds with 1 or 2 equiv. of 9-ethylguanine has been studied using (1)H NMR, (195)Pt NMR and ESI-MS spectroscopy, finding poor reactivity of 1 towards the model base, forming only the monosubstituted adduct. Surprisingly, compound 2, which is more sterically crowded, interacts more efficiently with the 9-EtG, forming a bifunctional adduct with two 9-EtG with substitution of the dmso and the chloride ligand. Unwinding studies of pUC19 plasmid DNA by compound 1 show similar unwinding properties to cisplatin.

  17. Synthesis, characterization and bioactive evaluation of copper(II) 5,10,15,20-tetrakis[α,α,α,α-2-(2,6-bis(4-methylpiperazine-1-yl-methyl)-4-iminomethyl phenol)phenyl] porphyrin: A picket-fence porphyrin (United States)

    Rajesh, K.; Rahiman, A. Kalilur; Bharathi, K. Shanmuga; Sreedaran, S.; Gangadevi, V.; Narayanan, V.


    We are interested in constructing deeper small cavities by adding more bulky substituents at the ortho-phenyl positions of tetrakis(o-aminophenyl)porphyrin. The synthesis of picket-fence porphyrin is initiated by the preparation of the tetrakis(o-nitrophenyl)porphyrin followed by the nitro to amino reduction and subsequent condensation with Schiff base ligand to form imine linkages of porphyrin complexes. The synthesis and characterization of a new series of picket-fence porphyrins and their copper complexes are described. 5,10,15,20-Tetrakis[α,α,α,α-2-(2,6-bis(4-methyl piperazine-1-yl-methyl)-4-iminomethyl phenol)phenyl] porphyrin can be synthesized from 2,6-bis[4-methylpiperazin-1-yl-methyl]-4-formylphenol (L) and 5,10,15,20-tetra[α,α,α,α-o-nitropheny1]-porphyrin. 5,10,15,20-Tetra[α,α,α,α-o-aminopheny1]-porphyrin was obtained by the reduction of 5,10,15,20-tetra[α,α,α,α-o-nitropheny1]-porphyrin. The spectral, electrochemical, antibacterial, antifungal and cytotoxicity properties of all the picket-fence porphyrin complexes were characterized and studied.

  18. 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 (United States)

    Gammons, Christopher H.


    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.

  19. Computational studies on the excited states of luminescent platinum(II) alkynyl systems of tridentate pincer ligands in radiative and nonradiative processes. (United States)

    Lam, Wai Han; Lam, Elizabeth Suk-Hang; Yam, Vivian Wing-Wah


    Platinum(II) alkynyl complexes of various tridentate pincer ligands, [Pt(trpy)(C≡CR)](+) (trpy = 2,2':6',2″-terpyridine), [Pt(R'-bzimpy)(C≡CR)](+) (R'-bzimpy = 2,6-bis(N-alkylbenzimidazol-2'-yl)pyridine and R' = alkyl), [Pt(R'-bzimb)(C≡CR)] (R'-bzimb = 1,3-bis(N-alkylbenzimidazol-2'-yl)benzene and R' = C4H9), have been found to possess rich photophysical properties. The emission in dilute solutions of [Pt(trpy)(C≡CR)](+) originated from a triplet alkynyl-to-tridentate pincer ligand-to-ligand charge transfer (LLCT) excited state, with mixing of a platinum-to-tridentate pincer ligand metal-to-ligand charge transfer (MLCT) excited state, while that of [Pt(R'-bzimb)(C≡CR)] originated from a triplet excited state of intraligand (IL) character of the tridentate ligand mixed with a platinum-to-tridentate ligand MLCT character. Interestingly, both emissions were observed in [Pt(R'-bzimpy)(C≡CR)](+) in some cases. In addition, [Pt(R'-bzimb)(C≡CR)] displayed a photoluminescence quantum yield higher than that of [Pt(R'-bzimpy)(C≡CR)](+). Computational studies have been performed on the representative complexes [Pt(trpy)(C≡CPh)](+) (1), [Pt(R'-bzimpy)(C≡CPh)](+) (2), and [Pt(R'-bzimb)(C≡CPh)] (3), where R' = CH3 and Ph = C6H5, to provide an in-depth understanding of the nature of their emissive origin as well as the radiative and nonradiative processes. In particular, the factors governing the ordering of the triplet excited states and radiative decay rate constants of the emissive state ((3)ES) have been examined. The potential energy profiles for the deactivation process from the (3)ES via triplet metal-centered ((3)MC) states have also been explored. This work reveals for the first time the potential energy profiles for the thermal deactivation pathway of square planar platinum(II) complexes.

  20. 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))


    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.

  1. 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: [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)


    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}.

  2. New surfactant phosphine ligands and platinum(II) metallosurfactants. Influence of metal coordination on the critical micelle concentration and aggregation properties. (United States)

    Parera, Elisabet; Comelles, Francesc; Barnadas, Ramon; Suades, Joan


    We have prepared the first platinum(II) metallosurfactants from a new family of linear surfactant phosphines Ph(2)P(CH(2))(n)SO(3)Na {1 (n = 2), 2 (n = 6), and 3 (n = 10)}, which were synthesized by reaction between the halosulfonates X(CH(2))(n)SO(3)Na and sodium diphenylphosphide. The metallosurfactants cis-[PtCl(2)L(2)] (L = 1-3) were obtained after reaction between the phosphines and PtCl(2) in dimethylsulfoxide. All compounds were fully characterized by the usual methods {NMR ((1)H, (13)C, (31)P, (195)Pt), IR, MS-ESI and HRMS}. By exploring the surfactant properties of phosphines 1-3 and their respective platinum metallosurfactants cis-[PtCl(2)L(2)] (L = 1-3) through surface tension measurements, dynamic light scattering spectroscopy, and cryo-TEM microscopy, we were able to analyze the influence of the metal coordination on the critical micelle concentration (cmc) and the aggregation properties. The cmc values of platinum metallosurfactants were considerably lower than those obtained for the free phosphines 1-3. This behavior could be understood by an analogy between the structure of cis-[PtCl(2)L(2)] complexes and bolaform surfactants. The calculated values of area per molecule also showed different tendencies between 1-3 and cis-[PtCl(2)L(2)] complexes, which could be explained on the basis of the possible conformations of these compounds in the air-water interface. The study of aggregates by dynamic light scattering spectroscopy and cryo-TEM microscopy showed the formation of spherical disperse medium size vesicles in all cases. However, substantial differences were observed between the three free phosphines (the population of micellar aggregates increased with long chain length) and also between phosphines and their respective metallosurfactants.

  3. Platinum(II/IV) complexes containing ethylenediamine-N,N'-di-2/3-propionate ester ligands induced caspase-dependent apoptosis in cisplatin-resistant colon cancer cells. (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


    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.

  4. Root bark extracts of Juncus effusus and Paeonia suffruticosa protect salivary gland acinar cells from apoptotic cell death induced by cis-platinum (II) diammine dichloride. (United States)

    Mukudai, Yoshiki; Kondo, Seiji; Shiogama, Sunao; Koyama, Tomoyuki; Li, Chunnan; Yazawa, Kazunaga; Shintani, Satoru


    Cis-platinum (II) diammine dichloride (CDDP) is a platinum-based anticancer agent, and is often used for chemotherapy for malignant tumors, albeit CDDP has serious side-effects, including xerostomia (dry mouth). Since patients with xerostomia have reduced quality of life, it is urgent and important to identify nontoxic and natural agents capable of reducing the adverse effect of chemotherapy on salivary gland function. Therefore, we commenced an institutional collaborative project in which candidates of herbal extracts were selected from more than 400 bioactive herbal products for their potential therapeutic effects not only on xerostomia, but also on oral diseases. In the present study, we report on two Chinese medical herbal extracts from the root barks of Juncus effusus and Paeonia suffruticosa. The two extracts showed a protective effect in NS-SV-Ac cells from the cytotoxicity and apoptosis caused by CDDP. The effect was dependent on the p53 pathway, protein kinase B/Akt 1 and mitochondrial apoptosis-related proteins (i.e. Bcl-2 and Bax), but was not dependent on nuclear factor κB. Notably, the apoptosis-protective effect of the extracts was not observed in adenocystic carcinoma cell lines. Although these extracts have been utilized in traditional Chinese medicine for hundreds of years, there are no reports to our knowledge, on their therapeutic effects on xerostomia. Thus, in the present study, we elucidated the potency of these herbal extracts as novel candidates for xerostomia to improve the quality of life of patients undergoing chemotherapy.

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

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


    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.

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

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


    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.

  7. Behaviour of palladium(II), platinum(IV), and rhodium(III) in artificial and natural waters: influence of reactor surface and geochemistry on metal recovery. (United States)

    Cobelo-Garcia, Antonio; Turner, Andrew; Millward, Geoffrey E; Couceiro, Fay


    The recovery of dissolved platinum group elements (PGE: Pd(II), Pt(IV) and Rh(III)) added to Milli-Q water, artificial freshwater and seawater and filtered natural waters has been studied, as a function of pH and PGE concentration, in containers of varying synthetic composition. The least adsorptive and/or precipitative loss was obtained for borosilicate glass under most of the conditions employed, whereas the greatest loss was obtained for low-density polyethylene. Of the polymeric materials tested, the adsorptive and/or precipitative loss of PGE was lowest for fluorinated ethylene propylene (Teflon). The loss of Pd(II) in freshwater was significant due to its affinity for surface adsorption and its relatively low solubility. The presence of natural dissolved organic matter increases the recovery of Pd(II) but enhances the loss of Pt(IV). The loss of Rh(III) in seawater was significant and was mainly due to precipitation, whereas Pd(II) recovery was enhanced, compared to freshwater, because of its complexation with chloride. The results have important implications regarding protocols employed for sample preservation and controlled laboratory experiments used in the study of the speciation and biogeochemical behaviour of PGE.

  8. Antitumor activity of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2- isopropyl-1,3-dioxolane]platinum(II), a new platinum analogue, as an anticancer agent. (United States)

    Kim, D K; Kim, H T; Cho, Y B; Tai, J H; Ahn, J S; Kim, T S; Kim, K H; Hong, W S


    The in vitro and in vivo antitumor activity of a new antitumor platinum complex, cis-malonato[(4R, 5R)-4,5- bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) (SKI2053R, NSC D644591), were evaluated and compared with those of cisplatin (CDDP) and carboplatin (CBDCA) using murine tumors. SKI 2053R was highly active in vitro against both L1210 murine leukemia and its CDDP-resistant subline, L1210/DDP; the relative resistances were 20.0-, 14.5-, and 2.7-fold for CDDP, CBDCA, and SKI 2053R, respectively. SKI 2053R showed activity comparable with or superior to either CDDP or CBDCA in mice implanted with L1210. In mice implanted with L1210/DDP, as compared with CBDCA, SKI 2053R showed high values for the percentage of treated survivors relative to controls and for numbers of cured mice, whereas CDDP had virtually no activity. In mice implanted with P388, all three drugs were highly active, but the intensity of activity was shown to be ranked in the following order: SKI 2053R > CDDP > CBDCA. The antitumor activity of SKI 2053R against Lewis lung carcinoma was comparable with that of both CDDP and CBDCA. The antitumor activity of SKI 2053R was further investigated against two human tumor xenografts, KATO III (stomach adenocarcinoma) and WiDr (colon adenocarcinoma), implanted s.c. in nude mice and was compared with that of CDDP. In SKI 2053R-treated groups, the time required for a mean tumor weight of 1,000 mg was 33.1 days in KATO III xenografts and 35.0 days in WiDr xenografts as compared with 30.2 and 27.2 days in CDDP-treated groups, respectively. SKI 2053R achieved growth-inhibition rates comparable with those of CDDP against KATO III (65% versus 59%) and WiDr xenografts (64% versus 54%) on day 35. These results indicate that SKI 2053R is an attractive candidate for further development as a clinically useful anticancer drug.

  9. Crystal structure of [5-bromo-2-(pyridin-2-yl-κN)phenyl-κC (1)](pentane-2,4-dionato-κ (2) O,O')platinum(II). (United States)

    Fukuda, Keito; Sugaya, Tomoaki; Ishihara, Koji


    The title cyclo-metalated platinum(II) complex with 2-(4-bromo-phen-yl)pyridinato and acetyl-acetonato ligands, [Pt(C11H7BrN)(C5H7O2)], consists of two crystallographically non-equivalent dimers, each stacked by π-π inter-actions with distances of ≃ 3.4 Å. In both dimers, the platinum(II) complexes are arranged anti-parallel to each other. Each complex exhibits a slightly distorted square-planar coordination environment around the central Pt(II) atom. The dihedral angles between two chelate rings including the Pt(II) atom in these complexes are 0.08 (12) and 1.54 (9)°.

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

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


    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.

  11. Discrete cyclic porphyrin arrays as artificial light-harvesting antenna. (United States)

    Aratani, Naoki; Kim, Dongho; Osuka, Atsuhiro


    The importance of photosynthesis has driven researchers to seek ways to mimic its fundamental features in simplified systems. The absorption of a photon by light-harvesting (antenna) complexes made up of a large number of protein-embedded pigments initiates photosynthesis. Subsequently the many pigments within the antenna system shuttle that photon via an efficient excitation energy transfer (EET) until it encounters a reaction center. Since the 1995 discovery of the circularly arranged chromophoric assemblies in the crystal structure of light-harvesting antenna complex LH2 of purple bacteria Rps. Acidophila, many designs of light-harvesting antenna systems have focused on cyclic porphyrin wheels that allow for efficient EET. In this Account, we review recent research in our laboratories in the synthesis of covalently and noncovalently linked discrete cyclic porphyrin arrays as models of the photosynthetic light-harvesting antenna complexes. On the basis of the silver(I)-promoted oxidative coupling strategy, we have prepared a series of extremely long yet discrete meso-meso-linked porphyrin arrays and covalently linked large porphyrin rings. We examined the photophysical properties of these molecules using steady-state absorption, fluorescence, fluorescence lifetime, fluorescence anisotropy decay, and transient absorption measurements. Both the pump-power dependence on the femtosecond transient absorption and the transient absorption anisotropy decay profiles are directly related to the EET processes within the porphyrin rings. Within these structures, the exciton-exciton annihilation time and the polarization anisotropy rise time are well-described in terms of the Forster-type incoherent energy hopping model. In noncoordinating solvents such as CHCl(3), meso-pyridine-appended zinc(II) porphyrins and their meso-meso-linked dimers spontaneously assemble to form tetrameric porphyrin squares and porphyrin boxes, respectively. In the latter case, we have demonstrated

  12. 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. (United States)

    Li, Yu-Lan; Qin, Qi-Pin; Liu, Yan-Cheng; Chen, Zhen-Feng; Liang, Hong


    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.

  13. Synthesis, singlet-oxygen photogeneration, two-photon absorption, photo-induced DNA cleavage and cytotoxic properties of an amphiphilic β-Schiff-base linked Ru(II) polypyridyl–porphyrin conjugate

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Hanzhong, E-mail: [Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan, Hubei 430074 (China); Ma, Wanpeng; Wang, Hongda; Cheng, Guoe [Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan, Hubei 430074 (China); Yuan, Han [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR (China); Wong, Wai-Kwok, E-mail: [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR (China); Institute of Advanced Materials, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR (China); Kwong, Daniel W.J. [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR (China); Tam, Hoi-Lam; Cheah, Kok-Wai [Department of Physics, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR (China); Institute of Advanced Materials, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR (China); Chan, Chi-Fai; Wong, Ka-Leung [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR (China)


    A novel porphyrin–polypyridyl ruthenium(II) conjugate (TPP–Ru), in which the ruthenium(II) polypyridyl moiety is linked to the β-position of the tetraphenylporphyrin via a Schiff base linkage, has been synthesized and characterized by {sup 1}H NMR, HRMS and UV–visible spectroscopy. The relative singlet oxygen quantum yield and two-photon absorption cross-section of this conjugate, together with its photo-induced DNA cleavage and cytotoxic activities were measured. The results show that the amphiphilic ruthenium(II) polypyridyl–porphyrin conjugate is an effective DNA photocleavage agent, with potential application in one- and two-photon absorption anti-cancer photodynamic therapy. - Highlights: • New porphyrin–ruthenium(II) polypyridyl complexes (TTP–Ru) have been synthesized. • The TTP–Ru shows substantial two-photon absorption cross-section (σ{sub 2}=391 GM). • The TTP–Ru exhibits a substantial {sup 1}O{sub 2} quantum yield (0.64±0.13). • The TTP–Ru exhibits a strong DNA cleavage activity upon photo-excitation. • The TTP–Ru is available for in vitro imaging and as a photodynamic therapy agent.

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

    Shahabadi, Nahid; Nemati, Leila


    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.

  15. DNA interstrand cross-links of an antitumor trinuclear platinum(II) complex: thermodynamic analysis and chemical probing. (United States)

    Malina, Jaroslav; Farrell, Nicholas P; Brabec, Viktor


    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.

  16. 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: [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: [College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061 (China); Zhang, Jinglai, E-mail: [Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China)


    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.

  17. Ultrafast stimulated emission and structural dynamics in nickel porphyrins.

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.; Wasinger, E. C.; Muresan, A. Z.; Attenkofer, K.; Jennings, G.; Lindsey, J. S.; Chen, L. X.; North Carolina State U.


    The excited-state structural dynamics of nickel(II)tetrakis(2,4,6-trimethylphenyl)porphyrin (NiTMP) and nickel(II)tetrakis(tridec-7-yl)porphyrin (NiSWTP) in a toluene solution were investigated via ultrafast transient optical absorption spectroscopy. An ultrashort stimulated emission between 620 and 670 nm from the S{sub 1} state was observed in both nickel porphyrins only when this state was directly generated via Q-band excitation, whereas such a stimulated emission was absent under B (Soret)-band excitation. Because the stimulated emission in the spectral region occurs only from the S{sub 1} state, this photoexcitation-wavelength-dependent behavior of Ni(II) porphyrins is attributed to a faster intersystem crossing from the S{sub 2} state than the internal conversion S{sub 2} {yields} S{sub 1}. The dynamics of the excited-state pathways involving the ({pi}, {pi}*) and (d, d) states varies with the meso-substituted peripheral groups, which is attributed to the nickel porphyrin macrocycle distortion from a planar configuration. Evidence for intramolecular vibrational relaxation within 2 ps and vibrational cooling in 6-20 ps of a (d, d) excited state has been established for NiTMP and NiSWTP. Finally, the lifetimes of the vibrationally relaxed (d, d) state also depend on the nature of the peripheral groups, decreasing from 200 ps for NiTMP to 100 ps for the bulkier NiSWTP.

  18. 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. (United States)

    Rani, Soni; Kumar, Sumit; Chandra, Sulekh


    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.

  19. An integrated platform for directly widely-targeted quantitative analysis of feces part II: An application for steroids, eicosanoids, and porphyrins profiling. (United States)

    Song, Yuelin; Song, Qingqing; Li, Jun; Zheng, Jiao; Li, Chun; Zhang, Yuan; Zhang, Lingling; Jiang, Yong; Tu, Pengfei


    Steroids, especially bile acids, along with eicosanoids and porphyrins in feces play pivotal roles for the clinical diagnosis of various diseases. However, their reliable measurement is extensively obstructed by poor stability, structural diversity, broad content ranges, and tedious sample preparation protocols that account for a majority of the measurement errors. In current study, in-depth component screening was initially carried out by flexibly integrating diverse modes, such as predefined multiple reaction monitoring, stepped multiple ion monitoring, neutral loss scan, and precursor ion scan on a hybrid triple quadrupole-linear ion trap mass spectrometer, which also provided MS(2) spectra via enhanced product ion experiments. Meanwhile, a hybrid ion trap-time of flight mass spectrometer served as a complementary tool by providing accurate mass spectral information. Afterwards, because authentic compounds were unavailable for most analytes, an online optimization strategy was then proposed to optimize parameters, including precursor-to-product ion transitions and spectrometric parameters, notably collision energy. Finally, direct analysis of all detected components in feces was carried out by employing a platform integrating online pressurized liquid extraction, turbulent flow chromatography, and LC-MS/MS, and applying those optimized parameters. Seventy-one compounds, including 52 steroids and 13 eicosanoids, together with 6 porphyrins, were found and annotated in a fecal pool, and then relatively quantified in various fecal matrices. The quantitative dataset was subjected for multivariate statistical analysis and significant differences were observed among the quantitative chemome profiles of the fecal matrices from different groups. The findings obtained in the two parts demonstrated that the analytical platform in combination with the work-flow is qualified for not only directly simultaneous measurement of diverse endogenous substances, but widely targeted

  20. Stacked antiaromatic porphyrins (United States)

    Nozawa, Ryo; Tanaka, Hiroko; Cha, Won-Young; Hong, Yongseok; Hisaki, Ichiro; Shimizu, Soji; Shin, Ji-Young; Kowalczyk, Tim; Irle, Stephan; Kim, Dongho; Shinokubo, Hiroshi


    Aromaticity is a key concept in organic chemistry. Even though this concept has already been theoretically extrapolated to three dimensions, it usually still remains restricted to planar molecules in organic chemistry textbooks. Stacking of antiaromatic π-systems has been proposed to induce three-dimensional aromaticity as a result of strong frontier orbital interactions. However, experimental evidence to support this prediction still remains elusive so far. Here we report that close stacking of antiaromatic porphyrins diminishes their inherent antiaromaticity in the solid state as well as in solution. The antiaromatic stacking furthermore allows a delocalization of the π-electrons, which enhances the two-photon absorption cross-section values of the antiaromatic porphyrins. This feature enables the dynamic switching of the non-linear optical properties by controlling the arrangement of antiaromatic π-systems on the basis of intermolecular orbital interactions.

  1. Platinum impact assessment


    Yip, Joyce Pui Yan


    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...

  2. 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. (United States)

    Fortin, Sébastien; Brasseur, Kevin; Morin, Nathalie; Asselin, Éric; Bérubé, Gervais


    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.

  3. Noncovalent functionalization of single-walled carbon nanotubes with porphyrins

    Energy Technology Data Exchange (ETDEWEB)

    Bassiouk, María; Basiuk, Vladimir A. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510 México D.F. (Mexico); Basiuk, Elena V., E-mail: [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510 México D.F. (Mexico); Álvarez-Zauco, Edgar [Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior C.U., 04510 México D.F. (Mexico); Martínez-Herrera, Melchor [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510 México D.F. (Mexico); Rojas-Aguilar, Aaron [Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional 2508, San Pedro Zacatenco, 07360 México D.F. (Mexico); Puente-Lee, Iván [Facultad de Química, Universidad Nacional Autónoma de México, Circuito Exterior C.U., 04510 México D.F. (Mexico)


    The covalent and noncovalent interactions of porphyrins and related tetraazamacrocyclic compounds with single-walled carbon nanotubes (SWNTs) is a subject of increasing research effort, directed toward the design of novel hybrid nanomaterials combining unique electronic and optical properties of both molecular species. In this report, we used different experimental techniques as well as molecular mechanics (MM) calculations to analyze the adsorption of meso-tetraphenylporphine (or 5,10,15,20-tetraphenyl-21H,23H-porphine, H{sub 2}TPP) and its complexes with Ni(II) and Co(II) (NiTPP and CoTPP, respectively), as well as hemin (a natural porphyrin), onto the surface of SWNTs. Altogether, the results suggested that all four porphyrin species noncovalently interact with SWNTs, forming hybrid nanomaterials. Nevertheless, of all four porphyrin species, the strongest interaction with SWNTs occurs in the case of CoTPP, which is able to intercalate and considerably disperse SWNT bundles, and therefore absorb onto the surface of individual SWNTs. In contrast, NiTPP, CoTPP and hemin, due to a weaker interaction, are unable to do so and therefore are only capable to adsorb onto the surface of SWNT bundles. According to the scanning tunneling microscopy (STM) imaging and MM results, the adsorption of CoTPP onto SWNT sidewalls results in the formation of porphyrin arrays in the shape of long-period interacting helixes with variable periodicity, possibly due to different diameters and chiralities of SWNTs present in the samples. Since the remaining porphyrin species were found to adsorb onto the surface of SWNT bundles, the precise geometry of the corresponding porphyrin/SWNT complexes is difficult to characterize.

  4. Synthesis and antitumor activity of platinum(II) complexes with trans-3,4-diamino-2,2,6,6-tetramethylpiperidine-1-oxyl. (United States)

    Sen', V D; Golubev, V A; Volkova, L M; Konovalova, N P


    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.

  5. Adsorption of platinum(IV) and palladium(II) from aqueous solution by thiourea-modified chitosan microspheres. (United States)

    Zhou, Limin; Liu, Jinhui; Liu, Zhirong


    The chitosan microparticles were prepared using the inverse phase emulsion dispersion method and modified with thiourea (TCS). TCS was characterized by scanning electron microscope (SEM), the Fourier transform infrared (FT-IR) spectra, sulfur elemental analysis, specific surface area and pore diameter. The effects of various parameters, such as pH, contact time, initial concentration and temperature, on the adsorption of Pt(IV) and Pd(II) by TCS were investigated. The results showed that the maximum adsorption capacity was found at pH 2.0 for both Pt(IV) and Pd(II). TCS can selectively adsorb Pt(IV) and Pd(II) from binary mixtures with Cu(II), Pb(II), Cd(II), Zn(II), Ca(II), and Mg(II). The adsorption reaction followed the pseudo-second-order kinetics, indicating the main adsorption mechanism of chemical adsorption. The isotherm adsorption equilibrium was well described by Langmuir isotherms with the maximum adsorption capacity of 129.9 mg/g for Pt(IV) and 112.4 mg/g for Pd(II). The adsorption capacity of both Pt(IV) and Pd(II) decreased with temperature increasing. The negative values of enthalpy (DeltaH degrees ) and Gibbs free energy (DeltaG degrees ) indicate that the adsorption process is exothermic and spontaneous in nature. The adsorbent was stable without loss of the adsorption capacity up to at least 5 cycles and the desorption efficiencies were above 95% when 0.5 M EDTA-0.5M H2SO4 eluent was used. The results also showed that the preconcentration factor for Pt(IV) and Pd(II) was 196 and 172, respectively, and the recovery was found to be more than 97% for both precious metal ions.

  6. Porphyrin-anthraquinone dyads: Synthesis, spectroscopy and photochemistry

    Indian Academy of Sciences (India)

    P Prashanth Kumar; G Premaladha; Bhaskar G Maiya


    Free-base (H2L2), copper(II) (CuL2) and zinc(II) (ZnL2) derivatives of a porphyrin-anthraquinone conjugate with an azomethine group separating the two photoactive subunits have been synthesized and characterized by mass (FAB), IR, UV-visible, 1H NMR and ESR spectroscopic techniques and also by cyclic and differential pulse voltammetric methods. Analysis of the data reveals that the spectral and electrochemical properties of the individual chromophoric entities are retained and that there is no specific - interaction between the porphyrin and anthraquinone subunits. H2L2 and ZnL2 are shown to exhibit substantial quenching (88-97%) of the porphyrin fluorescence compared to their corresponding monomeric analogues. An intramolecular electron-transfer mechanism is proposed for the substantial decrease in fluorescence in both derivatives. The fluorescence decays of porphyrin-anthraquinone conjugates are fit to 2/3 exponentials and indicate that multiple orientations of the porphyrin and anthraquinone groups contribute to the electron-transfer event. These results are in good agreement with steady-state fluorescence results. From the time-resolved fluorescence data, the electron-transfer rate constants are calculated, indicating ET values in the range of 1.1 × 109 to 9.9 × 1010 s-1 that are dependent upon the solvent.

  7. Mechanistic studies on the reactions of platinum(II) complexes with nitrogen- and sulfur-donor biomolecules. (United States)

    Bugarčić, Živadin D; Bogojeski, Jovana; Petrović, Biljana; Hochreuther, Stephanie; van Eldik, Rudi


    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.

  8. Molecular Simulations of Porphyrins and Heme Proteins

    Energy Technology Data Exchange (ETDEWEB)



    An overview of the use of classical mechanical molecular simulations of porphyrins, hydroporphyrins, and heme proteins is given. The topics cover molecular mechanics calculations of structures and conformer energies of porphyrins, energies of barriers for interconversion between stable conformers, molecular dynamics of porphyrins and heme proteins, and normal-coordinate structural analysis of experimental and calculated porphyrin structures. Molecular mechanics and dynamics are currently a fertile area of research on porphyrins. In the future, other computational methods such as Monte Carlo simulations, which have yet to be applied to porphyrins, will come into use and open new avenues of research into molecular simulations of porphyrins.

  9. Synthesis of carbon-14 labelled cis-malonato [(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane] platinum(II) (SKI 2053R)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae-Kee; Kim, Youngseok; Rim, Jonggill; Kim, Ganghyeok; Gam, Jongsik; Song, Sungkun; Yoo, Kwanghee; Kim, Key H. (Sunkyong Industries, Kyungki-Do (Korea, Republic of). Life Science Research Center)


    The synthesis of [sup 14]C-labelled cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolan e]platinum(II) from [1,4-[sup 14]C] D-tartaric acid is described. The overall radiochemical yield of the product in a eight-step sequence was 23.8% and radiochemical purity was 98.5%. (author).

  10. Anticancer platinum (IV) prodrugs with novel modes of activity. (United States)

    Chin, Chee Fei; Wong, Daniel Yuan Qiang; Jothibasu, Ramasamy; Ang, Wee Han


    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.

