A series of octanuclear-nickel(II) complexes supported by thiacalix[4]arenes.

Science.gov (United States)

Xiong, Kecai; Jiang, Feilong; Gai, Yanli; Zhou, Youfu; Yuan, Daqiang; Su, Kongzhao; Wang, Xinyi; Hong, Maochun

2012-03-05

A series of discrete complexes, [Ni(8)(BTC4A)(2)(μ(6)-CO(3))(2)(μ-CH(3)COO)(4)(dma)(4)]·H(2)O (1), [Ni(8)(BTC4A)(2)(μ(6)-CO(3))(2)(μ-Cl)(2)(μ-HCOO)(2)(dma)(4)]·2DMF·2CH(3)CN (2), [Ni(8)(PTC4A)(2) (μ(6)-CO(3))(2)(μ-CH(3)COO)(4)(dma)(4)]·DMF (3), and [Ni(8)(PTC4A)(2)(μ(6)-CO(3))(2)(μ-OH)(μ-HCOO)(3) (dma)(4)] (4) (p-tert-butylthiacalix[4]arene = H(4)BTC4A, p-phenylthiacalix[4]arene = H(4)PTC4A, dma = dimethylamine, and DMF = N,N'-dimethylformamide), have been prepared under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction analyses, powder XRD, and IR spectroscopy. These four complexes are stacked by dumbbell-like building blocks with one chairlike octanuclear-nickel(II) core, which is capped by two thiacalix[4]arene molecules and connected by two in situ generated carbonato anions and different auxiliary anions. This work implied that not only the solvent molecules but also the upper-rim groups of thiacalix[4]arenes have significant effects on the self-assembly of the dumbbell-like building blocks. The magnetic properties of complexes 1-4 were examined, indicating strong antiferromagnetic interactions between the nickel(II) ions in the temperature range of 50-300 K.

Ruthenium(II)- bipyridyl with extended π-system: Improved thermo ...

Indian Academy of Sciences (India)

aInorganic and Physical Chemistry Division, Indian Institute of Chemical Technology, Uppal Road, Tarnaka, ... A new extended thermo-stable high molar extinction coefficient bipyridyl ruthenium(II) complex ... cyanines and metal free organic sensitizers have been ..... Iodide-based ionic liquids are more viscous than.

Synthesis and complexation properties towards uranyl cation of carboxylic acid derivatives of p-tert-butyl-calix[6]arene

International Nuclear Information System (INIS)

Souane, R.

2005-03-01

In the fuel reprocessing plants radioactive metals, and more particularly, uranium in UO 2 2+ form in the various installations, have many varied physico-chemical forms and there is a risk of exposure and internal contamination in the nuclear industry. It is necessary to exert a medical control to ensure the protection of the health of the workers. This medical control is done by dosing uranyl cation in the urine of the exposed people. This work forms part of this context. Indeed, we prepared a ligand able to complex the ion uranyl and which is also to be grafted on a solid support. In the family of calixarenes, the calix[6]arenes functionalized by three or four carboxylic functions were selected like chelating molecules of the ion uranyl. The properties of complexation of these calixarenes were studied by potentiometry in methanol, under these conditions balances of protonation and complexation were determined and the constant partners were obtained using the Hyperquad program. We synthesized tri-carboxylic calix[6]arenes comprising of the groupings nitro (NO 2 ) in para position of phenol in order to see the influence of a substitution in para position on the complexation. We also synthesized calix[6]arenes tetra-carboxylic in order to show the role of an additional carboxylic acid grouping. The potentiometric study determined thermodynamic parameters of protonation and complexation of carboxylic calix[6]arenes. The results of the complexation highlighted which complex UO 2 L corresponding to the ligand para-tert-butyl-calix[6]arene tetra-acid is more stable than that corresponding to the ligand mono-nitro calix[6]arene tri-acid (ΔlogΒ110 = 4.3), and than the effect of the groupings nitro in para position has low influence on the complexation of UO 2 2+ . This makes it possible to consider as possible the grafting of the calix[6]arenes which one knows the behaviour of trapping. To this end we synthesized the ligand 23. (author)

Thermodynamic Study of the Complexation of p-Isopropylcalix[6]arene with Cs+ Cation in Dimethylsulfoxide-Acetonitrile Binary Media

Directory of Open Access Journals (Sweden)

Gholam Hossein Rounaghi

2011-09-01

Full Text Available The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log Kf of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (DH°c and DS°c for formation of (p-isopropyl-calix[6]arene·Cs+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents.

DNA interaction, antioxidant activity, and bioactivity studies of two ruthenium(II) complexes

Science.gov (United States)

Han, Bing-Jie; Jiang, Guang-Bin; Yao, Jun-Hua; Li, Wei; Wang, Ji; Huang, Hong-Liang; Liu, Yun-Jun

2015-01-01

Two new ruthenium(II) polypyridyl complexes [Ru(dmb)2(dcdppz)](ClO4)2 (1) and [Ru(bpy)2(dcdppz)](ClO4)2 (2) were prepared and characterized. The crystal structure of the complex 2 was solved by single crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group P21/n with a = 12.9622(14) Å, b = 17.1619(19) Å, c = 22.7210(3) Å, β = 100.930(2)°, R = 0.0536, Rω = 0.1111. The DNA-binding constants for complexes 1 and 2 were determined to be 1.92 × 105 (s = 1.72) and 2.24 × 105 (s = 1.86) M-1, respectively. The DNA-binding behaviors showed that complexes 1 and 2 interact with DNA by intercalative mode. The antioxidant activities of the ligand and the complexes were performed. Ligand, dcdppz, has no cytotoxicity against the selected cell lines. Complex 1 shows higher cytotoxicity than complex 2, but lower than cisplatin toward selected cell lines. The apoptosis and cell cycle arrest were investigated, and the apoptotic mechanism of BEL-7402 cells was studied by reactive oxygen species (ROS), mitochondrial membrane potential and western blot analysis. Complex 1 induces apoptosis in BEL-7402 cells through ROS-mediated mitochondrial dysfunction pathway and by regulating the expression of Bcl-2 family proteins.

The synthesis and complexation of novel azosubstituted calix[4]arenes and thiacalix[4]arenes

Czech Academy of Sciences Publication Activity Database

Lang, Kamil; Prošková, P.; Kroupa, J.; Morávek, J.; Stibor, I.; Pojarová, M.; Lhoták, P.

2008-01-01

Roč. 77, č. 3 (2008), s. 646-652 ISSN 0143-7208 R&D Projects: GA ČR GA203/07/1424 Grant - others:GA ČR(CZ) GA104/07/1242 Institutional research plan: CEZ:AV0Z40320502 Keywords : calix[4]arene * thiacalix[4]arene * alkylation Subject RIV: CA - Inorganic Chemistry Impact factor: 2.507, year: 2008

Cyclometalated Ruthenium(II) Anthraquinone Complexes Exhibit Strong Anticancer Activity in Hypoxic Tumor Cells.

Science.gov (United States)

Zeng, Leli; Chen, Yu; Huang, Huaiyi; Wang, Jinquan; Zhao, Donglei; Ji, Liangnian; Chao, Hui

2015-10-19

Hypoxia is the critical feature of the tumor microenvironment that is known to lead to resistance to many chemotherapeutic drugs. Six novel ruthenium(II) anthraquinone complexes were designed and synthesized; they exhibit similar or superior cytotoxicity compared to cisplatin in hypoxic HeLa, A549, and multidrug-resistant (A549R) tumor cell lines. Their anticancer activities are related to their lipophilicity and cellular uptake; therefore, these physicochemical properties of the complexes can be changed by modifying the ligands to obtain better anticancer candidates. Complex 1, the most potent member of the series, is highly active against hypoxic HeLa cancer cells (IC50 =0.53 μM). This complex likely has 46-fold better activity than cisplatin (IC50 =24.62 μM) in HeLa cells. This complex tends to accumulate in the mitochondria and the nucleus of hypoxic HeLa cells. Further mechanistic studies show that complex 1 induced cell apoptosis during hypoxia through multiple pathways, including those of DNA damage, mitochondrial dysfunction, and the inhibition of DNA replication and HIF-1α expression, making it an outstanding candidate for further in vivo studies. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diastereoselective formation of metallamacrocyclic (arene)Ru(II) and CpRh(III) complexes.

Science.gov (United States)

Lehaire, Marie-Line; Scopelliti, Rosario; Herdeis, Lorenz; Polborn, Kurt; Mayer, Peter; Severin, Kay

2004-03-08

The reaction of [(arene)RuCl(2)](2) (arene = cymene, 1,3,5-C(6)H(3)Me(3)) and [CpRhCl(2)](2) half-sandwich complexes with tridentate heterocyclic ligands in the presence of base has been investigated. In all cases, the chloro-ligands were substituted to give metallacyclic products with ring sizes between 4 and 18 atoms. The cyclization occurs in a highly diastereoselective fashion with chiral recognition between the different metal fragments. The complexes were comprehensively characterized by elemental analysis, NMR spectroscopy, and single crystal X-ray crystallography. For 2-hydroxy-nicotinic acid and 2-amino-nicotinic acid, dinuclear structures were obtained (15-17) whereas for 2,3-dihydroxyquinoline, 2,3-dihydroxyquinoxaline, and 6-methyl-2,3-phenazinediol, trimeric assemblies were found (19-22), and for 4-imidazolecarboxylic acid, a tetrameric assembly (18) was found.

Impact of aromaticity on anticancer activity of polypyridyl ruthenium(II) complexes: synthesis, structure, DNA/protein binding, lipophilicity and anticancer activity.

Science.gov (United States)

Čanović, Petar; Simović, Ana Rilak; Radisavljević, Snežana; Bratsos, Ioannis; Demitri, Nicola; Mitrović, Marina; Zelen, Ivanka; Bugarčić, Živadin D

2017-10-01

With the aim of assessing how the aromaticity of the inert chelating ligand can influence the activity of ruthenium(II) polypyridyl complexes, two new monofunctional ruthenium(II) complexes, [Ru(Cl-Ph-tpy)(phen)Cl]Cl (1) and [Ru(Cl-Ph-tpy)(o-bqdi)Cl]Cl (2) (where Cl-Ph-tpy = 4'-(4-chlorophenyl)-2,2':6',2″-terpyridine, phen = 1,10-phenanthroline, o-bqdi = o-benzoquinonediimine), were synthesized. All complexes were fully characterized by elemental analysis and spectroscopic techniques (IR, UV-Vis, 1D and 2D NMR, XRD). Their chemical behavior in aqueous solution was studied by UV-Vis and NMR spectroscopy showing that both compounds are relatively labile leading to the formation of the corresponding aqua species 1a and 2a. 1 H NMR spectroscopy studies performed on complexes 1 and 2 demonstrated that after the hydrolysis of the Cl ligand, they are capable to interact with guanine derivatives (i.e., 9-methylguanine (9MeG) and 5'-GMP) through the N7, forming monofunctional adduct. The kinetics and the mechanism of the reaction of complexes 1 and 2 with the biologically more relevant 5'-GMP ligand were studied by UV-Vis spectroscopy. DNA/protein interactions of the complexes have been examined by photophysical studies, which demonstrated a bifunctional binding mode of the complexes with DNA and the complexes strongly quench the fluorescence intensity of bovine serum albumin (BSA) through the mechanism of both static and dynamic quenching. Complexes 1 and 2 strongly induced apoptosis of treated cancer cells with high percentages of apoptotic cells and negligible percentage of necrotic cells. In addition, both ruthenium complexes decreased Bcl-2/Bax ratio causing cytochrome c mitochondrial release, the activation of caspase-3 and induction of apoptosis.

Evaluation of DNA binding, DNA cleavage, protein binding, radical scavenging and in vitro cytotoxic activities of ruthenium(II) complexes containing 2,4-dihydroxy benzylidene ligands

Energy Technology Data Exchange (ETDEWEB)

Mohanraj, Maruthachalam; Ayyannan, Ganesan; Raja, Gunasekaran; Jayabalakrishnan, Chinnasamy, E-mail: drcjbstar@gmail.com

2016-12-01

The new ruthenium(II) complexes with hydrazone ligands, 4-Methyl-benzoic acid (2,4-dihydroxy-benzylidene)-hydrazide (HL{sup 1}), 4-Methoxy-benzoic acid (2,4-dihydroxy-benzylidene)-hydrazide (HL{sup 2}), 4-Bromo-benzoic acid (2,4-dihydroxy-benzylidene)-hydrazide (HL{sup 3}), were synthesized and characterized by various spectro analytical techniques. The molecular structures of the ligands were confirmed by single crystal X-ray diffraction technique. The DNA binding studies of the ligands and complexes were examined by absorption, fluorescence, viscosity and cyclic voltammetry methods. The results indicated that the ligands and complexes could interact with calf thymus DNA (CT-DNA) through intercalation. The DNA cleavage activity of the complexes was evaluated by gel electrophoresis assay, which revealed that the complexes are good DNA cleaving agents. The binding interaction of the ligands and complexes with bovine serum albumin (BSA) was investigated using fluorescence spectroscopic method. Antioxidant studies showed that the complexes have a strong radical scavenging properties. Further, the cytotoxic effect of the complexes examined on cancerous cell lines showed that the complexes exhibit significant anticancer activity. - Highlights: • Synthesis of ruthenium(II) hydrazone complexes • Molecular structure of the ligands was elucidated by single crystal X-ray diffraction method. • The ligands and complexes interact with CT-DNA via intercalation. • The complexes possess significant antioxidant activity against DPPH, OH and NO radicals. • The complex 6 shows higher IC{sub 50} value than the other complexes against cancer cells.

Inclusion Complexes of a New Family of Non-Ionic Amphiphilic Dendrocalix[4]arene and Poorly Water-Soluble Drugs Naproxen and Ibuprofen

Directory of Open Access Journals (Sweden)

Khalid Khan

2017-05-01

Full Text Available The inclusion complexes of a new family of nonionic amphiphilic calix[4]arenes with the anti-inflammatory hydrophobic drugs naproxen (NAP and ibuprofen (IBP were investigated. The effects of the alkyl chain’s length and the inner core of calix[4]arenes on the interaction of the two drugs with the calix[4]arenes were explored. The inclusion complexes of Amphiphiles 1a–c with NAP and IBP increased the solubility of these drugs in aqueous media. The interaction of 1a–c with the drugs in aqueous media was investigated through fluorescence, molecular modeling, and 1H-NMR analysis. TEM studies further supported the formation of inclusion complexes. The length of lipophilic alkyl chains and the intrinsic cyclic nature of cailx[4]arene derivatives 1a–c were found to have a significant impact on the solubility of NAP and IBP in pure water.

Arene activation by a nonheme iron(III)-hydroperoxo complex: pathways leading to phenol and ketone products.

Science.gov (United States)

Faponle, Abayomi S; Banse, Frédéric; de Visser, Sam P

2016-07-01

Iron(III)-hydroperoxo complexes are found in various nonheme iron enzymes as catalytic cycle intermediates; however, little is known on their catalytic properties. The recent work of Banse and co-workers on a biomimetic nonheme iron(III)-hydroperoxo complex provided evidence of its involvement in reactivity with arenes. This contrasts the behavior of heme iron(III)-hydroperoxo complexes that are known to be sluggish oxidants. To gain insight into the reaction mechanism of the biomimetic iron(III)-hydroperoxo complex with arenes, we performed a computational (density functional theory) study. The calculations show that iron(III)-hydroperoxo reacts with substrates via low free energies of activation that should be accessible at room temperature. Moreover, a dominant ketone reaction product is observed as primary products rather than the thermodynamically more stable phenols. These product distributions are analyzed and the calculations show that charge interaction between the iron(III)-hydroxo group and the substrate in the intermediate state pushes the transferring proton to the meta-carbon atom of the substrate and guides the selectivity of ketone formation. These studies show that the relative ratio of ketone versus phenol as primary products can be affected by external interactions of the oxidant with the substrate. Moreover, iron(III)-hydroperoxo complexes are shown to selectively give ketone products, whereas iron(IV)-oxo complexes will react with arenes to form phenols instead.

Electrochemical DNA biosensor for detection of porcine oligonucleotides using ruthenium(II) complex as intercalator label redox

Energy Technology Data Exchange (ETDEWEB)

Halid, Nurul Izni Abdullah; Hasbullah, Siti Aishah; Heng, Lee Yook; Karim, Nurul Huda Abd [School of Chemical Sciences and Food Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia); Ahmad, Haslina; Harun, Siti Norain [Chemistry Department, Faculty of Science, Universiti Putra Malaysia, 43400, Serdang, Selangor (Malaysia)

2014-09-03

A DNA biosensor detection of oligonucleotides via the interactions of porcine DNA with redox active complex based on the electrochemical transduction is described. A ruthenium(II) complex, [Ru(bpy){sub 2}(PIP)]{sup 2+}, (bpy = 2,2′bipyridine, PIP = 2-phenylimidazo[4,5-f[[1,10-phenanthroline]) as DNA label has been synthesized and characterized by 1H NMR and mass spectra. The study was carried out by covalent bonding immobilization of porcine aminated DNA probes sequences on screen printed electrode (SPE) modified with succinimide-acrylic microspheres and [Ru(bpy){sub 2}(PIP)]{sup 2+} was used as electrochemical redox intercalator label to detect DNA hybridization event. Electrochemical detection was performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) over the potential range where the ruthenium (II) complex was active. The results indicate that the interaction of [Ru(bpy){sub 2}(PIP)]{sup 2+} with hybridization complementary DNA has higher response compared to single-stranded and mismatch complementary DNA.

Photophysical and physicochemical studies of rare earths complexes formed with calyx(n)arenes

International Nuclear Information System (INIS)

Ramirez, F.M.; Varbanov, S.; Corine, C.; Muller, G.; Fatin-Rouge, N.; Scopelliti, R.; Bunzli J, C.G.

2001-01-01

In this work, some of the photophysical and physicochemical properties are presented which are observed in the rare earths complexes that are formed with diverse functionalized calyx(n)arenes receptors where n=4-6 designed with predetermined properties and synthesized by own methods. (Author)

Synthesis and complexation properties towards uranyl cation of carboxylic acid derivatives of p-tert-butyl-calix[6]arene; Synthese et proprietes complexantes vis-a-vis de l'ion uranyle de derives carboxyliques du p-tert-butyl-calix[6]arene

Energy Technology Data Exchange (ETDEWEB)

Souane, R

2005-03-15

In the fuel reprocessing plants radioactive metals, and more particularly, uranium in UO{sub 2}{sup 2+} form in the various installations, have many varied physico-chemical forms and there is a risk of exposure and internal contamination in the nuclear industry. It is necessary to exert a medical control to ensure the protection of the health of the workers. This medical control is done by dosing uranyl cation in the urine of the exposed people. This work forms part of this context. Indeed, we prepared a ligand able to complex the ion uranyl and which is also to be grafted on a solid support. In the family of calixarenes, the calix[6]arenes functionalized by three or four carboxylic functions were selected like chelating molecules of the ion uranyl. The properties of complexation of these calixarenes were studied by potentiometry in methanol, under these conditions balances of protonation and complexation were determined and the constant partners were obtained using the Hyperquad program. We synthesized tri-carboxylic calix[6]arenes comprising of the groupings nitro (NO{sub 2}) in para position of phenol in order to see the influence of a substitution in para position on the complexation. We also synthesized calix[6]arenes tetra-carboxylic in order to show the role of an additional carboxylic acid grouping. The potentiometric study determined thermodynamic parameters of protonation and complexation of carboxylic calix[6]arenes. The results of the complexation highlighted which complex UO{sub 2}L corresponding to the ligand para-tert-butyl-calix[6]arene tetra-acid is more stable than that corresponding to the ligand mono-nitro calix[6]arene tri-acid ({delta}log{beta}110 = 4.3), and than the effect of the groupings nitro in para position has low influence on the complexation of UO{sub 2}{sup 2+}. This makes it possible to consider as possible the grafting of the calix[6]arenes which one knows the behaviour of trapping. To this end we synthesized the ligand 23

Bidentate urea derivatives of p-tert-butyldihomooxacalix[4]arene: neutral receptors for anion complexation.