  11. Gemcitabine-oxaliplatin combination for ovarian cancer resistant to taxane-platinum treatment: a phase II study from the GINECO group. (United States)

    Ray-Coquard, I; Weber, B; Cretin, J; Haddad-Guichard, Z; Lévy, E; Hardy-Bessard, A C; Gouttebel, M C; Geay, J-F; Aleba, A; Orfeuvre, H; Agostini, C; Provencal, J; Ferrero, J M; Fric, D; Dohollou, N; Paraiso, D; Salvat, J; Pujade-Lauraine, E


    Advanced ovarian carcinoma in early progression (<6 months) (AOCEP) is considered resistant to most cytotoxic drugs. Gemcitabine (GE) and oxaliplatin (OXA) have shown single-agent activity in relapsed ovarian cancer. Their combination was tested in patients with AOCEP in phase II study. Fifty patients pre-treated with platinum-taxane received q3w administration of OXA (100 mg m(-2), d1) and GE (1000 mg m(-2), d1, d8, 100-min infusion). Patient characteristics were a : median age 64 years (range 46-79),and 1 (84%) or 2 (16%) earlier lines of treatment. Haematological toxicity included grade 3-4 neutropaenia (33%), anaemia (8%), and thrombocytopaenia (19%). Febrile neutropaenia occurred in 3%. Non-haematological toxicity included grade 2-3 nausea or vomiting (34%), grade 3 fatigue (25%),and grade 2 alopecia (24%). Eighteen (37%) patients experienced response. Median progression-free (PF) and overall survivals (OS) were 4.6 and 11.4 months, respectively. The OXA-GE combination has high activity and acceptable toxicity in AOCEP patients. A comparison of the doublet OXA-GE with single-agent treatment is warranted.

  12. General pharmacology of cis-malonato[4R,5R)-4,5-bis-(aminomethyl)-2-isopropyl-1,3- dioxolane]platinum(II). (United States)

    Kim, D K; Ahn, J S; Ryu, G; Kim, K H; Park, C W; Kim, M S; Chung, M H; Shin, S G; Suh, Y H; Kim, Y S


    The general pharmacological properties of cis-malonato-[(4R,5R)-4,5- bis(aminomethyl)-2-isopropyl-1.3-dioxolane]platinum(II) (SKI 2053R, CAS 146665-77-2), a new potential anticancer agent, were investigated in mice, rats, guinea pigs, rabbits, cats and dogs. Intravenous administration of SKI 2053R had no effect on the central nervous system. SKI 2053R had no effect on the autonomic nervous system and smooth muscles except that it slightly inhibited the spontaneous motility of isolated rabbit ileum at a concentration of 5 x 10(-5) g/ml. SKI 2053R did not adversely affect the respiratory-cardiovascular system, gastrointestinal system, neuromuscular junction, or renal function. SKI 2053R did not significantly alter the levels of serum glucose, serum free fatty acid and plasma lactate, and did not induce hemolysis. SKI 2053R did not affect blood coagulation mechanism and liver function. SKI 2053R did not exhibit anti-inflammatory activity. It was observed that SKI 2053R increased the formation of hemolytic plaque by spleen cells of sensitized mice at high doses (10 mg/kg and 35 mg/kg). Therefore, it is concluded from these general pharmacological studies that SKI 2053R at the doses showing antitumor activity does not induce severe adverse effects on the central nervous, autonomic nervous, respiratory-cardiovascular, gastrointestinal, peripheral nervous, and other systems in experimental animals.

  13. Kinetics and mechanism of interaction of some bioactive ligands with cis-diaqua(cis-1,2-diaminocyclohexane)platinum(II) in aqueous medium

    Indian Academy of Sciences (India)

    P Karmakar; S Ray; S Mallick; B K Bera; A Mandal; S Mondal; A K Ghosh


    The substitution reaction of cis-[Pt(cis-dach)(H2O)2]2+ (where `dach’ is cis-1,2-diaminocyclohexane) with 2-thiouracil (S, N), 1,2-cyclohexanedionedioxime (N, N) and acetylacetone (O, O) were studied in aqueous solution in 0.10 M NaClO4 under pseudo-first order conditions as a functions of concentration, pH and temperature using UV-Vis spectrophotometry. The substitution reaction proceeds via rapid outer sphere association complex formation, followed by two slow consecutive steps. The first of these involves ligand-assisted deaquation, while second involves chelation as the second aqua ligand is displaced. The association equilibrium constant (KE) for the outer sphere complex formation has been evaluated together with rate constants for the two subsequent steps. The rate constants increase with increasing ligand concentration and the evaluated activation parameters for all reactions suggest an associative substitution mechanism for both the aqua ligand substitution processes. The product of the reaction has been characterized by IR, NMR and ESI-MS spectral analysis; which throws more light on the mechanistic behaviour of platinum(II) antitumour complexes.

  14. 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


    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.

  15. 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)


    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.

  16. Saturated Red Polymer Electrophosphorescent Devices with meso-Tetrakis (4-n-decanoyl-phenyl) Porphyrin Platinum (Ⅱ) Complex as Emitter%掺杂meso-四(对葵酰氧基苯基)卟啉铂的饱和红色聚合物发光器件

    Institute of Scientific and Technical Information of China (English)

    骆开均; 蒋世平; 张藜芳; 朱卫国; 王欣


    在聚2,7-(9,9-二辛基)芴(PFO)和30%的2-(对联苯基)-5-(对叔丁基苯基)-1,3,4-(噁)二唑(PBD)主体材料中掺杂短磷光寿命的meso-四(对正葵酰氧基苯基)卟啉铂(TDPPPt),制成聚合物基发光器件.器件结构为:ITO/PEDOT:PSS/PVK/PFO+ 30% PBD:TDPPPt/Ca/Al(ITO:氧化铟锡;PE DOT:聚3,4-乙撑二氧噻吩;PSS:聚苯乙烯磺酸盐;PVK:聚乙烯基咔唑).当客体掺杂浓度≥3%时,器件给出饱和的红色发射.当驱动电压从7V升高至14 V时,器件发光色度保持不变,CIE(国际发光照明委员会)色坐标稳定在(0.66,0.28)左右.器件的最大亮度和电流效率分别为1 390 cd/m2和1.34 cd/A.在电流密度100×10-3和150×10-3 A/cm2时,电流效率分别为1.18和0.99 cd/A,器件在高电流密度下具有良好的稳定性.%The saturated red polymer electrophosphorescent devices have been fabricated. With the device structures of ITO/PEDOT: PSS/PVK/PFO + 30% PBD: TDPPPt/Ca/Al (ITO:indium tin oxide, PEDOT: poly(3 ,4-ethylenedioxythiophene) , PSS: poly ( styrenesulfonate),PVKtpoly /V-vinyl carbazole) , based on short lifetime meso-tetrakis(4-n-decanoyl-phenyl) porphyrin platinum(H) complex(TDPPPt) and poly(2,7-9,9-dioctylfluorene ) ( PFO ) in which 30% 2-( bi-phenyl-4-yl) -5-( 4-tert-butylphenyl ) -1, 3 , 4-oxadiazole (PBD) was doped. The saturated red emission is obtained when doping concentration of TDPPPt is 3% ~ 10%. The CIE (Commission Internationale de L' Eclairage) coordinates of the device is about at (0. 66, 0. 28) and unchangeable when driven voltage increases from 7 V to 14 V. The maximum luminance and luminance efficiency (η1) is 1 390 cd/m2 at 18 V and 1.34 cd/A at 18 x 10-3 A/cm2, respectively. Furthermore, the devices show excellent stability under high driven current density. Η1 only drops to 88% and 73% of maximum efficiency at 100 X 10~3 A/cm2, and 150 X 10-3 A/cm2, respectively. We tentatively attribute excellent devices stability under high driven current density to the short

  17. cis-Dichlorido(dimethyl sulfoxide-κS(N,N,N′,N′-tetramethylguanidine-κN′′platinum(II

    Directory of Open Access Journals (Sweden)

    Ivan I. Eliseev


    Full Text Available In the title compound, cis-[PtCl2(C5H13N3(C2H6OS], the four-coordinate PtII atom is bonded to one N atom of the N,N,N′,N′-tetramethylguanidine ligand, one dimethyl sulfoxide S atom and two chloride ligands, forming a cis-square-planar geometry. The bond lengths and angles of the N—Pt—Cl functionality are typical for imine dichloridoplatinum(II complexes. The H atom of the imino group is oriented towards the O atom of the sulfoxide group of a neighboring molecule and forms an N—H...O hydrogen bond.

  18. Dichlorido{N-[2-(diphenylphosphanylbenzylidene]-2,6-diisopropylaniline-κ2P,N}platinum(II

    Directory of Open Access Journals (Sweden)

    Haleden Chiririwa


    Full Text Available The title compound, [PtCl2(C31H32NP], is a PtII complex with an NPCl2 coordination sphere in which the PtII atom is coordinated to the imino N and phosphane P atoms of the ligand and to two cis Cl ions, giving a slightly distorted square-planar geometry. The P—Pt—N angle is 89.80 (5° and the corresponding angle between the Cl ions is 87.92 (2°.

  19. Efficient and high yield one-pot synthesis of cyclometalated platinum(II) β-diketonates at ambient temperature. (United States)

    Hudson, Zachary M; Blight, Barry A; Wang, Suning


    Cyclometalated Pt(II) β-diketonates are widely used as efficient luminescent materials but are typically prepared at high temperatures in low yields using excess reagents. A one-pot synthesis of these complexes is described employing stoichiometric reagents and short reaction times at ambient temperature, giving yields of up to 94%. The method is applicable to a broad range of substrates including N^C, P^C, and C^C chelate Pt(II) complexes and different β-diketonate ligands.

  20. Solid-state phosphorescence of trans-bis(salicylaldiminato)platinum(II) complexes bearing long alkyl chains: morphology control towards intense emission. (United States)

    Komiya, Naruyoshi; Itami, Nao; Naota, Takeshi


    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

  1. Synthesis, characterization and photophysical studies of -triazolomethyl-bridged porphyrin-benzo--pyrone dyads

    Indian Academy of Sciences (India)

    Dileep Kumar Singh; Mahendra Nath


    A new series of zinc(II) -triazolomethyl-bridged porphyrin-benzo--pyrone dyads have been synthesized in appreciable yields through a copper(I)-catalyzed “click” reaction of zinc(II) 2-azidomethyl-5,10,15,20-tetraphenylporphyrin with various benzo--pyronoalkynes. These novel zinc(II) porphyrin-benzo--pyrone dyads successfully underwent demetallation in the presence of concentrated hydrochloric acid in chloroform at 25°C to form the corresponding free-base porphyrin analogues in good yields. The newly synthesized products were characterized on the basis of spectral data and evaluated for their electronic absorption and fluorescence properties. Some of these molecules have shown a significant intramolecular energy transfer between the benzo--pyrone and porphyrin subunits.

  2. Reversible thermally induced phase transition in ordered domains of Co(II)-5,10,15,20-tetrakis-(3,5-di-tert-butylphenyl)-porphyrin on Cu(111) (United States)

    Stark, Michael; Ditze, Stefanie; Thomann, Michael; Lungerich, Dominik; Jux, Norbert; Steinrück, Hans-Peter; Marbach, Hubertus


    We investigated the adsorption behavior of Co(II)-5,10,15,20-tetrakis-(3,5-di-tert-butylphenyl)-porphyrin (CoTTBPP) on Cu(111) by scanning tunneling microscopy (STM). At room temperature (RT), the coverage dependent adsorption behavior follows an expected scheme: at low coverage step decoration is found, which evolves into supramolecular domains with a hexagonal order at higher coverage. Interestingly, upon cooling the sample to 180 K the occurrence of a clearly distinguishable coexisting herringbone phase is observed. Upon heating to RT again, the herringbone phase vanishes. Thus a temperature dependent, fully reversible phase transition was observed. High resolution STM micrographs allow for the determination of the intramolecular conformations which are different for the two supramolecular arrangements. In addition, we studied the bias voltage dependent appearance of the molecule in STM and assigned a dominant contribution of the central Co at negative bias voltages close to the Fermi edge to the occupied dz2 orbital. Interestingly, the herringbone phase, which dominates at 180 K, exhibits a significantly higher molecular density than the monomodal hexagonal arrangement at RT, which is in line with the "normal" behavior of freezing substances.

  3. Synthesis and characterization of zinc(II, palladium(II and platinum(II complex with 2’-[1-(2-pyridinylethylidene] oxamohydrazide. The crystal structure of bis{2’-[1-(2-pyridinylethylidene]oxamohydrazido}zinc(II trihydrate

    Directory of Open Access Journals (Sweden)



    Full Text Available Complexes of Zn(II, Pd(II and Pt(II with 2’-[1-(2-pyridinylethylidene]oxamohydrazide (Hapsox were synthesized and their structures were determined. All the complexes are of a neutral type with two apsox ligands coordinated to Zn(II and one apsox ligand coordinated to Pd(II or Pt(II. In each case, the polydentate was coordinated via pyridine and hydrazone nitrogens and a-oxyazine oxygen, forming an octahedral geometry around Zn(II, and a square planar one around Pd(II and Pt(II. The structure determination was performed by IR, 1H-NMR and 13C-NMR spectroscopy, and for the Zn(II complex by X-ray structure analysis.

  4. Synthesis, Characterization, and Interaction with Biomolecules of Platinum(II Complexes with Shikimic Acid-Based Ligands

    Directory of Open Access Journals (Sweden)

    Yan Peng


    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.

  5. Bis(acetonitrile-κN(1,10-phenanthroline-κ2N,N′platinum(II bis(perchlorate

    Directory of Open Access Journals (Sweden)

    Kwang Ha


    Full Text Available The asymmetric unit of the title compound, [Pt(CH3CN2(C12H8N2](ClO42, contains one half of a cationic PtII complex and pair of half perchlorate anions, one of which is disordered over two sites in a 0.53 (3:0.47 (3 ratio. The complex and anions are disposed about a crystallographic mirror plane parallel to the ac plane passing through the Pt and Cl atoms. In the complex, the PtII ion lies in a distorted square-planar environment defined by four N atoms of the chelating 1,10-phenanthroline ligand and two distinct acetonitrile molecules. The component ions interact by means of intermolecular C—H...O hydrogen bonds.

  6. Bis[N,N-bis(diphenylphosphanylpentylamine-κ2P,P′]platinum(II bis(hexafluoridophosphate dichloromethane disolvate

    Directory of Open Access Journals (Sweden)

    Ilana Engelbrecht


    Full Text Available The PtII atom in the title compound, [Pt(C29H31NP22](PF62·2CH2Cl2, is coordinated by four P atoms from two bis(diphenylphosphanylpentylamine ligands with an average Pt—P distance of 2.300 (1 Å. The coordination around the PtII atom shows a highly distorted square-planar geometry, as evidenced by the P—Pt—P bite angles of 70.45 (3 and 70.64 (3°. The asymmetric unit contains two hexafluoridophosphate ions, the metal complex and two dichloromethane solvent molecules. One of the chloride atoms of one of the dichloromethane molecules is disordered over two sites in a 0.515 (3:0.485 (3 ratio. C—H...F hydrogen bonds stabilize the crystal packing.

  7. Phase I/II study of docetaxel combined with resminostat, an oral hydroxamic acid HDAC inhibitor, for advanced non-small cell lung cancer in patients previously treated with platinum-based chemotherapy. (United States)

    Tambo, Yuichi; Hosomi, Yukio; Sakai, Hiroshi; Nogami, Naoyuki; Atagi, Shinji; Sasaki, Yasutsuna; Kato, Terufumi; Takahashi, Toshiaki; Seto, Takashi; Maemondo, Makoto; Nokihara, Hiroshi; Koyama, Ryo; Nakagawa, Kazuhiko; Kawaguchi, Tomoya; Okamura, Yuta; Nakamura, Osamu; Nishio, Makoto; Tamura, Tomohide


    Objectives To determine the recommended dose and efficacy/safety of docetaxel combined with resminostat (DR) in non-small cell lung cancer (NSCLC) patients with previous platinum-based chemotherapy. Materials and Methods A multicenter, open-label, phase I/II study was performed in Japanese patients with stage IIIB/IV or recurrent NSCLC and prior platinum-based chemotherapy. The recommended phase II dose was determined using a standard 3 + 3 dose design in phase I part. Resminostat was escalated from 400 to 600 mg/day and docetaxel fixed at 75 mg/m(2). In phase II part, the patients were randomly assigned to docetaxel alone (75 mg/m(2)) or DR therapy. Docetaxel was administered on day 1 and resminostat on days 1-5 in the DR group. Treatment was repeated every 21 days until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS). Results A total of 117 patients (phase I part, 9; phase II part, 108) were enrolled. There was no dose-limiting toxicity in phase I part; the recommended dose for resminostat was 600 mg/day with 75 mg/m(2) of docetaxel. In phase II part, median PFS (95% confidence interval [CI]) was 4.2 (2.8-5.7) months with docetaxel group and 4.1 (1.5-5.4) months with DR group (hazard ratio [HR]: 1.354, 95% CI: 0.835-2.195; p = 0.209). Grade ≥ 3 adverse events significantly more common with DR group than docetaxel group were leukopenia, febrile neutropenia, thrombocytopenia, and anorexia. Conclusion In Japanese NSCLC patients previously treated with platinum-based chemotherapy, DR therapy did not improve PFS compared with docetaxel alone and increased toxicity.

  8. A label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) based on platinum (II)-oligonucleotide coordination induced gold nanoparticles aggregation. (United States)

    Fan, Daoqing; Zhai, Qingfeng; Zhou, Weijun; Zhu, Xiaoqing; Wang, Erkang; Dong, Shaojun


    Herein, a gold nanoparticles (AuNPs) based label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) was constructed for the first time. Four bases (G-G mismatch) mismatched streptavidin aptamer (MSAA) was used to protect AuNPs from salt-induced aggregation and recognize Pt (II) specifically. Only in the presence of Pt (II), coordination occurs between G-G bases and Pt (II), leading to the activation of streptavidin aptamer. Streptavidin coated magnetic beads (MBs) were used as separation agent to separate Pt (II)-coordinated MSAA. The residual less amount of MSAA could not efficiently protect AuNPs anymore and aggregation of AuNPs will produce a colorimetric product. With the addition of Pt (II), a pale purple-to-blue color variation could be observed by the naked eye. A detection limit of 150nM and a linear range from 0.6μM to 12.5μM for Pt (II) could be achieved without any amplification.

  9. Porphyrins at interfaces (United States)

    Auwärter, Willi; Écija, David; Klappenberger, Florian; Barth, Johannes V.


    Porphyrins and other tetrapyrrole macrocycles possess an impressive variety of functional properties that have been exploited in natural and artificial systems. Different metal centres incorporated within the tetradentate ligand are key for achieving and regulating vital processes, including reversible axial ligation of adducts, electron transfer, light-harvesting and catalytic transformations. Tailored substituents optimize their performance, dictating their arrangement in specific environments and mediating the assembly of molecular nanoarchitectures. Here we review the current understanding of these species at well-defined interfaces, disclosing exquisite insights into their structural and chemical properties, and also discussing methods by which to manipulate their intramolecular and organizational features. The distinct characteristics arising from the interfacial confinement offer intriguing prospects for molecular science and advanced materials. We assess the role of surface interactions with respect to electronic and physicochemical characteristics, and describe in situ metallation pathways, molecular magnetism, rotation and switching. The engineering of nanostructures, organized layers, interfacial hybrid and bio-inspired systems is also addressed.

  10. Synthesis of Covalently-Linked Linear Donor-Acceptor Copolymers Containing Porphyrins and Oligothiophenes

    Institute of Scientific and Technical Information of China (English)

    DUANMU,Chuan-Song; CHEN,Zhang-Ping; YU,Xue-Song


    @@ 5,15-Di-bithienyl porphyrin (1) and its Cu(Ⅱ), Zn (Ⅱ) complexes (2 and 3)[1] were polymerized according to Scheme 1 by chemical oxidation using FeCl3 as oxidant for making organic conductor, and the linear porphyrin-thiophene copolymers were obtained. The structures of the copolymers were identified by elemental analysis and IR spectra. The conductivity of poly 5,15-di-bithienyl porphyrin (4) doped with FeCl3 was measured to reach over 10-6 S/cm, which was in the range of semiconductor and higher than that of other porphyrin-thiophene copolymers prepared by Shimidzu. The higher conductivity may be due to the better conjugation between the thienyl group and the porphyrin ring. The thienylporphyrins 7 and 8 could not be polymerized under the similar conditions, but could be polymerized by electrochemical oxidation (working electrode: gold-plate electrode; counter electrode: platinum; reference: standard calomel electrode SEC; solvent: 0.1 mol·dm-3 n-Bu4NClO4 in dry MeCN).

  11. 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


    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.

  12. Vaulted trans-bis(salicylaldiminato)platinum(II) crystals: heat-resistant, chromatically sensitive platforms for solid-state phosphorescence at ambient temperature. (United States)

    Komiya, Naruyoshi; Okada, Minoru; Fukumoto, Kanako; Kaneta, Kenji; Yoshida, Atsushi; Naota, Takeshi


    The synthesis, structure, and solid-state emission of vaulted trans-bis(salicylaldiminato)platinum(II) complexes are described. A series of polymethylene (1: n=8; 2: n=9; 3: n=10; 4: n=11; 5: n=12; 6: n=13) and polyoxyethylene (7: m=2; 8: m=3; 9: m=4) vaulted complexes (R=H (a), 3-MeO (b), 4-MeO (c), 5-MeO (d), 6-MeO (e), 4-CF3O (f), 5-CF3O (g)) was prepared by treating [PtCl2(CH3CN)2] with the corresponding N,N'-bis(salicylidene)-1,ω-alkanediamines. The trans coordination, vaulted structures, and the crystal packing of 1-9 have been unequivocally established from X-ray diffraction studies. Unpredictable, structure-dependent phosphorescent emission has been observed for crystals of the complexes under UV excitation at ambient temperature, whereas these complexes are entirely nonemissive in the solution state under the same conditions. The long-linked complex crystals 4-6, 8, and 9 exhibit intense emission (Φ77K =0.22-0.88) at 77 K, whereas short-linked complexes 1-3 and 7 are non- or slightly emissive at the same temperature (Φ77K solid-state emission over the range of 98 nm can be performed simply by introducing MeO groups at different positions on the aromatic rings. Orange, yellow-green, red, and yellow emissions are observed in the glass and crystalline state upon 3-, 4-, 5-, and 6-MeO substitution, respectively, whereas those with CF3 O substituents have orange emission, irrespective of the substitution position. DFT calculations (B3LYP/6-31G*, LanL2DZ) showed that such chromatic variation is ascribed to the position-specific influence of the substituents on the highest-occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO) levels of the trans-bis(salicylaldiminato)platinum(II) platform. The solid-state emission and its heat resistance have been discussed on the basis of X-ray diffraction studies. The planarity of the trans-coordination sites is strongly correlated to the solid-state emission intensities of crystals 1-9 at lower

  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. (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


    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. 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. (United States)

    Icsel, Ceyda; Yilmaz, Veysel T; Kaya, Yunus; Samli, Hale; Harrison, William T A; Buyukgungor, Orhan


    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.

  15. 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)]. (United States)

    Nguyen Thi Thanh, Chi; Pham Van, Thong; Le Thi Hong, Hai; Van Meervelt, Luc


    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

  16. Pharmacokinetics of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3-dioxolane]platinum(II) in rats. (United States)

    Cho, Y B; Kim, D K; Kim, K H; Miyamoto, G


    The blood concentration-time profile, distribution, and excretion of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3-dioxolane]platinum(II) (CAS 146665-77-2, SKI 2053R), a new potential anticancer agent, were investigated in rats after intravenous administration of 14C-SKI 2053R. After a single intravenous administration, the radioactivity of blood declined in a biexponential fashion with the initial half-lives of 0.42 h and 0.37 h and with the terminal half-lives of 68.67 h and 64.67 h in male and female rats, respectively. Radioactivity was distributed very rapidly and extensively into all tissues except the central nervous system. The major amount of the radioactivity was found in the gastrointestinal contents, urine, and organs of elimination at all time points. The distribution pattern of 14C-SKI 2053R observed by the measurement of tissue concentrations was in accordance with that observed by whole-body autoradiography. The 0-7 days cumulative urinary and fecal recoveries of total radioactivity after a single dose were 83.0 +/- 4.5 (mean +/- S.D.) and 11.3 +/- 1.0% in male rats and 85.1 +/- 2.6 and 11.3 +/- 2.3% in female rats, respectively, resulting in total recoveries of 94.3 +/- 3.6% in male rats and 96.3 +/- 1.1% in female rats. The 0-24 h cumulative excretions of total radioactivity in the bile after a single dose were 8.7 +/- 0.4 and 15.8 +/- 3.5% in male and female rats, respectively, showing a significant sex difference.

  17. DNA studies of newly synthesized heteroleptic platinum(II) complexes [Pt(bpy)(iip)](2+) and [Pt(bpy)(miip)](2.). (United States)

    Coban, Burak; Tekin, Ishak Ozel; Sengul, Abdurrahman; Yildiz, Ufuk; Kocak, Izzet; Sevinc, Nergis


    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.

  18. Galactose conjugated platinum(II) complex targeting the Warburg effect for treatment of non-small cell lung cancer and colon cancer. (United States)

    Wu, Meng; Li, Hong; Liu, Ran; Gao, Xiangqian; Zhang, Menghua; Liu, Pengxing; Fu, Zheng; Yang, Jinna; Zhang-Negrerie, Daisy; Gao, Qingzhi


    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.

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

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


    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.

  20. trans-Platinum(II) complex of 3-aminoflavone - synthesis, X-ray crystal structure and biological activities in vitro. (United States)

    Fabijańska, Małgorzata; Studzian, Kazimierz; Szmigiero, Leszek; Rybarczyk-Pirek, Agnieszka J; Pfitzner, Arno; Cebula-Obrzut, Barbara; Smolewski, Piotr; Zyner, Elżbieta; Ochocki, Justyn


    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.

  1. (Biphenyl-2,2′-diyl[1,3-bis(diphenylphosphanylpropane-κ2P,P′]platinum(II

    Directory of Open Access Journals (Sweden)

    D. Paul Rillema


    Full Text Available The C2P2 donor set in the title compound, [Pt(C12H8(C27H26P2], defines a distorted planar coordination environment about the PtII atom with small deviations from planarity. The bidentate nature of the biphenyl dianionic ligand results in a C—Pt—C bond angle of 79.94 (16° and a P—Pt—P bond angle of 93.40 (4°. The average Pt—C bond length is 2.083 (3 Å [range 2.081 (4–2.085 (4 Å]; the average Pt—P bond length is 2.308 (8 Å [range 2.3030 (11–2.3136 (11 Å].

  2. Synthesis and characterization of a novel meso-porphyrin and its metallo derivatives

    Directory of Open Access Journals (Sweden)

    Paulo Cesar Bega


    Full Text Available There has been a growing interest in the properties of substituted meso-tetraarylporphyrins and metallo porphyrins as catalysts for oxidation of hydrocarbons, oxygen detection, among others. This work describes the synthesis of a new porphyrin, 5,10,15,20-tetrakis(4-butoxy-3-methoxyphenylporphyrin, and its metallo complexes. Herein it was used a readily available reactant, vanillin, as starting material which was submitted to alkylation with n-bromobutane affording the synthetic precursor. The desired porphyrin was obtained by reacting the O-alkylated aldehyde with pyrrole in the presence of propionic acid (Alder-Longo method. The purified porphyrin was then subjected to the metallation process using iron (II and manganese (II salts. The synthesized compounds were characterized by IR, UV-Vis, NMR and EPR spectroscopy.

  3. Novel palladium(II) and platinum(II) complexes with 1H-benzimidazol-2-ylmethyl-N-(4-bromo-phenyl)-amine: structural studies and anticancer activity. (United States)

    Abdel Ghani, Nour T; Mansour, Ahmed M


    [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.

  4. Merging porphyrins with organometallics: synthesis and applications. (United States)

    Suijkerbuijk, Bart M J M; Klein Gebbink, Robertus J M


    The coordination chemistry of porphyrins has traditionally involved the ability of the porphyrin's tetrapyrrolic core to accommodate metal ions of varying charges and sizes, and on the organometallic chemistry of the resulting metalloporphyrins. However, the organometallic chemistry of porphyrins is not necessarily restricted to the metal bound in the porphyrin core, but can also be extended to the porphyrin periphery, be it through direct metalation of the porphyrin macrocycle at the meso or beta position, or by attachment to or merger of the porphyrin skeleton with ligands, followed by metalation. This Review focuses on the synthetic strategies used for porphyrins with peripheral metal-carbon bonds. The exciting results that have been produced underscore the importance and future potential of this field.

  5. Blue-emitting platinum(II) complexes bearing both pyridylpyrazolate chelate and bridging pyrazolate ligands: synthesis, structures, and photophysical properties. (United States)

    Chang, Sheng-Yuan; Chen, Jing-Lin; Chi, Yun; Cheng, Yi-Ming; Lee, Gene-Hsiang; Jiang, Chang-Ming; Chou, Pi-Tai


    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.

  6. Comparison of maturity based on steroid and vanadyl porphyrin parameters: A new vanadyl porphyrin maturity parameter for higher maturities (United States)

    Sundararaman, Padmanabhan; Moldowan, J. Michael


    Correlations are demonstrated between steroid maturity parameters and the porphyrin maturity parameter (PMP) which is based on the ratio of specific vanadyl porphyrins C 28E /(C 28E + C 32D) measured by HPLC. Measurements from a global selection of > 100 rock extracts and oils show that PMP parallels changes in the C 29-sterane 20S/(20S + 20R) and tri/(tri + mono) aromatic steroid ratios, and that all three parameters appear to attain their maximum values at similar maturity levels. The triaromatic steroid side chain cracking parameter, TA I/(I + II), reaches approximately 20% of its maximum value when PMP has reached 100%. These results suggest that PMP is effective in the early to peak portion of the oil window. A new parameter, PMP-2, based on changes in the relative concentrations of two peaks in the HPLC fingerprint (vanadyl "etio" porphyrins), appears effective in assessing the maturity of source rocks beyond peak oil generation. In combination with PMP this parameter extends the effective range of vanadyl porphyrins parameters to higher maturities as demonstrated by a suite of oils from the Oriente Basin, Ecuador, South America.

  7. PLATINUM AND FUEL CELLS (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...

  8. Inhibition of Aβ42 peptide aggregation by a binuclear ruthenium(II)-platinum(II) complex: Potential for multi-metal organometallics as anti-amyloid agents. (United States)

    Kumar, Amit; Moody, Lamaryet; Olaivar, Jason F; Lewis, Nerissa A; Khade, Rahul L; Holder, Alvin A; Zhang, Yong; Rangachari, Vijayaraghavan


    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.

  9. Tunable and Efficient White Light Phosphorescent Emission Based on Single Component N-Heterocyclic Carbene Platinum(II) Complexes. (United States)

    Bachmann, Michael; Suter, Dominik; Blacque, Olivier; Venkatesan, Koushik


    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.

  10. Enhanced photocatalytic degradation activity over TiO{sub 2} nanotubes co-sensitized by reduced graphene oxide and copper(II) meso-tetra(4-carboxyphenyl)porphyrin

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Meng; Wan, Junmin, E-mail:; Hu, Zhiwen; Peng, Zhiqin; Wang, Bing


    Highlights: • CuTCPP/rGO-TNT photocatalysts are synthesized. • CuTCPP and rGO are helpful to induce interfacial charge transfer at surface junction. • CuTCPP and rGO are favorable for enhancing co-photocatalytic activity. • A deeper insight into the co-photocatalytic mechanism is put forward. • The photocatalyst are proven to be effective and chemically-stable catalysts. - Abstract: In this paper, TiO{sub 2} nanotubes (TNT) co-sensitized with copper(II) meso-tetra(4-carboxyphenyl)porphyrin (CuTCPP) and reduced graphene oxide nanosheets (rGO), which was fabricated through two-step improved hydrothermal method and heating reflux process. The effect of rGO and CuTCPP on the co-photocatalytic behavior of TNT for the degradation of Methylene Blue (MB) were measured under visible light irradiation. The photocatalysts have been characterized and analyzed by high-resolution transmission electron microscopy (TEM), selected area electronic diffraction (SAED), elemental mapping by energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and electron paramagnetic resonance (EPR). The results provide a deeper insight into the co-photocatalytic mechanism of CuTCPP/rGO-TNT nanocomposites. The degradation results showed a purification of more than 95% MB in wastewater, which is about 5 times higher than that of the pure TNT. The results also confirm the prepared CuTCPP/rGO-TNT nanocomposites possess superior co-photocatalytic activities.

  11. Helical chirality induction of expanded porphyrin analogues

    Indian Academy of Sciences (India)

    Jun-Ichiro Setsune


    Expanded porphyrin analogues with unique figure-eight conformation were prepared by way of useful pyrrole intermediates such as bis(azafulvene)s and 2-borylpyrrole. Supramolecular chirogenesis of cyclooctapyrrole O1 with 32-cycloconjugation was successfully applied to determine absolute configuration of chiral carboxylic acids. Dinuclear CuII complex of cyclooctapyrrole O2 with interrupted -conjugation was resolved by HPLC into enantiomers and their helical handedness was determined by theoretical simulation of their CD spectral pattern. Enantioselective induction of helicity in the metal helicate formation in the presence of a chiral promoter was demonstrated by using ()-(+)-1-(1-phenyl)ethylamine that favoured , helicity. Dinuclear CoII complexes of cyclotetrapyrroletetrapyridine O3 were found to be substitution labile and pick up amino acid anions in water. Those amino acid complexes of O3Co2 were rendered to adopt a particular unidirectional helical conformation preferentially depending on the ligated amino acid anion.

  12. Supramolecular ssDNA templated porphyrin and metalloporphyrin nanoassemblies with tunable helicity. (United States)

    Sargsyan, Gevorg; Leonard, Brian M; Kubelka, Jan; Balaz, Milan


    Free-base and nickel porphyrin-diaminopurine conjugates were formed by hydrogen-bond directed assembly on single-stranded oligothymidine templates of different lengths into helical multiporphyrin nanoassemblies with highly modular structural and chiroptical properties. Large red-shifts of the Soret band in the UV/Vis spectroscopy confirmed strong electronic coupling among assembled porphyrin-diaminopurine units. Slow annealing rates yielded preferentially right-handed nanostructures, whereas fast annealing yielded left-handed nanostructures. Time-dependent DFT simulations of UV/Vis and CD spectra for model porphyrin clusters templated on the canonical B-DNA and its enantiomeric form, were employed to confirm the origin of observed chiroptical properties and to assign the helicity of porphyrin nanoassemblies. Molar CD and CD anisotropy g factors of dialyzed templated porphyrin nanoassemblies showed very high chiroptical anisotropy. The DNA-templated porphyrin nanoassemblies displayed high thermal and pH stability. The structure and handedness of all assemblies was preserved at temperatures up to +85 °C and pH between 3 and 12. High-resolution transition electron microscopy confirmed formation of DNA-templated nickel(II) porphyrin nanoassemblies and their self-assembly into helical fibrils with micrometer lengths.

  13. A Cytostatic Ruthenium(II)-Platinum(II) Bis(terpyridyl) Anticancer Complex That Blocks Entry into S Phase by Up-regulating p27(KIP1). (United States)

    Ramu, Vadde; Gill, Martin R; Jarman, Paul J; Turton, David; Thomas, Jim A; Das, Amitava; Smythe, Carl


    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.

  14. 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.


    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

  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.


    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

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


    Thomas, J. Christopher; Peters, Jonas C.


    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...

  17. Theoretical Investigation on the Second-order Nonlinear Optical Properties of Chiral Amino Acid Zinc(Ⅱ) Porphyrins

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-Yang; TIAN Jun-Chun; YING Xiao; XU Zhi-Guang; LIAO Shi-Jun; CHANG Chi-Kwong


    Static second-order nonlinear optical effects of amino acid zinc(II) porphyrins 1, 2, 3 and 4 were calculated by the TDHF/PM3 method based on the molecular structures optimized at the semiempirical PM3 quantum chemistry level, showing due to the cancellation of symmetric center, these amino acid zinc(II) porphyrins exhibit second order nonlinear optical response. The analysis of β components indicated that these amino acid zinc(II) porphyrins are of multipolarizabilities, and they may be ascribed as the "mixture" of octupolar and dipoar molecules with ||βJ=3||/||βJ=1|| ≈ 5. It is found that there are no significant differences between the static β values of non-chiral and chiral amino acid zinc(II) porphyrins. However, the βxyz component, which is quite important to quadratic macroscopic х (2) susceptibility of chiral material, is increased significantly with the increase of side chain group of amino acids.

  18. Cyclic porphyrin dimers as hosts for coordinating ligands

    Indian Academy of Sciences (India)

    G Vaijayanthimala; V Krishnan; S K Mandal


    Bicovalently linked tetraphenylporphyrins bearing dioxypentane groups at the opposite (transoid, H4A) and adjacent (cisoid, H4B) aryl groups have been synthesised. Protonation of the free-base porphyrins leads to fully protonated species H8A4+/H8A4+ accompanied by expansion of cavity size of the bisporphyrins. The electrochemical redox studies of these porphyrins and their Zinc(II) derivatives revealed that the first ring oxidation proceeds through a two-electron process while the second ring oxidation occurs at two distinct one-electron steps indicating unsymmetrical charge distribution in the oxidized intermediate. The axial ligation properties of the Zinc(Il) derivatives of H4A/H4B with DABCO and PMDA investigated by spectroscopic and single crystal X-ray diffraction studies showed predominant existence of 1 : I complex. The Zn2A.DABCO complex assumes an interesting eclipsed structure wherein DABCO is located inside the cavity between the two porphyrin planes with Zn-N distances at 2.08 and 2.22 Å. The Zn atoms are pulled into the cavity due to coordination towards nitrogen atoms of DABCO and deviate from the mean porphyrin plane by 0.35 Å. The electrochemical redox potentials of the axially ligated metal derivatives are found to be sensitive function of the relative coordinating ability of the ligands and the conformation of the hosts.

  19. Preclinical toxicity and pharmacology of liposome-entrapped cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexane platinum(II). (United States)

    Perez-Soler, R; Lautersztain, J; Stephens, L C; Wright, K; Khokhar, A R


    Liposome-entrapped cis-bis-neodecanoate-trans-R,R-1,2-diaminocylohexane platinum(II) (L-NDDP) is a new lipophilic cisplatin derivative formulated in a liposomal carrier currently in phase I clinical trials. The preclinical toxicity and pharmacology of L-NDDP were studied in mice and dogs. At the LD50 dose (i.v. bolus) in mice (60.5 mg/kg or 181.5 mg/m2), a tenfold decrease in the granulocyte and platelet counts was observed in the absence of renal toxic effects. In dogs, the maximum tolerated dose (MTD) of L-NDDP given i.v. over a period of 45-60 min was 150 mg/m2. This dose produced significant vomiting (6-18 episodes), minimal renal dysfunction, a maximal decrease in granulocyte and platelet counts of from 30% to 70%, and acute and transient elevation of liver enzymes. Higher doses (225 and 300 mg/m2) resulted in severe gastrointestinal (GI) toxicity in one animal and the death of two others within 48 h. Autopsy results showed multifocal hemorrhages in the lungs, GI tract, kidney, and liver. Three dogs were treated monthly with the MTD up to a cumulative dose of 637.5-712.5 mg/m2 with excellent tolerance. No cumulative myelosuppression or liver dysfunction was observed, whereas a slight increase in the creatinine baseline level was detected in all three animals. Autopsy results at the end of the study showed mild changes limited to the liver, kidney, and GI tract. Pharmacologic studies showed that the drug was cleared, fitting a two-compartment model with a mean t1/2 alpha of 7.1 min and a t1/2 beta of 87.8 h. These studies show that L-NDDP can safely be given at therapeutic doses to animals and that the dose-limiting toxic effects consists of myelosuppression in mice and a multiorgan hemorrhagic syndrome related to vascular injury in dogs.

  20. Synthesis and characterization of electron donor-acceptor platinum(II) complexes composed of N,N-diphenylpyridineamine and triphenylamine ligands. (United States)

    Dai, Zhi; Metta-Magaña, Alejandro J; Nuñez, Jose E


    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

  1. Synthesis of antitumor azolato-bridged dinuclear platinum(ii) complexes with in vivo antitumor efficacy and unique in vitro cytotoxicity profiles. (United States)

    Komeda, Seiji; Takayama, Hiroshi; Suzuki, Toshihiro; Odani, Akira; Yamori, Takao; Chikuma, Masahiko


    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.

  2. Porphyrins Fused with Unactivated Polycyclic Aromatic Hydrocarbons

    KAUST Repository

    Diev, Vyacheslav V.


    A systematic study of the preparation of porphyrins with extended conjugation by meso,β-fusion with polycyclic aromatic hydrocarbons (PAHs) is reported. The meso-positions of 5,15-unsubstituted porphyrins were readily functionalized with PAHs. Ring fusion using standard Scholl reaction conditions (FeCl 3, dichloromethane) occurs for perylene-substituted porphyrins to give a porphyrin β,meso annulated with perylene rings (0.7:1 ratio of syn and anti isomers). The naphthalene, pyrene, and coronene derivatives do not react under Scholl conditions but are fused using thermal cyclodehydrogenation at high temperatures, giving mixtures of syn and anti isomers of the meso,β-fused porphyrins. For pyrenyl-substituted porphyrins, a thermal method gives synthetically acceptable yields (>30%). Absorption spectra of the fused porphyrins undergo a progressive bathochromic shift in a series of naphthyl (λ max = 730 nm), coronenyl (λ max = 780 nm), pyrenyl (λ max = 815 nm), and perylenyl (λ max = 900 nm) annulated porphyrins. Despite being conjugated with unsubstituted fused PAHs, the β,meso-fused porphyrins are more soluble and processable than the parent nonfused precursors. Pyrenyl-fused porphyrins exhibit strong fluorescence in the near-infrared (NIR) spectral region, with a progressive improvement in luminescent efficiency (up to 13% with λ max = 829 nm) with increasing degree of fusion. Fused pyrenyl-porphyrins have been used as broadband absorption donor materials in photovoltaic cells, leading to devices that show comparatively high photovoltaic efficiencies. © 2011 American Chemical Society.

  3. 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


    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.

  4. Fusing Porphyrins and Phospholes: Synthesis and Analysis of a Phosphorus-Containing Porphyrin. (United States)

    Higashino, Tomohiro; Yamada, Tomoki; Sakurai, Tsuneaki; Seki, Shu; Imahori, Hiroshi


    A phosphole-fused porphyrin dimer, as a representative of a new class of porphyrins with a phosphorus atom, was synthesized for the first time. The porphyrin dimer exhibits remarkably broadened absorption, indicating effective π-conjugation over the two porphyrins through the phosphole moiety. The porphyrin dimer possesses excellent electron-accepting character, which is comparable to that of a representative electron-accepting material, [60]PCBM. These results provide access to a new class of phosphorus-containing porphyrins with unique optoelectronic properties.

  5. Highly trifluoromethylated platinum compounds. (United States)

    Martínez-Salvador, Sonia; Forniés, Juan; Martín, Antonio; Menjón, Babil


    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.

  6. 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. (United States)

    Hong, W S; Kim, H T; Kim, K H; Kim, D K


    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.

  7. Electronically asymmetric bis(porphyrin) sandwich complexes

    Energy Technology Data Exchange (ETDEWEB)

    Girolami, G.S.; Gorlin, P.A.; Suslick, K.S. [Univ. of Illinois, Urbana, IL (United States)


    Bis(porphyrin)metal(IV) complexes (M(porph){sub 2}) have been extensively studies in recent years due to their structural, chemical, and spectroscopic similarity to the {open_quotes}special pair{close_quotes} found in the reaction center of photosynthetic bacteria. Strong interactions arise in the bis(porphyrin) complexes due to the short inter-porphyrin separation (< 3 {angstrom}), which results in properties not seen in mono(porphyrin) analogs. For example, the bis(porphyrin) complexes are considerably easier to oxidize than analogous mono(porphyrin) species, and the M(porph){sub 2{sup n+}} cations (n = 1,2) exhibit near-IR absorptions not found in simple mono(porphyrin)cations. As part of the authors continuing effort to understand the factors that govern the electronic structures of bis(porphyrin) supermolecules, the authors now describe the synthesis of a series of zirconium sandwich complexes. Introduction of electron-withdrawing or -donating groups on the {beta}-pyrrole position considerably affects the electronic properties of these molecules without altering their steric parameters. Thus, peripheral substitution allows modification of the inter-porphyrin {pi} interactions while keeping the inter-porphyrin separation constant. Previous studies have changed the identity of the central metal, but the electronic structure and the interplanar distance could not be varied independently.

  8. Ultrafast Photoinduced Electron Transfer in a π-Conjugated Oligomer/Porphyrin Complex

    KAUST Repository

    Aly, Shawkat Mohammede


    Controlling charge transfer (CT), charge separation (CS), and charge recombination (CR) at the donor-acceptor interface is extremely important to optimize the conversion efficiency in solar cell devices. In general, ultrafast CT and slow CR are desirable for optimal device performance. In this Letter, the ultrafast excited-state CT between platinum oligomer (DPP-Pt(acac)) as a new electron donor and porphyrin as an electron acceptor is monitored for the first time using femtosecond (fs) transient absorption (TA) spectroscopy with broad-band capability and 120 fs temporal resolution. Turning the CT on/off has been shown to be possible either by switching from an organometallic oligomer to a metal-free oligomer or by controlling the charge density on the nitrogen atom of the porphyrin meso unit. Our time-resolved data show that the CT and CS between DPP-Pt(acac) and cationic porphyrin are ultrafast (approximately 1.5 ps), and the CR is slow (ns time scale), as inferred from the formation and the decay of the cationic and anionic species. We also found that the metallic center in the DPP-Pt(acac) oligomer and the positive charge on the porphyrin are the keys to switching on/off the ultrafast CT process.

  9. Structural and electrochemical properties of -tetrabromo-mesotetrakis(4-alkyloxyphenyl)porphyrins and their metal complexes

    Indian Academy of Sciences (India)

    P Bhyrappa; C Arunkumar


    Crystal structure of 2,3,12,13-tetrabromo-5,10,15,20-tetrakis(4-butyloxy phenyl)porphinato copper(II) tetrahydrofuran solvate was examined and it features enhanced non-planar distortion of the porphyrin ring. The normal coordinate structural decomposition (NSD) analysis for the out-of-plane displacement of atoms of the macrocyclic ring in CuT(4-CnP)PBr4 ( = 4, 6) indicates mainly saddled distortion combined with small contribution from wave conformation. The electrochemical studies on MT (4-CnP)PBr4 (M = 2H, Cu(II), Zn(II)) revealed cathodic shift in redox potentials in contrast to the corresponding brominated porphyrins, MTPPBr4. This is perhaps due to non-planarity of the porphyrin ring and the positive inductive effect of the alkyloxy groups.

  10. Panitumumab and pegylated liposomal doxorubicin to platinum-resistant epithelial ovarian cancer with KRAS wild-type: An ongoing, nonrandomized, multicenter, phase II trial

    DEFF Research Database (Denmark)

    Dahl Steffensen, Karina; Waldstrøm, Marianne; Lund, B


    and the response rates are only 10-20% using non-cross-resistant chemotherapeutic agents. The increasing number of negative trials for OC treatment has prompted an evaluation of new biologic agents, which in combination with chemotherapy may result in improvement in survival. Panitumumab is a fully human...... of first or second line platinum-based chemotherapy. Only patients with maximum 2 prior lines of chemotherapy, measurable disease by CA125 criteria and with KRAS wild type are eligible. Patients are treated with panitumumab 6 mg/kg day 1 and day 15 and with PLD 40 mg/m2 day 1, every 4 weeks. Tumor...... to a total of 33 patients. At present, 15 patients have been enrolled. The primary endpoint is to investigate the response rate in platinum-resistant, KRAS wild- type OC patients treated with PLD supplemented with panitumumab. Translational research is included as a secondary endpoint and tumor tissue...

  11. Adsorption of volatile polonium species on metals in various gas atmospheres. Pt. II. Adsorption of volatile polonium on platinum, silver and palladium

    Energy Technology Data Exchange (ETDEWEB)

    Maugeri, Emilio Andrea; Joerg Neuhausen; Dressler, Rugard; Piguet, David; Voegele, Alexander; Schumann, Dorothea [Paul Scherrer Institut (PSI), Villigen (Switzerland). Lab. for Radiochemistry; Misiak, Ryszard [The Henryk Niewodniczanski Institute of Nuclear Physics, Krakow (Poland); Eichler, Robert [Paul Scherrer Institut (PSI), Villigen (Switzerland). Lab. for Radiochemistry; Bern Univ. (Switzerland). Dept. for Chemistry and Biochemistry


    This work presents the results obtained from studying the interaction between polonium compounds formed in different atmospheres and platinum, palladium and silver surfaces obtained by thermochromatography. These results are of crucial importance for the design of cover gas filter systems for lead-bismuth eutectic (LBE)-based nuclear facilities such as accelerator driven systems (ADS). The results obtained from studying the interaction of polonium and platinum under inert atmosphere and reducing atmospheres with and without addition of moisture show that polonium is deposited at temperatures between 993 and 1221 K, with adsorption enthalpies ranging from -235 to -291 kJ mol{sup -1}, indicating a very strong adsorption of the polonium species present on platinum surfaces. The interaction between polonium and silver was investigated using purified inert, reducing and oxidizing carrier gases. Results show a deposition temperature between 867 and 990 K, with adsorption enthalpies ranging from -205 to -234 kJ mol{sup -1}. The interaction of polonium and palladium was studied in purified helium and purified hydrogen. For both conditions a deposition temperature of 1221 K was observed corresponding to an adsorption enthalpy of -340 kJ mol{sup -1}. No highly volatile polonium species was formed at any of the applied experimental conditions.

  12. 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. (United States)

    Shahabadi, Nahid; Hadidi, Saba


    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.

  13. The Antimicrobial Activity of Porphyrin Attached Polymers (United States)

    Thompson, Lesley


    We are interested in testing the antimicrobial activity of a porphyrin that is attached to a polymer. The porphyrin (5-(4-carboxyphenyl)-10,15,20-tris-(4-pryridyl)) was synthesized from methyl 4-formyl benzoate, 4-pyridinecarboxaldehyde, and pyrrole and attached to a copolymer of polystyrene/poly(vinyl benzyl chloride), which was synthesized by free radical polymerization. The antimicrobial activity of the polymer-attached porphyrin was then determined for gram-negative E. Coli grown to 0.80 OD. In this procedure, glass slides were coated with polymer-attached porphyrin via dip-coating, and the E. Coli bacteria were plated in Luria Broth media. The plates were subsequently exposed to light overnight before they were incubated as porphyrins act as photo-sensitizers when irradiated with light. The polymer-attached porphyrin did exhibit antimicrobial activity and parameters that affect its efficiency will be discussed.

  14. Copolymerisation of Propylene Oxide and Carbon Dioxide by Dinuclear Cobalt Porphyrins

    KAUST Repository

    Anderson, Carly E.


    Two dinuclear cobalt porphyrins comprising different structural tethering motifs at the porphyrin periphery were synthesised, along with a representative mononuclear cobalt porphyrin, and their catalytic activities tested towards carbon dioxide-propylene oxide copolymerisation in the presence of bis(triphenylphosphoranyl)ammonium chloride cocatalyst. The catalytic activities of the mononuclear and the bis-para-tethered dinuclear cobalt porphyrin with selective formation of poly(propylene carbonate) are largely comparable, showing no benefit of dinuclearity in contrast to the case of cobalt salen complexes and suggesting that polymer growth proceeds exclusively from one metal centre. The alternative bis-ortho-tethered porphyrin demonstrated considerably reduced activity, with dominant formation of cyclic propylene carbonate, as a result of hindered substrate approach at the metal centre. Time-resolved UV/Vis spectroscopic studies suggested a general intolerance of the cobalt(III) porphyrin catalysts towards the copolymerisation conditions in the absence of carbon dioxide pressure, leading to catalytically inactive cobalt(II) species. In the presence of carbon dioxide, the bis-ortho-tethered catalyst showed the fastest deactivation, which is related to an unfavourable steric arrangement of the linker fragment, as was also confirmed by NMR spectroscopic measurements. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Platinum compounds with anti-tumour activity

    NARCIS (Netherlands)

    Plooy, A.C.M.; Lohman, P.H.M.


    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

  16. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de


    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.

  17. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de


    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

  18. Synthesis and Spectroscopic Characterization of Two Tetrasubstituted Cationic Porphyrin Derivatives

    Directory of Open Access Journals (Sweden)

    Newton M. Barbosa Neto


    Full Text Available An imidazolium tetrasubstituted cationic porphyrin derivative (the free base and its Zn(II complex with five-membered heterocyclic groups in the meso-positions were synthesized using microwave irradiation, and the compounds obtained characterized by 1H-NMR and mass spectrometry. We observed that under microwave irradiation the yield is similar to when the synthesis is performed under conventional heating, however, the time required to prepare the porphyrins decreases enormously. In order to investigate the electronic state of these compounds, we employed UV-Vis and fluorescence spectroscopy combined with quantum chemical calculations. The results reveal the presence, in both compounds, of a large number of electronic states involving the association between the Soret and a blue-shifted band. The Soret band in both compounds also shows a considerable solvent dependence. As for emission, these compounds present low quantum yield at room temperature and no solvent influence on the fluorescence spectra was observed.

  19. Behind platinum's sparkle. (United States)

    Yam, Vivian W W


    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.

  20. Porphyrin coordination polymer nanospheres and nanorods (United States)

    Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.


    A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

  1. Porphyrin Microparticles for Biological and Biomedical Applications (United States)

    Huynh, Elizabeth

    Lipids are one of the critical building blocks of life, forming the plasma membrane of cells. In addition, porphyrins also play an equally important role in life, for example, through carrying oxygen in blood. The importance of both these components is evident through the biological and biomedical applications of supramolecular structures generated from lipids and porphyrins. This thesis investigates new porphyrin microparticles based on porphyrin-lipid architecture and their potential applications in biology and medicine. In Chapter 1, a background on lipid and porphyrin-based supramolecular structures is presented and design considerations for generating multifunctional agents. Chapter 2 describes the generation of a monolayer porphyrin microparticle as a dual-modal ultrasound and photoacoustic contrast agent and subsequently, a trimodal ultrasound, photoacoustic and fluorescence contrast agent. Chapter 3 examines the optical and morphological response of these multimodality ultrasound-based contrast agents to low frequency, high duty cycle ultrasound that causes the porphyrin microparticles to convertinto nanoparticles. Chapter 4 examines the generation of bilayer micrometer-sized porphyrin vesicles and their properties. Chapter 5 presents a brief summary and potential future directions. Although these microscale structures are similar in structure, the applications of these structures greatly differ with potential applications in biology and also imaging and therapy of disease. This thesis aims to explore and demonstrate the potential of new simplified, supramolecular structures based on one main building block, porphyrin-lipid.

  2. Porphyrin coordination polymer nanospheres and nanorods (United States)

    Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.


    A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

  3. Influence of exposure and infusion times on the cytotoxicity and pharmacokinetics of cis-malonato[(4R, 5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) . (United States)

    Kim, H T; Kim, D K; Cho, Y B; Kim, T S; Jung, I; Kim, K H; Heo, D S; Bang, Y J; Shin, S G; Kim, N K


    The effect of exposure time on the in vitro cytotoxicity of a new platinum complex, cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolan e]platinum(II) (SKI 2053R) and cisplatin (CDDP) toward two human lung-adenocarcinoma cell lines (PC-9, PC-14) and two human stomach-adenocarcinoma cell lines (KATO III, MKN-45) was investigated by variation of the exposure time (1, 4, 12, and 24 h) and drug concentration to yield a constant product of drug concentration times exposure time (C x T). Exposure of cancer cells to low concentrations of SKI 2053R for 12 or 24 h resulted in a greater killing effect than did 1- or 4-h exposure to 24- or 6-fold higher concentrations; the inhibitory effects of SKI 2053R on the colony formation of all tumor cell lines except for KATO III were significantly increased with increasing exposure time (P < 0.05). However, the inhibitory effects of CDDP against all tumor cell lines tested except for PC-14 were inversely correlated with increasing exposure time (P < 0.05). The intracellular accumulation of SKI 2053R and CDDP was measured under the same conditions used in the cell-survival assay using MKN-45 cells. The amount of platinum accumulated from SKI 2053R into MKN-45 cells was greater for the treatment involving low concentrations and long-term exposures (12 and 24 h) than for that using high concentrations and short-term exposures (1 and 4 h) at the constant C x T values; however, the increased accumulation of CDDP was more prominent as the concentration was increased, even if the exposure time became shorter. The pharmacokinetics studies of SKI 2053R following 1-, 4-, 12-, and 24-h infusions were performed in beagle dogs. A single dose of SKI 2053R (5.0 mg/kg) was successively given over various infusion periods to three beagle dogs at 3-week intervals. The peak levels of ultrafiltrable platinum observed for SKI 2053R at the 1-, 4-, 12-, and 24-h infusions were 3.10+/-0.49 (mean +/- SD), 1.24+/-0.06, 0.43+/-0.07, and 0

  4. Re(I) bridged porphyrin dyads, triads and tetrads

    Indian Academy of Sciences (India)

    M Yedukondalu; M Ravikanth


    Porphyrin rings containing two meso-pyridyl groups either in cis or trans fashion can be used to construct Re(I) bridged multiporphyrin assemblies. The cis-dipyridyl porphyrins with various porphyrin cores such as N4, N3O, N3S, N2S2 have been used to react with Re(CO)5Cl in THF at refluxing temperature and constructed planar Re(I) bridged porphyrin dyads containing either one type of porphyrin subunit or two types of porphyrin subunits. The trans-dipyridyl porphyrins have been used to construct Re(I) bridged porphyrin squares. The porphyrin dyads have been explored for singlet-singlet energy transfer studies and porphyrin squares have been used for catalysis, chemical sensing, molecular sieving and photocurrent production studies. An overview of synthesis of Re(I) bridged porphyrin dyads, triads and tetrads and their interesting photophysical properties are highlighted in this paper.

  5. Panitumumab and pegylated liposomal doxorubicin to platinum-resistant epithelial ovarian cancer with KRAS wild-type: An ongoing, nonrandomized, multicenter, phase II trial

    DEFF Research Database (Denmark)

    Dahl Steffensen, Karina; Waldstrøm, Marianne; Lund, B


    , and head and neck cancer. No previous studies have evaluated the effect of panitumumab in OC based on KRAS mutation status. Methods: Eligibility criteria are confirmed stage I-IV primary epithelial ovarian/fallopian/peritoneal cancer patients with progression either during or within 6 months after end...... to a total of 33 patients. At present, 15 patients have been enrolled. The primary endpoint is to investigate the response rate in platinum-resistant, KRAS wild- type OC patients treated with PLD supplemented with panitumumab. Translational research is included as a secondary endpoint and tumor tissue...