Science.gov (United States)

Marcos, Paula M; Teixeira, Filipa A; Segurado, Manuel A P; Ascenso, José R; Bernardino, Raul J; Michel, Sylvia; Hubscher-Bruder, Véronique

2014-01-17

Three new bidentate ureidodihomooxacalix[4]arene derivatives (phenyl 5a, n-propyl 5b, and tert-butyl 5c) were synthesized in four steps from the parent compound p-tert-butyldihomooxacalix[4]arene and obtained in the cone conformation, as shown by NMR studies. The binding ability of these neutral receptors toward spherical, linear, trigonal planar, and tetrahedrical anions was assessed by (1)H NMR and UV-vis titrations. The structures and complexation energies of some complexes were also studied by DFT methods. The data showed that the association constants are strongly dependent on the nature of the substituent (aryl/alkyl) at the urea moiety. In general, for all the receptors, the association constants decrease with decrease of anion basicity. Ph-urea 5a is the best anion receptor, showing the strongest complexation for F(-) (log K(assoc) = 3.10 in CDCl3) and also high binding affinity for the carboxylates AcO(-) and BzO(-). Similar results were obtained by UV-vis studies and were also corroborated by DFT calculations.

Catalytic water oxidation by ruthenium(II) quaterpyridine (qpy) complexes: evidence for ruthenium(III) qpy-N,N'''-dioxide as the real catalysts.

Science.gov (United States)

Liu, Yingying; Ng, Siu-Mui; Yiu, Shek-Man; Lam, William W Y; Wei, Xi-Guang; Lau, Kai-Chung; Lau, Tai-Chu

2014-12-22

Polypyridyl and related ligands have been widely used for the development of water oxidation catalysts. Supposedly these ligands are oxidation-resistant and can stabilize high-oxidation-state intermediates. In this work a series of ruthenium(II) complexes [Ru(qpy)(L)2 ](2+) (qpy=2,2':6',2'':6'',2'''-quaterpyridine; L=substituted pyridine) have been synthesized and found to catalyze Ce(IV) -driven water oxidation, with turnover numbers of up to 2100. However, these ruthenium complexes are found to function only as precatalysts; first, they have to be oxidized to the qpy-N,N'''-dioxide (ONNO) complexes [Ru(ONNO)(L)2 ](3+) which are the real catalysts for water oxidation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photo-induced DNA cleavage and cytotoxicity of a ruthenium(II) arene anticancer complex

Czech Academy of Sciences Publication Activity Database

Brabec, Viktor; Prachařová, J.; Štěpánková, Jana; Sadler, P. J.; Kašpárková, Jana

2016-01-01

Roč. 160, JUL2016 (2016), s. 149-155 ISSN 0162-0134 R&D Projects: GA ČR(CZ) GA14-21053S; GA MŠk(CZ) LD14019 Institutional support: RVO:68081707 Keywords : Ruthenium anticancer complex * DNA cleavage * Phototoxicity Subject RIV: BO - Biophysics Impact factor: 3.348, year: 2016

Relating catalytic activity and electrochemical properties: The case of arene-ruthenium phenanthroline complexes catalytically active in transfer hydrogenation

Czech Academy of Sciences Publication Activity Database

Štěpnička, P.; Ludvík, Jiří; Canivet, J.; Süss-Fink, G.

2006-01-01

Roč. 359, č. 8 (2006), s. 2369-2374 ISSN 0020-1693 R&D Projects: GA AV ČR IAA4040304 Institutional research plan: CEZ:AV0Z40400503 Keywords : arene complexes * chloro complexes * aqua complexes Subject RIV: CG - Electrochemistry Impact factor: 1.674, year: 2006

Visible lights induced polymerization reactions: interactions between rose bengal and iron aren complex

International Nuclear Information System (INIS)

Burget, D.; Grotzinger, C.; Jacques, P.; Fouassier, J.P.

1999-01-01

The present paper is devoted to an investigation of the interactions between Rose Bengal (RB) and an Iron aren (Irg(+)) complex that are usable in visible light induced polymerization reactions. Steady state and flash photolysis experiments were performed in order to elucidate the nature of the intermediates formed after light excitation. A complete scheme of evolution of the excited states is discussed

Glycine Betaine Recognition through Cation−π Interactions in Crystal Structures of Glycine Betaine Complexes with C-Ethyl-pyrogallol[4]arene and C-Ethyl-resorcin[4]arene as Receptors

Directory of Open Access Journals (Sweden)

Ikuhide Fujisawa

2013-04-01

Full Text Available The glycine betaine (betaine, interacts with several types of proteins with diverse structures in vivo, and in the contact regions, the aromatic rings of protein residues are frequently found beside the trimethylammonium group of betaine, implying the importance of the cation−π interactions in recognition of this molecule. The crystal structures determined by X-ray crystallography of the complexes of betaine and C-ethyl-pyrogallol[4]arene (pyrogallol cyclic tetramer: PCT and betaine and C-ethyl-resorcin[4]arene (resorcinol cyclic tetramer: RCT mimic the conformations of betaine and protein complexes and show that the clathrate conformations are retained by the cation−π interactions. The difference of the conformation feature of betaine in the Protein Data Bank and in the Cambridge Structural Database was found by chance during the research and analyzed with the torsion angles.

Organometallic rhodium(III) and iridium(III) cyclopentadienyl complexes with curcumin and bisdemethoxycurcumin co-ligands.

Science.gov (United States)

Pettinari, Riccardo; Marchetti, Fabio; Pettinari, Claudio; Condello, Francesca; Petrini, Agnese; Scopelliti, Rosario; Riedel, Tina; Dyson, Paul J

2015-12-21

A series of half-sandwich cyclopentadienyl rhodium(III) and iridium(III) complexes of the type [Cp*M(curc/bdcurc)Cl] and [Cp*M(curc/bdcurc)(PTA)][SO3CF3], in which Cp* = pentamethylcyclopentadienyl, curcH = curcumin and bdcurcH = bisdemethoxycurcumin as O^O-chelating ligands, and PTA = 1,3,5-triaza-7-phosphaadamantane, is described. The X-ray crystal structures of three of the complexes, i.e. [Cp*Rh(curc)(PTA)][SO3CF3] (5), [Cp*Rh(bdcurc)(PTA)][SO3CF3] (6) and [Cp*Ir(bdcurc)(PTA)][SO3CF3] (8), confirm the expected "piano-stool" geometry. With the exception of 5, the complexes are stable under pseudo-physiological conditions and are moderately cytotoxic to human ovarian carcinoma (A2780 and A2780cisR) cells and also to non-tumorigenic human embryonic kidney (HEK293) cells, but lack the cancer cell selectivity observed for related arene ruthenium(II) complexes.

Synthesis and luminescence of Eu3+ and Tb3+ complexes with novel calix[4]arene ligands carrying 2,2'-bipyridine subunits

International Nuclear Information System (INIS)

Sabbatini, N.; Guardigli, M.; Manet, I.; Ungaro, R.; Casnati, A.; Fischer, C.; Ziessel, R.; Ulrich, G.

1995-01-01

Eu 3+ and Tb 3+ complexes with novel branched calix[4]arene ligands incorporating 2,2' -bipyridine subunits functionalized in the 6- or 5,5'-positions have been synthesized and their photophysical properties investigated. High luminescence intensity was obtained for the Eu 3+ complex of the calix[4]arene ligand carrying four 5,5' -substituted- 2,2' -bipyridines, which has high molar extinction coefficients (ε max 39 600 M -1 cm -1 ) and a high luminescence quantum yield (15%). (authors). 12 refs., 2 figs., 1 tab

Fifty years of oxacalix[3]arenes: A review

Directory of Open Access Journals (Sweden)

Kevin Cottet

2012-02-01

Full Text Available Hexahomotrioxacalix[3]arenes, commonly called oxacalix[3]arenes, were first reported in 1962. Since then, their chemistry has been expanded to include numerous derivatives and complexes. This review describes the syntheses of the parent compounds, their derivatives, and their complexation behaviour towards cations. Extraction data are presented, as are crystal structures of the macrocycles and their complexes with guest species. Applications in fields as diverse as ion selective electrode modifiers, fluorescence sensors, fullerene separations and biomimetic chemistry are described.

Two related lithium calixarene complexes, [p-tert-butylcalix[4]arene(OMe)(OH)2(OLi)](2).4MeCN and {p-tert-butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}(2).8MeCN, determined using synchrotron radiation.

Science.gov (United States)

Lee, Darren S; Elsegood, Mark R J; Redshaw, Carl; Zhan, Shuzhong

2009-08-01

The crystal structures of acetonitrile solvates of two related lithium calixarene complexes have been determined by low-temperature single-crystal X-ray diffraction using synchrotron radiation. Bis(mu-5,11,17,23-tetra-tert-butyl-26,28-dihydroxy-25-methoxy-27-oxidocalix[4]arene)dilithium(I) acetonitrile tetrasolvate, [Li2(C45H57O4)2].4C2H3N or [p-tert-butylcalix[4]arene(OMe)(OH)2(OLi)](2).4MeCN, (I), crystallizes with the complex across a centre of symmetry and with four molecules of unbound acetonitrile of crystallization per complex. Tetraacetonitrilebis(mu-5,11,17,23-tetra-tert-butyl-26,28-dihydroxy-25,27-dioxidocalix[4]arene)tetralithium(I) acetonitrile octasolvate, [Li4(C44H54O4)2(C2H3N)4].8C2H3N or {p-tert-butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}(2).8MeCN, (II), also crystallizes with the complex lying across a centre of symmetry and contains eight molecules of unbound acetonitrile per complex plus four more directly bound to two of the lithium ions, two on each ion. The cores of both complexes are partially supported by O-H...O hydrogen bonds. The methoxy methyl groups in (I) prevent the binding of any more than two Li+ ions, while the corresponding two O-atom sites in (II) bind an extra Li(+) ion each, making four in total. The calixarene cone adopts an undistorted cone conformation in (I), but an elliptical one in (II).

Reactivity studies of eta sup (6)-p-cymene ruthenium(II) carboxylato complexes towards azide some neutral ligands

Digital Repository Service at National Institute of Oceanography (India)

Singh, K.S.; Kollipara, M.R.

sub (2)O sub (4)(7) or C sub (2)CH sub (2)O sub (4)(10)] have been prepared by the reaction of [(p-cymene)RuCl sub (2)]sub (2) with the corresponding sodium salts of the carboxylic acids. Treatment of (eta sup (6)-p-cymene) ruthenium(II) carboxylato...

Arene-mercury complexes stabilized by gallium chloride: relative rates of H/D and arene exchange.

Science.gov (United States)

Branch, Catherine S; Barron, Andrew R

2002-11-27

We have previously proposed that the Hg(arene)(2)(GaCl(4))(2) catalyzed H/D exchange reaction of C(6)D(6) with arenes occurs via an electrophilic aromatic substitution reaction in which the coordinated arene protonates the C(6)D(6). To investigate this mechanism, the kinetics of the Hg(C(6)H(5)Me)(2)(GaCl(4))(2) catalyzed H/D exchange reaction of C(6)D(6) with naphthalene has been studied. Separate second-order rate constants were determined for the 1- and 2-positions on naphthalene; that is, the initial rate of H/D exchange = k(1i)[Hg][C-H(1)] + k(2i)[Hg][C-H(2)]. The ratio of k(1i)/k(2i) ranges from 11 to 2.5 over the temperature range studied, commensurate with the proposed electrophilic aromatic substitution reaction. Observation of the reactions over an extended time period shows that the rates change with time, until they again reach a new and constant second-order kinetics regime. The overall form of the rate equation is unchanged: final rate = k(1f)[Hg][C-H(1)] + k(2f)[Hg][C-H(2)]. This change in the H/D exchange is accompanied by ligand exchange between Hg(C(6)D(6))(2)(GaCl(4))(2) and naphthalene to give Hg(C(10)H(8))(2)(GaCl(4))(2,) that has been characterized by (13)C CPMAS NMR and UV-visible spectroscopy. The activation parameters for the ligand exchange may be determined and are indicative of a dissociative reaction and are consistent with our previously calculated bond dissociation for Hg(C(6)H(6))(2)(AlCl(4))(2). The initial Hg(arene)(2)(GaCl(4))(2) catalyzed reaction of naphthalene with C(6)D(6) involves the deuteration of naphthalene by coordinated C(6)D(6); however, as ligand exchange progresses, the pathway for H/D exchange changes to where the protonation of C(6)D(6) by coordinated naphthalene dominates. The site selectivity for the H/D exchange is initially due to the electrophilic aromatic substitution of naphthalene. As ligand exchange occurs, this selectivity is controlled by the activation of the naphthalene C-H bonds by mercury.

New ruthenium(II) carbonyl complexes bearing disulfide Schiff base ligands and their applications as catalyst for some organic transformations

Science.gov (United States)

Prakash, Govindan; Viswanathamurthi, Periasamy

2014-08-01

Schiff base disulfide ligands (H2L1-6) were synthesized from the condensation of cystamine with salicylaldehyde(H2L1), 5-chlorosalicylaldehyde(H2L2), o-vanillin(H2L3), 2-hydroxyacetophenone(H2L4), 3-methyl-2-hydroxyacetophenone(H2L5), and 2-hydroxy-1-naphthaldehyde(H2L6). H2L1-6 reacts with the ruthenium precursor complex [RuHCl(CO)(PPh3)3] in benzene giving rise to six new ruthenium(II) complexes of general formula [Ru(CO)L1-6]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV-Vis, NMR (1H and 13C) and Mass) techniques. An octahedral geometry was assigned for all the complexes based on the spectral data obtained. The catalytic efficiency of the new complexes in aldehyde to amide conversion in the presence of NaHCO3, N-alkylation of aniline in the presence of t-BuOK, and transfer hydrogenation of ketones in the presence of iPrOH/KOH reactions were studied. Furthermore, the effect of solvents and catalyst/substrate ratio on the catalytic aldehyde to amide conversion were also discussed.

A ruthenium(II) complex inhibits tumor growth in vivo with fewer side-effects compared with cisplatin.

Science.gov (United States)

Wang, Jin-Quan; Zhang, Ping-Yu; Ji, Liang-Nian; Chao, Hui

2015-05-01

The antitumor activity of a ruthenium(II) polypyridyl complex, Δ-[Ru(bpy)2(HPIP)](ClO4)2 (Δ-Ru1, where bpy=2,2'-bipyridine, HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline), was evaluated. The in vivo experiments showed that Δ-Ru1 inhibited the growth of a human cervical carcinoma cell line (HeLa) xenotransplanted into nude mice with efficiency similar to that of cisplatin. Histopathology examination of the tumors from treated xenograft models was consistent with apoptosis in tumor cells. Importantly, in striking contrast with cisplatin, Δ-Ru1 did not cause any detectable side effects on the kidney, liver, peripheral neuronal system, or the hematological system at the pharmacologically effective dose. The preclinical studies reported here provide support for the clinical use of Δ-Ru1 as an exciting new drug candidate with lower toxicity than cisplatin, endowed with proapoptotic properties. Copyright © 2015 Elsevier Inc. All rights reserved.

Influence of halogen substitution in the ligand sphere on the antitumor and antibacterial activity of half-sandwich ruthenium(II) complexes [RuX(η{sup 6}-arene)(C{sub 5}H{sub 4}N-2-cH=N-Ar)]{sup +}

Energy Technology Data Exchange (ETDEWEB)

Gichumbi, Joel M.; Omondi, Bernard; Friedrich, Holger B. [School of Chemistry, University of KwaZulu-Natal, Durban (South Africa); Lazarus, Geraldine; Singh, Moganavelli; Shaikh, Nazia; Chenia, Hafizah Y. [School of Life Sciences, University of KwaZulu-Natal, Durban (South Africa)

2017-06-01

New complexes [(η{sup 6}-p-cymene)Ru(C{sub 5}H{sub 4}N-2-CH=N-Ar)X]PF{sub 6} [X = Br (1), I (2); Ar = 4-fluorophenyl (a), 4-chlorophenyl (b), 4-bromophenyl (c), 4-iodophenyl (d), 2,5-dichlorophenyl (e)] were prepared, as well as 3a-3e (X = Cl) and the new complexes [(η{sup 6}-arene)RuCl(N-N)]PF{sub 6} [arene = C{sub 6}H{sub 5}OCH{sub 2}CH{sub 2}OH, N-N = 2,2{sup '}-bipyridine (4), 2,6-(dimethylphenyl)-pyridin-2-yl-methylene amine (5), 2,6-(diisopropylphenyl)-pyridin-2-yl-methylene amine (6); arene = p-cymene, N-N = 4-(aminophenyl)-pyridin-2-yl-methylene amine (7)]. X-ray diffraction studies were performed for 1a, 1b, 1c, 1d, 2b, 5, and 7. Cytotoxicities of 1a-1d and 2 were established versus human cancer cells epithelial colorectal adenocarcinoma (Caco-2) (IC{sub 50}: 35.8-631.0 μM), breast adenocarcinoma (MCF7) (IC{sub 50}: 36.3-128.8.0 μM), and hepatocellular carcinoma (HepG2) (IC{sub 50}: 60.6-439.8 μM), 3a-3e were tested against HepG2 and Caco-2, and 4-7 were tested against Caco-2. 1-7 were tested against non-cancerous human epithelial kidney cells. 1 and 2 were more selective towards tumor cells than the anticancer drug 5-fluorouracil (5-FU), but 3a-3e (X = Cl) were not selective. 1 and 2 had good activity against MCF7, some with lower IC{sub 50} than 5-FU. Complexes with X = Br or I had moderate activity against Caco-2 and HepG2, but those with Cl were inactive. Antibacterial activities of 1a, 2b, 3a, and 7 were tested against antibacterial susceptible and resistant Gram-negative and -positive bacteria. 1a, 2b, and 3a showed activity against methicillin-resistant S. aureus (MIC = 31-2000 μg.mL{sup -1}). (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Crystal structure of a supramolecular lithium complex of p-tert-butylcalix[4]arene

Directory of Open Access Journals (Sweden)

Manabu Yamada

2018-05-01

Full Text Available Crystals of a supramolecular lithium complex with a calix[4]arene derivative, namely tetramethanollithium 5,11,17,23-tetra-tert-butyl-25,26,27-trihydroxy-28-oxidocalix[4]arene methanol monosolvate, [Li(CH3OH4](C44H55O4·CH3OH or [Li(CH3OH4]+·(calix[4]arene−]·CH3OH (where calix[4]arene− represents a mono-anion species because of deprotonation of one H atom of the calixarene hydroxy groups, were obtained from p-tert-butylcalix[4]arene reacted with LiH in tetrahydrofuran, followed by recrystallization from methanol. The asymmetric unit comprises one mono-anionic calixarene molecule, one Li+ cation coordinated to four methanol molecules, and one methanol molecule included in the calixarene cavity. The calixarene molecule maintains a cone conformation by intramolecular hydrogen bonding between one phenoxide (–O− and three pendent calixarene hydroxy groups (–OH. The coordinated methanol molecules around the metal cation play a significant role in forming the supramolecular assembly. The crystal structure of this assembly is stabilized by three sets of intermolecular interactions: (i hydrogen bonds involving the –OH and –O− moieties of the calixarene molecules, the –OH groups of the coordinated methanol molecules, and the –OH group of the methanol molecule included in the calixarene cavity; (ii C—H...π interactions between the calixarene molecules and/or the coordinated methanol molecules; (iii O—H...π interactions between the calixarene molecule and the included methanol molecule.

X-Ray structure and cytotoxic activity of a picolinate ruthenium(II–arene complex

Directory of Open Access Journals (Sweden)

IVANKA IVANOVIĆ

2011-01-01

Full Text Available A ruthenium(II–arene complex with picolinic acid, [(η6-p-cymeneRuCl(pico]∙H2O, was prepared by the reaction of [(η6-p-cymeneRuCl2]2 with picolinic acid in a 1:2 molar ratio in 2-propanol. The compound was characterized by elemental analysis, and IR and NMR spectroscopy. X-ray diffraction analysis showed that the molecule adopts a “three-leg piano-stool” geometry, which is common for this type of complexes. The cytotoxic activity of the complex was tested in two human cancer cell lines HeLa (cervix and FemX (melanoma by MTT assay. The IC50 values were at 82.0 and 36.2 µmol dm-3 for HeLa and FemX cells, respectively.