  6. Quantitative measurement of porphyrins in biological tissues and evaluation of tissue porphyrins during toxicant exposures. (United States)

    Woods, J S; Miller, H D


    Porphyrins are formed in most eukaryotic tissues as intermediates in the biosynthesis of heme. Assessment of changes in tissue porphyrin levels occurring in response to the actions of various drugs or toxicants is potentially useful in the evaluation of chemical exposures and effects. The present paper describes a rapid and sensitive method for the extraction and quantitation of porphyrins in biological tissues which overcomes difficulties encountered in previously described methods, particularly the loss of porphyrins during extraction and interference of porphyrin quantitation by coeluting fluorescent tissue constituents. In this procedure 8- through 2-carboxyl porphyrins are quantitatively extracted from tissue homogenates using HCl and methanol and are subsequently separated from potentially interfering contaminants by sequential methanol/phosphate elution on a C-18 preparatory column. Porphyrins are then separated and measured by reversed-phase high-performance liquid chromatography and spectrofluorometric techniques. Recovery of tissue porphyrins using this method is close to 100% with an intraassay variability of less than 10%. We have employed this procedure to measure liver and kidney porphyrin concentrations in male Fischer rats and to define the distinctive changes in tissue porphyrin patterns associated with treatment with the hepatic and renal porphyrinogenic chemicals, allylisopropylacetamide, and methyl mercury hydroxide, respectively. This method is applicable to the measurement of tissue porphyrin changes resulting from drug or toxicant exposures in clinical, experimental or environmental assessments.

  7. Stage II recovery behavior of a series of ion-irradiated platinum (gold) alloys as studied by field-ion microscopy. [0. 10, 0. 62, and 4. 0 at. percent Au and pure Pt

    Energy Technology Data Exchange (ETDEWEB)

    Wei, C.Y.; Seidman, D.N.


    Direct and visible evidence was obtained for long-range migration of self-interstitial atoms (SIAs) in Stage II of three different ion-irradiated platinum (gold) alloys. Field-ion microscope (FIM) specimens of Pt--0.10, 0.62 and 4.0 at. percent Au alloys were irradiated in-situ with 30-keV W/sup +/ or Pt/sup +/ ions at a tip temperature of 35 to 41 K at 2 x 10/sup -9/ torr. Direct observation of the surfaces of the FIM specimens during isochronal warming experiments to 100 K showed that a flux of SIAs crossed the surfaces of the specimens between 40 to 100 K. The spectrum for each alloy consisted of two recovery peaks (substages II/sub B/ and II/sub C/). The results are explained on the basis of an impurity-delayed diffusion mechanism employing a two-level trapping model. The application of this diffusion model to the isochronal recovery spectra yielded a dissociation enthalpy (DELTAh/sub li-Au//sup diss/) and an effective diffusion coefficient for each substage; for substage II/sub B/ DELTAh/sub li-Au//sup diss/ (II/sub B/) = 0.15 eV and for substage II/sub C/ DELTAh/sub li-Au//sup diss/ (II/sub C/) = 0.24 eV. A series of detailed control experiments was also performed to show that the imaging electric field had not caused the observed long-range migration of SIAs and that the observed effects were not the result of surface artifacts. 14 figures, 6 tables.

  8. 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. (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


    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.

  9. 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. (United States)

    Akbar Ali, Mohammad; Mirza, Aminul Huq; Butcher, Raymond J; Tarafder, M T H; Keat, Tan Boon; Ali, A Manaf


    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

  10. Sedimentary porphyrins: Correlations with biological precursors

    Energy Technology Data Exchange (ETDEWEB)

    Callot, H.J.; Ocampo, R.; Albrecht, P. (Universite Louis Pasteur, Strasbourg (France))

    Over the past 6 years several sedimentary porphyrins (petroporphyrins, geoporphyrins) were correlated for the first time with biological precursors specific for classes of organisms (algae, photosynthetic bacteria (Chlorobiaceae)). This article discusses the various examples of correlations and the methods that led to these conclusions (isolation of pure porphyrins, structure determination using spectroscopic techniques, total synthesis, isotope measurements).

  11. Synthesis,Characterization,and Electrochemical Property of Nanometer Porphyrin Dimer

    Institute of Scientific and Technical Information of China (English)


    A nanometer porphyrin dimer was synthesized with fumaryl chloride as a bridge-linked reagent. The characterization was carried out with elemental analyses, 1H NMR, UV-Vis, and IR spectrometries, and then the electrochemical properties of the porphyrins were studied. The authors found that there was moderate electronic communication between the two porphyrin rings in the nanometer porphyrin dimer.

  12. Dermal administration of manganese porphyrin by iontophoresis. (United States)

    Ito, Fuminori; Imamura, Shinya; Asayama, Shoichiro; Kanamura, Kiyoshi; Kawakami, Hiroyoshi


    The present study describes a technique for dermal administration of cationic manganese porphyrin (Mn-porphyrin), an antioxidant with superoxide dismutase (SOD) activity, in hairless mouse. In general, the stratum corneum on the surface of the skin represents a barrier to passive diffusion of therapeutic agents by standard dermal administration. The present study investigated whether, dermal administration of Mn-porphyrin solution using iontophoresis, the electrical dermal administration technique, could overcome this barrier. We visually confirmed that Mn-porphyrin had penetrated to the reverse side of the hairless mouse skin after iontophoresis for a short period. With prolonged iontophoresis, the ratio of detectable Mn-porphyrin solution on the reverse side of the hairless mouse skin increased. In the future, this technique could provide an innovative approach for delivery of this antioxidant in intractable disease.

  13. Platinum hypersensitivity and desensitization. (United States)

    Miyamoto, Shingo; Okada, Rika; Ando, Kazumichi


    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:

  14. Highly fluorescent platinum(II) organometallic complexes of perylene and perylene monoimide, with Pt σ-bonded directly to the perylene core. (United States)

    Lentijo, Sergio; Miguel, Jesús A; Espinet, Pablo


    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.

  15. Monofunctional and Higher-Valent Platinum Anticancer Agents (United States)

    Johnstone, Timothy C.; Wilson, Justin J.


    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

  16. Bromoporphyrins as versatile synthons for modular construction of chiral porphyrins: cobalt-catalyzed highly enantioselective and diastereoselective cyclopropanation. (United States)

    Chen, Ying; Fields, Kimberly B; Zhang, X Peter


    5,10-Bis(2',6'-dibromophenyl)porphyrins bearing various substituents at the 10 and 20 positions were demonstrated to be versatile synthons for modular construction of chiral porphyrins via palladium-catalyzed amidation reactions with chiral amides. The quadruple carbon-nitrogen bond formation reactions were accomplished in high yields with different chiral amide building blocks under mild conditions, forming a family of D2-symmetric chiral porphyrins. Cobalt(II) complexes of these chiral porphyrins were prepared in high yields and shown to be active catalysts for highly enantioselective and diastereoselective cyclopropanation under a practical one-pot protocol (alkenes as limiting reagents and no slow addition of diazo reagents).

  17. Porphyrin-Based Photocatalytic Lithography

    Energy Technology Data Exchange (ETDEWEB)

    Bearinger, J; Stone, G; Christian, A; Dugan, L; Hiddessen, A; Wu, K J; Wu, L; Hamilton, J; Stockton, C; Hubbell, J


    Photocatalytic lithography is an emerging technique that couples light with coated mask materials in order to pattern surface chemistry. We excite porphyrins to create radical species that photocatalytically oxidize, and thereby pattern, chemistries in the local vicinity. The technique advantageously does not necessitate mass transport or specified substrates, it is fast and robust and the wavelength of light does not limit the resolution of patterned features. We have patterned proteins and cells in order to demonstrate the utility of photocatalytic lithography in life science applications.

  18. Porphyrin-based Photocatalytic Nanolithography

    Energy Technology Data Exchange (ETDEWEB)

    Bearinger, J P; Stone, G; Dugan, L C; Dasher, B E; Stockton, C; Conway, J W; Kuenzler, T; Hubbell, J A


    Nanoarray fabrication is a multidisciplinary endeavor encompassing materials science, chemical engineering and biology. We form nanoarrays via a new technique, porphyrin-based photocatalytic nanolithography (PCNL). The nanoarrays, with controlled features as small as 200 nm, exhibit regularly ordered patterns and may be appropriate for (a) rapid and parallel proteomic screening of immobilized biomolecules, (b) protein-protein interactions and/or (c) biophysical and molecular biology studies involving spatially dictated ligand placement. We demonstrate protein immobilization utilizing nanoarrays fabricated via PCNL on silicon substrates, where the immobilized proteins are surrounded by a non-fouling polymer background.

  19. Porphyrin-based Photocatalytic Nanolithography

    Energy Technology Data Exchange (ETDEWEB)

    Bearinger, J P; Stone, G; Dugan, L C; Dasher, B E; Stockton, C; Conway, J W; Kuenzler, T; Hubbell, J A


    Nanoarray fabrication is a multidisciplinary endeavor encompassing materials science, chemical engineering and biology. We form nanoarrays via a new technique, porphyrin-based photocatalytic nanolithography (PCNL). The nanoarrays, with controlled features as small as 200 nm, exhibit regularly ordered patterns and may be appropriate for (a) rapid and parallel proteomic screening of immobilized biomolecules, (b) protein-protein interactions and/or (c) biophysical and molecular biology studies involving spatially dictated ligand placement. We demonstrate protein immobilization utilizing nanoarrays fabricated via PCNL on silicon substrates, where the immobilized proteins are surrounded by a non-fouling polymer background.

  20. Novel drug delivery strategies for porphyrins and porphyrin precursors (United States)

    Morrow, D. I. J.; Donnelly, R. F.


    superficial lesions, such as actinic keratosis. In addition, photodynamic antimicrobial chemotherapy (PACT) is attracting increasing interest for the treatment of infection. However, delivery strategies for topical PDT and PACT are still based on application of rather simplistic cream and solution formulations, with little consideration given to thermodynamics, targeting or the physicochemical properties of the active agent. Purpose-designed dosage forms for topical delivery of aminolevulinic acid or its esters include creams containing penetration enhancers and/or iron chelators, pressure sensitive patches and bioadhesive patches. Such systems aim to enhance drug delivery across the stratum corneum and keratinised debris overlying neoplastic lesions and improve subsequent protoporphyrin IX (PpIX) production. The alternative to using porphyrin precursors is the use of pre-formed photosensitisers. However, owing to their relatively high molecular weights, conventional topical application is not appropriate. Innovative strategies, such as the use of needle-free injections and microneedle arrays, bypass the stratum corneum, enabling rapid and targeted delivery not only porphyrin precursors but also pre-formed photosensitisers. This presentation will review drug delivery work published to date in the fields of PDT and PACT. In addition, the benefits of employing the latest advances in pharmaceutical technology will be highlighted.

  1. 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 (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.


    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.

  2. Phenothiazine-bridged cyclic porphyrin dimers as high-affinity hosts for fullerenes and linear array of C60 in self-assembled porphyrin nanotube. (United States)

    Sakaguchi, Ken-ichi; Kamimura, Takuya; Uno, Hidemitsu; Mori, Shigeki; Ozako, Shuwa; Nobukuni, Hirofumi; Ishida, Masatoshi; Tani, Fumito


    Free-bases and a nickel(II) complex of phenothiazine-bridged cyclic porphyrin dimers bearing self-assembling 4-pyridyl groups (M2-Ptz-CPDPy(OCn); M = H2 or Ni, OCn = OC6 or OC3) at opposite meso-positions have been prepared as host molecules for fullerenes. The free-base dimer (H4-Ptz-CPDPy(OC6)) includes fullerenes with remarkably high association constants such as 3.9 ± 0.7 × 10(6) M(-1) for C60 and 7.4 ± 0.8 × 10(7) M(-1) for C70 in toluene. This C60 affinity is the highest value ever among reported receptors composed of free-base porphyrins. The nickel dimer (Ni2-Ptz-CPDPy(OC6)) also shows high affinities for C60 (1.3 ± 0.2 × 10(6) M(-1)) and C70 (over 10(7) M(-1)). In the crystal structure of the inclusion complex of C60 within H4-Ptz-CPDpy(OC3), the C60 molecule is located just above the centers of the porphyrins. The two porphyrin planes are almost parallel to each other and the center-to-center distance (12.454 Å) is close to the optimal separation (∼12.5 Å) for C60 inclusion. The cyclic porphyrin dimer forms a nanotube through its self-assembly induced by C-H···N hydrogen bonds between porphyrin β-CH groups and pyridyl nitrogens as well as π-π interactions of the pyridyl groups. The C60 molecules are linearly arranged in the inner channel of this nanotube.

  3. Self assembled films of porphyrins with amine groups at different positions: influence of their orientation on the corrosion inhibition and the electrocatalytic activity. (United States)

    Lokesh, Koodlur Sannegowda; De Keersmaecker, Michel; Adriaens, Annemie


    Self-assembled molecular films of two cobalt porphyrins with amine groups at different positions-(5,10,15,20-tetrakis-(2-aminophenyl) porphyrin-cobalt(II), [Co(II) (T(o-NH(2))PP)] and (5,10,15,20-tetrakis-(4-aminophenyl) porphyrin-cobalt(II), [Co(II)(T(p-NH(2))PP)]-were formed on a gold substrate. The functionalized surfaces were characterized using Raman spectroscopy, atomic force microscopy and electrochemical methods. Both modified gold surfaces completely mask the charge transfer of a [Fe(CN)(6)](3-/4-) redox couple in solution, indicating the layer is highly resistive in behavior. Electrochemical impedance spectroscopy analyses revealed that the porphyrin film with amine groups at ortho positions shows a higher charge-transfer resistance with a better protective behavior compared to the para position modified surface. Raman, AFM and EIS data suggests that an ortho amine positioned molecule forms a more compact layer compared to the para-positioned molecule. This can be explained in terms of their orientation on the gold surface. [Co(II)(T(o-NH(2))PP)] adopted a saddle shape orientation whereas [Co(II)(T(p-NH(2))PP)] adopted a flat orientation on the gold surface. The porphyrin modified gold electrode catalyzes the oxygen reduction at lower potentials compared to the bare gold electrode. The shift in the overvoltage was higher in case of molecules with flat orientation compared to the saddle shaped oriented porphyrin molecules on the surface.

  4. Aggregates of a cationic porphyrin as supramolecular probes for biopolymers. (United States)

    Occhiuto, Ilaria Giuseppina; Samperi, Mario; Trapani, Mariachiara; De Luca, Giovanna; Romeo, Andrea; Pasternack, Robert F; Scolaro, Luigi Monsù


    The copper(II) derivative of the dicationic trans-bis(N-methylpyridinium-4-yl)diphenylporphyrin (t-CuPagg) forms large fractal aggregates in aqueous solution under moderate ionic strength conditions. A kinetic investigation of the aggregation process allows for a choice of experimental conditions to quickly obtain stable assemblies in solution. These positively charged aggregates are able to interact efficiently with negatively charged chiral species, (including bacterial spores) leading to induced circular dichroism signals in the Soret region of the porphyrin, now acting as a sensitive chiroptical probe.

  5. A new C=C embedded porphyrin sheet with superior oxygen reduction performance

    Institute of Scientific and Technical Information of China (English)

    Yawei Li[1; Shunhong Zhang[2; Jiabing Yu[1; Qian Wang[2; Qiang Sun[1,2,3; Puru Jena[3


    C2 is a well-known pseudo-oxygen unit with an electron affinity of 3.4 eV. We show that it can exhibit metal-ion like behavior when embedded in a porphyrin sheet and form a metal-free two-dimensional material with superior oxygen reduction performance. Here, the positively charged C=C units are highly active for oxygen reduction reaction (ORR) via dissociation pathways with a small energy barrier of 0.09 eV, much smaller than that of other non-platinum group metal (non-PGM) ORR catalysts. Using a microkinetics-based model we calculated the partial current density to be 3.0 mA/cm2 at 0.65 V vs. a standard hydrogen electrode (SHE), which is comparable to that of the state-of-the-art Pt/C catalyst. We further confirm that the C=C embedded porphyrin sheet is dynamically and thermally stable with a quasi-direct band gap of 1.14 eV. The superior catalytic performance and geometric stability make the metal-free C=C porphyrin sheet ideal for fuel cell applications.

  6. 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. (United States)

    Łakomska, Iwona; Hoffmann, Kamil; Wojtczak, Andrzej; Sitkowski, Jerzy; Maj, Ewa; Wietrzyk, Joanna


    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)

  7. Porphyrin-aminoquinoline conjugates as telomerase inhibitors. (United States)

    Maraval, Alexandrine; Franco, Sonia; Vialas, Corine; Pratviel, Geneviève; Blasco, Maria A; Meunier, Bernard


    A series of metalloporphyrins was prepared in order to target the G-quadruplex structure of telomeric DNA for the design of antitelomerase compounds. The initial cationic tetramethylpyridiniumyl porphyrin was modified by the replacement of one or two methylpyridiniumyl groups by one or two 4-aminoquinoline moieties, at the meso position, in order to increase the cell penetration and the quadruplex affinity. The porphyrins were either metallated by manganese or by nickel. The degradation of quadruplex DNA was assayed in vitro with the manganese redox-active derivatives. All porphyrins complexes were capable of inhibiting the telomerase enzyme with IC50 values in the micromolar range (TRAP assay).

  8. 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. (United States)

    Uemura, Masako; Suzuki, Toshihiro; Nishio, Kazuto; Chikuma, Masahiko; Komeda, Seiji


    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.

  9. Zwitterionic and cationic bis(phosphine) platinum(II) complexes: structural, electronic, and mechanistic comparisons relevant to ligand exchange and benzene C-H activation processes. (United States)

    Thomas, J Christopher; Peters, Jonas C


    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

  10. Oxoferryl porphyrin/hydrogen peroxide system whose behavior is equivalent to hydroperoxoferric porphyrin. (United States)

    Kitagishi, Hiroaki; Tamaki, Mariko; Ueda, Takunori; Hirota, Shun; Ohta, Takehiro; Naruta, Yoshinori; Kano, Koji


    The reaction between H(2)O(2) and a pyridine-coordinated ferric porphyrin encapsulated by a cyclodextrin dimer yielded a hydroperoxoferric porphyrin intermediate, PFe(III)-OOH, which rapidly decomposed to oxoferryl porphyrin (PFe(IV)═O). Upon reaction with H(2)O(2), PFe(IV)═O reverted to PFe(III)-OOH, which was converted to carbon monoxide-coordinated ferrous porphyrin under a CO atmosphere. PFe(IV)═O in the presence of excess H(2)O(2) behaves as PFe(III)-OOH.

  11. Tin-porphyrin-assisted formation of coordination frameworks (United States)

    Titi, Hatem M.


    Novel 3D networks synthesized by two different methods are reported in this article. Structure 1 {[CdL2]·(solvent)}n consists of CdII-single metallic nodes held together by coordinated isonicotinate ligands (L) to form a 3D chiral framework (P41212). The resulting structure exhibits threefold-interpenetrated dia coordination networks. After a few weeks the crystals were re-measured to form 1a {[Cd(L)2(H2O)]·DMF}n with two interpenetrated dia nets which is thermodynamically more stable. On the other hand, the addition of the tin(IV)-porphyrin to the same reaction mixture led to the formation of 3D pseudo-isostructures, based on oxo-centered CdII and MnII/III cluster nodes, 2 {[Cd3(OH)L4(H2O)3](ClO4)}n and 3 {[Mn3(O)L4(DMF)3](ClO4)}n. These structures represent topologically bcg nets. Possible synthetic mechanism was proposed to emphasize the role of the tin(IV)-porphyrin that led to the construction of oxo-centered trinuclear clusters in 2 and 3.

  12. Emission spectroscopic properties of water soluble porphyrins in hydrogen peroxide chemiluminescence system with d- and f-electron metals (United States)

    Staninski, Krzysztof; Kaczmarek, Małgorzata; Lis, Stefan; Elbanowski, Marian


    Two water-soluble porphyrins: 4,4',4'',4'''-(porphine-5,10,15,20-tetrayl)-tetrakis (benzoic acid) (TCPPH 2) and 4,4',4'',4'''-(porphine-5,10,15,20-tetrayl)-tetrakis (benzenesulfonic acid) (TSPPH 2) have been subjected to spectroscopic study in the presence of d-electron metals: Zn(II) and Cu(II) and f-electron metals: La(III), Eu(III), Gd (III) and Yb(III). Results of the spectrophotometric study have provided evidence proving the complexation of Cu(II) and Zn(II) cations by porphine in water solutions and the complexation of lanthanide ions exclusively by peripheral carboxyl and sulfonic groups. For the first time, chemiluminescence of the systems containing porphyrins has been measured without the use of strongly luminescent reagents such as TCPO or luminol. The emission spectra of the systems porphyrin/metal ion/H 2O 2 have been recorded and the quantum yield of their luminescence has been measured. The absorption spectra of the systems recorded before and after the reaction in the presence of hydrogen peroxide are identical, which means that the porphyrin ring does not undergo destruction. A significant similarity between the fluorescence and chemiluminescence spectra indicates a possibility of excitation of porphyrins and their complexes in the reaction with hydrogen peroxide.

  13. β-Cyclodextrin as a Metal-anionic Porphyrin Complexation Accelerator in Aqueous Media. (United States)

    Ohtomo, Takao; Yokoyama, Aya; Konno, Mitsuyuki; Ohno, Osamu; Igarashi, Shukuro; Takagai, Yoshitaka


    The rate of the complexation reaction between anionic porphyrins and 11 metal ions was found to be accelerated by the presence of β-cyclodextrin (β-CD) in aqueous media at room temperature without the need for additional heating or sonication. The porphyrin complexation reaction with metal ions under aqueous conditions can be difficult due to the strong hydration energy between the metal ions and water. In this study, the specific role of β-CD as an accelerator was determined and found to enhance the typically slow reaction of the porphyrin with metal ions. A significant acceleration effect was exhibited when the model anionic porphyrin, 5,10,15,20-tetraphenyl-21H,23H-porphine-tetrasulfonic acid, and Pb(II) ions were combined in the presence of β-CD. Other than for Hg ion, the addition of β-CD decreased the metalation reaction time from 30 to 2 min. The order in the degree of acceleration was Pb > Zn, Cd > Cu > Fe, Pd > Sn > Ag, Co, Mn. Using Pb(II) as the model ion, it was determined that the complexation rate constant was enhanced by a factor of 2.4, while the dissociation rate constant was diminished by a factor of 135 in the presence of added β-CD relative to that in its absence. Overall, the complex was much more stable (formation equilibrium constant 324-fold greater in the β-CD medium. The formation of a ternary complex (cf. bicapped complex; (β-CD)2-porphyrin-metal ion) was demonstrated through the use of nuclear magnetic-resonance spectroscopy and mass spectrometry. This acceleration effect is expected to be applicable systems in which porphyrin ligands are employed for determining of metal ions in chemical analysis and separation science.

  14. Toxicity of platinum compounds. (United States)

    Hartmann, Jörg Thomas; Lipp, Hans-Peter


    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.

  15. Phase II study of capecitabine as palliative treatment for patients with recurrent and metastatic squamous head and neck cancer after previous platinum-based treatment (United States)

    Martinez-Trufero, J; Isla, D; Adansa, J C; Irigoyen, A; Hitt, R; Gil-Arnaiz, I; Lambea, J; Lecumberri, M J; Cruz, J J


    Background: Platinum-based therapy (PBT) is the standard therapy for recurrent and/or metastatic head and neck cancer (HNC), but the incidence of recurrence remains high. This study evaluates the efficacy and tolerability of capecitabine as palliative monotherapy for recurrent HNC previously treated with PBT. Methods: Patients aged 18–75 years, with Eastern Cooperative Oncology Group performance status 0–2, squamous HNC with locoregional and/or metastatic recurrence previously treated with PBT and adequate organ functions, were included. Capecitabine (1.250 mg m−2 BID) was administered on days 1–14 every 21 days for at least two cycles. Results: A total of 40 male patients with a median age of 58 years were analysed. All patients received a median number of four cycles of capecitabine (range: 1–9) and the median relative dose intensity was 91%. Seven patients were not evaluable for response. Overall response rate was 24.2%. Median time to progression and overall survival were 4.8 and 7.3 months, respectively. Haematological adverse events (AEs) grade 3/4 were reported in six patients. Most common grade 3/4 non-haematological AEs were asthenia (12.5%), palmar-plantar eritrodisestesia (10%), mucositis (10%), dysphagia (10%) and diarrhoea (7.5%). Conclusions: Capecitabine seems to be an active, feasible and well-tolerated mode of palliative treatment for advanced HNC patients who have previously received PBT schedules. PMID:20485287

  16. Bulky N(,N)-(di)alkylethane-1,2-diamineplatinum(II) compounds as precursors for generating unsymmetrically substituted platinum(IV) complexes. (United States)

    Pichler, Verena; Göschl, Simone; Meier, Samuel M; Roller, Alexander; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K


    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.

  17. Phase II study of biweekly cetuximab in combination with irinotecan as second-line treatment in patients with platinum-resistant gastro-oesophageal cancer

    DEFF Research Database (Denmark)

    Schønnemann, K R; Yilmaz, Mette Karen; Bjerregaard, J K;


    The purpose of this phase II trial was to evaluate the efficacy and safety of cetuximab and irinotecan as second-line treatment in patients with gastro-oesophageal adenocarcinoma.......The purpose of this phase II trial was to evaluate the efficacy and safety of cetuximab and irinotecan as second-line treatment in patients with gastro-oesophageal adenocarcinoma....

  18. Porphyrin-Based Nanostructures for Photocatalytic Applications

    Directory of Open Access Journals (Sweden)

    Yingzhi Chen


    Full Text Available Well-defined organic nanostructures with controllable size and morphology are increasingly exploited in optoelectronic devices. As promising building blocks, porphyrins have demonstrated great potentials in visible-light photocatalytic applications, because of their electrical, optical and catalytic properties. From this perspective, we have summarized the recent significant advances on the design and photocatalytic applications of porphyrin-based nanostructures. The rational strategies, such as texture or crystal modification and interfacial heterostructuring, are described. The applications of the porphyrin-based nanostructures in photocatalytic pollutant degradation and hydrogen evolution are presented. Finally, the ongoing challenges and opportunities for the future development of porphyrin nanostructures in high-quality nanodevices are also proposed.

  19. Porphyrins and phthalocyanines in solar photovoltaic cells


    Walter, Michael G.; Rudine, Alexander B.; Wamser, Carl C.


    This review summarizes recent advances in the use of porphyrins, phthalocyanines, and related compounds as components of solar cells, including organic molecular solar cells, polymer cells, and dye-sensitized solar cells. The recent report of a porphyrin dye that achieves 11% power conversion efficiency in a dye-sensitized solar cell indicates that these classes of compounds can be as efficient as the more commonly used ruthenium bipyridyl derivatives.

  20. 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...

  1. Porphyrin-loaded nanoparticles for cancer theranostics (United States)

    Zhou, Yiming; Liang, Xiaolong; Dai, Zhifei


    Porphyrins have been used as pioneering theranostic agents not only for the photodynamic therapy, sonodynamic therapy and radiotherapy of cancer, but also for diagnostic fluorescence imaging, magnetic resonance imaging and photoacoustic imaging. A variety of porphyrins have been developed but very few of them have actually been employed in clinical trials due to their poor selectivity to tumorous tissue and high accumulation rates in the skin. In addition, most porphyrin molecules are hydrophobic and form aggregates in aqueous media. Nevertheless, the use of nanoparticles as porphyrin carriers shows great promise to overcome these shortcomings. Encapsulating or attaching porphyrins to nanoparticles makes them more suitable for tissue delivery because we can create materials with a conveniently specific tissue lifetime, specific targeting, immune tolerance, and hydrophilicity as well as other characteristics through rational design. In addition, various functional components (e.g. for targeting, imaging or therapeutic functions) can be easily introduced into a single nanoparticle platform for cancer theranostics. This review presents the current state of knowledge on porphyrin-loaded nanoparticles for the interwined imaging and therapy of cancer. The future trends and limitations of prophyrin-loaded nanoparticles are also outlined.

  2. 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.


    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

  3. Oxygen reduction reaction at MWCNT-modified nanoscale iron(II) tetrasulfophthalocyanine: remarkable performance over platinum and tolerance toward methanol in alkaline medium

    CSIR Research Space (South Africa)

    Fashedemi, OO


    Full Text Available A nanoscale iron(II) tetrasulfophthalocyanine (nanoFeTSPc) catalyst obtained by co-ordinating with hexadecyltrimethylammonium bromide and subsequently anchored onto multi-walled carbon nanotubes (MWCNTs) for oxygen reduction reaction (ORR) has been...

  4. Electron Transport through Porphyrin Molecular Junctions (United States)

    Zhou, Qi

    The goal of this work is to study the properties that would affect the electron transport through a porphyrin molecular junction. This work contributes to the field of electron transport in molecular junctions in the following 3 aspects. First of all, by carrying out experiments comparing the conductance of the iron (III) porphyrin (protected) and the free base porphyrin (protected), it is confirmed that the molecular energy level broadening and shifting occurs for porphyrin molecules when coupled with the metal electrodes, and this level broadening and shifting plays an important role in the electron transport through molecular junctions. Secondly, by carrying out an in-situ deprotection of the acetyl-protected free base porphyrin molecules, it is found out that the presence of acetyl groups reduces the conductance. Thirdly, by incorporating the Matrix-assisted laser desorption/ionization (MALDI) spectrum and the in-situ deprotection prior to formation of molecular junctions, it allows a more precise understanding of the molecules involved in the formation of molecular junctions, and therefore allows an accurate analysis of the conductance histogram. The molecules are prepared by self-assembly and the junctions are formed using a Scanning Tunneling Microscopy (STM) molecular break junction technique. The porphyrin molecules are characterized by MALDI in solution before self-assembly to a gold/mica substrate. The self-assembled monolayers (SAMs) of porphyrins on gold are characterized by Ultraviolet-visible (UV-Vis) reflection spectroscopy to confirm that the molecules are attached to the substrate. The SAMs are then characterized by Angle-Resolved X-ray photoelectron spectroscopy (ARXPS) to determine the thickness and the average molecular orientation of the molecular layer. The electron transport is measured by conductance-displacement (G-S) experiments under a given bias (-0.4V). The conductance value of a single molecule is identified by a statistical analysis

  5. Pseudo-rotation mechanism for fast olefin exchange and substitution processes at orthometalated C,N-complexes of platinum(II). (United States)

    Otto, Stefanus; Samuleev, Pavel V; Polyakov, Vladimir A; Ryabov, Alexander D; Elding, Lars I


    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.

  6. Biomineralization of platinum by microorganisms (United States)

    Pavlova, L. M.; Radomskaya, V. I.; Shumilova, L. P.; Ionov, A. M.; Sorokin, P.


    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.

  7. 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


    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

  8. Cisplatin and platinum drugs at the molecular level. (Review). (United States)

    Boulikas, Teni; Vougiouka, Maria


    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

  9. Molecular Catalysis of O2 Reduction by Iron Porphyrins in Water: Heterogeneous versus Homogeneous Pathways. (United States)

    Costentin, Cyrille; Dridi, Hachem; Savéant, Jean-Michel


    Despite decades of active attention, important problems remain pending in the catalysis of dioxygen reduction by iron porphyrins in water in terms of selectivity and mechanisms. This is what happens, for example, for the distinction between heterogeneous and homogeneous catalysis for soluble porphyrins, for the estimation of H2O2/H2O product selectivity, and for the determination of the reaction mechanism in the two situations. With water-soluble iron tetrakis(N-methyl-4-pyridyl)porphyrin as an example, procedures are described that allow one to operate this distinction and determine the H2O2/H2O product ratio in each case separately. It is noteworthy that, despite the weak adsorption of the iron(II) porphyrin on the glassy carbon electrode, the contribution of the adsorbed complex to catalysis rivals that of its solution counterpart. Depending on the electrode potential, two successive catalytic pathways have been identified and characterized in terms of current-potential responses and H2O2/H2O selectivity. These observations are interpreted in the framework of the commonly accepted mechanism for catalytic reduction of dioxygen by iron porphyrins, after checking its compatibility with a change of oxygen concentration and pH. The difference in intrinsic catalytic reactivity between the catalyst in the adsorbed state and in solution is also discussed. The role of heterogeneous catalysis with iron tetrakis(N-methyl-4-pyridyl)porphyrin has been overlooked in previous studies because of its water solubility. The main objective of the present contribution is therefore to call attention, by means of this emblematic example, to such possibilities to reach a correct identification of the catalyst, its performances, and reaction mechanism. This is a question of general interest, so that reduction of dioxygen remains a topic of high importance in the context of contemporary energy challenges.

  10. Mammary excretion and placental transfer of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane] platinum(II) in rats. (United States)

    Cho, Y B; Kim, K H; Kim, D K; Miyamoto, G


    The mammary excretion and placental transfer of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolan e] platinum(II) (CAS 146665-77-2, SKI 2053R), a new potential anticancer agent, were investigated in the lactating or pregnant rats after a single intravenous administration of 14C-SKI 2053R (20 mg/kg, 100 microCi/kg). The radioactivity of the milk declined in a biexponential fashion with an initial half-life of 0.39 h and with a terminal half-life of 14.05 h in the lactating rats. The radioactivity of the milk was lower than that of plasma until 1 h after dosing, but was higher than that of plasma from 4 h after dosing. 14C-SKI 2053R was well distributed to most tissues including uterus and placenta in the pregnant rats, but the levels of radioactivity in the amniotic fluid and fetuses were markedly lower than that in the maternal plasma. Therefore, it is concluded that SKI 2053R scarcely passes the blood-placenta barrier, which was confirmed by the whole-body autoradiography study.

  11. Novel Antitumor Platinum(II) Conjugates Containing the Nonsteroidal Anti-inflammatory Agent Diclofenac: Synthesis and Dual Mechanisms of Antiproliferative Effects. (United States)

    Intini, Francesco Paolo; Zajac, Juraj; Novohradsky, Vojtech; Saltarella, Teresa; Pacifico, Concetta; Brabec, Viktor; Natile, Giovanni; Kasparkova, Jana


    One concept how to improve anticancer effects of conventional metallodrugs consists in conjugation of these compounds with other biologically (antitumor) active agents, acting by a different mechanism. Here, we present synthesis, biological effects, and mechanisms of action of new Pt(II) derivatives containing one or two nonsteroidal anti-inflammatory diclofenac (DCF) ligands also known for their antitumor effects. The antiproliferative properties of these metallic conjugates show that these compounds are potent and cancer cell selective cytotoxic agents exhibiting activity in cisplatin resistant and the COX-2 positive tumor cell lines. One of these compounds, compound 3, in which DCF molecules are coordinated to Pt(II) through their carboxylic group, is more potent than parental conventional Pt(II) drug cisplatin, free DCF and the congeners of 3 in which DCF ligands are conjugated to Pt(II) via a diamine. The potency of 3 is due to several factors including enhanced internalization that correlates with enhanced DNA binding and cytotoxicity. Mechanistic studies show that 3 combines multiple effects. After its accumulation in cells, it releases Pt(II) drug capable of binding/damaging DNA and DCF ligands, which affect distribution of cells in individual phases of the cell cycle, inhibit glycolysis and lactate transport, collapse mitochondrial membrane potential, and suppress the cellular properties characteristic of metastatic progression.

  12. A porphyrin-stabilized iridium oxide water oxidation catalyst

    National Research Council Canada - National Science Library

    Pillai, Smitha; Gust, Devens; Moore, Ana L; Kodis, Gerdenis; Mallouk, Thomas E; Moore, Thomas A; Bergkamp, Jesse; Sherman, Benjamin D


    Colloidal solutions of iridium oxide hydrate (IrO 2 ·nH 2 O) were formed using porphyrin stabilizers bearing malonate-like functional groups at each of the four meso positions of the porphyrin ring...

  13. A Convenient Synthetic Method of Metal Dendritic Porphyrins

    Institute of Scientific and Technical Information of China (English)

    Wen Bin CUI; Jie ZHOU; Lei CHEN; Xiao Bin DENG; Chun GUO


    A convenient synthetic method of metal dendritic porphyrins through the convergent synthetic strategy is described. The porphyrin core were linked with the synthetic fragments by forming ether or ester bonds to give five target compounds were prepared.

  14. Porphyrin content of the cysticercus of Taenia solium. (United States)

    Larralde, C; Zedillo, G M; Lagunoff, D; Ludowyke, R; Montoya, R M; Goodsaid, F; Dreyfus, G; Sciutto, E; Govezensky, T; Diaz, M L


    The strong red fluorescence of the cysticercus of Taenia solium depends on the presence of several porphyrins in the vesicular fluid of the parasite: probably protoporphyrin IX, coproporphyin I or III, and 2 decarboxylated porphyrins intermediate between uroporphyrin and coproporphyrin. Cyst porphyrins associated to form conglomerates of high molecular weight that dissociated in acid solutions and were not antigenic themselves nor associated with antigenic molecules. An appreciable fraction of the porphyrins was capable of undergoing oxidation and reduction, indicating that some of the porphyrins were complexed with metal ions. The metabolic basis for the accumulation of porphyrins is unknown. Preliminary results suggest that conditions deleterious to the cysticercus cause release of porphyrins so that the appearance of porphyrins in the cerebrospinal fluid of neurocysticercotic patients may prove useful in monitoring therapeutic attacks on the parasite.

  15. Concerning the Deactivation of Cobalt(III)-Based Porphyrin and Salen Catalysts in Epoxide/CO 2 Copolymerization

    KAUST Repository

    Xia, Wei


    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Functioning as active catalysts for propylene oxide (PO) and carbon dioxide copolymerization, cobalt(III)-based salen and porphyrin complexes have drawn great attention owing to their readily modifiable nature and promising catalytic behavior, such as high selectivity for the copolymer formation and good regioselectivity with respect to the polymer microstructure. Both cobalt(III)-salen and porphyrin catalysts have been found to undergo reduction reactions to their corresponding catalytically inactive cobalt(II) species in the presence of propylene oxide, as evidenced by UV/Vis and NMR spectroscopies and X-ray crystallography (for cobalt(II)-salen). Further investigations on a TPPCoCl (TPP=tetraphenylporphyrin) and NaOMe system reveal that such a catalyst reduction is attributed to the presence of alkoxide anions. Kinetic studies of the redox reaction of TPPCoCl with NaOMe suggests a pseudo-first order in cobalt(III)-porphyrin. The addition of a co-catalyst, namely bis(triphenylphosphine)iminium chloride (PPNCl), into the reaction system of cobalt(III)-salen/porphyrin and PO shows no direct stabilizing effect. However, the results of PO/CO2 copolymerization by cobalt(III)-salen/porphyrin with PPNCl suggest a suppressed catalyst reduction. This phenomenon is explained by a rapid transformation of the alkoxide into the carbonate chain end in the course of the polymer formation, greatly shortening the lifetime of the autoreducible PO-ring-opening intermediates, cobalt(III)-salen/porphyrin alkoxides. CO2 saves: The deactivation of cobalt(III)-porphyrin and salen catalysts in propylene oxide/carbon dioxide copolymerization is systematically investigated, revealing a proposed mechanism for the catalyst reduction (see scheme).

  16. A light-harvesting array of synthetic porphyrins (United States)

    Davila, Jorge; Harriman, Anthony; Milgrom, Lionel R.


    An array of five porphyrin molecules has been synthesized and used as a simple model of the light-harvesting complex found in natural photosynthesis. Efficient Förster energy transfer occurs from antenna zinc porphyrins to a central free-base porphyrin molecule. This central porphyrin retains long-lived singlet and triplet excited states that can be quenched by diffusional processes, Both electron and energy transfer quenching reactions can be observed.

  17. Tuning the activity of platinum(IV) anticancer complexes through asymmetric acylation. (United States)

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


    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.

  18. Characterization of vanadium compounds in selected crudes. I. Porphyrin and non-porphyrin separation

    Energy Technology Data Exchange (ETDEWEB)

    Biggs, W.R.; Fetzer, J.C.; Brown, R.J.; Reynolds, J.G.


    The authors have applied size-exclusion chromatography (SEC-HPLC) and reversed-phase chromatography (RP-HPLC), with element specific detection, (inductively coupled and direct current plasma atomic emission spectroscopy (ICP and DCP)), to selected crude oils - Boscan, Beta, Morichal, Arabian Heavy, and Maya - and their separated fractions. By these procedures, they have further characterized both the V porphyrin and the V non-porphyrin compounds. From the SEC-HPLC-ICP profiles of the heavy crude oils they found the V compounds generally have a bimodal distribution, with maxima at approx. 800 and 9000 polystyrene equivalent (PS) molecular weight (MW). Arabian Heavy, though, had relatively few of the small V compounds. The crude oils were separated into porphyrin and non-porphyrin fractions by methanol extraction. From the SEC-HPLC-ICP profiles of the porphyrin fraction, they identified and quantitated the maximum at approx. MW 800 (PS) as being V porphyrins. The remaining V compounds are non-porphyrin. 39 references, 4 figures, 2 tables.

  19. Electronic spectra and photophysics of platinum(II) complexes with alpha-diimine ligands - Solid-state effects. I - Monomers and ligand pi dimers (United States)

    Miskowski, Vincent M.; Houlding, Virginia H.


    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.

  20. Resonance Raman study on distorted symmetry of porphyrin in nickel octaethyl porphyrin

    Indian Academy of Sciences (India)

    S Tewari; R Das; A Chakraborty; Ramendu Bhattacharjee


    The resonance Raman (RR) spectra of nickel octaethyl porphyrin, Ni(OEP), in CH2Cl2 (solvent) at different excitations such as 514.5, 488.0, 441.6 and 406.7 nm are recorded and analysed. The results of the theory of distortion-induced RR intensity is applied to the observed spectra to determine the excited electronic state symmetry of porphyrin in Ni(OEP). It is concluded that the porphyrin molecule (D4h structure) attains a non-polar distorted structure of D2 symmetry rather than S4 symmetry in CH2Cl2 solution.

  1. Pharmacokinetics, tissue distribution, and excretion of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3- dioxolane]platinum(II) in dogs. (United States)

    Cho, Y B; Kim, K H; Kim, D K


    The pharmacokinetics, tissue distribution, and excretion of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3- dioxolane]platinum(II) (SKI 2053R), a new potential anticancer agent, were investigated in dogs after a single intravenous administration of [14C]SKI 2053R (7 mg/kg, 100 microCi/kg). Total radioactivity in the plasma and ultrafiltrable plasma declined in a biexponential fashion with the initial half-lives of 0.63 +/- 0.05 hr (mean +/- SD) and 0.53 +/- 0.05 hr, and with the terminal half-lives of 51.08 +/- 3.26 hr and 15.19 +/- 3.75 hr, respectively. Radioactivity was well distributed into all tissues except the central nervous system. The majority of the radioactivity was found in the gastrointestinal contents, urine, and organs of elimination at all time points. The distribution pattern of [14C]SKI 2053R in the whole-body autoradiograms was consistent with that observed by the measurement of tissue concentrations. The 0-7 days cumulative urinary and fecal recoveries of total radioactivity were 87.30 +/- 2.93% and 8.68 +/- 1.30%, respectively, resulting in a total recovery of 95.98 +/- 1.61% of the administered dose. A large portion of [14C]SKI 2053R was distributed into the cellular fraction of mouse or rat blood, but was not into that of dog or human blood in vitro. The in vitro and in vivo binding of [14C]SKI 2053R to plasma protein was minimal to moderate.

  2. Synthesis, characterization and In-Vitro cytotoxic studies of 5,10,15,20 tetra pyridyl porphyrin coordinated to four [Ru (bipy2 Cl]+ groups

    Directory of Open Access Journals (Sweden)

    S. Uthayanila


    Full Text Available Ruthenium possesses several favorable properties suited to rational anticancer drug design when conjugation with the porphyrin moiety was accomplished through peripheral pyridyl rings. The ruthenium porphyrin conjugates are soluble at least moderately in aqueous solution and are thus suitable for biological investigations in particular for cytotoxicity and photocyotoxicity tests. In present study the compound 5,10,15,20 tetra pyridyl porphyrin coordinated to four [Ru (bipy2 Cl]+ groups (meso-5,10,15,20 tetrakis {4(chloro-bis-bipyridyl ruthenium(II pyridyl} porphyrin is synthesized by modified Alder method. This compound is characterized by UV-Visible Spectroscopy, FT-IR Spectroscopy, 1H-NMR spectroscopy, Fluorescence Spectroscopy and Cyclic Voltametry. In-Vitro anticancer activity of the compounds have been evaluated by MTT (3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay method. The results show that the compound is cytotoxic against human lymphoma cancer cells.

  3. New Porphyrin/Fe-Loaded TiO2 Composites as Heterogeneous Photo-Fenton Catalysts for the Efficient Degradation of 4-Nitrophenol

    Directory of Open Access Journals (Sweden)

    Giuseppe Mele


    Full Text Available A new class of porphyrin(Pp/Fe co-loaded TiO2 composites opportunely prepared by impregnation of [5,10,15,20-tetra(4-tert-butylphenyl] porphyrin (H2Pp or Cu(II[5,10,15,20-tetra(4-tert-butylphenyl] porphyrin (CuPp onto Fe-loaded TiO2 particles showed high activities by carrying out the degradation of 4-nitrophenol (4-NP as probe reaction in aqueous suspension under heterogeneous photo-Fenton-like reactions by using UV-visible light. The combination of porphyrin-Fe-TiO2 in the presence of H2O2 showed to be more efficient than the simple bare TiO2 or Fe-TiO2.

  4. (Biphenyl-2,2′-diyl)[1,3-bis(diphenylphosphanyl)propane-κ2P,P′]platinum(II)


    D. Paul Rillema; Curtis Moore; Ali Jehan


    The C2P2 donor set in the title compound, [Pt(C12H8)(C27H26P2)], defines a distorted planar coordination environment about the PtII atom with small deviations from planarity. The bidentate nature of the biphenyl dianionic ligand results in a C—Pt—C bond angle of 79.94 (16)° and a P—Pt—P bond angle of 93.40 (4)°. The average Pt—C bond length is 2.083 (3) Å [range 2.081 (4)–2.085 (4) Å]; the average Pt—P bond length is 2.308 (8) Å [range 2.3030 (11)–2.3136 (11) Å]....

  5. Microwave synthesis of mono- and bis-tetrazolato complexes via 1,3-dipolar cycloaddition of organonitriles with platinum(II)-bound azides. (United States)

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


    [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.

  6. 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. (United States)

    Mandal, Sutanuva; Castiñeiras, Alfonso; Mondal, Tapan K; Mondal, Arindam; Chattopadhyay, Dhrubajyoti; Goswami, Sreebrata


    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.

  7. Chiroptical properties, binding affinity, and photostability of a conjugated zinc porphyrin dimer complexed with left-handed Z-DNA and right-handed B-DNA. (United States)

    Choi, Jung Kyu; Reed, Aisha; Balaz, Milan


    We have studied the UV-vis absorption and chiroptical properties, binding affinity and photostability of a conjugated positively charged butadiyne-linked Zn(ii) porphyrin dimer bound to DNA sequence poly(dG-dC)2. Right-handed B-DNA, spermine-induced Z-DNA and Co(iii)-induced Z-DNA have been explored. Resonance light scattering (RLS) spectra showed formation of porphyrin aggregates in the presence of all DNA forms with the largest aggregates formed with B-DNA. The porphyrin dimer gave rise to induced bisignate circular dichroism (CD) signals in the presence of the left-handed Z-DNA conformations. On the other hand, the dimer stayed nearly chiroptically silent when complexed with the B-form of poly(dG-dC)2. Our results indicated that the conjugated Zn(ii) porphyrin dimer can be used as a sensor for the chiroptical detection of Z-DNA in the visible (400-500 nm) and near-infrared region of the electromagnetic spectrum (700-800 nm). The helicity of DNA had little effect on the dimer binding affinities. The photostability of the porphyrin dimer complexed with any form of DNA was higher than that of the free molecule. The porphyrin dimer bound to Z-DNA exhibited slower photobleaching than the B-DNA dimer complex.

  8. Preparation and enhanced visible light-driven catalytic activity of ZnO microrods sensitized by porphyrin heteroaggregate

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiangqing [Department of Chemical Engineering, Laboratory of New Energy Materials, Shanghai Institute of Technology, 120 Caobao Road, Shanghai 200235 (China); Cheng Ying [School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Kang Shizhao, E-mail: [Department of Chemical Engineering, Laboratory of New Energy Materials, Shanghai Institute of Technology, 120 Caobao Road, Shanghai 200235 (China); Mu Jin [School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)


    An inorganic-organic composite (ZnO/TAPPI-CoTPPS) composed of ZnO microrods and nano-heteroaggregates containing tetrakis(4-trimethylaminophenyl) porphyrin (TAPPI) and tetrakis(4-sulfonatophenyl) porphyrin cobalt(II) (CoTPPS), has been achieved by a simple mixing method. From the solid diffuse reflectance UV-vis spectrum of ZnO/TAPPI-CoTPPS, it can be observed that the Soret band of the porphyrin heteroaggregate of ZnO/TAPPI-CoTPPS is blue-shifted in comparison with that of the pure TAPPI-CoTPPS heteroaggregate while the Q bands are red-shifted, which demonstrates that there exists some interaction between the porphyrin heteroaggregate and ZnO. In addition, the photodegradation of rhodamine B (RhB) in water catalyzed by ZnO/TAPPI-CoTPPS was investigated at room temperature. Under visible light irradiation ({lambda} {>=} 420 nm), the photocatalytic activity of the ZnO/TAPPI-CoTPPS composite was higher than those of the porphyrin monomers modified ZnO composite and pure ZnO.

  9. Evolving concepts in the management of drug resistant ovarian cancer: dose dense chemotherapy and the reversal of clinical platinum resistance. (United States)

    Pinato, David J; Graham, Janet; Gabra, Hani; Sharma, Rohini


    Despite the initially high response rate to standard front-line debulking surgery followed by platinum-based chemotherapy, the relapse rate in ovarian cancer is high and many patients will recur within 6 months of completing platinum based treatment. These patients may still require further chemotherapy despite being considered "platinum resistant". In this setting, response rates to conventionally scheduled second line platinum and non-platinum agents is low, ranging between 5% and 15%. There is an emerging body of evidence that in this scenario, chemotherapeutic activity can be enhanced using unconventionally scheduled "dose-dense" platinum and non-platinum based regimens with improved response rates of up to 65%. Randomised studies to evaluate the impact of this approach on survival in recurrent, platinum resistant disease are urgently required to confirm the promising phase II findings if there is to be a change in the standard of care of patients with platinum resistant disease. In this review we discuss the evolving strategies to overcome resistance in patients with platinum resistant ovarian cancer with a particular focus on alterations in dose schedule as a means of reversing platinum resistance. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. 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.


    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-.

  11. Monofunctional platinum(II) complexes with potent tumor cell growth inhibitory activity: the effect of a hydrogen-bond donor/acceptor N-heterocyclic ligand. (United States)

    Margiotta, Nicola; Savino, Salvatore; Gandin, Valentina; Marzano, Christine; Natile, Giovanni


    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.

  12. Luminescent pincer platinum(II) complexes with emission quantum yields up to almost unity: photophysics, photoreductive C-C bond formation, and materials applications. (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


    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).

  13. trans-Dichloridobis{dicyclo­hex­yl[4-(dimethyl­amino)­phen­yl]phosphane-κP}platinum(II) dichloro­methane disolvate (United States)

    Davis, Wade L.; Meijboom, Reinout


    In the title complex, trans-[PtCl2{P(C6H11)2(4-Me2NC6H4)}2]·2CH2Cl2, the PtII atom is located on an inversion centre, resulting in a trans-square-planar geometry. Important geometric parameters are the Pt—P and Pt—Cl bond lengths of 2.3258 (6) and 2.3106 (6) Å, respectively, and the P—Pt—Cl angles of 89.64 (2) and 90.36 (2)°. The effective cone angle for the dicyclo­hex­yl[4-(dimethyl­amino)­phen­yl]phosphane unit was calculated to be 164°. The compound crystallizes with two dichloro­methane solvent mol­ecules; one of which is severely disordered and was treated using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. PMID:23468763

  14. Platinum nitride with fluorite structure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Rong; Zhang, Xiao-Feng


    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.

  15. Fluorescence and Thermostability of Nanometer Porphyrin Trimer

    Institute of Scientific and Technical Information of China (English)


    A nanometer porphyrin trimer was firstly synthesized with 1,3-dibromopropane as a bridge-linked agent and the fluorescence property and thermostability were studied. The results show that the fluorescence property and thermostability of the trimer are different from those of monoporphyrin. The effects of the molecule structure on the optical property and the thermostability were also studied in detail.

  16. A p-quinodimethane-bridged porphyrin dimer. (United States)

    Zeng, Wangdong; Ishida, Masatoshi; Lee, Sangsu; Sung, Young Mo; Zeng, Zebing; Ni, Yong; Chi, Chunyan; Kim, Dongho; Wu, Jishan


    A p-quinodimethane (p-QDM)-bridged porphyrin dimer 1 has been prepared for the first time. An unexpected Michael addition reaction took place when we attempted to synthesize compound 1 by reaction of the cross-conjugated keto-linked porphyrin dimers 8a and 8b with alkynyl/aryl Grignard reagents. Alternatively, compound 1 could be successfully prepared by intramolecular Friedel-Crafts alkylation of the diol-linked porphyrin dimer 14 with concomitant oxidation in air. Compound 1 shows intense one-photon absorption (OPA, λ(max)=955 nm, ε=45400 M(-1) cm(-1)) and a large two-photon absorption (TPA) cross-section (σ((2))(max)=2080 GM at 1800 nm) in the near-infrared (NIR) region due to its extended π-conjugation and quinoidal character. It also exhibits a short singlet excited-state lifetime of 25 ps. The cyclic voltammogram of 1 displays multiple redox waves with a small electrochemical energy gap of 0.86 eV. The ground-state geometry, electronic structure, and optical properties of 1 have been further studied by density functional theory (DFT) calculations and compared with those of the keto-linked dimer 8b. This research has revealed that incorporation of a p-QDM unit into the porphyrin framework had a significant impact on its optical and electronic properties, leading to a novel NIR OPA and TPA chromophore.

  17. Metallic nanoshells on porphyrin-stabilized emulsions (United States)

    Wang, Haorong; Song, Yujiang; Shelnutt, John A; Medforth, Craig J


    Metal nanostructures formed by photocatalytic interfacial synthesis using a porphyrin-stabilized emulsion template and the method for making the nanostructures. Catalyst-seeded emulsion droplets are employed as templates for hollow-nanoshell growth. The hollow metal nanospheres may be formed with or without inclusions of other materials.

  18. Langmuir Blodgett films of porphyrins and phthalocyanines

    CERN Document Server

    Portus, D


    Phthalocyanines and porphyrins have been studied for many years as bulk, thick and thin films. Their use in Langmuir and Langmuir-Blodgett films is governed by their peripheral substituents. These can enhance or reduce their ability to form 'quality' ultra-thin films. There are a number of potential and current applications for thin films of porphyrins and phthalocyanines, which include CD-R discs and gas-sensors. It is the latter that this PhD has focussed on. Ultra-thin films of phthalocyanines, porphyrins and a porphyrin/phthalocyanine hybrid dye were deposited onto glass microscope slides, gold-coated glass microscope slides and quartz crystals. These assemblies were then characterised using Ultraviolet-Visible spectroscopy, pressure-area isotherms, surface plasmon resonance and a quartz crystal microbalance to try and determine the nature of the molecules on the surface of the substrate. The thin films were exposed to chlorine gas and the change in their absorption spectrum and (in some cases) their surf...

  19. Harnessing chemoselective imine ligation for tethering bioactive molecules to platinum(IV) prodrugs. (United States)

    Wong, Daniel Yuan Qiang; Lau, Jia Yi; Ang, Wee Han


    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.

  20. 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 (United States)

    Malitch, K. N.; Efimov, A. A.; Ronkin, Yu. L.


    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

  1. Self Assembled Films of Porphyrins with Amine Groups at Different Positions: Influence of Their Orientation on the Corrosion Inhibition and the Electrocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Koodlur Sannegowda Lokesh


    Full Text Available Self-assembled molecular films of two cobalt porphyrins with amine groups at different positions—(5,10,15,20-tetrakis-(2-aminophenyl porphyrin-cobalt(II, [Co(II (T(o-NH2PP] and (5,10,15,20-tetrakis-(4-aminophenyl porphyrin-cobalt(II, [Co(II(T(p-NH2PP]—were formed on a gold substrate. The functionalized surfaces were characterized using Raman spectroscopy, atomic force microscopy and electrochemical methods. Both modified gold surfaces completely mask the charge transfer of a [Fe(CN6]3−/4− redox couple in solution, indicating the layer is highly resistive in behavior. Electrochemical impedance spectroscopy analyses revealed that the porphyrin film with amine groups at ortho positions shows a higher charge-transfer resistance with a better protective behavior compared to the para position modified surface. Raman, AFM and EIS data suggests that an ortho amine positioned molecule forms a more compact layer compared to the para-positioned molecule. This can be explained in terms of their orientation on the gold surface. [Co(II(T(o-NH2PP] adopted a saddle shape orientation whereas [Co(II(T(p-NH2PP] adopted a flat orientation on the gold surface. The porphyrin modified gold electrode catalyzes the oxygen reduction at lower potentials compared to the bare gold electrode. The shift in the overvoltage was higher in case of molecules with flat orientation compared to the saddle shaped oriented porphyrin molecules on the surface.

  2. Substituent effects of iron porphyrins: Structural, kinetic, and theoretical studies

    Energy Technology Data Exchange (ETDEWEB)

    Lu Xiaoquan, E-mail: [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070 (China); Ma Junying; Sun Ruiping; Nan Mina; Meng Fanfu; Du Jie; Wang Xiaoyan; Shang Hui [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070 (China)


    Substituent effects of iron porphyrin complexes on the structures and kinetic processes have been examined for the first time. Basing on the premise that iron porphyrin is functional analogous to heme, a series of iron porphyrin derivatives bearing different substituents at the meso positions of the corrole ring are investigated as to their electrochemistry, the relationships among the electron transfer (ET) processes, their structures, and orbital energies. The good coherence between the experiment and theory indicates that the ET rate can be accelerated when electron-donating substituents are introduced to the iron porphyrin ring. Finally, the implications of the results are discussed in the influence of stability of iron porphyrin complexes on the ability to carry molecular oxygen, which may suggest it possible to dominate the biological activity of heme by selecting the appropriate substituents to iron porphyrin ring.