Ruthenium(II) arene complexes with chelating chloroquine analogue ligands: Synthesis, characterization and in vitro antimalarial activity†

Science.gov (United States)

Glans, Lotta; Ehnbom, Andreas; de Kock, Carmen; Martínez, Alberto; Estrada, Jesús; Smith, Peter J.; Haukka, Matti; Sánchez-Delgado, Roberto A.; Nordlander, Ebbe

2012-01-01

Three new ruthenium complexes with bidentate chloroquine analogue ligands, [Ru(η6-cym)(L1)Cl]Cl (1, cym = p-cymene, L1 = N-(2-((pyridin-2-yl)methylamino)ethyl)-7-chloroquinolin-4-amine), [Ru(η6-cym)(L2)Cl]Cl (2, L2 = N-(2-((1-methyl-1H-imidazol-2-yl)methylamino)ethyl)-7-chloroquinolin-4-amine) and [Ru(η6-cym)(L3)Cl] (3, L3 = N-(2-((2-hydroxyphenyl)methylimino)ethyl)-7-chloroquinolin-4-amine) have been synthesized and characterized. In addition, the X-ray crystal structure of 2 is reported. The antimalarial activity of complexes 1–3 and ligands L1, L2 and L3, as well as the compound N-(2-(bis((pyridin-2-yl)methyl)amino)ethyl)-7-chloroquinolin-4-amine (L4), against chloroquine sensitive and chloroquine resistant Plasmodium falciparum malaria strains was evaluated. While 1 and 2 are less active than the corresponding ligands, 3 exhibits high antimalarial activity. The chloroquine analogue L2 also shows good activity against both the choloroquine sensitive and the chloroquine resistant strains. Heme aggregation inhibition activity (HAIA) at an aqueous buffer/n-octanol interface (HAIR50) and lipophilicity (D, as measured by water/n-octanol distribution coefficients) have been measured for all ligands and metal complexes. A direct correlation between the D and HAIR50 properties cannot be made because of the relative structural diversity of the complexes, but it may be noted that these properties are enhanced upon complexation of the inactive ligand L3 to ruthenium, to give a metal complex (3) with promising antimalarial activity. PMID:22249579

Stability of the ammonium-p-tert-butylcalix[4]arene-tetrakis (N,N-diethylacetamide) complex in nitrobenzene saturated with water

International Nuclear Information System (INIS)

Makrlik, E.

2006-01-01

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium NH 4 + (aq)+NaL + (nb) ↔ NH 4 L + (nb)+Na + (aq) taking place in the two-phase water-nitrobenzene system (L = p-tert-butylcalix[4]arene-tetrakis (N,N-diethylacetamide); aq = aqueous phase, nb = nitrobenzene phase) was evaluated as logK ex (NH 4 + ,NaL + ) = -1.8. Further, the stability constant of the p-tert-butylcalix[4]arene-tetrakis (N,N-diethylacetamide)-ammonium complex in nitrobenzene saturated with water was calculated for a temperature of 25 deg C: logβ nb (NH 4 L + ) = 6.7. (author)

Noncovalent Complexation of Monoamine Neurotransmitters and Related Ammonium Ions by Tetramethoxy Tetraglucosylcalix[4]arene

Science.gov (United States)

Torvinen, Mika; Kalenius, Elina; Sansone, Francesco; Casnati, Alessandro; Jänis, Janne

2012-02-01

The noncovalent complexation of monoamine neurotransmitters and related ammonium and quaternary ammonium ions by a conformationally flexible tetramethoxy glucosylcalix[4]arene was studied by electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry. The glucosylcalixarene exhibited highest binding affinity towards serotonin, norepinephrine, epinephrine, and dopamine. Structural properties of the guests, such as the number, location, and type of hydrogen bonding groups, length of the alkyl spacer between the ammonium head-group and the aromatic ring structure, and the degree of nitrogen substitution affected the complexation. Competition experiments and guest-exchange reactions indicated that the hydroxyl groups of guests participate in intermolecular hydrogen bonding with the glucocalixarene.

Binding properties of oxacalix[4]arenes derivatives toward metal cations; Interactions entre cations metalliques et derives des oxacalix[4]arenes

Energy Technology Data Exchange (ETDEWEB)

Mellah, B

2006-11-15

The objective of this work was to establish the binding properties of oxacalix[4]arene derivatives with different numbers of the oxa bridges, functional groups (ketones, pyridine, ester, amide and methoxy) and conformations. Their interactions with alkali and alkaline-earth, heavy and transition metal cations have been evaluated according to different approaches: (i) extraction of corresponding picrates from an aqueous phase into dichloromethane; (ii) determination of the thermodynamic parameters of complexation in methanol and/or acetonitrile by UV-spectrophotometry and micro-calorimetry; (iii) determination of the stoichiometry of the complexes by ESI-MS; (iv) {sup 1}H-NMR titrations allowing to localize the metal ions in the ligand cavity. In a first part dealing on homo-oxacalix[4]arenes, selectivities for Na{sup +}, K{sup +}, Ca{sup 2+}, Pb{sup 2+} and Mn{sup 2+} of ketones derivatives was shown. The presence of oxa bridge in these derivatives increases their efficiency while decreasing their selectivity with respect to related calixarenes. The pyridine derivative prefers transition and heavy metal cations, in agreement with the presence of the soft nitrogen atoms. In the second part, di-oxacalix[4]arene ester and secondary amide derivatives were shown to be less effective than tertiary amide counterparts but to present high selectivities for Li{sup +}, Ba{sup 2+}, Zn{sup 2+} and Hg{sup 2+}. A third part devoted to the octa-homo-tetra-oxacalix[4]arene tetra-methoxy shows that the 1:1 metal complexes formed are generally more stable than those of calixarenes, suggesting the participation of the oxygen atoms of the bridge in the complexation. Selectivity for Cs{sup +}, Ba{sup 2+}, Cu{sup 2+} and Hg{sup 2+} were noted. (author)

SYNTHESIS OF TETRA-p-PROPENYLTETRAESTERCALIX[4]ARENE AND TETRA-p-PROPENYLTETRACARBOXYLICACIDCALIX[4]ARENE FROM p-t-BUTYLPHENOL

Directory of Open Access Journals (Sweden)

Triana Kusumaningsih

2010-06-01

Full Text Available A research has been conducted to synthesize tetra-p-propenyltetraestercalix[4]arene and tetra-p-propenyltetracarboxylicacidcalix[4] arene using p-t-butylphenol as a starting material. The synthesis was carried out in following stages, i.e (1 synthesis of p-t-butylcalix[4]arene from p-t-butylphenol, (2 debutylation of p-t-butylcalix[4]arene, (3 tetraallilation of 25,26,27,28-tetrahydroxycalix[4]arene with NaH and allilbromida in dry tetrahydrofuran, (4 Claissen rearrangement of 25,26,27,28-tetrapropenyloxycalix[4]arene, (5 esterification of tetra-p-propenyltetrahydroxycalix[4]arene, (6 hydrolisis of tetra-p-propenyltetraestercalix[4]arene. The all structures of products were observed by means of melting point, FTIR, and 1H-NMR spectrometers. Tetra-p-propenyltetraestercalix[4]arene compound was obtained as yellow liquid product in 55.08% yield. Tetra-p-propenyltetracarboxylicacidcalix[4]arene compound was obtained as white solid product with the melting point 135-137 °C at decomposed and in 70.05% yield.   Keywords: calix[4]arene, Claissen rearrangement, esterification, hydrolisis

Molecular recognition study of ethosuximide by the supramolecular probe, p-t-butyl calix(8)arene

Energy Technology Data Exchange (ETDEWEB)

Meenakshi, C., E-mail: geethu.laxi@gmail.com [Department of Chemistry, Shri Meenakshi Government College for Women (Autonomous), Madurai 625002 (India); Sangeetha, P.; Ramakrishnan, V. [Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai 625021 (India)

2013-06-15

The supramolecule, p-t-Butyl calix(8)arene, forms inclusion complex with the antiseizure drug molecule, ethosuximide. This feature is explained on the basis of optical absorption spectroscopy. Here p-t-Butyl calix(8)arene is the host molecule and ethosuximide is the guest molecule. The stoichiometry of the host–guest complex and the binding constant has been determined using Benesi–Hildebrand plot. Based on the result obtained the structure of the inclusion complex has been proposed. -- Highlights: ► Third generation supramolecule, t-butyl calix (8) arene, is used as a host molecule. ► Anti seizure drug molecule is used as a guest molecule. ► Inclusion complex is formed between the host and guest molecule.

Ruthenium(II) carbonyl compounds with the 4'-chloro-2,2':6',2''-terpyridine ligand.

Science.gov (United States)

Tatikonda, Rajendhraprasad; Haukka, Matti

2017-04-01

Two ruthenium carbonyl complexes with the 4'-chloro-2,2':6',2''-terpyridine ligand (tpy-Cl, C 15 H 10 ClN 3 ), i.e. [RuCl(tpy-Cl)(CO) 2 ][RuCl 3 (CO) 3 ] (I) [systematic name: cis -di-carbonyl-chlorido(4'-chloro-2,2':6',2''-terpyridine-κ 3 N )ruthenium(II) fac -tricarbonyltri-chlorido-ruthenate(II)], and [RuCl 2 (tpy-Cl)(CO) 2 ] (II) [ cis -dicarbonyl- trans -di-chlorido(4'-chloro-2,2':6',2''-terpyridine-κ 2 N 1 , N 1' )ruthenium(II)], were synthesized and characterized by single-crystal X-ray diffraction. The Ru II atoms in both centrosymmetric structures (I) and (II) display similar, slightly distorted octa-hedral coordination spheres. The coordination sphere in the complex cation in compound (I) is defined by three N atoms of the tridentate tpy-Cl ligand, two carbonyl carbon atoms and one chlorido ligand; the charge is balanced by an octa-hedral [Ru(CO) 3 Cl 3 ] - counter-anion. In the neutral compound (II), the tpy-Cl ligand coordinates to the metal only through two of its N atoms. The coordination sphere of the Ru II atom is completed by two carbonyl and two chlorido ligands. In the crystal structures of both (I) and (II), weak C-H⋯Cl inter-actions are observed.

Ruthenium(II) 2,2'-bibenzimidazole complex as a second-sphere receptor for anions interaction and colorimeter.

Science.gov (United States)

Cui, Ying; Niu, Yan-Li; Cao, Man-Li; Wang, Ke; Mo, Hao-Jun; Zhong, Yong-Rui; Ye, Bao-Hui

2008-07-07

A ruthenium(II) complex [Ru(bpy) 2(H 2bbim)](PF 6) 2 ( 1) as anions receptor has been exploited, where Ru(II)-bpy moiety acts as a chromophore and the H 2bbim ligand as an anion binding site. A systematic study suggests that 1 interacts with the Cl (-), Br (-), I (-), NO 3 (-), HSO 4 (-), and H 2PO 4 (-) anions via the formation of hydrogen bonds. Whereas 1 undergoes a stepwise process with the addition of F (-) and OAc (-) anions: formation of the monodeprotonated complex [Ru(bpy) 2(Hbbim)] with a low anion concentration, followed by the double-deprotonated complex [Ru(bpy) 2(bbim)], in the presence of a high anion concentration. These stepwise processes concomitant with the changes of vivid colors from yellow to orange brown and then to violet can be used for probing the F (-) and OAc (-) anions by naked eye. The deprotonation processes are not only determined by the basicity of the anion but also related to the strength of hydrogen bonding, as well as the stability of the formed compounds. Moreover, a double-deprotonated complex [Ru(bpy) 2(bbim)].CH 3OH.H 2O ( 3) has been synthesized, and the structural changes induced by the deprotonation has also been investigated. In addition, complexes [Ru(bpy) 2(Hbbim)] 2(HOAc) 3Cl 2.12H 2O ( 2), [Ru(bpy) 2(Hbbim)](HCCl 3CO 2)(CCl 3CO 2).2H 2O ( 4), and [Ru(bpy) 2(H 2bbim)](CF 3CO 2) 2.4H 2O ( 5) have been synthesized to observe the second sphere coordination between the Ru(II)-H 2bbim moiety and carboxylate groups via hydrogen bonds in the solid state.

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

Science.gov (United States)

Mayer, Florian; Tiruvadi Krishnan, Sriram; Schühle, Daniel T.; Eliseeva, Svetlana V.; Petoud, Stéphane; Tóth, Éva; Djanashvili, Kristina

2018-01-01

Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analogue substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth). We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analogue demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behaviour. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Post-synthetic modification of mesoporous zinc-adeninate framework with tris(2,2′-biprydine) ruthenium(II) complex and its electrochemiluminescence

Energy Technology Data Exchange (ETDEWEB)

Park, Ji Eun; Shin, Ik Soo [Dept. of Chemistry, Soongsil University, Seoul (Korea, Republic of); Oh, Hye Jae; An, Ji Hyun [Dept. of Chemistry Education, Seoul National University, Seoul (Korea, Republic of)

2017-04-15

Herein we report a redox-active metal-organic framework (MOF) via post-synthetic cation exchange with tris(2,2′-biprydine) ruthenium(II) complex (Ru(bpy){sub 3}{sup 2+}). A porous anionic zinc-adeninate framework (bMOF-100) is spacious enough to easily entrap 2.43 of Ru(bpy){sub 3}{sup 2+} cations within the mesopore. The encapsulation supported the framework structure preventing any distortion from a rapid solvent evaporation under SEM observation. Ru(bpy){sub 3}{sup 2+}@bMOF-100 was then immobilized on the surface of glassy carbon electrode, and its electrocatalytic and electrochemiluminescent (ECL) properties were investigated in aqueous and organic solution. Especially, Ru(bpy){sub 3}{sup 2+}@bMOF-100 showed the excellent electrochemical properties of Ru(bpy){sub 3}{sup 2+}, but gradual decomposition of the MOF structure was observed under electrochemical measurements because of the sluggish oxidation of adeninate ligand.

Complexation of the cesium cation with 1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown-6

Czech Academy of Sciences Publication Activity Database

Makrlík, E.; Dybal, Jiří; Vaňura, P.

2013-01-01

Roč. 295, č. 2 (2013), s. 1299-1303 ISSN 0236-5731 R&D Projects: GA ČR GA203/09/1478 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : cesium cation * substituted calix[4]arene-crown-6 * complexation Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.415, year: 2013

Binding properties of oxacalix[4]arenes derivatives toward metal cations

International Nuclear Information System (INIS)

Mellah, B.

2006-11-01

The objective of this work was to establish the binding properties of oxacalix[4]arene derivatives with different numbers of the oxa bridges, functional groups (ketones, pyridine, ester, amide and methoxy) and conformations. Their interactions with alkali and alkaline-earth, heavy and transition metal cations have been evaluated according to different approaches: (i) extraction of corresponding picrates from an aqueous phase into dichloromethane; (ii) determination of the thermodynamic parameters of complexation in methanol and/or acetonitrile by UV-spectrophotometry and micro-calorimetry; (iii) determination of the stoichiometry of the complexes by ESI-MS; (iv) 1 H-NMR titrations allowing to localize the metal ions in the ligand cavity. In a first part dealing on homo-oxacalix[4]arenes, selectivities for Na + , K + , Ca 2+ , Pb 2+ and Mn 2+ of ketones derivatives was shown. The presence of oxa bridge in these derivatives increases their efficiency while decreasing their selectivity with respect to related calixarenes. The pyridine derivative prefers transition and heavy metal cations, in agreement with the presence of the soft nitrogen atoms. In the second part, di-oxacalix[4]arene ester and secondary amide derivatives were shown to be less effective than tertiary amide counterparts but to present high selectivities for Li + , Ba 2+ , Zn 2+ and Hg 2+ . A third part devoted to the octa-homo-tetra-oxacalix[4]arene tetra-methoxy shows that the 1:1 metal complexes formed are generally more stable than those of calixarenes, suggesting the participation of the oxygen atoms of the bridge in the complexation. Selectivity for Cs + , Ba 2+ , Cu 2+ and Hg 2+ were noted. (author)

Ruthenium(II) bipyridine complexes bearing quinoline-azoimine (NN'N″) tridentate ligands: synthesis, spectral characterization, electrochemical properties and single-crystal X-ray structure analysis.

Science.gov (United States)

Al-Noaimi, Mousa; Abdel-Rahman, Obadah S; Fasfous, Ismail I; El-khateeb, Mohammad; Awwadi, Firas F; Warad, Ismail

2014-05-05

Four octahedral ruthenium(II) azoimine-quinoline complexes having the general molecular formula [Ru(II)(L-Y)(bpy)Cl](PF6) {L-Y=YC6H4N=NC(COCH3)=NC9H6N, Y=H (1), CH3 (2), Br (3), NO2 (4) and bpy=2,2'-bipyrdine} were synthesized. The azoimine-quinoline based ligands behave as NN'N″ tridentate donors and coordinated to ruthenium via azo-N', imine-N' and quinolone-N″ nitrogen atoms. The composition of the complexes has been established by elemental analysis, spectral methods (FT-IR, electronic, (1)H NMR, UV/Vis and electrochemical (cyclic voltammetry) techniques. The crystal structure of complex 1 is reported. The Ru(II) oxidation state is greatly stabilized by the novel tridentate ligands, showing Ru(III/II) couples ranging from 0.93-1.27 V vs. Cp2Fe/Cp2Fe(+). The absorption spectrum of 1 in dichloromethane was modeled by time-dependent density functional theory (TD-DFT). Copyright © 2014 Elsevier B.V. All rights reserved.

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

Directory of Open Access Journals (Sweden)

Florian Mayer

2018-01-01

Full Text Available Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analog substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth. We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analog demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behavior. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Insights into the Intramolecular Properties of η6-Arene-Ru-Based Anticancer Complexes Using Quantum Calculations

Directory of Open Access Journals (Sweden)

Adebayo A. Adeniyi

2013-01-01

Full Text Available The factors that determine the stability and the effects of noncovalent interaction on the η6-arene ruthenium anticancer complexes are determined using DFT method. The intramolecular and intra-atomic properties were computed for two models of these half-sandwich ruthenium anticancer complexes and their respective hydrated forms. The results showed that the stability of these complexes depends largely on the network of hydrogen bonds (HB, strong nature of charge transfer, polarizability, and electrostatic energies that exist within the complexes. The hydrogen bonds strength was found to be related to the reported anticancer activities and the activation of the complexes by hydration. The metal–ligand bonds were found to be closed shell systems that are characterised by high positive Laplacian values of electron density. Two of the complexes are found to be predominantly characterised by LMCT while the other two are predominately characterised by MLCT.

Design and synthesis of ruthenium(II) OCO pincer type NHC ...

Indian Academy of Sciences (India)

The tridentate nature of the tBu(OCO)2− ligand as well as some level of steric protection ... our previous results of ruthenium(II) o-hydroxyaryl sub- stituted bidentate NHC ...... (a) Ribelin T, Katz C E, English D G, Smith S,. Manukyan A K, Day ...

Solvation Effect on Complexation of Alkali Metal Cations by a Calix[4]arene Ketone Derivative.

Science.gov (United States)

Požar, Josip; Nikšić-Franjić, Ivana; Cvetnić, Marija; Leko, Katarina; Cindro, Nikola; Pičuljan, Katarina; Borilović, Ivana; Frkanec, Leo; Tomišić, Vladislav

2017-09-14

The medium effect on the complexation of alkali metal cations with a calix[4]arene ketone derivative (L) was systematically examined in methanol, ethanol, N-methylformamide, N,N-dimethylformamide, dimethyl sulfoxide, and acetonitrile. In all solvents the binding of Na + cation by L was rather efficient, whereas the complexation of other alkali metal cations was observed only in methanol and acetonitrile. Complexation reactions were enthalpically controlled, while ligand dissolution was endothermic in all cases. A notable influence of the solvent on NaL + complex stability could be mainly attributed to the differences in complexation entropies. The higher NaL + stability in comparison to complexes with other alkali metal cations in acetonitrile was predominantly due to a more favorable complexation enthalpy. The 1 H NMR investigations revealed a relatively low affinity of the calixarene sodium complex for inclusion of the solvent molecule in the calixarene hydrophobic cavity, with the exception of acetonitrile. Differences in complex stabilities in the explored solvents, apart from N,N-dimethylformamide and acetonitrile, could be mostly explained by taking into account solely the cation and complex solvation. A considerable solvent effect on the complexation equilibria was proven to be due to an interesting interplay between the transfer enthalpies and entropies of the reactants and the complexes formed.