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

    Wong, Daniel Yuan Qiang; Ang, Wee Han


    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.

  4. Photophysical properties of self-aggregated porphyrin: semiconductor nanoassemblies


    Zenkevich, E.; Blaudeck, T.; Abdel-Mottaleb, M.; Cichos, F.; Shulga, A.; von Borczyskowski, C.


    Colloidal semiconductor nanocrystals from CdSe show photoluminescence quenching via titration with porphyrin derivatives. This quenching is an indication of the formation of nanoassemblies via surface attachment of pyridyl linker groups. As a consequence of the complex formation, dynamic and/or static interactions between QD and porphyrins are induced. Quenching efficiencies depend critically on sample stability, temperature, solvent, and electronic properties of the porphyrins. In order to o...

  5. Photophysical properties of self-aggregated porphyrin: semiconductor nanoassemblies

    Directory of Open Access Journals (Sweden)

    E. Zenkevich


    Full Text Available Colloidal semiconductor nanocrystals from CdSe show photoluminescence quenching via titration with porphyrin derivatives. This quenching is an indication of the formation of nanoassemblies via surface attachment of pyridyl linker groups. As a consequence of the complex formation, dynamic and/or static interactions between QD and porphyrins are induced. Quenching efficiencies depend critically on sample stability, temperature, solvent, and electronic properties of the porphyrins. In order to optimize photoinduced dynamic processes these parameters have to be under control.

  6. Ultrasonic method for the preparation of organic porphyrin nanoparticles. (United States)

    Kashani-Motlagh, Mohamad Mehdi; Rahimi, Rahmatollah; Kachousangi, Marziye Javaheri


    We report the synthesis and optical properties of organic porphyrin nanoparticles with narrow size distribution and good dispersibility. Nanoparticles were produced by a combination of precipitation and sonication, termed the "ultrasonic method". The resulting [tetrakis(para-chlorophenyl)porphyrin]TClPP nanoparticles were stable in solution without precipitation for at least 30 days. No self aggregation of the constituent porphyrin chromophores was observed. The TClPP nanoparticles exhibited interesting optical properties, particularly a large bathochromic shift in the absorption spectra.

  7. Synthesis of Novel Tailed Porphyrins with Covalently Linked Saccharide

    Institute of Scientific and Technical Information of China (English)


    The reaction of 5-(p-hydroxyphenyl)-10,15,20-(p-methoxy phenyl) porphyrin with Br(CH2)4Br produced monobromo substituted porphyrin 1. The tailed porphyrins 2-4 were synthesized by the reactions of 1 with small molecular offering biological activities such as D-glucose, D-glucuronic acid. These new compounds were confirmed by 1H NMR, IR, UV-vis and element analyses.

  8. -pyrrole substituted porphyrin-pyrene dyads using vinylene spacer: Synthesis, characterization and photophysical properties

    Indian Academy of Sciences (India)

    P Silviya Reeta; Ravi Kumar Kanaparthi; L Giribabu


    We have designed and synthesized donor-acceptor conjugates having donor pyrene at the pyrrole- position of either free-base porphyrin or Zn(II) porphyrin using vinylene spacer. Both the dyads have been completely characterized by elemental analysis,MALDI-MS, UV-Vis., and fluorescence (steady state and timeresolved) spectroscopies as well as cyclic voltammetry. The absorption maxima of both dyads are red-shifted by 8-12 nm. The ground state properties showed that there exist minimum - interaction between the aromatic subunits of these D-A systems. Quenched emission was observed in both the dyads when excited at 290 nm. The quenched emission explained in terms of intramolecular excitation energy transfer competes with the photo-induced electron transfer reaction in these D-A system.

  9. Molecular electrocatalysis for oxygen reduction by cobalt porphyrins adsorbed at liquid/liquid interfaces. (United States)

    Su, Bin; Hatay, Imren; Trojánek, Antonín; Samec, Zdenek; Khoury, Tony; Gros, Claude P; Barbe, Jean-Michel; Daina, Antoine; Carrupt, Pierre-Alain; Girault, Hubert H


    Molecular electrocatalysis for oxygen reduction at a polarized water/1,2-dichloroethane (DCE) interface was studied, involving aqueous protons, ferrocene (Fc) in DCE and amphiphilic cobalt porphyrin catalysts adsorbed at the interface. The catalyst, (2,8,13,17-tetraethyl-3,7,12,18-tetramethyl-5-p-amino-phenylporphyrin) cobalt(II) (CoAP), functions like conventional cobalt porphyrins, activating O(2) via coordination by the formation of a superoxide structure. Furthermore, due to the hydrophilic nature of the aminophenyl group, CoAP has a strong affinity for the water/DCE interface as evidenced by lipophilicity mapping calculations and surface tension measurements, facilitating the protonation of the CoAP-O(2) complex and its reduction by ferrocene. The reaction is electrocatalytic as its rate depends on the applied Galvani potential difference between the two phases.

  10. A Study of Porphyrins in Petroleum Source Rocks

    Energy Technology Data Exchange (ETDEWEB)

    Huseby, Berit


    This thesis discusses several aspects of porphyrin geochemistry. Degradation experiments have been performed on the Messel oil shale (Eocene, Germany) to obtain information on porphyrins bound or incorporated into macromolecular structures. Thermal heating of the preextracted kerogen by hydrous pyrolysis was used to study the release of porphyrins and their temperature dependent changes during simulated diagenesis and catagenesis. Selective chemical degradation experiments were performed on the preextracted sediment to get more detailed information about porphyrins that are specifically bound to the macromolecular structures via ester bonds. From the heating experiments, in a separate study, the porphyrin nitrogen content in the generated bitumens was compared to the bulk of organic nitrogen compounds in the fraction. The bulk nitrogen contents in the generated bitumens, the water phase and the residual organic matter was recorded to establish the distribution of nitrogen between the kerogen and product phases. Porphyrins as biomarkers were examined in naturally matured Kimmeridge clay source rocks (Upper Jurassic, Norway), and the use of porphyrins as general indicators of maturity was evaluated. Underlying maturity trends in the biomarker data was investigated by Partial Least Squares analysis. Porphyrin as indicators of depositional conditions was also addressed, where the correlations between the (amounts) abundance of nickel and vanadyl porphyrins were mapped together with other descriptors that are assumed to be indicative of redox depositional conditions. 252 refs., 28 figs., 4 tabs.

  11. Study on Polarographic Absorption Wave of Soluble Porphyrin Copper Complex

    Institute of Scientific and Technical Information of China (English)

    HE; YuFeng


    The porphyrins is a kind of sensitive color-producing reagent. However, its selectivity is low. If the porphyrin is used in polarographic analysis, the selectivity and sensitivity can be improved. Copper is one of the most important trace element in human and mammalian body. The polarographic method is a kind of important method in determination of metal ion [1]. In this paper, meso-tetra (4-sulfonylphenyl) porphyrin (H2TPPS4) is used as the soluble ligand. The polarographic absorption behavior of meso-tetra (4-sulfonylphenyl) porphyrin complex with copper ion has been studied.  ……

  12. Study on Polarographic Absorption Wave of Soluble Porphyrin Copper Complex

    Institute of Scientific and Technical Information of China (English)


    @@ The porphyrins is a kind of sensitive color-producing reagent. However, its selectivity is low. If the porphyrin is used in polarographic analysis, the selectivity and sensitivity can be improved. Copper is one of the most important trace element in human and mammalian body. The polarographic method is a kind of important method in determination of metal ion [1]. In this paper, meso-tetra (4-sulfonylphenyl) porphyrin (H2TPPS4) is used as the soluble ligand. The polarographic absorption behavior of meso-tetra (4-sulfonylphenyl) porphyrin complex with copper ion has been studied.

  13. Spectroscopic studies of porphyrin functionalized multiwalled carbon nanotubes and their interaction with TiO2 nanoparticles surface (United States)

    Zannotti, Marco; Giovannetti, Rita; D'Amato, Chiara Anna; Rommozzi, Elena


    UV-vis and fluorescence investigations about the non-covalent interaction, in ethanolic solutions, of multi-wall carbon nanotube (MWCNT) with Coproporphyrin-I, and its Cu(II) and Zn(II) complexes (MCPIs) have been reported. Evidence of binding between MWCNTs and porphyrins was discovered from spectral adsorption decrease with respect to free porphyrins and by the exhibition of photoluminescence quenching with respect to free porphyrins demonstrating that MWCNT@MCPIs are potential donor-acceptor complexes. Equilibrium and kinetic aspects in the interactions with monolayer transparent TiO2 thin films with the obtained MWCNT@MCPIs are clarified showing their effective adsorption by porphyrin links on the TiO2 monolayer support, with respect to not only MWCNTs, according to the Langmuir model and with pseudo-first-order kinetics. Morphological description of the adsorption of MWCNT@MCPIs on TiO2 with scanning electron microscopy has been reported. The obtained experimental evidences describe therefore MWCNT@MCPIs as potential sensitizers in the DSSC (Dye-Sensitized Solar Cell) applications.

  14. Spectroscopic analysis of porphyrin compounds irradiated with visible light in chloroform with addition of β-myrcene (United States)

    Makarska-Bialokoz, Magdalena; Gladysz-Plaska, Agnieszka


    The behaviour of two porphyrins, 5,10,15,20-tetraphenyl-21H,23H-porphine (H2TPP) and 5,10,15,20-tetra(4-pyridyl)-21H, 23H-porphine (H2TPyP), as well as their Zn(II) complexes (ZnTPP and ZnTPyP), have been studied analysing their absorption and steady-state fluorescence spectra in chloroform with addition of β-myrcene. After irradiation with visible light the free-base porphyrins have been converted to the form of dication on account of hydrochloric acid generated as a result of chloroform decomposition induced by β-myrcene. Whereas in case of their Zn(II) complexes the mechanism of action is more complicated, leading presumably to the formation of the aggregated metalloporphyrin species with chloride ions playing the bridging role. The pseudo-first-order rate constants of the absorption quenching process were calculated for all the systems examined, with respect to the porphyrin concentration. The most effective irradiation was observed in case of H2TPP porphyrin.

  15. Theoretical study of conjugated porphyrin polymers

    DEFF Research Database (Denmark)

    Pedersen, T.G.; Lynge, T.B.; Kristensen, P.K.


    The optical gap of conjugated triply linked porphyrin chains is exceptionally low (similar to 0.5 eV). Hence, such chains are candidates for organic infrared detectors and solar cells harvesting the infrared part of the solar spectrum. However, a low exciton binding energy is required for these a......The optical gap of conjugated triply linked porphyrin chains is exceptionally low (similar to 0.5 eV). Hence, such chains are candidates for organic infrared detectors and solar cells harvesting the infrared part of the solar spectrum. However, a low exciton binding energy is required...... for these applications. From a theoretical analysis of excitons in long metalloporphyrin chains, we demonstrate that the binding energy is much lower than in usual conjugated polymers. Our calculated absorption spectra are in good agreement with measurements. (c) 2004 Elsevier B.V. All rights reserved....

  16. Recent Approaches to Platinum(IV) Prodrugs: A Variety of Strategies for Enhanced Delivery and Efficacy. (United States)

    Najjar, Anas; Rajabi, Naeema; Karaman, Rafik


    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

  17. Understanding platinum-induced ototoxicity. (United States)

    Langer, Thorsten; am Zehnhoff-Dinnesen, Antoinette; Radtke, Susanne; Meitert, Johannes; Zolk, Oliver


    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.

  18. LDRD final report on synthesis of shape-and size-controlled platinum and platinum alloy nanostructures on carbon with improved durability.

    Energy Technology Data Exchange (ETDEWEB)

    Shelnutt, John Allen; Garcia, Robert M.; Song, Yujiang; Moreno, Andres M.; Stanis, Ronald J.


    This project is aimed to gain added durability by supporting ripening-resistant dendritic platinum and/or platinum-based alloy nanostructures on carbon. We have developed a new synthetic approach suitable for directly supporting dendritic nanostructures on VXC-72 carbon black (CB), single-walled carbon nanotubes (SWCNTs), and multi-walled carbon nanotubes (MWCNTs). The key of the synthesis is to creating a unique supporting/confining reaction environment by incorporating carbon within lipid bilayer relying on a hydrophobic-hydrophobic interaction. In order to realize size uniformity control over the supported dendritic nanostructures, a fast photocatalytic seeding method based on tin(IV) porphyrins (SnP) developed at Sandia was applied to the synthesis by using SnP-containing liposomes under tungsten light irradiation. For concept approval, one created dendritic platinum nanostructure supported on CB was fabricated into membrane electrode assemblies (MEAs) for durability examination via potential cycling. It appears that carbon supporting is essentially beneficial to an enhanced durability according to our preliminary results.

  19. (F(8)TPP)Fe(II)/O(2) reactivity studies [F(8)TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2-)]: spectroscopic (UV-Visible and NMR) and kinetic study of solvent-dependent (Fe/O(2) = 1:1 or 2:1) reversible O(2)-reduction and ferryl formation. (United States)

    Ghiladi, R A; Kretzer, R M; Guzei, I; Rheingold, A L; Neuhold, Y M; Hatwell, K R; Zuberbühler, A D; Karlin, K D


    In this report, we describe in detail the O(2)-binding chemistry of the metalloporphyrin (F(8)TPP)Fe(II) (1). This complex was synthesized from aqueous dithionite reduction of (F(8)TPP)Fe(III)-Cl (X-ray structure reported: C(55)H(36)ClF(8)FeN(4)O; a = 13.6517(2) A, b = 13.6475(2) A, c = 26.3896(4), alpha = 90 degrees, beta = 89.9776(4) degrees, gamma = 90 degrees; monoclinic, P2(1)/c, Z = 4). Complex 1 crystallizes from toluene/heptane solvent system as a bis(toluene) solvate, (F(8)TPP)Fe(II).(C(7)H(8))(2), with ferrous ion in the porphyrin plane (C(58)H(36)F(8)FeN(4); a = 20.9177(2) A, b = 11.7738(2) A, c = 19.3875(2), alpha = 90 degrees, beta = 108.6999(6) degrees, gamma = 90 degrees; monoclinic, C2/c, Z = 4; Fe-N(4)(av) = 2.002 A; N-Fe-N (all) = 90.0 degrees ). Close metal-arene contacts are also observed at 3.11-3.15 A. Upon oxygenation of 1 at 193 K in coordinating solvents, UV-visible and (2)H and (19)F NMR spectroscopies revealed the presence of a reversibly formed dioxygen adduct, formulated as the heme-superoxo complex (S)(F(8)TPP)Fe(III)-(O(2)(-)) (2) (S = solvent) [(i) tetrahydrofuran (THF) solvent: UV-visible, 416 (Soret), 536 nm; (2)H NMR: delta(pyrrole) 8.9 ppm; (ii) EtCN solvent: UV-visible, 414 (Soret), 536 nm; (iii) acetone solvent: UV-visible, 416 (Soret), 537 nm; (2)H NMR: delta(pyrrole) 8.9 ppm]. Dioxygen-uptake manometry (THF, 193 K) revealed an O(2):1 oxygenation stoichiometry of 1.02:1, consistent with the heme-superoxo formulation of 2. Stopped-flow UV-visible spectrophotometry studies of the (F(8)TPP)Fe(II) (1)/O(2) reaction in EtCN and THF solvents were able to provide kinetic and thermodynamic insight into the reversible formation of 2 [(i) EtCN: Delta H degrees = -40 +/- 5 kJ/mol; Delta S degrees = -105 +/- 23 J/(K mol); k(1) = (5.57 +/- 0.04) x 10(3) M(-)(1) s(-)(1) (183 K); Delta H(++) = 38.6 +/- 0.2 kJ/mol; Delta S(++) = 42 +/- 1 J/(K mol); (ii) THF: Delta H* = -37.5 +/- 0.4 kJ/mol; Delta S* = -109 +/- 2 J/(K mol)]. The (F(8)TPP)Fe(II

  20. Porphyrin and heme metabolism and the porphyrias. (United States)

    Bonkovsky, Herbert L; Guo, Jun-Tao; Hou, Weihong; Li, Ting; Narang, Tarun; Thapar, Manish


    Porphyrins and metalloporphyrins are the key pigments of life on earth as we know it, because they include chlorophyll (a magnesium-containing metalloporphyrin) and heme (iron protoporphyrin). In eukaryotes, porphyrins and heme are synthesized by a multistep pathway that involves eight enzymes. The first and rate-controlling step is the formation of delta-aminolevulinic acid (ALA) from glycine plus succinyl CoA, catalyzed by ALA synthase. Intermediate steps occur in the cytoplasm, with formation of the monopyrrole porphobilinogen and the tetrapyrroles hydroxymethylbilane and a series of porphyrinogens, which are serially decarboxylated. Heme is utilized chiefly for the formation of hemoglobin in erythrocytes, myoglobin in muscle cells, cytochromes P-450 and mitochondrial cytochromes, and other hemoproteins in hepatocytes. The rate-controlling step of heme breakdown is catalyzed by heme oxygenase (HMOX), of which there are two isoforms, called HMOX1 and HMOX2. HMOX breaks down heme to form biliverdin, carbon monoxide, and iron. The porphyrias are a group of disorders, mainly inherited, in which there are defects in normal porphyrin and heme synthesis. The cardinal clinical features are cutaneous (due to the skin-damaging effects of excess deposited porphyrins) or neurovisceral attacks of pain, sometimes with weakness, delirium, seizures, and the like (probably due mainly to neurotoxic effects of ALA). The treatment of choice for the acute hepatic porphyrias is intravenous heme therapy, which repletes a critical regulatory heme pool in hepatocytes and leads to downregulation of hepatic ALA synthase, which is a biochemical hallmark of all forms of acute porphyria in relapse.

  1. Past and future: porphyria and porphyrins. (United States)

    Norman, Robert A


    Porphyria is a compelling disease--disrupted enzyme pathways, heightened sensitivities, and a fascinating history tied in with tales of Dracula. This review discusses the history, pathophysiology, classification, and treatment of porphyria. It further discusses the way in which research on the etiologies of the various porphyrias has led to the development of porphyrin-based photodynamic therapy, which shows great promise in targeted therapy for a variety of serious pathologies.

  2. Lighting porphyrins and phthalocyanines for molecular photovoltaics. (United States)

    Martínez-Díaz, M Victoria; de la Torre, Gema; Torres, Tomás


    The field of organic photovoltaics (OPV) represents one of the most promising technological areas. Porphyrins and phthalocyanines are perfectly suited for their integration in light energy conversion systems. These colored macrocycles exhibit very attractive physical properties, particularly very high extinction coefficients in the visible and near IR regions, where the maximum of the solar photon flux occurs, that is necessary for efficient photon harvesting, besides a rich redox chemistry, as well as photoinduced electron transfer and semiconducting capabilities.

  3. Binary ionic porphyrin nanosheets: electronic and light-harvesting properties regulated by crystal structure (United States)

    Tian, Yongming; M. Beavers, Christine; Busani, Tito; Martin, Kathleen E.; Jacobsen, John L.; Mercado, Brandon Q.; Swartzentruber, Brian S.; van Swol, Frank; Medforth, Craig J.; Shelnutt, John A.


    Crystalline solids self-assembled from anionic and cationic porphyrins provide a new class of multifunctional optoelectronic micro- and nanomaterials. A 1 : 1 combination of zinc(ii) tetra(4-sulfonatophenyl)porphyrin (ZnTPPS) and tin(iv) tetra(N-methyl-4-pyridiniumyl)porphyrin (SnTNMePyP) gives porphyrin nanosheets with high aspect ratios and varying thickness. The room temperature preparation of the nanosheets has provided the first X-ray crystal structure of a cooperative binary ionic (CBI) solid. The unit cell contains one and one-half molecules of aquo-ZnTPPS4- (an electron donor) and three half molecules of dihydroxy-SnTNMePyP4+ (an electron acceptor). Charge balance in the solid is reached without any non-porphyrinic ions, as previously determined for other CBI nanomaterials by non-crystallographic means. The crystal structure reveals a complicated molecular arrangement with slipped π-π stacking only occurring in isolated dimers of one of the symmetrically unique zinc porphyrins. Consistent with the crystal structure, UV-visible J-aggregate bands indicative of exciton delocalization and extended π-π stacking are not observed. XRD measurements show that the structure of the Zn/Sn nanosheets is distinct from that of Zn/Sn four-leaf clover-like CBI solids reported previously. In contrast with the Zn/Sn clovers that do exhibit J-aggregate bands and are photoconductive, the nanosheets are not photoconductive. Even so, the nanosheets act as light-harvesting structures in an artificial photosynthesis system capable of reducing water to hydrogen but not as efficiently as the Zn/Sn clovers.Crystalline solids self-assembled from anionic and cationic porphyrins provide a new class of multifunctional optoelectronic micro- and nanomaterials. A 1 : 1 combination of zinc(ii) tetra(4-sulfonatophenyl)porphyrin (ZnTPPS) and tin(iv) tetra(N-methyl-4-pyridiniumyl)porphyrin (SnTNMePyP) gives porphyrin nanosheets with high aspect ratios and varying thickness. The room

  4. Platinum availability for future automotive technologies. (United States)

    Alonso, Elisa; Field, Frank R; Kirchain, Randolph E


    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.

  5. Chiroptical properties of anionic and cationic porphyrins and metalloporphyrins in complex with left-handed Z-DNA and right-handed B-DNA. (United States)

    Choi, Jung Kyu; D'Urso, Alessandro; Balaz, Milan


    We report the chiroptical signature and binding interactions of cationic (meso-tetrakis(4-N-methylptridyl)porphyrin, 2HT4) and anionic (meso-tetrakis(4-sulfonatophenyl)porphyrin, 2HTPPS) porphyrins and their zinc(II) and nickel(II) derivatives (ZnT4, ZnTPPS, NiT4, and NiTPPS) with right-handed B-form and two forms of left-handed Z-form of alternating guanine-cytosine polydeoxynucleotide poly(dG-dC)2. NiTPPS is able to spectroscopically discriminate between spermine-induced Z-DNA and Co(III)-induced Z-DNA via new induced circular dichroism signal in the visible region of the electromagnetic spectrum.

  6. Quantum Chemical Investigations on Electron Transport Characteristics of Porphyrin and Metal-porphyrin

    Institute of Scientific and Technical Information of China (English)


    Recently, molecular electronics has become increasingly important. By applying the hybrid density functional theory coupled with the Green's function method, the current-voltage characteristics of the molecular junctions composed of gold-porphyrin-gold and gold-copper porphyrin-gold were investigated. The role of the metal coordination effect in organic molecular electron transport was highlighted. Although the thresholds of the bias voltage for both molecules were almost the same, approximately 0.9 V, the metal compound showed a larger increase in current because of the metal-coordination-enhanced molecule-electrode coupling in the frontier molecular orbitals.

  7. Polyamide platinum anticancer complexes designed to target specific DNA sequences. (United States)

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


    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.

  8. Synthesis, antinociceptive and anti-inflammatory effects of porphyrins. (United States)

    Alonso-Castro, Angel Josabad; Zapata-Morales, Juan Ramón; Hernández-Munive, Abigail; Campos-Xolalpa, Nimsi; Pérez-Gutiérrez, Salud; Pérez-González, Cuauhtémoc


    Porphyrins are natural compounds with several biological activities. We report the synthesis and the evaluation of the anti-inflammatory and antinociceptive effects of 4 porphyrins: 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetra(4'-fluorophenyl)porphyrin (TpFPP), 5,10,15,20-tetra(4'-chlorophenyl)porphyrin (TpClPP), and 5,10,15,20-tetra(4'-bromophenyl)porphyrin (TpBrPP). The in vitro anti-inflammatory effects were evaluated on heat-induced hemolysis. The antinociceptive effects were evaluated using the hot plate and formalin tests. The in vivo anti-inflammatory assays were tested on the acute and chronic TPA (12-O-tetradecanoylphorbol 13-acetate) method to induce ear edema. The anti-arthritic effects were evaluated using carrageenan kaolin induced arthritis (CKIA). All porphyrins inhibited hemolysis with similar potency than naproxen (NPX). In the antinociceptive tests, all porphyrins tested at 200mg/kg showed similar effects compared to 100mg/kg NPX. In the in vivo anti-inflammatory acute assay, only three porphyrins (TPP, TpFPP and TpBrPP) decreased inflammation with similar activity than 2mg/ear indomethacin (IND). Further anti-inflammatory experiments were carried out with TPP, TpFPP and TpBrPP. In the in vivo anti-inflammatory chronic assay, porphyrins decreased inflammation with similar activity than 8mg/kg IND. Porphyrins tested at 200mg/kg showed anti-arthritic effects. The antinociceptive, anti-inflammatory and arthritic activities of porphyrins suggest that these compounds might be a good alternative for the treatment of inflammatory diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Saddle-shaped porphyrins for dye-sensitized solar cells: new insight into the relationship between nonplanarity and photovoltaic properties. (United States)

    Shahroosvand, Hashem; Zakavi, Saeed; Sousaraei, Ahmad; Eskandari, Mortaza


    We report on the theoretical and experimental studies of the new dye-sensitized solar cells functionalized with 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin zinc(II) complexes bearing 2- and 8-bromo substituents at the β positions. In agreement with the results of TD-DFT calculations, the absorption maxima of di- and octa-brominated Zn(II) complexes, ZnTCPPBr2 and ZnTCPPBr8, exhibited large red-shift compared to that of the non-brominated free base porphyrin (H2TCPP). Furthermore, DFT calculations showed that the higher stabilization of the LUMO levels relative to the HOMO ones makes the HOMO-LUMO gap of the brominated Zn-porphyrins models smaller compared to that of the nonbrominated counterparts, which explains the red shifts of the Soret and Q bands of the brominated compounds. Solar cells containing the new saddle-shaped Zn(II) porphyrins were subjected to analysis in a photovoltaic calibration laboratory to determine their solar to electric energy conversion. In this regard, we found that the overall conversion efficiency of ZnTCPPBr8 adsorbed on TiO2 nanocrystalline films was 5 times as large as that of ZnTCPPBr2 adsorbed on the same films. The effect of the increasing number of Br groups on the photovoltaic performance of the complexes was compared to the results of computational methods using ab initio DFT molecular dynamics simulations and quantum dynamics calculations of electronic relaxation to investigate the interfacial electron transfer (IET) in TCPPBrx/TiO2-anatase nanostructures. Better IET in ZnTCPPBr8 compared to ZnTCPPBr2, and in H2TCPP was evaluated from interfacial electron transfer (IET) simulations. The IET results indicate that electron injection in ZnTCPPBr8-TiO2 (τ = 25 fs) can be up to 5 orders of magnitude faster than ZnTCPPBr2-TiO2 (τ = 125 fs). Both experimental and theoretical results demonstrate that the increase of the number of bromo-substituents at the β-pyrrole positions of the porphyrin macrocycle created a new class of

  10. A Photoactivatable Platinum(IV) Complex Targeting Genomic DNA and Histone Deacetylases. (United States)

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


    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.

  11. Photoinduced DNA damage and cytotoxicity by a triphenylamine-modified platinum-diimine complex. (United States)

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


    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.

  12. The Versatile Behavior of Platinum Alkyne Complexes towards XeF2 : Formation of Fluorovinyl and Fluorido Complexes. (United States)

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


    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.

  13. Cyano- and polycyanometallo-porphyrins as catalysts for alkane oxidation (United States)

    Ellis, Jr., Paul E.; Lyons, James E.


    New compositions of matter comprising cyano-substituted metal complexes of porphyrins are catalysts for the oxidation of alkanes. The metal is iron, chromium, manganese, ruthenium, copper or cobalt. The porphyrin ring has cyano groups attached thereto in meso and/or .beta.-pyrrolic positions.

  14. Photocontrol over cooperative porphyrin self-assembly with phenylazopyridine ligands. (United States)

    Hirose, Takashi; Helmich, Floris; Meijer, E W


    The cooperative self-assembly of chiral zinc porphyrins is regulated by a photoresponsive phenylazopyridine ligand. Porphyrin stacks depolymerize into dimers upon axial ligation and the strength of the coordination is regulated by its photoinduced isomerization, which shows more than 95 % conversion ratio for both photostationary states.

  15. Porphyrin-based sensor nanoarchitectonics in diverse physical detection modes. (United States)

    Ishihara, Shinsuke; Labuta, Jan; Van Rossom, Wim; Ishikawa, Daisuke; Minami, Kosuke; Hill, Jonathan P; Ariga, Katsuhiko


    Porphyrins and related families of molecules are important organic modules as has been reflected in the award of the Nobel Prizes in Chemistry in 1915, 1930, 1961, 1962, 1965, and 1988 for work on porphyrin-related biological functionalities. The porphyrin core can be synthetically modified by introduction of various functional groups and other elements, allowing creation of numerous types of porphyrin derivatives. This feature makes porphyrins extremely useful molecules especially in combination with their other interesting photonic, electronic and magnetic properties, which in turn is reflected in their diverse signal input-output functionalities based on interactions with other molecules and external stimuli. Therefore, porphyrins and related macrocycles play a preeminent role in sensing applications involving chromophores. In this review, we discuss recent developments in porphyrin-based sensing applications in conjunction with the new advanced concept of nanoarchitectonics, which creates functional nanostructures based on a profound understanding of mutual interactions between the individual nanostructures and their arbitrary arrangements. Following a brief explanation of the basics of porphyrin chemistry and physics, recent examples in the corresponding fields are discussed according to a classification based on physical modes of detection including optical detection (absorption/photoluminescence spectroscopy and energy and electron transfer processes), other spectral modes (circular dichroism, plasmon and nuclear magnetic resonance), electronic and electrochemical modes, and other sensing modes.

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

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


    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.

  17. Electrochemical oxidation of carbon monoxide: from platinum single crystals to low temperature fuel catalysts. Part II: Electrooxidation of H2, CO and H2/CO mixtures on well characterized PtMo alloy

    Directory of Open Access Journals (Sweden)



    Full Text Available The oxidation of hydrogen and hydrogen–carbon monoxide mixture has been investigated on well-characterized metallurgically prepared platinum–molybdenum (PtMo alloys. It was concluded that the optimum surface concentration of molybdenum is near 23 mol.%. Based on experimentally determined parameters and simulations, the mechanism of the oxidation of CO/H2 mixtures is discussed.

  18. Rigid, Branched Porphyrin Antennas: Control over Cascades of Unidirectional Energy Funneling and Charge Transfer. (United States)

    Wolf, Maximilian; Herrmann, Astrid; Hirsch, Andreas; Guldi, Dirk M


    Porphyrin arrays consisting of three peripheral Zinc porphyrins (ZnPs) and a central free base porphyrin (H2P)-all rigidly linked to each other-serve as light-harvesting antennas as well as electron donors and are flexibly coupled to an electron-accepting C60 to realize the unidirectional flow of (i) excited-state energy from the ZnPs at the periphery to the H2P, (ii) electrons to C60, and (iii) holes to H2P and, subsequently, to ZnP. Dynamics following photoexcitation are elucidated by time-resolved transient absorption measurements on the femto-, pico-, nano-, and microsecond time scales and are examined by multiwavelength as well as target analyses. Hereby, full control over the charge shift between H2P and ZnP to convert the (ZnP)3-H2P(•+)-C60(•-) charge-separated state into (ZnP)3(•+)-H2P-C60(•-) charge-separated state is enabled by the solvent polarity: It is deactivated/switched-off in apolar toluene, while in polar benzonitrile it is activated/switched-on. Activating/switching impacts the recovery of the ground state via charge recombination rates, which differ by up to 2 orders of magnitude. All charge-separated states lead to the repopulation of the ground state with dynamics that are placed in the inverted region of the Marcus parabola.

  19. Corroles-Porphyrins: A Teamwork for Gas Sensor Arrays

    Directory of Open Access Journals (Sweden)

    Rosamaria Capuano


    Full Text Available Porphyrins provide an excellent material for chemical sensors, and they have been used for sensing species both in air and solution. In the gas phase, the broad selectivity of porphyrins is largely dependant on molecular features, such as the metal ion complexed at the core of the aromatic ring and the peripheral substituents. Although these features have been largely exploited to design gas sensor arrays, so far, little attention has been devoted to modify the sensing properties of these macrocycles by variation of the molecular aromatic ring. In this paper, the gas sensing properties of a porphyrin analog, the corrole, are studied in comparison with those of the parent porphyrin. Results show that changes in the aromatic ring have important consequences on the sensitivity and selectivity of the sensors and that porphyrins and corroles can positively cooperate to enhance the performance of sensor arrays.

  20. Electrochemical metallization of self-assembled porphyrin monolayers. (United States)

    Nann, Thomas; Kielmann, Udo; Dietrich, Christoph


    Multifunctional sensor systems are becoming increasingly important in electroanalytical chemistry. Together with ongoing miniaturization there is a need for micro- and nanopatterning tools for thin electroactive layers (e.g. self-assembling monolayers). This paper documents a method for production of a micro-array of different metal-porphyrin monolayers with different sensor properties. A new method has been developed for the selective and local metallization of bare porphyrin monolayers by cathodic pulsing and sweeping. The metal-porphyrin monolayers obtained were characterized by cyclic voltammetry. It was shown that porphyrin monolayers can be metallized with manganese, iron, cobalt, and nickel by use of the new method. It is expected that all types of metal-porphyrin monolayers can be produced in the same manner.

  1. Preparation and characterization of monosubstituted porphyrins immobilized on nanosilica

    Indian Academy of Sciences (India)

    Ebrahim Ahmadi; Ali Ramazani; Asemeh Mashhadi-Malekzadeh; Zahra Hamdi; Zahra Mohamadnia


    Three kinds of heteroaldehydes, -(3-triethoxysilylpropyl)-4-formyl benzamide (TPHA/SiO2), were prepared by the reaction of terephthalaldehydic acid with different silica supports such as hexagonal SBA-15, spherical SBA-15 and amorphous SiO2 for comparison purposes. Anchoring of this aldehyde to different supports allows the synthesis of mono-substituted porphyrins without the production of di-, tri- and tetra-substituted porphyrin side products. The exclusion of the aforementioned side products during the synthesis of monosubstituted porphyrins greatly reduced the complexity during purification of the product. Absorption spectrophotometry was performed on silica gel immobilizing porphyrin (CPTTP), free base tetraphenylporphyrin (H2TPP) and heteroaldehydes (TPHA/SiO2) using UV–Visible instrument and confirmed the presence of porphyrin on the structure of CPTTP.

  2. Spectroscopic evidence of xanthine compounds fluorescence quenching effect on water-soluble porphyrins (United States)

    Makarska-Bialokoz, Magdalena


    The formation of π-stacked complexes between water-soluble porphyrins: 4,4‧,4″,4″‧-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis-(benzoic acid) (H2TCPP), 5,10,15,20-tetrakis(4-sulfonatophenyl)-21H,23H-porphine (H2TPPS4), 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H2TTMePP), 5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H,23H-porphine tetra-p-tosylate (H2TMePyP), the Cu(II) complexes of H2TTMePP and H2TMePyP, as well as chlorophyll a with xanthine, theophylline (1,3-dimethylxanthine) and theobromine (3,7-dimethylxanthine) has been studied analysing their absorption and steady-state fluorescence spectra in aqueous (or acetone in case of chlorophyll a) solution. During titration by the compounds from xanthine group the bathochromic effect in the porphyrin absorption spectra as well as the hypochromicity of the porphyrin Soret maximum can be noticed. The fluorescence quenching effect observed during interactions in the systems examined suggests the process of static quenching. The association and fluorescence quenching constants are of the order of magnitude of 103 - 102 mol-1. The results obtained show that xanthine and its derivatives can quench the fluorescence of the porphyrins according to the number of methyl groups in the molecule of quencher.

  3. A new member of the oxygen-photosensitizers family: a water-soluble polymer binding a platinum complex. (United States)

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


    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.

  4. Cross-reactivity of Halogenated Platinum Salts (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...

  5. N-Annulated perylene substituted zinc–porphyrins with different linking modes and electron acceptors for dye sensitized solar cells

    KAUST Repository

    Luo, Jie


    Three new N-annulated perylene (NP) substituted porphyrin dyes WW-7-WW-9 with different linking modes and accepting groups were synthesized and applied in Co(ii)/(iii) based dye sensitized solar cells (DSCs). The bay-linked porphyrins WW-7 and WW-8 exhibited moderate power conversion efficiency (PCE = 4.4% and 4.8%, respectively), while the peri-linked porphyrin dye WW-9 showed a PCE up to 9.2% which is slightly lower than that of our reference dye WW-6. Detailed physical measurements (optical and electrochemical), DFT calculations, and photovoltaic characterizations were performed to understand how the structural changes affect their light-harvesting ability, molecular orbital profile, energy level alignment, and eventually the photovoltaic performance. It turned out that the lower efficiencies of the cells based on WW-7 and WW-8 could be ascribed to the weak π-conjugation between the bay-substituted NP and phenylethynyl substituted porphyrin unit. The introduction of a benzothiadiazole acceptor at the anchoring group has induced a significant red shift of the IPCE action spectra of WW-8 and WW-9, by about 90 nm and 50 nm as compared to that of WW-7 and WW-6, respectively. However, less efficient electron injection was observed. Our studies gave some insight into the important role of electronic interactions between different components when one designs a dye for high-efficiency DSCs. © The Royal Society of Chemistry 2016.

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

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


    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.

  7. Porphyrin-magnetite nanoconjugates for biological imaging

    LENUS (Irish Health Repository)

    Nowostawska, Malgorzata


    Abstract Background The use of silica coated magnetic nanoparticles as contrast agents has resulted in the production of highly stable, non-toxic solutions that can be manipulated via an external magnetic field. As a result, the interaction of these nanocomposites with cells is of vital importance in understanding their behaviour and biocompatibility. Here we report the preparation, characterisation and potential application of new "two-in-one" magnetic fluorescent nanocomposites composed of silica-coated magnetite nanoparticles covalently linked to a porphyrin moiety. Method The experiments were performed by administering porphyrin functionalised silica-coated magnetite nanoparticles to THP-1 cells, a human acute monocytic leukaemia cell line. Cells were cultured in RPMI 1640 medium with 25 mM HEPES supplemented with heat-inactivated foetal bovine serum (FBS). Results We have synthesised, characterised and analysed in vitro, a new multimodal (magnetic and fluorescent) porphyrin magnetic nanoparticle composite (PMNC). Initial co-incubation experiments performed with THP-1 macrophage cells were promising; however the PMNC photobleached under confocal microscopy study. β-mercaptoethanol (β-ME) was employed to counteract this problem and resulted not only in enhanced fluorescence emission, but also allowed for elongated imaging and increased exposure times of the PMNC in a cellular environment. Conclusion Our experiments have demonstrated that β-ME visibly enhances the emission intensity. No deleterious effects to the cells were witnessed upon co-incubation with β-ME alone and no increases in background fluorescence were recorded. These results should present an interest for further development of in vitro biological imaging techniques.

  8. Protonolysis of Dialkyl- and Alkylarylplatinum(II) Complexes and Geometrical Isomerization of the Derived Monoorgano-Solvento Complexes: Clear-Cut Examples of Associative and Dissociative Pathways in Platinum(II) Chemistry. (United States)

    Romeo, Raffaello; Plutino, Maria Rosaria; Elding, Lars I.


    Protonolysis of the complexes cis-[PtR(2)(PEt(3))(2)] (R = Me, Et, Pr(n)(), Bu(n)(), CH(2)C(Me)(3), CH(2)Si(Me)(3)) and cis-[Pt(R)(R')(PEt(3))(2)] (R = Ph, 2-MeC(6)H(4), 2,4,6-Me(3)C(6)H(2); R' = Me) in methanol selectively cleaves one alkyl group, yielding cis-[Pt(R)(PEt(3))(2)(MeOH)](+) and alkanes. The reactions occur as single-stage conversions from the substrate to the product. There is no evidence by UV and by low-temperature (1)H and (31)P NMR spectroscopy for the presence of significant amounts of Pt(II) or Pt(IV) intermediate species. Reactions are first order with respect to complex and proton concentrations and are strongly retarded by steric congestion at the Pt-C bond, varying from k(2) = (2.65 +/- 0.08) x 10(5) M(-)(1) s(-)(1) for R = R' = Et to k(2) = 9.80 +/- 0.44 M(-)(1)s(-)(1) for R = R'= CH(2)Si(Me)(3). Low enthalpies of activation and largely negative volumes of activation are associated with the process. The mechanism involves a rate-determining proton transfer either to the metal-carbon sigma bond (S(E)2 mechanism) or to the metal center (S(E)(oxidative) mechanism), followed by fast extrusion of the alkane and simultaneous blocking of the vacant coordination site by the solvent to generate cis-[Pt(R)(PEt(3))(2)(MeOH)](+) species. The subsequent slower process, cis to trans isomerization of cis-[Pt(R)(PEt(3))(2)(MeOH)](+), is characterized by high values of enthalpies of activation, positive entropies of activation, and largely positive volumes of activation. The reaction is shown to proceed through the dissociative loss of the weakly bonded molecule of solvent and the interconversion of two geometrically distinct T-shaped 14-electron 3-coordinate intermediates. The presence of beta-hydrogens on the residual alkyl chain produces a great acceleration of the rate (R = Me, k(i) = 0.0026 s(-)(1); R = Et, k(i) = 44.9 s(-)(1)) as a consequence of the stabilization of the 3-coordinate [Pt(R)(PEt(3))(2)](+) transition state through an incipient agostic

  9. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)


    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. Water Dispersible and Biocompatible Porphyrin-Based Nanospheres for Biophotonics Applications: A Novel Surfactant and Polyelectrolyte-Based Fabrication Strategy for Modifying Hydrophobic Porphyrins. (United States)

    Sheng, Ning; Zong, Shenfei; Cao, Wei; Jiang, Jianzhuang; Wang, Zhuyuan; Cui, Yiping


    The hydrophobility of most porphyrin and porphyrin derivatives has limited their applications in medicine and biology. Herein, we developed a novel and general strategy for the design of porphyrin nanospheres with good biocompatibility and water dispersibility for biological applications using hydrophobic porphyrins. In order to display the generality of the method, we used two hydrophobic porphyrin isomers as starting material which have different structures confirmed by an X-ray technique. The porphyrin nanospheres were fabricated through two main steps. First, the uniform porphyrin nanospheres stabilized by surfactant were prepared by an interfacially driven microemulsion method, and then the layer-by-layer method was used for the synthesis of polyelectrolyte-coated porphyrin nanospheres to reduce the toxicity of the surfactant as well as improve the biocompatibility of the nanospheres. The newly fabricated porphyrin nanospheres were characterized by TEM techniques, the electronic absorption spectra, photoluminescence emission spectra, dynamic light scattering, and cytotoxicity examination. The resulting nanospheres demonstrated good biocompatibility, excellent water dispersibility and low toxicity. In order to show their application in biophotonics, these porphyrin nanospheres were successfully applied in targeted living cancer cell imaging. The results showed an effective method had been explored to prepare water dispersible and highly stable porphyrin nanomaterial for biophotonics applications using hydrophobic porphyrin. The approach we reported shows obvious flexibility because the surfactants and polyelectrolytes can be optionally selected in accordance with the characteristics of the hydrophobic material. This strategy will expand the applications of hydrophobic porphyrins owning excellent properties in medicine and biology.

  11. Coordination and metalation bifunctionality of Cu with 5,10,15,20-tetra(4-pyridyl)porphyrin: toward a mixed-valence two-dimensional coordination network. (United States)

    Li, Yang; Xiao, Jie; Shubina, Tatyana E; Chen, Min; Shi, Ziliang; Schmid, Martin; Steinrück, Hans-Peter; Gottfried, J Michael; Lin, Nian


    We investigated the coordination self-assembly and metalation reaction of Cu with 5,10,15,20-tetra(4-pyridyl)porphyrin (2HTPyP) on a Au(111) surface by means of scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory calculations. 2HTPyP was found to interact with Cu through both the peripheral pyridyl groups and the porphyrin core. Pairs of pyridyl groups from neighboring molecules coordinate Cu(0) atoms, which leads to the formation of a supramolecular metal-organic coordination network. The network formation occurs at room temperature; annealing at 450 K enhances the process. The interaction of Cu with the porphyrin core is more complex. At room temperature, formation of an initial complex Cu(0)-2HTPyP is observed. Annealing at 450 K activates an intramolecular redox reaction, by which the coordinated Cu(0) is oxidized to Cu(II) and the complex Cu(II)TPyP is formed. The coordination network consists then of Cu(II) complexes linked by Cu(0) atoms; that is, it represents a mixed-valence two-dimensional coordination network consisting of an ordered array of Cu(II) and Cu(0) centers. Above 520 K, the network degrades and the Cu atoms in the linking positions diffuse into the substrate, while the Cu(II)TPyP complexes form a close-packed structure that is stabilized by weak intermolecular interactions. Density functional theory investigations show that the reaction with Cu(0) proceeds via formation of an initial complex between metal atom and porphyrin followed by formation of Cu(II) porphyrin within the course of the reaction. The activation barrier of the rate limiting step was found to be 24-37 kcal mol(-1) depending on the method used. In addition, linear coordination of a Cu atom by two CuTPyP molecules is favorable according to gas-phase calculations. © 2012 American Chemical Society

  12. High Fluorescent Porphyrin-PAMAM-Fluorene Dendrimers. (United States)

    Garfias-Gonzalez, Karla I; Organista-Mateos, Ulises; Borja-Miranda, Andrés; Gomez-Vidales, Virginia; Hernandez-Ortega, Simon; Cortez-Maya, Sandra; Martínez-García, Marcos


    Two new classes of dendrimers bearing 8 and 32 fluorene donor groups have been synthesized. The first and second generations of these porphyrin-PAMAM-fluorene dendrimers were characterized by 1H-NMR, 13C-NMR, FTIR, UV-vis spectroscopy, elemental analyses and MALDI-TOF mass spectrometry. The UV-vis spectra showed that the individual properties of donor and acceptor moieties were preserved, indicating that the new dendrimers could be used as photosynthetic antennae. Furthermore, for fluorescent spectroscopy, these dendrimers showed good energy transfer.

  13. Coating Carbon Fibers With Platinum (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.


    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.

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

    Directory of Open Access Journals (Sweden)

    Jurisevic Milena


    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.

  15. Mono- and di-bromo platinum(IV) prodrugs via oxidative bromination: synthesis, characterization, and cytotoxicity. (United States)

    Xu, Zoufeng; Wang, Zhigang; Yiu, Shek-Man; Zhu, Guangyu


    Platinum(IV)-based anticancer prodrugs have attracted much attention due to their relative inertness under physiological conditions, being activated inside cells, and their capacity for functionalization with a variety of small-molecule or macromolecule moieties. Novel asymmetric platinum(IV) compounds synthesized through expedient and unique methods are desired. Here we utilize N-bromosuccinimide (NBS) and carry out oxidative bromination on platinum(II) drugs, namely cisplatin, carboplatin, and oxaliplatin, to obtain asymmetric and mono-bromo platinum(IV) prodrugs. Different solvents are used to obtain various compounds, and the compounds are further functionalized. Di-bromo compounds are also obtained through NBS-directed oxidative bromination in ethanol. The crystal structures of representative compounds are discussed, and the reduction potentials of some compounds are examined. A cytotoxicity test shows that the mono- and di-bromo platinum(IV) compounds are active against human ovarian cancer cells. Our study enriches the family of asymmetric platinum(IV) prodrugs and provides with a convenient strategy to obtain brominated platinum(IV) complexes.

  16. Photoreduction of Carbon Dioxide to Formic Acid in Aqueous Suspension: A Comparison between Phthalocyanine/TiO2 and Porphyrin/TiO2 Catalysed Processes

    Directory of Open Access Journals (Sweden)

    Giuseppe Mele


    Full Text Available Composite materials prepared by loading polycrystalline TiO2 powders with lipophilic highly branched Cu(II- and metal-free phthalocyanines or porphyrins, which have been used in the past as photocatalysts for photodegradative processes, have been successfully tested for the efficient photoreduction of carbon dioxide in aqueous suspension affording significant amounts of formic acid. The results indicated that the presence of the sensitizers is beneficial for the photoactivity, confirming the important role of Cu(II co-ordinated in the middle of the macrocycles. A comparison between Cu(II phthalocyanines and Cu(II porphyrins indicated that the Cu(II- phthalocyanine sensitizer was more efficient in the photoreduction of CO2 to formic acid, probably due to its favorable reduction potential.

  17. Photoreduction of carbon dioxide to formic acid in aqueous suspension: a comparison between phthalocyanine/TiO2 and porphyrin/TiO2 catalysed processes. (United States)

    Mele, Giuseppe; Annese, Cosimo; D'Accolti, Lucia; De Riccardis, Alberto; Fusco, Caterina; Palmisano, Leonardo; Scarlino, Anna; Vasapollo, Giuseppe


    Composite materials prepared by loading polycrystalline TiO2 powders with lipophilic highly branched Cu(II)- and metal-free phthalocyanines or porphyrins, which have been used in the past as photocatalysts for photodegradative processes, have been successfully tested for the efficient photoreduction of carbon dioxide in aqueous suspension affording significant amounts of formic acid. The results indicated that the presence of the sensitizers is beneficial for the photoactivity, confirming the important role of Cu(II) co-ordinated in the middle of the macrocycles. A comparison between Cu(II) phthalocyanines and Cu(II) porphyrins indicated that the Cu(II)- phthalocyanine sensitizer was more efficient in the photoreduction of CO2 to formic acid, probably due to its favorable reduction potential.

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


    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.

  19. Resonance Raman Intensities and Structure of S2 State of Nickel(II) Porphyrin by Time-Dependent Approach%时间域方法分析镍卟啉的共振拉曼强度与S2激发态结构

    Institute of Scientific and Technical Information of China (English)

    陈东明; 丛涤非; 何天敬; 章应辉; 刘凡镇


    Resonance Raman intensities and UV-visible absorption spectrum of nickel(II) porphyrin (NiP) were analyzed with time-dependent formulas under standard approximations for Condon mechanism of enhancement. The resultant dimensionless displacements on S2 state are comparable with those obtained by Spiro et al. from Kramers-Kronig transform methods. It was deduced from the calculations that there are large dimensionless displacements on the excited state along ν8 and ν2 coordinates. These normal modes consist of relatively large components of CβCβ, Cα Cm bond stretching and CαCmCα bond bending motions. Compared with the ground state, the average bond-lengths of CβCβ, CαCm, and CαN bonds at S2 state increase respectively by 0.27, 0.14, and 0.07pm,while that of CαCβ bond decreases by 0.20pm,which are well in coincident with the SPMO calculations in literature.%研究了入射光波长与S0→S2跃迁共振的情形下,卟啉镍配合物(NiP)的振动拉曼光谱。用时间域方法计算了NiP的共振拉曼强度和吸收光谱。结果表明,相对于基态,S2态NiP的分子构型沿着ν8和ν2简正坐标有较大的位移。这些简正坐标主要涉及卟啉环的CαCm键和CβCβ键伸缩运动,以及CαCmCα变角运动。与基态相比, S2态的CβCβ、 CαCm和CαN键分别增大0.27、 0.14、 0.07 pm,而CαCβ键则减小0.20 pm,与前人的赝势分子轨道计算(SPMO)结果相近。还从RR强度角度讨论了S2态的Jahn-Teller畸变。

  20. 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


    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.

  1. Porphyrins as Theranostic Agents from Prehistoric to Modern Times

    Directory of Open Access Journals (Sweden)

    Yumiao Zhang, Jonathan F. Lovell


    Full Text Available Long before humans roamed the planet, porphyrins in blood were serving not only as indispensable oxygen carriers, but also as the bright red contrast agent that unmistakably indicates injury sites. They have proven valuable as whole body imaging modalities have emerged, with endogenous hemoglobin porphyrins being used for new approaches such as functional magnetic resonance imaging and photoacoustic imaging. With the capability for both near infrared fluorescence imaging and phototherapy, porphyrins were the first exogenous agents that were employed with intrinsic multimodal theranostic character. Porphyrins have been used as tumor-specific diagnostic fluorescence imaging agents since 1924, as positron emission agents since 1951, and as magnetic resonance (MR contrast agents since 1987. Exogenous porphyrins remain in clinical use for photodynamic therapy. Because they can chelate a wide range of metals, exogenous porphyrins have demonstrated potential for use in radiotherapy and multimodal imaging modalities. Going forward, intrinsic porphyrin biocompatibility and multimodality will keep new applications of this class of molecules at the forefront of theranostic research.

  2. Randomized phase II trial of carboplatin versus paclitaxel and carboplatin in platinum-sensitive recurrent advanced ovarian carcinoma: a GEICO (Grupo Espanol de Investigacion en Cancer de Ovario) study. (United States)

    González-Martín, A J; Calvo, E; Bover, I; Rubio, M J; Arcusa, A; Casado, A; Ojeda, B; Balañá, C; Martínez, E; Herrero, A; Pardo, B; Adrover, E; Rifá, J; Godes, M J; Moyano, A; Cervantes, A


    The aim of this study was to determine whether the response rate for the paclitaxel-carboplatin combination is superior to carboplatin alone in the treatment of patients with platinum-sensitive recurrent ovarian carcinoma. Patients with recurrent ovarian carcinoma, 6 months after treatment with a platinum-based regimen and with no more than two previous chemotherapy lines, were randomized to receive carboplatin area under the curve (AUC) 5 (arm A) or paclitaxel 175 mg/m(2) + carboplatin AUC 5 (arm B). The primary end point was objective response, following a 'pick up the winner' design. Secondary end points included time to progression (TTP), overall survival, tolerability and quality of life (QoL). Eighty-one patients were randomized and included in the intention-to-treat analysis. The response rate in arm B was 75.6% [26.8% complete response (CR) + 48.8% partial response (PR)] [95% confidence interval (CI) 59.7% to 87.6%] and 50% in arm A (20% CR + 30% PR) (95% CI 33.8% to 66.2%). No significant differences were observed in grade 3-4 hematological toxicity. Conversely, mucositis, myalgia/arthralgia and peripheral neurophaty were more frequent in arm B. Median TTP was 49.1 weeks in arm B (95% CI 36.9-61.3) and 33.7 weeks in arm A (95% CI 25.8-41.5). No significant differences were found in the QoL analysis. Paclitaxel-carboplatin combination is a tolerable regimen with a higher response rate than carboplatin monotherapy in platinum-sensitive recurrent ovarian carcinoma.

  3. Porphyrin Interactions with Wild Type and Mutant Mouse Ferrochelatase

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Gloria C.; Franco, Ricardo; Lu, Yi; Ma, Jian-Guo; Shelnutt, John A.


    Ferrochelatase (EC, the terminal enzyme of the heme biosynthetic pathway, catalyzes Fe2+ chelation into protoporphyrin IX. Resonance Raman and W-visible absorbance spectroscopes of wild type and engineered variants of murine ferrochelatase were used to examine the proposed structural mechanism for iron insertion into protoporphyrin by ferrochelatase. The recombinant variants (i.e., H207N and E287Q) are enzymes in which the conserved amino acids histidine-207 and glutamate-287 of murine ferrochelatase were substituted with asparagine and glutamine, respectively. Both of these residues are at the active site of the enzyme as deduced from the Bacillus subtilis ferrochelatase three-dimensional structure. Addition of free base or metalated porphyrins to wild type ferrochelatase and H207N variant yields a quasi 1:1 complex, possibly a monomeric protein-bound species. In contrast, the addition of porphyrin (either free base or metalated) to E287Q is sub-stoichiometric, as this variant retains bound porphyrin in the active site during isolation and purification. The specificity of porphyrin binding is confirmed by the narrowing of the structure-sensitive resonance Raman lines and the vinyl vibrational mode. Resonance Raman spectra of free base and metalated porphyrins bound to the wild type ferrochelatase indicate a nonplanar distortion of the porphyrin macrocycle, although the magnitude of the distortion cannot be determined without first defining the specific type of deformation. Significantly, the extent of the nonplanar distortion varies in the case of H207N- and E287Q-bound porphyrins. In fact, resonance Raman spectral decomposition indicates a homogeneous ruffled distortion for the nickel protoporphyrin bound to the wild type ferrochelatase, whereas both a planar and ruffled conformations are present for the H207N-bound porphyrin. Perhaps more revealing is the unusual resonance , 3 Raman spectrum of the endogenous E287Q-bound porphyrin, which has

  4. Meso-functionalized octamethoxyporphyrins: A new class of nonasubstituted porphyrins

    Indian Academy of Sciences (India)

    Pradeepta K Panda; V Krishnan


    Octamethoxyporphyrin containing multiple-donor substituents has been functionalized for the first time. A large number of its mono-meso-substituted derivatives with substituents such as nitro, amino, N-methylamino, formyl, hydroxymethyl, oxime, cyano and carboxy functional groups have been synthesized and characterized. They form a new class of nonasubstituted porphyrins. Crystallographic studies on the cyano derivative show that the -C N group is in conjugation with the prophyrin -system. The calculated optical transition energies and the electron densities on the imino nitrogens of the synthesised porphyrins using AMI calculations correlate well with the experimentally observed data. Mesosubstituted porphyrins are found to be essentially planar.

  5. 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. (United States)

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


    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

  6. Nanocarriers for delivery of platinum anticancer drugs☆ (United States)

    Oberoi, Hardeep S.; Nukolova, Natalia V.; Kabanov, Alexander V.; Bronich, Tatiana K.


    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

  7. Anodic stripping tin titration: a method for the voltammetric determination of platinum at trace levels. (United States)

    Giussani, Barbara; Roncoroni, Simone; Nemenyi, Anna; Dal Santo, Vladimiro; Monticelli, Damiano; Recchia, Sandro


    We propose here a novel voltammetric method for the determination of platinum at trace levels. The method is based on the interference that platinum generates on the anodic stripping signal of tin acidic solutions: in appropriate conditions platinum uses the intermediate formation of tin(II) ions, taking place during the tin cathodic reduction, to reduce itself and to form mixed Pt(II)-Sn(II) chloro-complexes. From the analysis of the anodic stripping plots obtained after subsequent additions of tin in a Pt-containing solution, it is possible to quantify accurately and precisely the Pt concentration from 3 ppb to more than 10 ppm. This novel method is validated for the analysis of Pt in heterogeneous catalysts, but in principle could be extended to other matrixes.

  8. Extraction and separation studies of platinum(IV) with N-n-octylaniline. (United States)

    Lokhande, T N; Anuse, M A; Chavan, M B


    N-n-octylaniline in xylene is used for the extractive separation of platinum(IV) from acidic media. Platinum(IV) was extracted quantitatively with 10 ml of 3% reagent in xylene from 0.5 to 10 and 2.5 to 10 M hydrochloric and sulphuric acid, respectively. It was stripped from organic phase with water and estimated photometrically with stannous chloride. The effect of metal ion, acids, reagent concentration and of various foreign ions has been investigated. The method affords binary separation of platinum(IV) from iron(III), cobalt(II), nickel(II) and copper(II), and is applicable to the analysis of synthetic mixtures and alloys. The method is fast, accurate and precise.