Arene ruthenium(II) azido complexes incorporating N intersection O chelate ligands: Synthesis, spectral studies and 1,3-dipolar-cycloaddition to a coordinated azide in ruthenium(II) compounds

Digital Repository Service at National Institute of Oceanography (India)

Singh, K.S.; Kaminsky, W.

showed a slightly different spectra pattern for p- cymene ligand as compared to the rest of the complexes. For instant, the complex 1 exhibits two doublets for diastereotopic methyl protons of the isopropyl group at around δ 1.12-0.99 (Fig. 1). Likewise... formed are exclusively N(2) bound isomer which is supported by their NMR spectral data. For instant, the proton NMR spectrum of 8 displayed a, singlet at δ 3.75 assignable to the protons of a methoxy carbonyl group while for complex 9 a quartet...

Intramolecularly bridged calix[4]arenes with pronounced complexation ability toward neutral compounds

Czech Academy of Sciences Publication Activity Database

Slavík, P.; Eigner, Václav; Lhoták, P.

2015-01-01

Roč. 17, č. 11 (2015), s. 2788-2791 ISSN 1523-7060 Institutional support: RVO:68378271 Keywords : calix[4]arene * mercuration * brigding * x-ray crystallography * Jana2006 Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 6.732, year: 2015

A new probe of solvent accessibility of bound photosensitizers. 1. Ruthenium(II) and osmium(II) photosensitizers in sodium lauryl sulfate micelles

International Nuclear Information System (INIS)

Hauenstein, B.L. Jr.; Dressick, W.J.; Buell, S.L.; Demas, J.N.; DeGraff, B.A.

1983-01-01

A new method of measuring solvent accessibility of photosensitizers bound to organized media is presented. In particular, the solvent accessibility of a series of ruthenium(II) and osmium(II) photosensitizers bound to sodium lauryl sulfate micelles has been determined. The method takes advantage of the large solvent deuterium effect on the excited-state lifetimes of these complexes. The solvent accessibility of the bound complexes correlates with the hydrophobicity of the ligands. The potential application of this method to a variety of other systems is mentioned

In vitro evaluation of the cyto-genotoxic potential of Ruthenium(II) SCAR complexes: a promising class of antituberculosis agents.

Science.gov (United States)

De Grandis, Rone Aparecido; Resende, Flávia Aparecida; da Silva, Monize Martins; Pavan, Fernando Rogério; Batista, Alzir Azevedo; Varanda, Eliana Aparecida

2016-03-01

Tuberculosis is a top infectious disease killer worldwide, caused by the bacteria Mycobacterium tuberculosis. Increasing incidences of multiple drug-resistance (MDR) strains are emerging as one of the major public health threats. However, the drugs in use are still incapable of controlling the appalling upsurge of MDR. In recent years a marked number of research groups have devoted their attention toward the development of specific and cost-effective antimicrobial agents against targeted MDR-Tuberculosis. In previous studies, ruthenium(II) complexes (SCAR) have shown a promising activity against MDR-Tuberculosis although few studies have indeed considered ruthenium toxicity. Therefore, within the preclinical requirements, we have sought to determine the cyto-genotoxicity of three SCAR complexes in this present study. The treatment with the SCARs induced a concentration-dependent decrease in cell viability in CHO-K1 and HepG2 cells. Based on the clonogenic survival, SCAR 5 was found to be more cytotoxic while SCAR 6 exhibited selectivity action on tumor cells. Although SCAR 4 and 5 did not indicate any mutagenic activity as evidenced by the Ames and Cytokinesis block micronucleus cytome assays, the complex SCAR 6 was found to engender a frameshift mutation detected by Salmonella typhimurium in the presence of S9. Similarly, we observed a chromosomal damage in HepG2 cells with significant increases of micronuclei and nucleoplasmic bridges. These data indicate that SCAR 4 and 5 complexes did not show genotoxicity in our models while SCAR 6 was considered mutagenic. This study presented a comprehensive genotoxic evaluation of SCAR complexes were shown to be genotoxic in vitro. All in all, further studies are required to fully elucidate how the properties can affect human health. Copyright © 2016 Elsevier B.V. All rights reserved.

The role of uranium-arene bonding in H2O reduction catalysis

Science.gov (United States)

Halter, Dominik P.; Heinemann, Frank W.; Maron, Laurent; Meyer, Karsten

2018-03-01

The reactivity of uranium compounds towards small molecules typically occurs through stoichiometric rather than catalytic processes. Examples of uranium catalysts reacting with water are particularly scarce, because stable uranyl groups form that preclude the recovery of the uranium compound. Recently, however, an arene-anchored, electron-rich uranium complex has been shown to facilitate the electrocatalytic formation of H2 from H2O. Here, we present the precise role of uranium-arene δ bonding in intermediates of the catalytic cycle, as well as details of the atypical two-electron oxidative addition of H2O to the trivalent uranium catalyst. Both aspects were explored by synthesizing mid- and high-valent uranium-oxo intermediates and by performing comparative studies with a structurally related complex that cannot engage in δ bonding. The redox activity of the arene anchor and a covalent δ-bonding interaction with the uranium ion during H2 formation were supported by density functional theory analysis. Detailed insight into this catalytic system may inspire the design of ligands for new uranium catalysts.

STRATEGI PENGEMBANGAN AGROINDUSTRI GULA SEMUT AREN

Directory of Open Access Journals (Sweden)

Nur Afni Evalia

2015-03-01

Full Text Available Aren is a type of palm that has a highly potential economic value. Lareh Sago Sub-district is the largest producer in the District of Lima Puluh Kota; however, it is only processed to produce wine and molded sugar. This study aimed to formulate a strategy for the sugar palm sugar agro-industrial development in Lareh Sagohalaban. The research method was a case study in the form of quantitative descriptive, and the data were processed using IFE/EFE, SWOT and AHP. The values obtained from IFE and EFE matrixes were 2.646 and 2.298 respectively. From the SWOT analysis, alternative strategies were obtained, namely, SO Strategy: Strengthening the R & D to develop market-based sugar processing for commercial scale and diversification of palm downstream products; WO Strategy: Improving upstream subsystem to develop nursery based on palm local seed varieties and providing institutional assistance; ST Strategy: Determining agro-technopark for palm industrialization, providing assistance in the form of appropriate packaging technology accordance with the standards, and WT Strategy: increasing commitment and cooperation among stakeholders in strengthening palm agro-industry, increasing marketing and promotion for the expansion and sanction policy for any company selling Aren in the form of wine. From the result of AHP analysis, the determinant factors in developing the business include Technology (0.439, the Government as the actor (0.577, and product diversification as the strategy (0.388.Keyword: Aren (palm, cluster- agro technopark, IFE/EFE matrixes, SWOT analysis, AHPABSTRAKAren (Arenga pinnata Merr adalah jenis palma yang memiliki potensi nilai ekonomi yang tinggi. Kecamatan Lareh sago halaban merupakan penghasil Aren terbesar di Kabupaten Lima Puluh Kota, namun dalam pengolahannya masih mengolah menjadi gula cetak dan lebih banyak dalam bentuk tuak. Penelitian ini bertujuan merumuskan strategi pengembangan agroindustri gula semut aren di Kecamatan

EFEKTIVITAS NIRA AREN SEBAGAI BAHAN PENGEMBANG ADONAN ROTI

Directory of Open Access Journals (Sweden)

Mody Lempang

2013-12-01

Full Text Available Fermentation is a natural process that happen in fresh-sweet sap of aren trees (Arenga pinnata Merr., because many kinds of microorganism stay and life in this substance e.g. bakteria (Acetobacter acetic and yeast (Saccharomyces tuac. Species of yeast from genus of Saccharomyses, e.g. Saccharomyses serivisae is wellknown as microorganism that can ferment sugar (glucose into alchohol and CO2. This natural process as well happen in aren sap, so that this substance potencially using as a swollen agent of bread or cake dough. This research objective is to recognize the effectiveness of aren sap as a swollen agent of bread dough. Fermentation duration of bread dough was one hour by using swollen agent of fresh, 10 hours old and 20 hours old of aren sap. Daily yield of sap tapped from aren trees in Maros district, South Sulawesi province was 7 litre (4-5 litre collected in the morning and 2-3 litre colected in the afternoon. Aren sap containt some of nutritions e.g. carbohydrate, protein, fat, vitamin C and mineral. Sweet taste of aren sap caused by it’s charbohydrate content of 11.18%. The effectiveness of aren sap as a swollen agent of bread dough is lower than instant (commercial yeast. The older of aren sap the lower of it’s effectiveness as a swollen agent of dough and kuality of bread yield.　　　　Keywords : Sap, Arenga pinnata, swollen agent, bread dough

A ruthenium(II) complex as turn-on Cu(II) luminescent sensor based on oxidative cyclization mechanism and its application in vivo

Science.gov (United States)

Zhang, Yunfei; Liu, Zonglun; Yang, Kui; Zhang, Yi; Xu, Yongqian; Li, Hongjuan; Wang, Chaoxia; Lu, Aiping; Sun, Shiguo

2015-02-01

Copper ions play a vital role in a variety of fundamental physiological processes not only in human beings and plants, but also for extensive insects and microorganisms. In this paper, a novel water-soluble ruthenium(II) complex as a turn-on copper(II) ions luminescent sensor based on o-(phenylazo)aniline was designed and synthesized. The azo group would undergo a specific oxidative cyclization reaction with copper(II) ions and turn into high luminescent benzotriazole, triggering significant luminescent increasements which were linear to the concentrations of copper(II) ions. The sensor distinguished by its high sensitivity (over 80-fold luminescent switch-on response), good selectivity (the changes of the emission intensity in the presence of other metal ions or amino acids were negligible) and low detection limit (4.42 nM) in water. Moreover, the copper(II) luminescent sensor exhibited good photostability under light irradiation. Furthermore, the applicability of the proposed sensor in biological samples assay was also studied and imaged copper(II) ions in living pea aphids successfully.

Crystal Structure of an L-Carnitine Complex with Pyrogallol[4]arene

International Nuclear Information System (INIS)

Fujisawa, I; Takeuchi, D; Kitamura, Y; Okamoto, R; Aoki, K

2012-01-01

L-Carnitine is essential for the transport of long-chain fatty acids from cytosol into mitochondria for generating metabolic energy. The survey of crystal structures of carnitine-containing proteins in the Protein Data Bank reveals that carnitine can take several conformations with the quarternary trimethylammonium terminal being always bound to aromatic residues through cation-π interactions in acyltransferases or carnitine-binding proteins. In order to demonstrate the importance of cation-π interaction as a carnitine recognition mechanism in the artificial receptor-ligand system that mimics the carnitine-binding sites, we have determined the crystal structure of a complex formed between L-carnitine and pyrogallol[4]arene (pyrogallol cyclic tetramer: PCT) as a carnitine receptor, 2PCT·2(L-carnitine)·4EtOH. There form two crystallographically independent monomeric [PCT·L-carnitine] substructures, which further form an obliquely arranged capsule-like dimeric [PCT·L-carnitine] 2 structure through a pair of O-H (PCT)···O (L-carnitine) hydrogen bonds. This is the first report of PCT complex with chiral molecules. In each of the two monomeric [PCT·L-carnitine] substructures, the L-carnitine molecule takes the elongated form with an intramolecular hydrogen bond between the hydroxyl group and the carboxylate oxygen, and the cationic trimethylammonium moiety is incorporated into the cavity of the bowl-shaped PCT molecule through cation-π interactions. These features are similar to those at the D-carnitine-binding site in the crystal structure of the glycine betaine/carnitine/choline-binding protein complex.

Robust binding between carbon nitride nanosheets and a binuclear ruthenium(II) complex enabling durable, selective CO{sub 2} reduction under visible light in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Kuriki, Ryo; Ishitani, Osamu; Maeda, Kazuhiko [Department of Chemistry, School of Science, Tokyo Institute of Technology (Japan); Yamamoto, Muneaki; Yoshida, Tomoko [Advanced Research Institute for Natural Science and Technology, Osaka City University (Japan); Higuchi, Kimitaka; Yamamoto, Yuta; Akatsuka, Masato; Yagi, Shinya [Institute of Materials and Systems for Sustainability, Nagoya University (Japan); Lu, Daling [Suzukakedai Materials Analysis Division, Technical Department, Tokyo Institute of Technology, Yokohama (Japan)

2017-04-18

Carbon nitride nanosheets (NS-C{sub 3}N{sub 4}) were found to undergo robust binding with a binuclear ruthenium(II) complex (RuRu') even in basic aqueous solution. A hybrid material consisting of NS-C{sub 3}N{sub 4} (further modified with nanoparticulate Ag) and RuRu' promoted the photocatalytic reduction of CO{sub 2} to formate in aqueous media, in conjunction with high selectivity (approximately 98 %) and a good turnover number (>2000 with respect to the loaded Ru complex). These represent the highest values yet reported for a powder-based photocatalytic system during CO{sub 2} reduction under visible light in an aqueous environment. We also assessed the desorption of RuRu' from the Ag/C{sub 3}N{sub 4} surface, a factor that can contribute to a loss of activity. It was determined that desorption is not induced by salt additives, pH changes, or photoirradiation, which partly explains the high photocatalytic performance of this material. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Bifunctional amine-tethered ruthenium(II) arene complexes form monofunctional adducts on DNA

Czech Academy of Sciences Publication Activity Database

Melchart, M.; Habtemariam, A.; Nováková, Olga; Moggach, S.A.; Fabbiani, F.P.A.; Parsons, S.; Brabec, Viktor; Sadler, P.J.

2007-01-01

Roč. 46, č. 21 (2007), s. 8950-8962 ISSN 0020-1669 R&D Projects: GA ČR(CZ) GA305/05/2030; GA ČR(CZ) GA203/06/1239; GA AV ČR(CZ) 1QS500040581; GA AV ČR(CZ) KAN200200651 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : DNA * ruthenium * cancer Subject RIV: BO - Biophysics Impact factor: 4.123, year: 2007

Inclusion complex formation of ternary system: Fluoroscein-p-sulfonato calix[4]arene-Cu(2+) by cooperative binding.

Science.gov (United States)

Gawhale, Sharadchandra; Jadhav, Ankita; Rathod, Nilesh; Malkhede, Dipalee; Chaudhari, Gajanan

2015-09-05

The aqueous solution of fluorescein-para sulfonato calix[4]arene-metal ion complex has been studied based on absorption, fluorescence, (1)H NMR and FTIR spectroscopic results. It was found that the fluorescence intensity quenched regularly upon addition of pSCX4 and metal ion. The quenching constants and binding constants were determined for pSCX4-FL and pSCX4-FL-Cu(2+) systems. 1:1 stoichiometry is obtained for pSCX4-Cu(2+) system by continuous variation method. The NMR and IR results indicates the interaction among FL, pSCX4 and Cu(2+). The combined results demonstrate the cooperative binding to design the complex for ternary system. The life time for binary and ternary system has been studied. Copyright © 2015 Elsevier B.V. All rights reserved.

Ruthenium, osmium and rhodium complexes of polypyridyl ligands ...

Indian Academy of Sciences (India)

Unknown

Discipline of Silicates and Catalysis, Central Salt and Marine Chemicals ... However, synthetic methods have also been developed to prepare complexes with ... 3.2 Synthesis and characterisation of ruthenium(II) and osmium(II) complexes18, ...

A supramolecular photosensitizer system based on the host-guest complexation between water-soluble pillar[6]arene and methylene blue for durable photodynamic therapy.

Science.gov (United States)

Yang, Kui; Wen, Jia; Chao, Shuang; Liu, Jing; Yang, Ke; Pei, Yuxin; Pei, Zhichao

2018-06-05

A supramolecular photosensitizer system WP6-MB was synthesized based on water-soluble pillar[6]arene and the photosensitizer methylene blue (MB) via host-guest interaction. MB can complex with WP6 directly with a high complex constant without further modification. In particular, WP6-MB can reduce the dark toxicity of MB remarkably. Furthermore, it can efficiently overcome photobleaching and extend the time for singlet oxygen production of MB upon light irradiation, which is significant for durable photodynamic therapy.

Comparison of hydration reactions for "piano-stool" RAPTA-B and [Ru(η6- arene)(en)Cl]+ complexes: Density functional theory computational study

Science.gov (United States)

Chval, Zdeněk; Futera, Zdeněk; Burda, Jaroslav V.

2011-01-01

The hydration process for two Ru(II) representative half-sandwich complexes: Ru(arene)(pta)Cl2 (from the RAPTA family) and [Ru(arene)(en)Cl]+ (further labeled as Ru_en) were compared with analogous reaction of cisplatin. In the study, quantum chemical methods were employed. All the complexes were optimized at the B3LYP/6-31G(d) level using Conductor Polarizable Continuum Model (CPCM) solvent continuum model and single-point (SP) energy calculations and determination of electronic properties were performed at the B3LYP/6-311++G(2df,2pd)/CPCM level. It was found that the hydration model works fairly well for the replacement of the first chloride by water where an acceptable agreement for both Gibbs free energies and rate constants was obtained. However, in the second hydration step worse agreement of the experimental and calculated values was achieved. In agreement with experimental values, the rate constants for the first step can be ordered as RAPTA-B > Ru_en > cisplatin. The rate constants correlate well with binding energies (BEs) of the Pt/Ru-Cl bond in the reactant complexes. Substitution reactions on Ru_en and cisplatin complexes proceed only via pseudoassociative (associative interchange) mechanism. On the other hand in the case of RAPTA there is also possible a competitive dissociation mechanism with metastable pentacoordinated intermediate. The first hydration step is slightly endothermic for all three complexes by 3-5 kcal/mol. Estimated BEs confirm that the benzene ligand is relatively weakly bonded assuming the fact that it occupies three coordination positions of the Ru(II) cation.

Microwave-Assisted Synthesis of Arene Ru(II Complexes Induce Tumor Cell Apoptosis Through Selectively Binding and Stabilizing bcl-2 G-Quadruplex DNA

Directory of Open Access Journals (Sweden)

Yanhua Chen

2016-05-01

Full Text Available A series of arene Ru(II complexes coordinated with phenanthroimidazole derivatives, [(η6-C6H6Ru(lCl]Cl(1b L = p-ClPIP = 2-(4-Chlorophenylimidazole[4,5f] 1,10-phenanthroline; 2b L = m-ClPIP = 2-(3-Chlorophenylimidazole[4,5f] 1,10-phenanthroline; 3b L = p-NPIP = 2-(4-Nitrophenylimidazole[4,5f] 1,10-phenanthroline; 4b L = m-NPIP = 2-(3-Nitrophenyl imidazole [4,5f] 1,10-phenanthroline were synthesized in yields of 89.9%–92.7% under conditions of microwave irradiation heating for 30 min to liberate four arene Ru(II complexes (1b, 2b, 3b, 4b. The anti-tumor activity of 1b against various tumor cells was evaluated by MTT assay. The results indicated that this complex blocked the growth of human lung adenocarcinoma A549 cells with an IC50 of 16.59 μM. Flow cytometric analysis showed that apoptosis of A549 cells was observed following treatment with 1b. Furthermore, the in vitro DNA-binding behaviors that were confirmed by spectroscopy indicated that 1b could selectively bind and stabilize bcl-2 G-quadruplex DNA to induce apoptosis of A549 cells. Therefore, the synthesized 1b has impressive bcl-2 G-quadruplex DNA-binding and stabilizing activities with potential applications in cancer chemotherapy.

Electrochemical Studies for Cation Recognition with Diazo-Coupled Calix[4]arenes

Directory of Open Access Journals (Sweden)

Bongsu Kim

2015-01-01

Full Text Available The electrochemical properties of diazophenylcalix[4]arenes bearing ortho-carboxyl group (o-CAC and ortho-ester group (o-EAC, respectively, in the presence of various metal ions were investigated by voltammetry in CH3CN. o-CAC and o-EAC showed voltammetric changes toward divalent metal ions and no significant changes with monovalent alkali metal ions. However, o-CAC preferentially binds with alkaline earth and transition metal ions, whereas no significant changes in voltammetric signals are observed in o-EAC with alkaline earth metal ions. o-EAC only binds with other transition metal ions. This can be explained on metal ion complexation-induced release of proton from the azophenol to the quinone-hydrazone tautomer followed by internal complexation of the metal ion with aid of nitrogen atoms and ortho-carbonyl groups in the diazophenylazocalix[4]arenes.

Farmer’s Motivation in Aren Sugar Processing Business

Science.gov (United States)

Abdullah, W. G.; Rianse, U.; Muhidin; Widayati, W.; Mihrad, E. S.; Taridala, S. A. A.; Rianse, I. S.; Baka, W. K.

2018-02-01

The objectives of the research were to analyze socio-economic characteristics and motivation of farmers in aren sugar processing business in Kolaka District, Southeast Sulawesi, Indonesia. The analysis used in this research was quantitative descriptive analysis. The results showed that average state of socio-economic characteristics of aren sugar farmer that were in the category of productive age, which was 46.12 years old, has fulfil basic education category (9 years education), low category of dependents as many as three people, the Average experience of aren sugar processing business during 18 years, and the average aren trees were tapped as much as seven trees, every day, (b) farmer’s motivation in aren sugar processing business in low category, with the indicator is the motive of imitation, economic, security, affiliations, awards, and self-actualization.

Synthesis, DNA Cleavage Activity, Cytotoxicity, Acetylcholinesterase Inhibition, and Acute Murine Toxicity of Redox-Active Ruthenium(II) Polypyridyl Complexes.

Science.gov (United States)

Alatrash, Nagham; Narh, Eugenia S; Yadav, Abhishek; Kim, Mahn-Jong; Janaratne, Thamara; Gabriel, James; MacDonnell, Frederick M

2017-07-06

Four mononuclear [(L-L) 2 Ru(tatpp)] 2+ and two dinuclear [(L-L) 2 Ru(tatpp)Ru(L-L) 2 ] 4+ ruthenium(II) polypyridyl complexes (RPCs) containing the 9,11,20,22-tetraazatetrapyrido[3,2-a:2',3'-c:3'',2''-l:2''',3'''-n]pentacene (tatpp) ligand were synthesized, in which L-L is a chelating diamine ligand such as 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), 3,4,7,8-tetramethyl-1,10-phenanthroline (Me 4 phen) or 4,7-diphenyl-1,10-phenanthroline (Ph 2 phen). These Ru-tatpp analogues all undergo reduction reactions with modest reducing agents, such as glutathione (GSH), at pH 7. These, plus several structurally related but non-redox-active RPCs, were screened for DNA cleavage activity, cytotoxicity, acetylcholinesterase (AChE) inhibition, and acute mouse toxicity, and their activities were examined with respect to redox activity and lipophilicity. All of the redox-active RPCs show single-strand DNA cleavage in the presence of GSH, whereas none of the non-redox-active RPCs do. Low-micromolar cytotoxicity (IC 50 ) against malignant H358, CCL228, and MCF7 cultured cell lines was mainly restricted to the redox-active RPCs; however, they were substantially less toxic toward nonmalignant MCF10 cells. The IC 50 values for AChE inhibition in cell-free assays and the acute toxicity of RPCs in mice revealed that whereas most RPCs show potent inhibitory action against AChE (IC 50 values <15 μm), Ru-tatpp complexes as a class are surprisingly well tolerated in animals relative to other RPCs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

New Calix[4]arene dibenzocrown ethers for selective sensing of cesium ion in aqueous environment

International Nuclear Information System (INIS)

Kim, Jong Seung; Kim, Jong Kuk; Choi, Wang Kyu; Lee, Kune Woo; Oh, Won Jin

1997-01-01

1,3-dialkoxycalix[4]arene dibenzocrown ethers (6-9) were successfully synthesized in the fixed 1,3-alternate conformation with over 90% yields by the reaction of corresponding 1,3dialkoxycalix[4]arenes 2-5 with dibenzodimesylate 13 in acetonitrile as a solvent in the presence of cesium carbonate as a base. In view of cyclization yield, the use of dimesylate is found to be better than that of dibenzoditosylate. With an unusual AB pattern in 1 H NMR spectrum for compound 9, it is suggested that conformational structure of 1,3-diallyloxycalix[4]arene dibenzocrown ether be less flexible than that of usual 1,3-alternate calixcrown ether, probably due to steric effects of two ally1 group. Complexation of the corresponding calix[4]arene 6-9 toward alkali metal ions using single flux method through bulk liquid membrane system was found to give a high cesium selectivity. 28 refs., 1 tab., 1 fig

New Calix[4]arene dibenzocrown ethers for selective sensing of cesium ion in aqueous environment

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Seung; Kim, Jong Kuk [Konyang University, Nonsan (Korea, Republic of); Choi, Wang Kyu; Lee, Kune Woo; Oh, Won Jin [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1997-12-31

1,3-dialkoxycalix[4]arene dibenzocrown ethers (6-9) were successfully synthesized in the fixed 1,3-alternate conformation with over 90% yields by the reaction of corresponding 1,3dialkoxycalix[4]arenes 2-5 with dibenzodimesylate 13 in acetonitrile as a solvent in the presence of cesium carbonate as a base. In view of cyclization yield, the use of dimesylate is found to be better than that of dibenzoditosylate. With an unusual AB pattern in {sup 1}H NMR spectrum for compound 9, it is suggested that conformational structure of 1,3-diallyloxycalix[4]arene dibenzocrown ether be less flexible than that of usual 1,3-alternate calixcrown ether, probably due to steric effects of two ally1 group. Complexation of the corresponding calix[4]arene 6-9 toward alkali metal ions using single flux method through bulk liquid membrane system was found to give a high cesium selectivity. 28 refs., 1 tab., 1 fig.

Photorefractive IR-spectrum composites prepared from polyimide and ruthenium(II) tetra-15-crown-5-phthalocyaninate with axially coordinated triethylenediamine molecules

International Nuclear Information System (INIS)

Vannikov, A.V.; Grishina, A.D.; Gorbunova, Yu.G.; Enakieva, Yu.Yu.; Krivenko, T.V.; Savel'ev, V.V.; Tsivadze, A.Yu.

2006-01-01

Photoelectric, non-linear optical, and photorefractive properties of aromatic polyimine doped with ruthenium(II) complex with tetra-15-crown-5-phthalocyanine and axially coordinated triethylenediamine molecules, (R 4 Pc)Ru(TED) 2 , where R 4 Pc 2- and TED denote 4,5,4',5',4'',5'',4''',5'''-tetrakis-(1,4,7,10,13- pentaoxatridecamethylene)phthalocyaninate ion and triethylenediamine molecule, respectively, were studied. It is established that supramolecular ensembles on the basis of the complex make an aromatic polyimide layer photoelectrically sensitive to 1064-nm Nd : YAG laser radiation, exhibit third-order susceptibility, and, consequently, impart photorefractive properties to the polymer layer at this wavelength [ru

Cellular responses of BRCA1-defective and triple-negative breast cancer cells and in vitro BRCA1 interactions induced by metallo-intercalator ruthenium(II) complexes containing chloro-substituted phenylazopyridine

International Nuclear Information System (INIS)

Nhukeaw, Tidarat; Temboot, Pornvichai; Hansongnern, Kanidtha; Ratanaphan, Adisorn

2014-01-01

Triple-negative breast cancer (TNBC) is defined by the absence of expression of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2. Breast cancers with a BRCA1 mutation are also frequently triple-negative. Currently, there is a lack of effective therapies and known specific molecular targets for this aggressive breast cancer subtype. To address this concern, we have explored the cellular responses of BRCA1-defective and triple-negative breast cancer cells, and in vitro BRCA1 interactions induced by the ruthenium(II) complexes containing the bidentate ligand, 5-chloro-2-(phenylazo)pyridine. Triple-negative MDA-MB-231, BRCA1-defective HCC1937 and BRCA1-competent MCF-7 breast cancer cell lines were treated with ruthenium(II) complexes. The cytoxoxicity of ruthenium-induced breast cancer cells was evaluated by a real time cellular analyzer (RTCA). Cellular uptake of ruthenium complexes was determined by ICP-MS. Cell cycle progression and apoptosis were assessed using propidium iodide and Annexin V flow cytometry. The N-terminal BRCA1 RING protein was used for conformational and functional studies using circular dichroism and in vitro ubiquitination. HCC1937 cells were significantly more sensitive to the ruthenium complexes than the MDA-MB-231 and MCF-7 cells. Treatment demonstrated a higher degree of cytotoxicity than cisplatin against all three cell lines. Most ruthenium atoms were retained in the nuclear compartment, particularly in HCC1937 cells, after 24 h of incubation, and produced a significant block at the G2/M phase. An increased induction of apoptotic cells as well as an upregulation of p53 mRNA was observed in all tested breast cancer cells. It was of interest that BRCA1 mRNA and replication of BRCA1-defective cells were downregulated. Changes in the conformation and binding constants of ruthenium-BRCA1 adducts were observed, causing inactivation of the RING heterodimer BRCA1/BARD1-mediated E3 ubiquitin ligase activity

Laser Spectroscopic and Theoretical Studies of Encapsulation Complexes of Calix[4]arene

Energy Technology Data Exchange (ETDEWEB)

Kaneko, Shohei; Inokuchi, Yoshiya; Ebata, Takayuki; Apra, Edoardo; Xantheas, Sotiris S.

2011-10-13

The complexes between the host calix[4]arene (C4A) and various guest molecules such as NH3, N2, CH4, and C2H2 have been investigated via experimental and theoretical methods. The S1-S0 electronic spectra of these guest-host complexes are observed by mass-selected resonant two-photon ionization (R2PI) and laser induced fluorescence (LIF) spectroscopy. The infrared (IR) spectra of the complexes formed in molecular beams are obtained by IR-UV double resonance (IR-UV DR) and IR photodissociation (IRPD) spectroscopy. The supramolecular structures of the complexes are investigated by electronic structure methods (density functional and second order perturbation theory). The current results for the various molecular guests are put in perspective with the previously reported ones for the C4A-Rare Gas (Rg) (Phys. Chem. Chem. Phys. 2007, 126, 141101) and C4A-H2O complexes (J. Phys. Chem. A, 2010, 114, 2967). The electronic spectra of the complexes of C4A with N2, CH4 and C2H2 exhibit red-shifts of similar magnitudes with the ones observed for the C4A-Rg complexes, whereas the complexes of C4A with H2O and NH3 show much larger red-shifts. Most of the IR-UV DR spectra of the complexes, except for C4A-C2H2, show a broad hydrogen bonded OH stretching band with a peak at ~3160 cm-1. The analysis of the experimental results, in agreement with the ones resulted from the electronic structure calculations, suggest that C4A preferentially forms endo-complexes with all the guest species reported in this study. We discuss the similarities and differences of the structures, binding energies and the nature of the interaction between the C4A host and the various guest species. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy

Calix[4]arene Based Single-Molecule Magnets

Energy Technology Data Exchange (ETDEWEB)

Karotsis, Georgios; Teat, Simon J.; Wernsdorfer, Wolfgang; Piligkos, Stergios; Dalgarno, Scott J.; Brechin, Euan K.

2009-06-04

n = 4-8) also suggests they should be excellent candidates as ligands for the isolation of molecular magnets, but to date their use in the isolation of paramagnetic cluster compounds is rather limited. Herein we present the first Mn cluster and the first SMM to be isolated using any methylene bridged calix[n]arene - a ferromagnetically coupled mixed-valence [Mn{sub 2}{sup III}Mn{sub 2}{sup II}] complex housed between either two TBC4s or two C4s.

15,17-Di-2-propenylcalix[4]arene-25,26,27,28-tetrol: self-complexation and C-H...O interactions

NARCIS (Netherlands)

Harkema, Sybolt; van Loon, Jan-Dirk; van Loon, Jan-Dirk; Verboom, Willem; Reinhoudt, David

1998-01-01

The crystal structure of 15,17-di-2-propenylcalix[4]arene-25,26,27,28-tetrol [systematic name: 15,17-di-2-propenylpentacyclo[19.3.1.13,7.19,13.115,19]octacosa-1(25), 3,5,7(26),9,11,13 (27),15,17,19 (28),21,23-dodecaene-25,26,27,28-tetrol], C34H32O4, was determined. The calix[4]arene molecule shows a

Para-ter-butyl of calix(4)arene with acetamide-ether as inorganic-organic receiver

International Nuclear Information System (INIS)

Ramirez, F.M. de; Scopelliti, R.; Muller, G.; Buenzli J, C.G.; Charbonniere, L.

2001-01-01

A new functionalized calix(4)arene was designed and constructed with predetrmined properties to form lanthanides complexes and to sensibilize its luminescent properties. This, in addition to sensibilize that photophysical property and once formed the complex resulted a good receiver of organic molecules as it is demonstrated the crystal structure of the lutetium complex. (Author)

Neutral glycoconjugated amide-based calix[4]arenes: complexation of alkali metal cations in water.

Science.gov (United States)

Cindro, Nikola; Požar, Josip; Barišić, Dajana; Bregović, Nikola; Pičuljan, Katarina; Tomaš, Renato; Frkanec, Leo; Tomišić, Vladislav

2018-02-07

Cation complexation in water presents a unique challenge in calixarene chemistry, mostly due to the fact that a vast majority of calixarene-based cation receptors is not soluble in water or their solubility has been achieved by introducing functionalities capable of (de)protonation. Such an approach inevitably involves the presence of counterions which compete with target cations for the calixarene binding site, and also rather often requires the use of ion-containing buffer solutions in order to control the pH. Herein we devised a new strategy towards the solution of this problem, based on introducing carbohydrate units at the lower or upper rim of calix[4]arenes which comprise efficient cation binding sites. In this context, we prepared neutral, water-soluble receptors with secondary or tertiary amide coordinating groups, and studied their complexation with alkali metal cations in aqueous and methanol (for the comparison purpose) solutions. Complexation thermodynamics was quantitatively characterized by UV spectrometry and isothermal titration calorimetry, revealing that one of the prepared tertiary amide derivatives is capable of remarkably efficient (log K ≈ 5) and selective binding of sodium cations among alkali metal cations in water. Given the ease of the synthetic procedure used, and thus the variety of accessible analogues, this study can serve as a platform for the development of reagents for diverse purposes in aqueous media.

Reduction of a cerium(III) siloxide complex to afford a quadruple-decker arene-bridged cerium(II) sandwich

Energy Technology Data Exchange (ETDEWEB)

Kelly, Rory P.; Scopelliti, Rosario; Mazzanti, Marinella [Institut des Sciences et Ingenierie Chimiques, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland); Maron, Laurent [Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquees, Toulouse (France)

2017-12-04

Organometallic multi-decker sandwich complexes containing f-elements remain rare, despite their attractive magnetic and electronic properties. The reduction of the Ce{sup III} siloxide complex, [KCeL{sub 4}] (1; L=OSi(OtBu){sub 3}), with excess potassium in a THF/toluene mixture afforded a quadruple-decker arene-bridged complex, [K(2.2.2-crypt)]{sub 2}[{(KL_3Ce)(μ-η"6:η"6-C_7H_8)}{sub 2}Ce] (3). The structure of 3 features a [Ce(C{sub 7}H{sub 8}){sub 2}] sandwich capped by [KL{sub 3}Ce] moieties with a linear arrangement of the Ce ions. Structural parameters, UV/Vis/NIR data, and DFT studies indicate the presence of Ce{sup II} ions involved in δ bonding between the Ce cations and toluene dianions. Complex 3 is a rare lanthanide multi-decker complex and the first containing non-classical divalent lanthanide ions. Moreover, oxidation of 1 by AgOTf (OTf=O{sub 3}SCF{sub 3}) yielded the Ce{sup IV} complex, [CeL{sub 4}] (2), showing that siloxide ligands can stabilize Ce in three oxidation states. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synthesis of some (eta-arene)dihydridorhenium cations and their reactions with LiAlH4 and LiAlD4

International Nuclear Information System (INIS)

Baudrey, D.; Boydell, P.; Ephritikhine, M.

1986-01-01

A series of cations [Re(eta-arene)H 2 (PPh 3 ) 2 ] + (arene benzene, toluene, p-xylene, or mesitylene) was prepared from the corresponding neutral dihydridocyclohexadienyl complexes by treatment with CPh 3 BF 4 . These cations reacted with LiAlH 4 and LiAlD 4 to form dihydridocyclohexadienyl complexes. The unusual selectivity of the hydride attack is explained by steric interactions between the ring methyl groups and the bulky phosphine ligands. The initial product of the reaction of the eta-mesitylene cation with LiAlD 4 allows the isomerisation mechanism for the cyclohexadienyl complexes to be clarified. (author)

3-Methylindole-Based Tripodal Tetraphosphine Ruthenium Complexes in N2 Coordination and Reduction and Formic Acid Dehydrogenation

Directory of Open Access Journals (Sweden)

Fenna F. van de Watering

2017-10-01

Full Text Available The ruthenium(II complexes RuCl2L1H, RuCl2L1CF3, RuCl2L1OMe and RuCl2L2H were synthesized from [Ru(η6-benzeneCl(μ-Cl]2 and the corresponding tripodal tris-3-methylindolephosphine-based ligands L1H, L1CF3, L1OMe, and L2H. Stoichiometric reduction of these complexes with KC8 yielded the corresponding ruthenium(0 dinitrogen complexes. The latter complexes were studied in the N2 reduction with chlorosilanes and KC8, yielding stoichiometric amounts of the silylamines. The synthesized ruthenium(II complexes are also active catalysts for the formic acid dehydrogenation reaction.

Electrochemiluminescence and chemiluminescence of a carboxylic acid derivative of ruthenium(II) tris-(2,2'-bipyridine) chelate synthesized for labeling purposes

International Nuclear Information System (INIS)

Jiang Qinghong; Sun Shiguo; Hakansson, Markus; Langel, Kaarina; Ylinen, Tiina; Suomi, Johanna; Kulmala, Sakari

2006-01-01

Synthesis, purification and characterization of [4-ethoxycarbonyl-4'-carboxy-2,2'-bipyridine]bis(2,2'-bipyridine) ruthenium(II) hexafluorophosphate is described. This complex is shown to be electrochemiluminescent in aqueous solution during cathodic pulse polarization of thin insulating film-coated electrodes. Electrochemiluminescence (ECL) lifetime of the complex was observed to be ca. 40 μs at oxide-coated n-silicon electrodes; thus time-resolved detection is also possible. The ECL emission maximum of this carboxylate derivative is somewhat red-shifted when compared with an unmodified Ru(bpy) 3 2+ . Because the present complex can be easily covalently coupled with antibodies and oligonucleotides it is usable as an electrochemiluminescent label in various bioaffinity assays. The present chelates also produce strong chemiluminescence during dissolution of metallic magnesium in aqueous solution

Effect of pendant group length upon metal ion complexation in acetonitrile by di-ionized calix[4]arenes bearing two dansyl fluorophores.

Science.gov (United States)

Ocak, Ummühan; Ocak, Miraç; Shen, Xin; Surowiec, Kazimierz; Bartsch, Richard A

2009-11-01

A series of three di-ionizable calix[4]arenes with two pendant dansyl (1-dimethylaminonaphthalene-5-sulfonyl) groups linked to the lower rims was synthesized. Structures of the three ligands were identical except for the length of the spacers which connected the two dansyl groups to the calix[4]arene scaffold. Following conversion of the ligands into their di-ionized di(tetramethylammonium) salts, absorption and emission spectrophotometry were utilized to probe the influence of metal cation (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Ag+, Cd2+, Co2+, Fe2+, Hg2+, Mn2+, Pb2+, Zn2+ and Fe3+) complexation in acetonitrile. Upon complexation with these metal cations, emission spectra underwent marked red shifts and quenching of the dansyl group fluorescence for the di-ionized ligand with the shortest spacer. A similar effect was noted for the di-ionized ligand with an intermediate spacer for all of the metal ions, except Ba2+. For the di-ionized ligand with the longest spacer, the metal cations showed different effects on the emission spectrum. Li+, Mg2+, Ca2+ and Ba2+ caused enhancement of emission intensity with a red shift. Other metal cations produce quenching with red shifts in the emission spectra. Transition metal cations interacted strongly with all three di-ionized ligands. In particular, Fe3+ and Hg2+ caused greater than 99% quenching of the dansyl fluorescence in the di-ionized ligands.