  9. Meeting report on 8th International Symposium on Platinum and Other Metal Coordination Compounds in Cancer Chemotherapy. (United States)

    Kelland, L R


    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).

  10. Preparation and biodistribution of copper-67-labeled porphyrins and porphyrin-A6H immunoconjugates

    Energy Technology Data Exchange (ETDEWEB)

    Bhalgat, Mahesh K.; Roberts, Jeanette C.; Mercer-Smith, Janet A.; Knotts, Brenda D.; Vessella, Robert L.; Lavallee, David K


    The synthetic porphyrins, N-benzyl-5,10,15,20-tetrakis (4-carboxyphenyl)porphine (N-bzHTCPP) and N-4-nitrobenzyl-5-(4-carboxyphenyl)-10,15,20-tris(4-sulfophenyl)porphine (N-bzHCS{sub 3}P), represent excellent radiocopper chelating agents that may find utility in antibody-mediated diagnosis and/or therapy. N-bzHCS{sub 3}P was conjugated to an anti-renal cell carcinoma (RCC) antibody, A6H, and labeled with copper-67. {sup 67}CuCS{sub 3}P-A6H was studied for its biodistribution in human RCC xenograft-bearing nude mice, along with the radiolabeled free porphyrins. The porphyrins resulted in tumor:blood ratios in the range of 3 to 4 after 48 h. The radiolabeled antibody achieved a tumor:blood ratio of over 16 after 45 h, indicating accumulation at the desired site. However, unwanted localization also occurred in the liver and spleen, which will have to be rectified before realizing the full potential of this approach.

  11. Challenging Density Functional Theory Calculations with Hemes and Porphyrins

    Directory of Open Access Journals (Sweden)

    Sam P. de Visser


    Full Text Available In this paper we review recent advances in computational chemistry and specifically focus on the chemical description of heme proteins and synthetic porphyrins that act as both mimics of natural processes and technological uses. These are challenging biochemical systems involved in electron transfer as well as biocatalysis processes. In recent years computational tools have improved considerably and now can reproduce experimental spectroscopic and reactivity studies within a reasonable error margin (several kcal·mol−1. This paper gives recent examples from our groups, where we investigated heme and synthetic metal-porphyrin systems. The four case studies highlight how computational modelling can correctly reproduce experimental product distributions, predicted reactivity trends and guide interpretation of electronic structures of complex systems. The case studies focus on the calculations of a variety of spectroscopic features of porphyrins and show how computational modelling gives important insight that explains the experimental spectra and can lead to the design of porphyrins with tuned properties.

  12. Porphyrin Diacid-Polyelectrolyte Assemblies: Effective Photocatalysts in Solution

    Directory of Open Access Journals (Sweden)

    Sabine Frühbeißer


    Full Text Available Developing effective and versatile photocatalytic systems is of great potential in solar energy conversion. Here we investigate the formation of supramolecular catalysts by electrostatic self-assembly in aqueous solution: Combining positively charged porphyrins with negatively charged polyelectrolytes leads to nanoscale assemblies where, next to electrostatic interactions, π–π interactions also play an important role. Porphyrin diacid-polyelectrolyte assemblies exhibit a substantially enhanced catalytic activity for the light-driven oxidation of iodide. Aggregates with the hexavalent cationic porphyrin diacids show up to 22 times higher catalytic activity than the corresponding aggregates under neutral conditions. The catalytic activity can be increased by increasing the valency of the porphyrin and by choice of the loading ratio. The structural investigation of the supramolecular catalysts took place via atomic force microscopy and small angle neutron scattering. Hence, a new facile concept for the design of efficient and tunable self-assembled photocatalysts is presented.

  13. Organo-platinum complexes as antitumor agents (review). (United States)

    Hill, J M; Speer, R J


    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.

  14. Supramolecular Organization of Porphyrin and Phthalocyanine by Complementary Coordination

    Institute of Scientific and Technical Information of China (English)

    Yoshiaki; Kobuke; Masakuni; Fujita; Toshimasa; Sugimura; Akiharu; Satake


    1 Results We have already established a methodology of supramolecular organization of porphyrin and phthalocyanine by complementary coordination of the imidazolyl substituent to their metal centers.Since the stability constants reached a range of 1011 to 1012 M-1 in nonpolar solvents,it allowed construction of stable structures such as special pair of photosynthetic reaction center and light-harvesting antenna complex of photosynthetic bacteria.Here,we report one-dimensional array of porphyrin for the d...

  15. Covalently Linked Dyads and Triads of Phthalocyanines and Porphyrins


    Aljuhani, Ateyat Allah


    The phthalocyanines are a family of intensively coloured compounds, with some important properties and are classified as important materials for many applications. Structurally, a phthalocyanine is similar to a porphyrin. In chapter one, a brief introduction of their synthesis, properties, and applications is given along with some examples of phthalocyanine dimers. The preparation of new functionalised phthalocyanine and porphyrin compounds has been the subject of intense research over the la...

  16. Tetrakis(4-tert-butylphenyl) substituted and fused quinoidal porphyrins

    KAUST Repository

    Zeng, Wangdong


    4-tert-Butylphenyl-substituted and fused quinoidal porphyrins 1 and 2 are prepared for the first time. They show (1) intense one-photon absorption in the far-red/near-infrared region, (2) enhanced two-photon absorption compared with aromatic porphyrin monomers, and (3) amphoteric redox behavior. Their geometry and electronic structure are studied by DFT calculations. This journal is © 2012 The Royal Society of Chemistry.

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

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


    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.

  18. Hollow platinum alloy tailored counter electrodes for photovoltaic applications (United States)

    Li, Pinjiang; Zhang, Yange; Fa, Wenjun; Yang, Xiaogang; Wang, Liang


    Without sacrifice of photovoltaic performances, low-platinum alloy counter electrodes (CEs) are promising in bringing down the fabrication cost of dye-sensitized solar cells (DSSCs). We present here the realization of ZnO nanostructure assisted hollow platinum-nickel (PtNi) alloy microstructure CEs with a simple hydrothermal methods and maximization of electrocatalytic behaviors by tuning Zn precursors. The maximal power conversion efficiency is up to 8.74% for the liquid-junction dye-sensitized solar cells with alloyed PtNi0.41 electrode, yielding a 37.6% cell efficiency enhancement in comparison with pristine solar cell from planar Pt electrode. Moreover, the dissolution-resistant and charge-transfer abilities toward I-/I3- redox electrolyte have also been markedly enhanced due to competitive dissolution reactions and alloying effects.

  19. Impact of iron porphyrin complexes when hydroprocessing algal HTL biocrude

    Energy Technology Data Exchange (ETDEWEB)

    Jarvis, Jacqueline M.; Sudasinghe, Nilusha M.; Albrecht, Karl O.; Schmidt, Andrew J.; Hallen, Richard T.; Anderson, Daniel B.; Billing, Justin M.; Schaub, Tanner M.


    We apply Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for direct characterization of iron-porphyrins in hydrothermal liquefaction (HTL) biocrude oils derived from two algae: Tetraselmis sp. and cyanobacteria. The ironporphyrin compounds are shown to cause catalyst bed plugging during hydroprocessing due to iron deposition. Inductively-coupled plasma optical emission spectrometry (ICPOES) was utilized for iron quantitation in the plugged catalyst beds formed through hydroprocessing of the two HTL biocrudes and identifies an enrichment of iron in the upper five centimeters of the catalyst bed for Tetraselmis sp. (Fe=100,728 ppm) and cyanobacteria (Fe=115,450 ppm). Direct infusion FT-ICR MS analysis of the two HTL biocrudes with optimized instrument conditions facilitates rapid screening and identification of iron-porphyrins without prior chromatographic separation. With FT-ICR MS we identify 138 unique iron-porphyrin compounds in the two HTL biocrudes that are structurally similar to metal-porphyrins (e.g. Ni and V) observed in petroleum. No ironporphyrins are observed in the cyanobacteria HTL biocrude after hydroprocessing, which indicates that iron-porphyrin structures in the HTL biocrude are degraded during hydroprocessing. Hydrodemetallization reactions that occur through hydroprocessing of HTL biocrudes could be responsible for the decomposition of iron-porphyrin structures leading to metal deposition in the catalyst bed that result in catalyst deactivation and bed plugging, and must be addressed for effective upgrading of algal HTL biocrudes.

  20. Crystal fields of porphyrins and phthalocyanines (United States)

    Johnson, P. S.; Boukahil, I.; Himpsel, F. J.; Kennedy, C.; Jersett, N.; Cook, P. L.; Garcia-Lastra, J. M.


    Polarization-dependent X-ray absorption spectroscopy at the N 1s and metal 2p edges is combined with density functional and atomic multiplet calculations to determine the crystal field parameters 10Dq, Ds, and Dt of transition metal (Mn, Fe, Co, Ni) phthalocyanines and octaethylporphyrins. Octaethyl porphyrins are observed to lie flat on Si with native oxide, while phthalocyanines lie on edge. Strong polarization dependence is found at all edges, which facilitates a unique determination of the crystal field parameters. Crystal field values from PBE density functional calculations provide helpful starting values, which are refined by fitting atomic multiplet calculations to the data. Since the crystal field affects electron-hole separation in solar cells, the systematic set of crystal field parameters obtained here can be useful for optimizing dyes for solar cells.

  1. Heptaphyrins: Expanded porphyrins with seven heterocyclic rings

    Indian Academy of Sciences (India)

    Venkataramanarao G Anand; Simi K Pushpan; Sundararaman Venkatraman; Tavarekere K Chandrashekar


    Expanded porphyrins containing seven pyrrole/heterocyclic rings linked in a cyclic fashion are termed heptaphyrins. The number of -electrons in heptaphyrins depends on the number of meso carbon bridges used to link the heterocyclic rings, accordingly heptaphyrins with 28-electrons and 30 -electrons are reported to date. Both condensation reactions of the appropriate precursors and acid-catalysed oxidative coupling reactions have been utilized to synthesise the heptaphyrins. The 30 heptaphyrins exhibit rich structural diversity where some of the heterocyclic rings in the macrocycle undergo a 180° ring flipping. An overview of the synthetic methods employed for the synthesis of heptaphyrins, their spectroscopic properties, structural behaviour and aromatic properties are highlighted in this paper.

  2. In vitro effects of combinations of cis-amminedichloro (2-methylpyridine) platinum (II) (ZD0473) with other novel anticancer drugs on the growth of SBC-3, a human small cell lung cancer cell line. (United States)

    Kanzawa, F; Akiyama, Y; Saijo, N; Nishio, K


    Among numerous clinical regimens of combination chemotherapy, synergy has been observed to be particularly marked with combinations containing cisplatin (CDDP). However, the clinical use of CDDP has sometimes been limited by acquired resistance. The new-generation platinum drug, ZD0473, was synthesized with the aim of hindering the reaction of the drug with thiols, by the introduction of a 2-methylpyridine ligand. This enables the drug to exert antitumor activity against cisplatin-resistant cancer cells with elevated glutathione and/or metallothionein levels. The drug was also shown experimentally to overcome cisplatin resistance due to impaired drug accumulation, and enhanced DNA repair/tolerance to platinum-DNA adducts. We investigated the effects of combinations of ZD0473 with other anticancer drugs on the growth of a human small-cell lung cancer cell line (SBC-3). Six novel anticancer drugs were tested: docetaxel (TXT), paclitaxel (TXL), vinorelbine (VNB), irinotecan (CPT-11), gemcitabine (GEM) and pemetrexed (MTA). The growth inhibitory effect of the drugs was measured by MTT assay and the effects of the combination regimens were evaluated by the combination index analysis method developed by Chou and Talalay. Synergy was demonstrated for the combination regimens of ZD0473-GEM and ZD0473-TXL, while an additive effect was observed with combinations containing TXT, VNB, CPT-11 or MTA. In the case of the ZD0473-GEM combination, synergy was observed over a wide range of inhibition levels at dose ratios of 50:1, 100:1 and 250:1. The level of synergy was equivalent to that observed for combinations of CDDP-etoposide, CDDP-GEM and nedaplatin-CPT-11. The results suggest that the combination of ZD0473 with GEM merits further investigation in small cell lung cancer.

  3. Antitumor activities and interaction with DNA of oxaliplatin-type platinum complexes with linear or branched alkoxyacetates as leaving groups. (United States)

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


    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.

  4. Surface characterization of platinum electrodes. (United States)

    Solla-Gullón, José; Rodríguez, Paramaconi; Herrero, Enrique; Aldaz, Antonio; Feliu, Juan M


    The quantitative analysis of the different surface sites on platinum samples is attempted from pure voltammetric data. This analysis requires independent knowledge of the fraction of two-dimensional (111) and (100) domains. Specific site-probe reactions are employed to achieve this goal. Irreversibly-adsorbed bismuth and tellurium have been revealed to be sensitive to the presence of (111) terrace domains of different width whereas almost all sites involved in (100) ordered domains have been characterized through germanium adatoms. The experimental protocol follows that used with well-defined single-crystal electrodes and, therefore, requires careful control of the surface cleanliness. Platinum basal planes and their vicinal stepped surfaces have been employed to obtain calibration plots between the charge density measured under the adatom redox peak, specific for the type of surface site, and the corresponding terrace size. The evaluation of the (100) bidimensional domains can also be achieved using the voltammetric profiles, once the fraction of (111) ordered domains present in the polyoriented platinum has been determined and their featureless contribution has been subtracted from the whole voltammetric response. Using that curve, it is possible to perform a deconvolution of the adsorption states of the polycrystalline sample different from those related to (111) domains. The fraction of (100)-related states in the deconvoluted voltammogram can then be compared to that expected from the independent estimation coming from the charge involved in the redox process undergone by the irreversibly-adsorbed germanium and thus check the result of the deconvolution. The information about the surface-site distribution can also be applied to analyze the voltammetric profile of nanocrystalline platinum electrodes.

  5. Request for Correction 11001 Toxicological Review of Halogenated Platinum Salts and Platinum Compounds (United States)

    Request for Correction by the International Platinum Group Metals Association seeking the correction of information disseminated in the draft EPA document Toxicological Review of Halogenated Platinum Salts and Platinum Compounds: In Support of Summary Information on the Integrated Risk Information System (IRIS).

  6. Zinc(II and copper(II complexes with pheophytin and mesoporphyrin and their stability to UV-B irradiation: Vis spectroscopy studies

    Directory of Open Access Journals (Sweden)

    Zvezdanović Jelena B.


    Full Text Available Stability of Zn(II and Cu(II complexes of porphyrin derivatives (pheophytin and mesoporphyrin to UV-B -irradiation has been studied by absorbance spectroscopy in 95% ethanol. The chosen porphyrins as well as their heavy metal complexes undergo photochemical decomposition obeying first-order kinetics. In general, pheophytin is more stable than mesoporphyrin to UV-B irradiation. On the other hand, stability of Zn(II-complex is smaller than Cu(II-complex both for pheophytin and mesoporphyrin; however while Cu(II-complex with pheophytin is more stable than the one with mesoporphyrin, with Zn(II-complex the situation is vice versa.

  7. Phosphoric acid fuel cell platinum use study (United States)

    Lundblad, H. L.


    The U.S. Department of Energy is promoting the private development of phosphoric acid fuel cell (PAFC) power plants for terrestrial applications. Current PAFC technology utilizes platinum as catalysts in the power electrodes. The possible repercussions that the platinum demand of PAFC power plant commercialization will have on the worldwide supply and price of platinum from the outset of commercialization to the year 2000 are investigated. The platinum demand of PAFC commercialization is estimated by developing forecasts of platinum use per unit of generating capacity and penetration of PAFC power plants into the electric generation market. The ability of the platinum supply market to meet future demands is gauged by assessing the size of platinum reserves and the capability of platinum producers to extract, refine and market sufficient quantities of these reserves. The size and timing of platinum price shifts induced by the added demand of PAFC commercialization are investigated by several analytical methods. Estimates of these price shifts are then used to calculate the subsequent effects on PAFC power plant capital costs.

  8. Use of Novel Cardanol-Porphyrin Hybrids and Their TiO2-Based Composites for the Photodegradation of 4-Nitrophenol in Water

    Directory of Open Access Journals (Sweden)

    Giuseppe Mele


    Full Text Available Cardanol, a well known hazardous byproduct of the cashew industry, has been used as starting material for the synthesis of useful differently substituted “cardanol-based” porphyrins and their zinc(II, copper(II, cobalt(II and Fe(III complexes. Novel composites prepared by impregnation of polycrystalline TiO2 powder with an opportune amount of “cardanol-based” porphyrins, which act as sensitizers for the improvement of the photo-catalytic activity of the bare TiO2, have been used in the photodegradation in water of 4-nitrophenol (4-NP, which is a toxic and bio-refractory pollutant, dangerous for ecosystems and human health.

  9. Tetrathiafulvalene-fused porphyrins via quinoxaline linkers: symmetric and asymmetric donor-acceptor systems. (United States)

    Jia, Hongpeng; Schmid, Belinda; Liu, Shi-Xia; Jaggi, Michael; Monbaron, Philippe; Bhosale, Sheshanath V; Rivadehi, Shadi; Langford, Steven J; Sanguinet, Lionel; Levillain, Eric; El-Khouly, Mohamed E; Morita, Ysushi; Fukuzumi, Shunichi; Decurtins, Silvio


    A tetrathiafulvalene (TTF) donor is annulated to porphyrins (P) via quinoxaline linkers to form novel symmetric P-TTF-P triads 1 a-c and asymmetric P-TTF dyads 2 a,b in good yields. These planar and extended π-conjugated molecules absorb light over a wide region of the UV/Vis spectrum as a result of additional charge-transfer excitations within the donor-acceptor assemblies. Quantum-chemical calculations elucidate the nature of the electronically excited states. The compounds are electrochemically amphoteric and primarily exhibit low oxidation potentials. Cyclic voltammetric and spectroelectrochemical studies allow differentiation between the TTF and porphyrin sites with respect to the multiple redox processes occurring within these molecular assemblies. Transient absorption measurements give insight into the excited-state events and deliver corresponding kinetic data. Femtosecond transient absorption spectra in benzonitrile may suggest the occurrence of fast charge separation from TTF to porphyrin in dyads 2 a,b but not in triads 1 a-c. Clear evidence for a photoinduced and relatively long lived charge-separated state (385 ps lifetime) is obtained for a supramolecular coordination compound built from the ZnP-TTF dyad and a pyridine-functionalized C(60) acceptor unit. This specific excited state results in a (ZnP-TTF)(⋅+) ⋅⋅⋅(C(60) py)(⋅-) state. The binding constant of Zn(II) ⋅⋅⋅py is evaluated by constructing a Benesi-Hildebrand plot based on fluorescence data. This plot yields a binding constant K of 7.20×10(4)  M(-1), which is remarkably high for bonding of pyridine to ZnP. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Synthesis and Characterization of One-dimensional and Two-Dimensional Porphyrin Polymers* (Ⅰ)

    Institute of Scientific and Technical Information of China (English)


    @@Porphyrin polymers are of interest in relation to conductive materials[1, 2], catalysts for photosynthetic charge separation[3], or the fundamental features in biological systems[4]. There have been many versatile studies about them[5,6]. The one-dimensional “Shish Kebab” porphyrin polymers synthesized with a new method different from those reported and Schiff base porphyrin polymers with two-dimensional nano-structure have provided a new field of study. The present paper covers highly ordered porphyrin polymers.

  11. Synthesis and characterization of potential iron–platinum drugs and supplements by laser liquid photolysis

    Directory of Open Access Journals (Sweden)

    Forbes A


    Full Text Available Steven S Nkosi,1,2 Bonex W Mwakikunga,4 Elias Sideras-Haddad,2 Andrew Forbes1,31CSIR National Laser Centre, Pretoria, South Africa; 2DST/NRF Centre for Excellence in Strong Materials and School of Physics, University of the Witwatersrand, Johannesburg, 3School of Physics, University of KwaZulu-Natal, Durban, South Africa; 4DST/CSIR National Centre for Nano-Structured Materials, Pretoria, South AfricaAbstract: Highly crystalline nanospherical iron–platinum systems were produced by 248 nm laser irradiation of a liquid precursor at different laser fluences, ranging from 100–375 mJ/cm2. The influence of laser intensity on particle size, iron composition, and structure was systematically investigated. Different nanostructures of iron–platinum alloy and chemically disordered iron–platinum L10 phase were obtained without annealing. The prepared precursor solution underwent deep photolysis to polycrystalline iron–platinum nanoalloys through Fe(III acetylacetonate and Pt(II acetylacetonate. Fe(II and Pt(I acetylacetone decomposed into Fe0 and Pt0 nanoparticles. We found that the (001 diffraction peak shifted linearly to a lower angle, with the last peak shifting in opposition to the others. This caused the face-centered cubic L10 structure to change its composition according to laser fluence. The nanostructures were shown to contain iron and platinum only by energy-dispersive spectroscopy at several spots. The response of these iron–platinum nanoparticles to infrared depends on their stoichiometric composition, which is controlled by laser fluence.Keywords: nanostructures, iron, platinum, nanoparticles, laser liquid photolysis, composition

  12. Activity of topotecan given intravenously for 5 days every three weeks in patients with advanced non-small cell lung cancer pretreated with platinum and taxanes: a phase II study. (United States)

    Gonzalez, Emilio Esteban; Villanueva, Noemi; Fra, Joaquin; Berros, Jose Pablo; Jimenez, Paula; Luque, María; Muñiz, Isabel; Blay, Pilar; Fernandez, Yolanda; Vieitez, José María; Muriel, Carolina; Sanmamed, Miguel; Coto, Pablo Pardo; Izquierdo, Marta; Estrada, Enrique; Lacave, Angel J


    Topotecan, a semi-synthetic camptothecin analogue with topoisomerase I interaction, has shown to be an active agent in the treatment of advanced refractory lung cancer. This paper describes the authors' experience with this drug when used as a single agent in patients (pts) with advanced non-small cell lung cancer (NSCLC) refractory to platinum- and taxane-containing chemotherapy regimens. Thirty-five patients with NSCLC refractory to previous chemotherapy and KI ≥ 60% were included in the study. Their characteristics are as follows: median age of 52 years (range 43-69) and Karnofsky PS of 70 (60-80); 27 were male and 8 were female. Twenty-one (60%) patients had adenocarcinoma; eleven (31.4%), squamous cell, and three (8.5%), undifferentiated carcinoma. There was a median of two disease sites and two prior chemotherapy regimens. Topotecan was administered at a dose of 1.25 mg/m(2) I.V. daily for 5 days, repeated every 21 days until disease progression, maximal response, or intolerable toxicity. After 73 cycles, patients received a median of 2 treatment cycles (1-9). All patients except one were considered evaluable for toxicity; eight episodes (24%) of nausea/vomiting and two episodes (6%) of grade 1-2 asthenia, respectively, were reported. Four (12%) patients developed grade 1-2 anemia and two (6%) subjects suffered grade 3 anemia. Seven (21%) patients had grade 1-2 neutropenia and one (3%) presented grade 5 neutropenia. In 33 patients evaluable for activity of the 35 subjects included in the study; one (2.8%) presented a partial response; nine (25.7%) had stable disease, and 23 (65.7%) exhibited disease progression. Median time to progression and overall survival were 54 (12-210) and 70 (12-324) days, respectively. Intravenous topotecan at that dose and administration schedule displays scant activity in terms of response rate in individuals with advanced NSCLC previously treated with platinum and taxanes. The role and usefulness of chemotherapy in this setting

  13. Real-time observation of ultrafast electron injection at graphene–Zn porphyrin interfaces

    KAUST Repository

    Masih, Dilshad


    We report on the ultrafast interfacial electron transfer ( ET) between zinc( II) porphyrin ( ZnTMPyP) and negatively charged graphene carboxylate ( GC) using state- of- the- art femtosecond laser spectroscopy with broadband capabilities. The steady- state interaction between GC and ZnTMPyP results in a red- shifted absorption spectrum, providing a clear indication for the binding affinity between ZnTMPyP and GC via electrostatic and p- p stacking interactions. Ultrafast transient absorption ( TA) spectra in the absence and presence of three different GC concentrations reveal ( i) the ultrafast formation of singlet excited ZnTMPyP*, which partially relaxes into a long- lived triplet state, and ( ii) ET from the singlet excited ZnTMPyP* to GC, forming ZnTMPyP + and GC , as indicated by a spectral feature at 650- 750 nm, which is attributed to a ZnTMPyP radical cation resulting from the ET process.

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


    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.

  15. Synthesis of Metal Porphyrins Tailed with Salicylic Acid and their Interaction with Bovine Serum Albumin

    Institute of Scientific and Technical Information of China (English)

    Tao JIA; Kai WANG; Yi Mei ZHAO; Zao Ying LI


    A synthetic method of porphyrins tailed with salicylic substituents is described. Reaction of bromoalkoxyphenyl porphyrin 1 with salicylic acid gave porphyrins 2~5. These new compounds were confirmed by 1H NMR, IR, UV-vis, MS and elemental analysis, and observed their interaction with bovine serum albumin (BSA) in fluorescence spectrum.

  16. Synthesis of β,β'-Porphyrin Dimer Linked by Vinylene

    Institute of Scientific and Technical Information of China (English)

    Jiang, Xuliang; Li, Panli; Wang, Yucheng; Shen, Qi; Tao, Jingchao; Shi, Weimin


    Synthesis of a novel β,β'-tetraalkylporphyrin dimer linked by vinylene was discribed, in which the dimer was readily prepared from a porphyrin-derived Wittig reagent and a mono-formylated porphyrin via Wittig reaction. No π-conjugation between the two porphyrin rings was obserbed, and the dimer was in trans form.

  17. Synthesis and Purification of Porphyrin-Schiff Base Using Ethyl Vanillin

    Institute of Scientific and Technical Information of China (English)


    A novel porphyrin-Schiff base was synthesized via the condensation of 5-(4-aminophenyl)-10,15,20-triphenylporphyrin and ethyl vanillin. After analyzing the level of purification of the porphyrin-Schiff base, it was successfully separated. This porphyrin-Schiff base was characterized by using UV-Vis, IR, 1 H NMR and MS spectroscopy.

  18. Morphological characterization of metal porphyrin tailed with aspirin interacting with bovine serum albumin congeries

    Institute of Scientific and Technical Information of China (English)


    The porphyrins tailed with acetylsalicylic acid (ASA) and Zn (or Cu) complexes were prepared. Meanwhile, morphological images, such as shape and size of porphyrins-BSA congeries were observed by using atomic force microscopy (AFM). The result showed the interaction of BSA and prepared porphyrins led to obvious change of shape and size of BSA congeries.

  19. First platinum moderated positron beam based on neutron capture

    CERN Document Server

    Hugenschmidt, C; Repper, R; Schreckenbach, K; Sperr, P; Triftshaeuser, W


    A positron beam based on absorption of high energy prompt gamma-rays from thermal neutron capture in sup 1 sup 1 sup 3 Cd was installed at a neutron guide of the high flux reactor at the ILL in Grenoble. Measurements were performed for various source geometries, dependent on converter mass, moderator surface and extraction voltages. The results lead to an optimised design of the in-pile positron source which will be implemented at the Munich research reactor FRM-II. The positron source consists of platinum foils acting as gamma-e sup + e sup - -converter and positron moderator. Due to the negative positron work function moderation in heated platinum leads to emission of monoenergetic positrons. The positron work function of polycrystalline platinum was determined to 1.95(5) eV. After acceleration to several keV by four electrical lenses the beam was magnetically guided in a solenoid field of 7.5 mT leading to a NaI-detector in order to detect the 511 keV gamma-radiation of the annihilating positrons. The posi...

  20. Porphyrin and bodipy molecular rotors as microviscometers (United States)

    Kimball, Joseph Daniel, III

    Viscosity, a fluid's internal resistance to flow and resist molecular diffusion, is a fundamental property of fluid media. Determining the bulk viscosity of a fluid has been easy to relatively simple to accomplish for many years, yet in the recent decade there has been a focus on techniques to measure a fluid's microviscosity. Microviscosity differs from bulk viscosity such that microviscosity is the friction experienced by a single particle interacting with its micron-sized local environment. Macroscopic methods to evaluate the viscosity are well established, but methods to determine viscosity on the microscale level remains unclear. This work determines the viability of three molecular rotors designed as probes for microviscosity in organic media, ionic liquids, and in the cellular microenvironment. Understanding microviscosity is important because it one of the main properties of any fluid and thus has an effect on any diffusion related processes. A variety of mass and signal transport phenomena as well as intermolecular interactions are often governed by viscosity. Molecular rotors are a subclass of intramolecular charge transfer fluorophores which form a lower energy twisted state. This results in a charge separated species which is highly sensitive to its surrounding microenviroment's viscosity as high viscosity limits its ability to form this twisted state. Once excited, there are deactivation routes which the excited fluorophore can undergo: radiative and non-radiative. Both were studied in this work. In the case of a radiative decay, as seen in porphyrin dimer, the energy is released in the form of a photon and is seen as a shifted band in the emission structure. The conformation of the porphyrin dimer was found to be influenced differently by ionic liquids as compared to molecular solvents, indicating the microheterogenous nature of ionic liquids play a role in the conformation. For non-radiative decays, BODIPY dyads and triads were investigated. The