Encapsulation and solid state sequestration of gases by calix[6]arene-based molecular containers.

Science.gov (United States)

Lavendomme, Roy; Ajami, Daniela; Moerkerke, Steven; Wouters, Johan; Rissanen, Kari; Luhmer, Michel; Jabin, Ivan

2017-06-13

Two calix[6]arene-based molecular containers were synthesized in high yields. These containers can encapsulate small guests through a unique "rotating door" complexation process. The sequestration of greenhouse gases is clearly demonstrated. They can be stored in the solid state for long periods and released via dissolution of the inclusion complex.

Calix[6]arenes functionalized with malondiamides at the upper rim as possible extractants for lanthanide and actinide cations

International Nuclear Information System (INIS)

Almaraz, M.; Esperanza, S.; Magrans, O.; Mendoza, J. de; Pradus, P.

2001-01-01

Lipophilic malondiamides have been recently employed successfully as extractants for lanthanide and actinide cations from strongly acidic media. Many complexes between malondiamides and lanthanide-actinides cations have been studied by different techniques. For many of these complexes it has been observed that more than one malondiamide ligand participates in the complexation of each metallic cation. Incorporation of two or three malondiamide moieties into a calixarene platform would probably improve both extraction and selectivity with respect to the already tested malondiamides. According to CPK examination, a calix[6]arene substituted at the upper rim with two or three malondiamide moieties should constitute a promising ligand for lanthanide and actinide cations due to co-operative complexation with the malondiamides. Based on these considerations, we synthesised calix[6]arenes functionalized with malonic acid derivatives. (author)

Dual Ligand-Enabled Nondirected C-H Olefination of Arenes.

Science.gov (United States)

Chen, Hao; Wedi, Philipp; Meyer, Tim; Tavakoli, Ghazal; van Gemmeren, Manuel

2018-02-23

The application of the Pd-catalyzed oxidative C-H olefination of arenes, also known as the Fujiwara-Moritani reaction, has traditionally been limited by the requirement for directing groups on the substrate or the need to use the arene in large excess, typically as a (co)solvent. Herein the development of a catalytic system is described that, through the combined action of two complementary ligands, makes it possible to use directing-group-free arenes as limiting reagents for the first time. The reactions proceed under a combination of both steric and electronic control and enable the application of this powerful reaction to valuable arenes, which cannot be utilized in excess. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation of the host-guest complexation between 4-sulfocalix[4]arene and nedaplatin for potential use in drug delivery

Science.gov (United States)

Fahmy, Sherif Ashraf; Ponte, Fortuna; Abd El-Rahman, Mohamed K.; Russo, Nino; Sicilia, Emilia; Shoeib, Tamer

2018-03-01

Macromolecules including macrocyclic species have been reported to have the potential to encapsulate biologically active compounds such as drugs through host-guest complexation to increase their solubility, stability and bioavailability. In this paper the first experimental and theoretical investigation of the complexation between nedaplatin, a second generation antineoplastic drug, and p-4-sulfocalix[4]arene, a macromolecule possessing a bipolar amphiphilic structure with good biocompatibility and relatively low haemolytic toxicity for potential use as a drug delivery system is presented. Data from 1H NMR, UV, Job's plot analysis, HPLC and DFT calculations are detailed and suggest the formation of a 1:1 complex. The stability constant of the complex was experimentally estimated to be 3.6 × 104 M- 1 and 2.1 × 104 M- 1 which correspond to values of - 6.2 and - 5.9 kcal mol- 1, respectively for the free energy of complexation while the interaction free energy is calculated to be - 4.9 kcal mol- 1. The formed species is shown to be stabilised in solution through hydrogen bonding between the host and the guest which may allow for this strategy to be effective for potential use in drug delivery.

Carrier-facilitated transport of Cd(II) through a supported liquid membrane containing thiacalix[4]arene derivatives as ionophore

International Nuclear Information System (INIS)

Zaghbani, Asma; Tayeb, Rafik; Dhahbi, Mahmoud

2009-01-01

The feasibility of a facilitated transport process of cadmium ions through a SLM system incorporating new extractant agents, thiacalix[4]arenes, was studied. These molecules have sulfur atoms instead of usual methylene bridges. The chemical modification of the upper or the lower rim provides a great variety of supra molecules having different complexation ability and different conformational behaviour. The efficiency of the transport across the inner membrane organic liquid phase is shown to depend on the chemical (affinity) and structural (conformational states possible) parameters of these complexing molecules. In this work, two different thiacalix[4]arenes were selected as effective ionophore for the treatment of liquid media loaded in Cd(II). The results show that these thiacalix[4]arenes derivative ensure facilitated transport of cadmium cations through supported liquid membranes. Especially, the non-substituted thiacalix[4]arene can be considered as an effective extractant agent. The incidence of several parameters on transport efficiency such as pH of both aqueous solutions and carrier concentration was studied. The permeation of the species is due to a proton potential gradient (the driving force of the process) existing between the two opposite sides of the SLM. The initial flux, J, is found to be equal to 6.7.10 -7 mol.m -2 .s -1 , under optimal experimental conditions.

Study on the inclusion interaction of p-sulfonated calix[n]arenes with Vitamin K3 using methylene blue as a spectral probe.

Science.gov (United States)

Lu, Qin; Gu, Jiashan; Yu, Huapeng; Liu, Chun; Wang, Lun; Zhou, Yunyou

2007-09-01

The characteristics of host-guest complexation between p-sulfonated calix[n]arene (SCnA, n = 4, 6) and Vitamin K(3) (VK(3)) were investigated by fluorescence spectrometry and absorption spectrometry using methylene blue (MB) as a probe. Interaction with MB and SCnA led to an obvious decrease in fluorescence intensity of MB, accompanying with shifts of emission peaks. Absorption peaks also showed interesting changes; however, when VK(3) was added, fluorescence intensity and absorbance recovered and a slight and slow red shift was observed. The obtained results showed that the inclusion ability of p-sulphonated calix[n]arenes towards VK(3) was the order: p-sulphonated calix[6]arene (SC6A) >p-sulphonated calix[4]arene (SC4A). Relative mechanism was proposed to explain the inclusion process.

CALIX[4]ARENE C-145 EFFECTS ON СELLULAR HAEMOSTASIS

Directory of Open Access Journals (Sweden)

V. O. Chernyshenko

2016-06-01

Full Text Available The aim of the research was to study a potential antithrombotic sodium salt of calix[4]arene-methylene-bis-phosphonic acid (С-145 — on activation and aggregation of platelets in vivo, as well as on proliferation and apoptosis of endothelial cells in the cell culture. Effects of calix[4]arene С-145 estimated in vitro after addition to the platelet rich plasma, and in vivo after intravenous injection into rabbit bloodstream in equivalent amounts (46 μM. Aggregation of platelets was induced by adenosine diphosphate and detected using aggregometer Solar AP2110. Platelet shape and cytoplasmic granularity were monitored on COULTER EPICS XL Flow Cytometer. The level of tissuetype plasminogen activator — tPA — was estimated using enzyme-linked immunosorbent assay ELISA. Effects of calix[4]arene C-145 on culture of endotelial cells cells was studied using 3-(4,5-Dimethylthiazol-2-yl-2,5-Diphenyltetrazolium Bromide — MTT-test. The population of proliferative pool of cells (G2/M+S was determined using flow cytometry. Aggregometry and flow cytometry showed that calix[4]arene C-145 did not activate platelets nor affect their aggregation in vitro. However intravenous injection of calix[4]arene C-145 into the bloodstream of healthy rabbits leads to strong inhibition of platelet aggregation and changes of shape and granularity of most of the platelets after 2 hours of administration. Any additional appearance of endothelial cells activation marker tPA in vivo and any inhibition of calix[4]arene C-145 on proliferation of endothelial cells in cell culture did not observe. So calix[4]arene C-145 had strong anti-platelet effect in vivo that was not a result of their direct action on platelets or endothelial cells in vitro. This allowed to assume the possibility of calix[4]arene C-145 use as an effective antithrombotic agent.

A multi-target caffeine derived rhodium(i) N-heterocyclic carbene complex: evaluation of the mechanism of action.

Science.gov (United States)

Zhang, Jing-Jing; Muenzner, Julienne K; Abu El Maaty, Mohamed A; Karge, Bianka; Schobert, Rainer; Wölfl, Stefan; Ott, Ingo

2016-08-16

A rhodium(i) and a ruthenium(ii) complex with a caffeine derived N-heterocyclic carbene (NHC) ligand were biologically investigated as organometallic conjugates consisting of a metal center and a naturally occurring moiety. While the ruthenium(ii) complex was largely inactive, the rhodium(i) NHC complex displayed selective cytotoxicity and significant anti-metastatic and in vivo anti-vascular activities and acted as both a mammalian and an E. coli thioredoxin reductase inhibitor. In HCT-116 cells it increased the reactive oxygen species level, leading to DNA damage, and it induced cell cycle arrest, decreased the mitochondrial membrane potential, and triggered apoptosis. This rhodium(i) NHC derivative thus represents a multi-target compound with promising anti-cancer potential.

Kinetic effects of sulfur oxidation on catalytic nitrile hydration: nitrile hydratase insights from bioinspired ruthenium(II) complexes.

Science.gov (United States)

Kumar, Davinder; Nguyen, Tho N; Grapperhaus, Craig A

2014-12-01

Kinetic investigations inspired by the metalloenzyme nitrile hydratase were performed on a series of ruthenium(II) complexes to determine the effect of sulfur oxidation on catalytic nitrile hydration. The rate of benzonitrile hydration was quantified as a function of catalyst, nitrile, and water concentrations. Precatalysts L(n)RuPPh3 (n = 1-3; L(1) = 4,7-bis(2'-methyl-2'-mercapto-propyl)-1-thia-4,7-diazacyclononane; L(2) = 4-(2'-methyl-2'-sulfinatopropyl)-7-(2'-methyl-2'-mercapto-propyl)-1-thia-4,7-diazacyclononane; L(3) = 4-(2'-methyl-2'-sulfinatopropyl)-7-(2'-methyl-2'-sulfenato-propyl)-1-thia-4,7-diazacyclononane) were activated by substitution of triphenylphosphine with substrate in hot dimethylformamide solution. Rate measurements are consistent with a dynamic equilibrium between inactive aqua (L(n)Ru-OH2) and active nitrile (L(n)Ru-NCR) derivatives with K = 21 ± 1, 9 ± 0.9, and 23 ± 3 for L(1) to L(3), respectively. Subsequent hydration of the L(n)Ru-NCR intermediate yields the amide product with measured hydration rate constants (k's) of 0.37 ± 0.01, 0.82 ± 0.07, and 1.59 ± 0.12 M(-1) h(-1) for L(1) to L(3), respectively. Temperature dependent studies reveal that sulfur oxidation lowers the enthalpic barrier by 27 kJ/mol, but increases the entropic barrier by 65 J/(mol K). Density functional theory (DFT) calculations (B3LYP/LanL2DZ (Ru); 6-31G(d) (all other atoms)) support a nitrile bound catalytic cycle with lowering of the reaction barrier as a consequence of sulfur oxidation through enhanced nitrile binding and attack of the water nucleophile through a highly organized transition state.

Complexation study of a tert-butyl-calix[4]arene-based 2-hydroxynaphthalene ligand with uranium(VI) in non-aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Bauer, Anne; Schmeide, Katja [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

2017-06-01

The actinide uranium, well known from nuclear power cycle, plays also a role in rare earth production as it is an undesired constituent of the respective ores. To facilitate the production of rare earth elements, uranium has to be removed. Due to their modifiable selectivity and solubility calix[n]arenes are interesting compounds for the extraction of actinides and lanthanides. The mechanism of uranium(VI) interaction with a tert-butyl-calix[4]arene-based 2-hydroxynaphthalene ligand (L1) was studied by TRLFS, UV-vis spectroscopy and isothermal calorimetry.

Synthesis of some (eta-arene)dihydridorhenium cations and their reactions with LiAlH/sub 4/ and LiAlD/sub 4/

Energy Technology Data Exchange (ETDEWEB)

Baudrey, D.; Boydell, P.; Ephritikhine, M.

1986-03-01

A series of cations (Re(eta-arene)H/sub 2/(PPh/sub 3/)/sub 2/)/sup +/ (arene benzene, toluene, p-xylene, or mesitylene) was prepared from the corresponding neutral dihydridocyclohexadienyl complexes by treatment with CPh/sub 3/BF/sub 4/. These cations reacted with LiAlH/sub 4/ and LiAlD/sub 4/ to form dihydridocyclohexadienyl complexes. The unusual selectivity of the hydride attack is explained by steric interactions between the ring methyl groups and the bulky phosphine ligands. The initial product of the reaction of the eta-mesitylene cation with LiAlD/sub 4/ allows the isomerisation mechanism for the cyclohexadienyl complexes to be clarified.

Report on the auscultation of the Arenal's Dam: P.H. Arenal

International Nuclear Information System (INIS)

Cordero Calderon, C.F.

1996-02-01

To verify the correct functioning of the works that the Instituto Costarricense de Electricidad constructs, they have established different types of auscultation for the Arenal's. Thus they make investigations to know new methodologies that contributes to the improvement and to the elimination of risks in the different works (author)

Ab initio design of drug carriers for zoledronate guest molecule using phosphonated and sulfonated calix[4]arene and calix[4]resorcinarene host molecules

Science.gov (United States)

Jang, Yong-Man; Yu, Chol-Jun; Kim, Jin-Song; Kim, Song-Un

2018-04-01

Monomolecular drug carriers based on calix[n]-arenes and -resorcinarenes containing the interior cavity can enhance the affinity and specificity of the osteoporosis inhibitor drug zoledronate (ZOD). In this work we investigate the suitability of nine different calix[4]-arenes and -resorcinarenes based macrocycles as hosts for the ZOD guest molecule by conducting {\\it ab initio} density functional theory calculations for structures and energetics of eighteen different host-guest complexes. For the optimized molecular structures of the free, phosphonated, sulfonated calix[4]-arenes and -resorcinarenes, the geometric sizes of their interior cavities are measured and compared with those of the host-guest complexes in order to check the appropriateness for host-guest complex formation. Our calculations of binding energies indicate that in gaseous states some of the complexes might be unstable but in aqueous states almost all of the complexes can be formed spontaneously. Of the two different docking ways, the insertion of ZOD with the \\ce{P-C-P} branch into the cavity of host is easier than that with the nitrogen containing heterocycle of ZOD. The work will open a way for developing effective drug delivering systems for the ZOD drug and promote experimentalists to synthesize them.

Metathetical Redox Reaction of (Diacetoxyiodo)arenes and Iodoarenes.

Science.gov (United States)

Jobin-Des Lauriers, Antoine; Legault, Claude Y

2015-12-17

The oxidation of iodoarenes is central to the field of hypervalent iodine chemistry. It was found that the metathetical redox reaction between (diacetoxyiodo)arenes and iodoarenes is possible in the presence of a catalytic amount of Lewis acid. This discovery opens a new strategy to access (diacetoxyiodo)arenes. A computational study is provided to rationalize the results observed.

Synthesis of Water-Soluble Amino Functionalized Multithiacalix[4]arene via Quaternization of Tertiary Amino Groups

Directory of Open Access Journals (Sweden)

Roman Nosov

2018-05-01

Full Text Available A convenient approach to the synthesis of multithiacalix[4]arene derivatives containing amino groups and phthalimide fragments by the formation of quaternary ammonium salts is presented. As the initial macrocycle for the synthesis of multithiacalix[4]arenes, a differently substituted p-tert-butylthiacalix[4]arene containing bromoacetamide and three phthalimide fragments was used in a 1,3-alternate conformation. The macrocycle in cone conformation containing the tertiary amino groups was found to be a convenient core for the multithiacalix[4]arene systems. Interaction of the core multithiacalix[4]arene with monobromoacetamide derivatives of p-tert-butylthiacalix[4]arene resulted in formation in high yields of pentakisthiacalix[4]arene containing quaternary ammonium and phthalimide fragments. The removal of phthalimide groups led to the formation of amino multithiacalix[4]arene in a good yield. Based on dynamic light scattering, it was shown that the synthesized amino multithiacalix[4]arene, with pronounced hydrophobic and hydrophilic fragments, formed dendrimer-like nanoparticles in water via direct supramolecular self-assembly.

An Effective Hg2+-Selective Fluorescent Chemosensor Based on a Calix[4]arene Bearing Four Dansyl Amides

Institute of Scientific and Technical Information of China (English)

LI Guang-Ke; LIU Min; YANG Guo-Qiang; CHEN Chuan-Feng; HUANG Zhi-Tang

2008-01-01

A new calix[4]arene-based fluorescent chemosensor bearing four dansyl amides on the upper rim (1) was con- veniently synthesized, which showed high sensitivity and selectivity toward Hg2+ over a wide range of metal ions in 50% aqueous acetonitrile. The complexation of Hg2+ ion induced a strong fluorescence quenching of 1 due to a well-defined electron transfer process from the dansyl group(s) to the metal center. Compared with compounds 2 and 3, tetradansyl amide substituted calix[4]arene 1 showed a preorganized and coordinated complexing site for metal ions. Moreover, the detection limit for Hg2. was found to be 3.41×10-6 mol·L-1, which might make 1 a po-tentially practical Hg2+-selective fluorescent sensor in aqueous system.

Why Aren't Philosophers and Educators Speaking to Each Other? Some Reasons for Hope.

Science.gov (United States)

Ellett, Frederick S., Jr.

2002-01-01

Responds to Arcilla's article, "Why Aren't Philosophers and Educators Speaking to One Another?" noting complexities that complicate the answer and suggesting that they are indeed communicating if one accepts a broader definition of philosophers and educators. The essay asserts that little educational research and theory has had much…

Preparation of Pillar[5]arene-Based [2]Rotaxanes by a Stopper-Exchange Strategy.

Science.gov (United States)

Nierengarten, Iwona; Meichsner, Eric; Holler, Michel; Pieper, Pauline; Deschenaux, Robert; Delavaux-Nicot, Béatrice; Nierengarten, Jean-François

2018-01-02

A pillar[5]arene-containing rotaxane building block bearing exchangeable stoppers has been prepared in multigram scale quantities with high yields from the reaction of 2,4-dinitrophenol (DNP) with the inclusion complex resulting from the association of dodecanedioyl chloride with 1,4-diethoxypillar[5]arene. Stopper exchange reactions have been achieved by treatment of the resulting DNP diester with various amines through an addition-elimination mechanism preventing the unthreading of the axle component during the reaction and thus preserving the [2]rotaxane structures. The resulting diamide [2]rotaxane derivatives have thus been obtained in good to excellent yields. Importantly, [2]rotaxanes difficult or impossible to prepare by direct introduction of the two stoppers in a single synthetic step are now easily available. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

pKa Determination of water-soluble calix[4]arenes

NARCIS (Netherlands)

Shinkai, Seiji; Araki, Koji; Grootenhuis, P.D.J.; Reinhoudt, David

1991-01-01

Neutral, water-soluble 5,11,17,23-tetrakis[bis-(2-hydroxyethyl)aminosulphonyl]calix[4]arene-25,26,27,28-tetraol and 5,11,17,23-tetranitrocalix[4]arene-25,26,27,28-tetraol have been synthesized and the pKa values of the OH groups determined in an aqueous system.

(II) complexes containing isocyanide and labile nitrile ligands

African Journals Online (AJOL)

A new ruthenium(II) complex containing both acetonitrile and propionitrile moieties as coordinating ligands has been prepared. The treatment of the polymer [{RuCl2(COD)}x], (COD = cycloocta-1,5-diene) (1) with a mixture of acetonitrile and propionitrile under reflux produced a new precursor ...

The effect of specific solvent-solute interactions on complexation of alkali-metal cations by a lower-rim calix[4]arene amide derivative.

Science.gov (United States)

Horvat, Gordan; Stilinović, Vladimir; Kaitner, Branko; Frkanec, Leo; Tomišić, Vladislav

2013-11-04

Complexation of alkali-metal cations with calix[4]arene secondary-amide derivative, 5,11,17,23-tetra(tert-butyl)-25,26,27,28-tetra(N-hexylcarbamoylmethoxy)calix[4]arene (L), in benzonitrile (PhCN) and methanol (MeOH) was studied by means of microcalorimetry, UV and NMR spectroscopies, and in the solid state by X-ray crystallography. The inclusion of solvent molecules (including acetonitrile, MeCN) in the calixarene hydrophobic cavity was also investigated. The classical molecular dynamics (MD) simulations of the systems studied were carried out. By combining the results obtained using the mentioned experimental and computational techniques, an attempt was made to get an as detailed insight into the complexation reactions as possible. The thermodynamic parameters, that is, equilibrium constants, reaction Gibbs energies, enthalpies, and entropies, of the investigated processes were determined and discussed. The stability constants of the 1:1 (metal:ligand) complexes measured by different methods were in very good agreement. Solution Gibbs energies of the ligand and its complexes with Na(+) and K(+) in methanol and acetonitrile were determined. It was established that from the thermodynamic point of view, apart from cation solvation, the most important reason for the huge difference in the stability of these complexes in the two solvents lay in the fact that the transfer of complex species from MeOH to MeCN was quite favorable. That could be at least partly explained by a more exergonic inclusion of the solvent molecule in the complexed calixarene cone in MeCN as compared to MeOH, which was supported by MD simulations. Molecular and crystal structures of the lithium cation complex of L with the benzonitrile molecule bound in the hydrophobic calixarene cavity were determined by single-crystal X-ray diffraction. As far as we are aware, for the first time the alkali-metal cation was found to be coordinated by the solvent nitrile group in a calixarene adduct. According to

Cyclometallated ruthenium(II) carbonyl complexes with 1 ...

Indian Academy of Sciences (India)

The characterization of the complexes having the ... Electronic spectra of the complexes display multiple strong absorptions in the ... Microanalyses (CHN) were performed by using a ..... proton.47,49 Absence of this signal in the spectra of.

Optical, electrical and sensing properties of β-ketoimine calix[4]arene thin films

Energy Technology Data Exchange (ETDEWEB)

Echabaane, M., E-mail: mosaab.echabaane@yahoo.fr [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia); Rouis, A. [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia); Bonnamour, I. [Institut de Chimie and Biochimie Moléculaires and Supramoléculaires (ICBMS), UMR CNRS 5246, 43 Boulevard du 11 Novembre 1918, Université Claude Bernard Lyon 1, 69100 Villeurbanne (France); Ben Ouada, H. [Laboratoire des Interfaces et Matériaux Avancés (LIMA), Faculté des Sciences de Monastir, Avenue de l' environnement, 5000 Monastir (Tunisia)

2013-09-16

Optical, electrical and ion sensing properties of β-ketoimine calix[4]arene thin films have been investigated. These calix[4]arene derivative films exhibit absorption spectra with a resolved electronic structure in the UV–vis and the energy gap was found to be 3.65 eV. Electrical properties of ITO/β-ketoimine calix[4]arene/Al devices have been investigated by I–V characteristics and impedance spectroscopy measurements. The conduction is governed by space-charge-limited current (SCLC) mechanism. The impedance spectroscopy study showed a hopping transport process, a typical behavior of disordered materials. The device was modeled by a single parallel resistor and capacitor network in series with a resistance. The β-ketoimine calix[4]arene was used for the conception of the novel optical chemical sensor and the detection of Cu{sup 2+} ions was monitored by UV–visible spectroscopy. The linear dynamic range for the determination of Cu{sup 2+} has been 10{sup −5}–10{sup −3.7} M with a detection limit of 10{sup −5} M. The characteristics of this optode such as regeneration, repeatability, reproducibility, short-term stability, life time and ion selectivity have been discussed. - Highlights: • We examine optical properties of β-ketoimine calix[4]arene ligand. • We investigate the electric properties of ITO/β-ketoimine calix[4]arene/Al device. • We study the sensing properties of optode films for the detection of copper (II)

Functionalized alkoxy arene diazonium salts from paracetamol.

Science.gov (United States)

Schmidt, Bernd; Berger, René; Hölter, Frank

2010-03-21

Arene diazonium tetrafluoroborates can be synthesized from aromatic acetamides via a sequence of deacetylation, diazotation and precipitation, induced by anion exchange. The reaction is conducted as a convenient one-flask transformation with consecutive addition of the appropriate reagents. Exchange of solvents or removal of byproducts prior to isolation of the product is not required. The arene diazonium salts are isolated from the reaction mixture by simple filtration. Two complementary protocols are presented, and the utility of the reaction is exemplified for a synthesis of the diarylheptanoid natural product de-O-methyl centrolobine.

Pd(II)-Catalyzed Olefination of Electron-Deficient Arenes Using 2,6-Dialkylpyridine Ligands

Science.gov (United States)

Zhang, Yang-Hui; Shi, Bing-Feng; Yu, Jin-Quan

2009-01-01

Pd(II)-catalyzed meta-olefination of highly electron deficient arenes is achieved through the use of a rationally designed mutually repulsive ligand. The combination of directed and non-directed C–H functionalization of arenes provides a versatile route for the synthesis of highly sought-after 1,2,4-trisubstituted arenes. PMID:19296661

Experimental and DFT study on the complexation of the silver cation with calix[4]arene-bis(t-octylbenzo-18-crown-6)

International Nuclear Information System (INIS)

Makrlik, E.; Toman, P.; Vanura, P.

2013-01-01

From extraction experiments and γ-activity measurements, the exchange extraction constant corresponding to the equilibrium Ag + (aq) + 1 x Cs + (org) ⇔ 1 x Ag + (org) + Cs + (aq) taking place in the two-phase water-phenyltrifluoromethyl sulfone (FS 13) system (1 = calix[4]arene-bis(t-octylbenzo-18-crown-6); aq = aqueous phase, org = FS 13 phase) was evaluated as logK ex (Ag + , 1 x Cs + ) = -1.5 ± 0.1. Further, the stability constant of the 1 x Ag + complex in FS 13 saturated with water was calculated for a temperature of 25 deg C: log β org(1 x Ag + ) = 10.1 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1 x Ag + was derived. In the resulting 1 x Ag + complex, the 'central' cation Ag + is bound by eight bond interactions to six oxygen atoms from the respective 18-crown-6 moiety and to two carbons of the corresponding two benzene rings of the parent ligand 1 via cation-π interaction. (author)

Comparative Study of Tributyltin Adsorption onto Mesoporous Silica Functionalized with Calix[4]arene, p-tert-Butylcalix[4]arene and p-Sulfonatocalix[4]arene

Directory of Open Access Journals (Sweden)

Sana Alahmadi

2014-04-01

Full Text Available The adsorption of tributyltin (TBT, onto three mesoporous silica adsorbents functionalized with calix[4]arene, p-tert-butylcalix[4]arene and p-sulfonatocalix[4]arene (MCM-TDI-C4, MCM-TDI-PC4 and MCM-TDI-C4S, respectively has been compared. Batch adsorption experiments were carried out and the effect of contact time, initial TBT concentration, pH and temperature were studied. The Koble–Corrigan isotherm was the most suitable for data fitting. Based on a Langmuir isotherm model, the maximum adsorption capacities were 12.1212, 16.4204 and 7.5757 mg/g for MCM-TDI-C4, MCM-TDI-PC4 and MCM-TDI-C4S, respectively. The larger uptake and stronger affinity of MCM-TDI-PC4 than MCM-TDI-C4 and MCM-TDI-C4S probably results from van der Waals interactions and the pore size distribution of MCM-TDI-PC4. Gibbs free energies for the three adsorption processes of TBT presented a negative value, reflecting that TBT/surface interactions are thermodynamic favorable and spontaneous. The interaction processes were accompanied by an increase of entropy value for MCM-TDI-C4 and MCM-TDI-C4S (43.7192 and 120.7609 J/mol K, respectively and a decrease for MCM-TDI-PC4 (−37.4704 J/mol K. It is obviously observed that MCM-TDI-PC4 spontaneously adsorbs TBT driven mainly by enthalpy change, while MCM-TDI-C4 and MCM-TDI-C4S do so driven mainly by entropy changes.

The synthesis and alkylation of p-tetrakischloro-calix[4]arene

Directory of Open Access Journals (Sweden)

E. A. Ivanova

2014-11-01

Full Text Available This work is devoted to the development of a chlorination of a calixarenes and a testing of the methods for their preparation to investigate the biological activity of the obtained compounds. New convinient undescribed in the literature methods of the chlorination using sulphuryl chloride or sodium hypochlorite were designed. By the using de-tert-butylcalix[4]arene, containing lower rin the ethoxy(hydroxycarbonyl metoxy groups, as the starting compounds in the same reactin l aed to mixture of the produts. The reaction of the calix[4]arene and the sulfuryl chloride led to the tetra-kis-chlorocalix[4]arene with good yield (95 %.

Investigation on Al(III) and Zn(II) complexes containing a calix[4]arene bearing two 8-oxyquinoline pendant arms used as emitting materials for OLEDs

International Nuclear Information System (INIS)

Bagatin, Izilda A.; Legnani, Cristiano; Cremona, Marco

2009-01-01

A comparison between [Al·1] 3+ and [Zn·1] 2+ complexes (1 = 5,11,17,23-tetra-tert-butyl-25,27-bis[(quinoline-8-oxy)propyloxy]-26, 28-dihydroxy-calix[4]arene) has been made using electrochemical techniques and the experimental results obtained in the fabrication of organic light emitting devices (OLEDs). The electrochemically determined values of the ionization potential I p and electron affinity E a parameters for the [Al·1] 3+ (I p = 5.82eV, E a = 2.80eV) and [Zn·1] 2+ (I p = 5.67eV, E a = 2.32eV) evidenced that the [Al·1] 3+ complex is a better electron transporting layer with respect to the Zn complex one. The fabricated OLEDs based on these supramolecular complexes show a superior quality with the [Al·1] 3+ systems expected from the energy level diagrams

Influence of different ruthenium(II) bipyridyl complex on the photocatalytic H{sub 2} evolution over TiO{sub 2} nanoparticles with mesostructures

Energy Technology Data Exchange (ETDEWEB)

Peng, Tianyou [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Hubei Key Laboratory for Catalysis and Material Science, College of Chemistry and Material Science, South-Central University for Nationalities, Wuhan 430074 (China); Ke, Dingning; Cai, Ping; Dai, Ke; Ma, Liang; Zan, Ling [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China)

2008-05-15

H{sub 2} production over dye-sensitized Pt/TiO{sub 2} nanoparticles with mesostructures (m-TiO{sub 2}) under visible light ({lambda} > 420 nm) was investigated by using methanol as electron donors. Experimental results indicate that three types of ruthenium(II) bipyridyl complex dyes (one binuclear Ru, two mononuclear Ru), which can be attached to Pt/m-TiO{sub 2} with different linkage modes, show different photosensitization effects due to their different coordination circumstances and physicochemical properties. The dye tightly linked with m-TiO{sub 2} has better durability but the lowest H{sub 2} evolution efficiency, whereas the loosely attached dyes possess higher H{sub 2} evolution efficiency and preferable durability. It seems that the dynamic equilibrium between the linkage of the ground state dye with TiO{sub 2} and the divorce of the oxidization state dye from the surfaces plays a crucial role in the photochemical behavior during the photocatalyst sensitization process. It is helpful to improve the H{sub 2} evolution efficiency by enhancing the electron injection and hindering the backward transfer. The binuclear Ru(II) dye shows a better photosensitization in comparison with mononuclear Ru(II) dyes due to its large molecular area, conjugation system, and ''antenna effect'', which, in turn, improve the visible light harvesting and electron transfer between the dye molecules and TiO{sub 2}. (author)

The NiCl2-Li-arene(cat.) combination: a versatile reducing mixture.

Science.gov (United States)

Alonso, Francisco; Yus, Miguel

2004-06-20

The NiCl2.2H2O-Li-arene(cat.) combination described in this tutorial review has shown to be a useful and versatile mixture able to reduce a broad range of functionalities bearing carbon-carbon multiple bonds, as well as carbon-heteroatom and heteroatom-heteroatom single and multiple bonds. The analogous deuterated combination, NiCl2.2D2O-Li-arene(cat.), allows the easy incorporation of deuterium in the reaction products. Alternatively, the anhydrous NiCl2-Li-arene (or polymer-supported arene)(cat.) system generates a highly reactive metallic nickel, which in the presence of molecular hydrogen at atmospheric pressure is able to catalyze the hydrogenation of almost the same type of functionalities mentioned above.

UTILIZATION OF AREN (Arenga pinnata Merr. SAWMILLING WASTE FOR EDIBLE MUSHROOM CULTIVATION MEDIA

Directory of Open Access Journals (Sweden)

Djarwanto

2016-04-01

Full Text Available Aren (Arenga pinnata Merr. is a multipurpose tree that can be utilized for palm sugar, alcoholic drinks, beverages and construction wood. The use of aren sawdust has not been studied intensively. This study examines the utilization of aren sawdust as cultivation media for edible mushrooms. Aren sawdust was mixed with rice bran, CaCO3, gypsum, fertilizers and distilled water before sterilization in 30 minutes pressurized autoclave at 1210C and 1.5atm. The mixed media was inoculated with pure cultures containing four mushrooms species (Pleurotus flabellatus, P. ostreatus, P. sajor-caju and Lentinula edodes and incubated for five weeks to allow mycelium growth producing fruit bodies. The fruit bodies were harvested everyday within four months and examined for its gained mushroom-weight and biological conversion efficiency/BE. The core part of aren trunk was cut into smaller pieces of 10 cm (width by 5 cm (thickness, by 120 cm (length. Each core sample was bored from the surface inward, creating holes with a particular distance apart. Each hole was inoculated with pure cultures containing 6 mushroom species (four species above, P. cystidiosus and Auricularia polytricha. The inoculated samples were slanted on bamboo support, and placed in a bamboo hut. Harvesting was carried out everyday after the fruiting body became mature and examined for its gained mushroom weight. Results show that the use of sawdust supplemented with nutritious material is more likely to improve the mushroom yield than that of aren sawn-timber core. In this case, the BE values with aren-sawdust media were 21.97-89.45% (P. flabellatus, 15.36-105.36% (P. ostreatus, 63.88-76.86% (P. sajor-caju, and up to 62.88% (L. edodes. Meanwhile, the yields (gained mushroom weight with aren sawn-timber media were 210g (P. ostreatus, 368g (P. flabellatus, 331g (P. sajor-caju and 48g (A. polytricha; however, P. cystidiosus and L. edodes inoculated on aren stem core failed to grow.

Synthesis and binding properties of calix[4]arene diamide dicarboxylic acids

International Nuclear Information System (INIS)

Arnaud-Neu, F.; Barboso, S.; Schwing-Weill, M.J.; Casnati, A.; Pinalli, A.; Ungaro, R.

2000-01-01

Calix[4]arenes diametrically substituted at the lower rim with two carboxylic acid and two tertiary amide binding groups were obtained in good yields and their acid-base properties studied in methanol solution. Complexation studies, performed in methanol by potentiometry, show that mononuclear (MLH z , z = 0,1) or dinuclear (M 2 L) complexes are formed with alkali metal cations, whereas M x L 2 H z (x=1,2,z = 0,1) species, involving two ligands, are also present with alkaline-earth cations. Both ligands show a remarkable selectivity for Ca 2+ and Sr 2+ among alkali and alkaline-earth metal ions. (authors)

AREN - A non-governmental organization acting in public formation and information

International Nuclear Information System (INIS)

Mauna, Traian; Anghelescu, Serban Mihnea

1998-01-01

The Romanian Association for Nuclear Energy - AREN, founded eight years ago as non-governmental and non-profit organization, is deploying its activity on a voluntary basis. The association comprises 248 fellows, as physical persons, 17 juridical supporting fellows and eight honorary fellows, outstanding personalities with special contributions in promoting Romanian nuclear power development, 'Ionel Purica' - prize winners. AREN co-operates with other domestic NGO's and other sister organizations from abroad, is a collective member of the General Association of Romanian Engineers and is affiliated to European Nuclear Society (ENS). For specialist and public information AREN is publishing and disseminating the following four publications: 1 - 'Energia Nucleara' (Nuclear Energy) journal; 2 - the bulletin 'Nucleus' brought from ENS and translated in Romanian language; 3 - the news 'NUC NET', adopted, worked up and translated in Romanian; 4 - the periodic bulletin 'Nuclear News'. Yearly, AREN organizes the 'Nuclear Energy Days' and the biennial International Symposium of Nuclear Energy (SIEN). (authors)

The contrasting chemistry and cancer cell cytotoxicity of bipyridine and bipyridinediol ruthenium(II) arene complexes

Czech Academy of Sciences Publication Activity Database

Bugarcic, T.; Habtemariam, A.; Štěpánková, Jana; Heringová, Pavla; Kašpárková, Jana; Deeth, R.J.; Johnstone, R.D.L.; Prescimone, A.; Parkin, A.; Parsons, S.; Brabec, Viktor; Sadler, P.J.

2008-01-01

Roč. 47, č. 24 (2008), s. 11470-11486 ISSN 0020-1669 R&D Projects: GA MŠk(CZ) LC06030; GA MŠk(CZ) ME08017; GA MŠk(CZ) OC08003; GA AV ČR(CZ) 1QS500040581; GA AV ČR(CZ) KAN200200651; GA AV ČR(CZ) IAA400040803; GA MZd(CZ) NR8562 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : DNA * ruthenium * cancer Subject RIV: BO - Biophysics Impact factor: 4.147, year: 2008

Macromolecules containing bipyridine and terpyridine metal complexes: towards metallo-supramolecular polymers

NARCIS (Netherlands)

Schubert, U.S.; Eschbaumer, C.

2002-01-01

The ability of a broad range of N-heterocycles to act as very effective and stable complexation agents for several transition metal ions, such as cobalt(II), copper(II), nickel(II), and ruthenium(II), has long been known in analytical chemistry. This behavior was later utilized in supramolecular

High water contents in basaltic melt inclusions from Arenal volcano, Costa Rica

Science.gov (United States)

Wade, J. A.; Plank, T.; Hauri, E. H.; Melson, W. G.; Soto, G. J.

2004-12-01

Despite the importance of water to arc magma genesis, fractionation and eruption, few quantitative constraints exist on the water content of Arenal magmas. Early estimates, by electron microprobe sum deficit, suggested up to 4 wt% H2O in olivine-hosted basaltic andesite melt inclusions (MI) from pre-historic ET-6 tephra (Melson, 1982), and up to 7 wt% H2O in plagioclase and orthopyroxene-hosted dacitic MI from 1968 lapilli (Anderson, 1979). These high water contents are consistent with abundant hornblende phenocrysts in Arenal volcanics, but inconsistent with geochemical tracers such as 10Be and Ba/La that suggest a low flux of recycled material (and presumably water) from the subduction zone. In order to test these ideas, and provide the first direct measurements of water in mafic Arenal magmas, we have studied olivine-hosted MI from the prehistoric (900 yBP; Soto et al., 1998) ET3 tephra layer. MI range from andesitic (> 58% SiO2) to basaltic compositions ( 4 wt%) found here for Arenal basaltic MI support the semi-quantitative data from earlier studies, but are somewhat unexpected given predictions from slab tracers. Arenal water contents (4%) approach those of the 1995 eruption of Cerro Negro in Nicaragua (4-5 wt% in basaltic MI; Roggensack et al., 1997), despite the fact that the latter has Ba/La of > 100, while Arenal has Ba/La Journal of Geology; Melson, William G. (1982) Boletin de Volcanologia; Roggensack et al. (1997) Science; Soto et al. (1998) OSIVAM; Williams-Jones et al. (2001) Journal of Volc. and Geoth. Res.

Synthesis and Photophysical and Electrochemical Properties of Functionalized Mono-, Bis-, and Trisanthracenyl Bridged Ru(II Bis(2,2′:6′,2″-terpyridine Charge Transfer Complexes

Directory of Open Access Journals (Sweden)

Adewale O. Adeloye

2014-01-01

Full Text Available With the aim of developing new molecular devices having long-range electron transfer in artificial systems and as photosensitizers, a series of homoleptic ruthenium(II bisterpyridine complexes bearing one to three anthracenyl units sandwiched between terpyridine and 2-methyl-2-butenoic acid group are synthesized and characterized. The complexes formulated as bis-4′-(9-monoanthracenyl-10-(2-methyl-2-butenoic acid terpyridyl ruthenium(II bis(hexafluorophosphate (RBT1, bis-4′-(9-dianthracenyl-10-(2-methyl-2-butenoic acid terpyridyl ruthenium(II bis(hexafluorophosphate (RBT2, and bis-4′-(9-trianthracenyl-10-(2-methyl-2-butenoic acid terpyridyl ruthenium(II bis(hexafluorophosphate (RBT3 were characterized by elemental analysis, FT-IR, UV-Vis, photoluminescence, 1H and 13C NMR spectroscopy, and electrochemical techniques by elemental analysis, FT-IR, UV-Vis, photoluminescence, 1H and 13C NMR spectroscopy, and electrochemical techniques. The cyclic voltammograms (CVs of (RBT1, (RBT2, and (RBT3 display reversible one-electron oxidation processes at E1/2 = 1.13 V, 0.71 V, and 0.99 V, respectively (versus Ag/AgCl. Based on a general linear correlation between increase in the length of π-conjugation bond and the molar extinction coefficients, the Ru(II bisterpyridyl complexes show characteristic broad and intense metal-to-ligand charge transfer (MLCT band absorption transitions between 480–600 nm, ε=9.45×103 M−1 cm−1, and appreciable photoluminescence spanning the visible region.

Chlorodifluoromethane-triggered formation of difluoromethylated arenes catalysed by palladium

Science.gov (United States)

Feng, Zhang; Min, Qiao-Qiao; Fu, Xia-Ping; An, Lun; Zhang, Xingang

2017-09-01

Difluoromethylated aromatic compounds are of increasing importance in pharmaceuticals, agrochemicals and materials. Chlorodifluoromethane (ClCF2H), an inexpensive, abundant and widely used industrial raw material, represents the ideal and most straightforward difluoromethylating reagent, but introduction of the difluoromethyl group (CF2H) from ClCF2H into aromatics has not been reported. Here, we describe a direct palladium-catalysed difluoromethylation method for coupling ClCF2H with arylboronic acids and esters to generate difluoromethylated arenes with high efficiency. The reaction exhibits a remarkably broad substrate scope, including heteroarylboronic acids, and was used for difluoromethylation of a range of pharmaceuticals and biologically active compounds. Preliminary mechanistic studies revealed that a palladium difluorocarbene intermediate is involved in the reaction. Although numerous metal-difluorocarbene complexes have been prepared, the catalytic synthesis of difluoromethylated or difluoromethylenated compounds involving metal-difluorocarbene complexes has not received much attention. This new reaction therefore also opens the door to understand metal-difluorocarbene complex catalysed reactions.

p-tert-Butylcalix[8]arene: an extremely versatile platform for cluster formation.

Science.gov (United States)

Taylor, Stephanie M; Sanz, Sergio; McIntosh, Ruaraidh D; Beavers, Christine M; Teat, Simon J; Brechin, Euan K; Dalgarno, Scott J

2012-12-07

p-tert-Butylcalix[4]arene is a bowl-shaped molecule capable of forming a range of polynuclear metal clusters under different experimental conditions. p-tert-Butylcalix[8]arene (TBC[8]) is a significantly more flexible analogue that has previously been shown to form mono- and binuclear lanthanide (Ln) metal complexes. The latter (cluster) motif is commonly observed and involves the calixarene adopting a near double-cone conformation, features of which suggested that it may be exploited as a type of assembly node in the formation of larger polynuclear lanthanide clusters. Variation in the experimental conditions employed for this system provides access to Ln(1), Ln(2), Ln(4), Ln(5), Ln(6), Ln(7) and Ln(8) complexes, with all polymetallic clusters containing the common binuclear lanthanide fragment. Closer inspection of the structures of the polymetallic clusters reveals that all but one (Ln(8)) are in fact based on metal octahedra or the building blocks of octahedra, with the identity and size of the final product dependent upon the basicity of the solution and the deprotonation level of the TBC[8] ligand. This demonstrates both the versatility of the ligand towards incorporation of additional metal centres, and the associated implications for tailoring the magnetic properties of the resulting assemblies in which lanthanide centres may be interchanged. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Report on Auscultation of the Arenal's Dam P. H. Arenal

International Nuclear Information System (INIS)

1994-09-01

The Costa Rican Electricity Institute (Instituto Costarricense de Electricidad), always has been worried to verify the good state of the works and thus to guarantee its operation. For that reason, it has established different sorts of auscultation to the Arenal's Dam. This report analyzes the geo-hydraulic, structural and topographic auscultation. It also includes information about the new techniques used by the ARCAL XVIII RLA/8/018; application of Tracer Techniques for the study of water leakage in dams and damming projects. (author). 18 charts, 2 maps, 4 tabs

High performance oligomers: synthesis and photochemical properties of calix(n)arene containing various photoreactive groups

International Nuclear Information System (INIS)

Nishikubo, T.; Kameyama, A.

1999-01-01

Photoreactive calix(n)arenes containing radical polymerizable (meth)acrylate groups, and catatonically polymerizable vinyl ether, propargyl ether, oxirane and oxetane groups were synthesized by certain reactions of calix(n)arenes with the corresponding (meth)acrylic acid derivatives, vinyl ether compound, epibromohydrin and oxetane derivatives, respectively. The photochemical reaction of these calix(n)arene derivatives were also examined

Thiacalix[4]arene derivatives as extractants for metal ions in aqueous solutions: Application to the selective facilitated transport of Ag(I)

Energy Technology Data Exchange (ETDEWEB)

Zaghbani, Asma [Laboratoire Eau et Technologies Membranaires, CERTE, BP 273, 8020 Soliman (Tunisia); Fontas, Claudia [Department of Chemistry, University of Girona, 17071 Girona (Spain)], E-mail: claudia.fontas@udg.edu; Hidalgo, Manuela [Department of Chemistry, University of Girona, 17071 Girona (Spain); Tayeb, Rafik; Dhahbi, Mahmoud [Laboratoire Eau et Technologies Membranaires, CERTE, BP 273, 8020 Soliman (Tunisia); Vocanson, Francis; Lamartine, Roger [Universite de Lyon, Lyon, F-69003 (France); Universite Lyon 1, Villeurbanne, F-69622 (France); CNRS, UMR 5246, ICBMS, equipe CSAp, 43 boulevard du 11 novembre 1918, Villeurbanne, F-69622 (France); Seta, Patrick [Institut Europeen des Membranes, UMR CNRS 5635, 1919 route de Mende, 34293 Montpellier (France)

2008-07-01

The complexation abilities of different thiacalix[4]arene derivatives towards some rare earth metal ions, metallic pollutants, and noble metals have been investigated in liquid-liquid experiments. Thiacalix[4]arene dissolved in chloroform effectively extracts Pd(II) (in acidic chloride media) and also Ag(I), Cd(II), Sm(III) and Ce(III), all buffered at pH 6 or 8. The modification of this compound to form an amide derivative results in an effective extraction of noble metals, ranked according to Au(III) > Pd(II) > Pt(IV) > Ag(I). Moreover, a supported liquid membrane system for silver transport has been developed based on thiacalix[4]arene dissolved in NPOE, and parameters affecting its efficiency have been investigated, such as the stripping composition and the pH of the feed solution. Finally, the selectivity of the membrane system has been evaluated by using as feed sources mixtures of silver and other metal ion000.

Elution behavior of N-heterocyclic derivatives of mixed ruthenium(II)-sulfoxide complexes in reversed-phase high-performance liquid chromatography

International Nuclear Information System (INIS)

Toma, H.E.; Silva, D.O.

1991-01-01

The elution behaviour of a series of dichlorobis-(dimethylsulfoxide)bis(N-heterocyclic) ruthenium(II) complexes has been investigated using reversed-phase HPLC. Similar trends as those displayed by the free N-heterocyclic bases have been observed for the complexes, essentially reflecting the hydrophobic properties of the aromatic ligands. (orig.)

THE ADSORPTION OF Pb(II AND Cr(III BY POLYPROPYLCALIX[4]ARENE POLYMER

Directory of Open Access Journals (Sweden)

Suryadi Budi Utomo

2010-06-01

Full Text Available A research has been conducted to investigate the adsorption behavior of Pb(II and Cr(III onto polypropylcalix[4]arene polymer. The polypropylcalix[4]arene polymer was synthesized in the presence of H2SO4 catalyst and chloroform under N2 condition for 5 h using 25-allyloxy-26,27,28-trihydroxycalyx[4]arene as the precursor. The Polymer was obtained as yellow crystal with melting point of  288-290 °C and its relative molecular weight was 44.810 g.mol-1. The application of polypropylcalix[4]arene for trapping heavy metal cations and its adsorption model were examined by stirring the suspension of the calixarene in the sample solutions for various pH, time, and concentration of Pb(II and Cr(III solution. Effect of pH on batch experiments for the mentioned ions indicated that the optimum pH for metal binding were 5 for lead(II and chromium(III. The adsorption model of metal ions on polypropylcalix[4]arene followed both the pseudo second order adsorption of Ho's and Langmuir isotherm adsorption kinetics models with rate constant (k were 6.81 x 101 min-1 for Pb(II and 2.64 x 10-2 min-1 for Cr(III. The adsorption equilibrium constant, K, were 5.84 x 105 L.mol-1 for Pb(II and 4.66 x 105 L.mol-1 for Cr(III. The maximum adsorption capacity of polypropylcalix[4]arene to Pb(II and Cr(III were 16.31 and 18.14 mg.g-1 with adsorption energy of 32.90 and 32.34 kJ.mol-1, respectively.   Keywords: polypropylcalix[4]arene, adsorption, Pb(II, and Cr(III

Synthesis of calix[6]arenes partially functionalized at the upper rim

NARCIS (Netherlands)

Casnati, Alessandro; Domiano, Laura; Pochini, Andrea; Ungaro, Rocco; Carramolino, Mar; Magrans, J. Oriol; Nieto, Pedro M.; Lopez-Prados, Javier; Prados, Pilar; de Mendoza, Javier; Janssen, Rob G.; Janssen, R.G.; Verboom, Willem; Reinhoudt, David

1995-01-01

Several new examples of calix[6]arenes selectively functionalized at the upper rim are reported. Starting from calix[6]arenes 1,3,5-tri-, 1,2,4,5-tetra- and 1,2,3,4,5-pentaalkylated at the lower rim, it is possible to isolate macrocycles 2,4,6-tri-, 3,6-di- and 6-mono functionalized at the upper rim

Remediation of cadmium-contaminated soil by extraction with para-sulphonato-thiacalix[4]arene, a novel supramolecular receptor

International Nuclear Information System (INIS)

Li Yushuang; Hu Xiaojun; Song Xueying; Sun Tieheng

2012-01-01

Batch extractions were conducted to evaluate the performance of para-sulphonato-thiacalix[4]arene (STC[4]A), a novel supramolecular receptor, for removing cadmium (Cd) from soil. The extraction mechanism was investigated by determination of the conditional stability constants (log K) of the STC[4]A-Cd complex. The influences of various variables were examined, including pH, contact time, and extractant concentration. The Cd extraction efficiency increased with increasing pH, reaching the maximum at pH 11 and then declining at higher pH values. This pH dependence was explained by the variation in the log K value of the STC[4]A-Cd complex along with pH change. When the STC[4]A dose was increased to an STC[4]A:Cd molar ratio of 2.5:1, Cd was exhaustively removed (up to 96.8%). The comparison experiment revealed that the Cd extraction performance of STC[4]A was almost equivalent to that of EDTA and significantly better than that of natural organic acids. STC[4]A extraction could efficiently prevent co-dissolution of soil minerals. - Highlights: ► First report on para-sulphonato-thiacalix[4]arene (STC[4]A) as extractant for soil washing. ► The Cd extraction performance of STC[4]A was almost equivalent to that of EDTA. ► STC[4]A extraction could efficiently avoid the dissolution of soil minerals, such as K, Ca, Mn. ► Extraction mechanism was investigated by determination of log K values of STC[4]A-Cd complex. ► A rational explanation for the pH dependence of extraction performance was given. - This is the first report on para-sulphonato-thiacalix[4]arene as an extractant for soil washing, which proved to be very efficient for Cd removal and could prevent co-dissolution of soil minerals.

Nitration of Thiacalix[4]arene Derivatives

Czech Academy of Sciences Publication Activity Database

Lhoták, P.; Svoboda, J.; Stibor, I.; Sýkora, Jan

2002-01-01

Roč. 43, č. 41 (2002), s. 7413-7417 ISSN 0040-4039 R&D Projects: GA ČR GA104/00/1722 Keywords : derivatives * nitation of thiacalix[4]arene Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.357, year: 2002

The solid-state structures of organic salts formed by calix[4]arene dihydroxyphosphonic acid with nucleic bases cations: adeninium, cytosinium, guaninium and uracilium

KAUST Repository

Shkurenko, Aleksander

2018-02-19

Calix[4]arene dihydroxyphosphonic acid has been demonstrated to possess an interesting range of biological properties, including atypical anti-cancer activity. The robustness of calix[4]arene dihydroxyphosphonic acid and its ubiquitous dimeric motif offers perspectives for pre-defined solid state complexation with small molecules. In the current article we describe co-crystals (organic salts) of calix[4]arene dihydroxyphosphonic acid with four nucleic base cations: adeninium, cytosinium, guaninium and uracilium. A number of characteristic interactions between the components in the four co-crystals are pointed out also using the Hirshfeld surface analysis. All the four co-crystals are based on layers of calix[4]arene dimers, alternating with layers of nucleic acid molecules. Two of the reported crystal structures (cytosinium and guaninium) are 1D channel-type structures, while the two others (adeninium and uracilium) represent 2D channel-type structures. In three out of four reported structures, interactions between the cations of nucleic bases are present generating 1D chains of cations. A constant motif is that the nucleic base is present in a type of cavity formed by one aromatic ring and a phosphonic acid moiety.

Organoruthenium Complexes with CN Ligands are Highly Potent Cytotoxic Agents that Act by a New Mechanism of Action

Czech Academy of Sciences Publication Activity Database

Novohradský, Vojtěch; Yellol, J.; Stuchlíková, O.; Santana, M.D.; Kostrhunová, Hana; Yellol, G.; Kašpárková, Jana; Bautista, D.; Ruiz, J.; Brabec, Viktor

2017-01-01

Roč. 23, č. 61 (2017), s. 15294-15299 ISSN 0947-6539 R&D Projects: GA ČR(CZ) GA17-05302S Institutional support: RVO:68081707 Keywords : chemotherapeutic-agents * ruthenium(ii) complexes * iridium(iii) complexes Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 5.317, year: 2016

Cu(II)-mediated ortho C-H alkynylation of (hetero)arenes with terminal alkynes.

Science.gov (United States)

Shang, Ming; Wang, Hong-Li; Sun, Shang-Zheng; Dai, Hui-Xiong; Yu, Jin-Quan

2014-08-20

Cu(II)-promoted ortho alkynylation of arenes and heteroarenes with terminal alkynes has been developed to prepare aryl alkynes. A variety of arenes and terminal alkynes bearing different substituents are compatible with this reaction, thus providing an alternative disconnection to Sonogashira coupling.

PENGOLAHAN GULA AREN (Arrenga Pinnata Merr DI DESA BANUA HANYAR KABUPATEN HULU SUNGAI TENGAH

Directory of Open Access Journals (Sweden)

Rosidah R Radam

2016-11-01

Full Text Available Gula aren salah satu pemanis yang telah diproduksi oleh bangsa Indonesia sejak lama. Gula aren sebagai alternatif bahan pemanis makanan dan merupakan mata pencaharian sampingan bagi kebanyakan masyarakat di Desa Banua Hanyar. Tujuan penelitian ini untuk mengetahui produktivitas dan kontribusi terhadap pendapatan masyarakat. Objek penelitian ini adalah pembuat gula aren. Data yang dikumpulkan terdiri dari  karakteristik responden, proses pembuatan gula aren, perhitungan produktivitas dan kontribusinya terhadap pendapatan masyarakat. Produktivitas gula aren (Arenga pinnata Merr berkisar antara 0,465 Kg/hari hingga 1,137 kg/hari. Kontribusi dari pengolahan gula aren sebesar 60,48% dari pendapatan masyarakat. Tingkat kesejahteraan masyarakat termasuk dalam golongan termiskin dengan pendapatan tahunan per kapita Rp.962 919,- atau setara dengan 148 kg beras. Disarankan perlu pembentukan kelompok tani dengan tujuan keseragaman dalam harga pasar gula aren. Peningkatan kualitas dengan peningkatan bentuk cetakan, kemasan dan aneka  rasa. Sehingga produk gula aren dapat dijual di pasar modern. Palm sugar is a sweetener that has been produced by the nation of Indonesia since long ago.  Palm sugar as an alternative sweetener foodstuffs as well as an second job for most people in the Banua Hanyar village.  The purpose of this research to know the productivity and contribution to community income. The object of this research is the maker of palm sugar. Data collected as data characteristics, the process of making palm sugar, calculation of productivity and its contribution to household income. Productivity sugar palm (Arenga pinnata Merr ranged from 0.465 Kg / day up to 1,137 kg / day. Contributions from processing palm sugar by 60.48% of household income. The level of welfare including in the poorest of the poor with annual income  per capita of IDR 962 919, - or the equivalent of 148 kg of rice.  Need formation of farmer groups with the goal of

Reinvestigating 2,5-di(pyridin-2-yl)pyrazine ruthenium complexes : Selective deuteration and Raman spectroscopy as tools to probe ground and excited-state electronic structure in homo- and heterobimetallic complexes

NARCIS (Netherlands)

Schulz, M.; Hirschmann, J.; Draksharapu, A.; Singh Bindra, G.; Soman, S.; Paul, A.; Groarke, R.; T. Pryce, M.; Rau, S.; R. Browne, W.; Vos, J.

2011-01-01

The mono- (1) and dinuclear (2) ruthenium(II) bis(2,2'-bipyridine) complexes of 2,5-di(pyridin-2-yl)pyrazine (2,5-dpp), for which the UV/Vis absorption and emission as well as electrochemical properties have been described earlier, are reinvestigated here by resonance, surface enhanced and transient

Hydroxyquinoline-calix[4]arene-conjugates as ligands for lanthanide complexes. Preparation, characterization, and extraction properties

Energy Technology Data Exchange (ETDEWEB)

Mansel, Alexander [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Reactive Transport; Jaeschke, A.; Kischel, M.; Kersting, B. [Leipzig Univ. (Germany). Inst. fuer Anorganische Chemie

2017-06-01

The synthesis of a calixarene-based N{sub 4}O{sub 4} donor ligand H{sub 6}L, in which two 8-hydroxyquinoline-2-carbaldehyde units are appended via hydrazone-carbonylmethoxy linkages in a 1,3-arrangement to the lower rim of tert-butyl-calix[4]arene and its coordination properties towards Eu{sup 3+} are described. Moreover, the ligand H{sub 6}L was found to extract Eu{sup 3+} and Tb{sup 3+} at pH 7-8 from aqueous solution, as established by radiotracing using the radionuclides {sup 160}Tb and {sup 152} Eu.

Thia-arenes as source apportionment tracers for urban air particulate

International Nuclear Information System (INIS)

McCarry, B.E.; Allan, L.M.; Mehta, S.; Marvin, C.H.

1995-01-01

Over sixty respirable air particulate samples were selected from a large number of filters collected in Hamilton, Ontario, Canada. Depending on the wind direction these sites were either predominantly upwind or predominantly downwind of the industrial sources. The sixty filters were extracted and analyzed using GC-MS for a range of PAH and sulfur-containing PAH (thia-arenes). Various reference standards (coal tar, diesel exhaust, urban air particulate) and source samples (coke oven condensate) were analyzed as well. A set of air particulate samples collected in another city alongside a highway provided an urban vehicular air sample. Unique thia-arene profiles were noted in the reference and source samples which provided the basis for this source apportionment work; two main approaches were used: (1) analysis of alkylated derivatives of thia-arenes with a molecular mass of 184 amu and (2) analysis of 234 amu isomers. The diesel exhaust and urban vehicular samples gave identical profiles while the coal tar and coke oven samples also had identical profiles but in different respects. The air samples collected at samplers located upwind of the coke ovens showed thia-arene profiles which were similar to the profile observed with a diesel exhaust reference material. However, air samples collected downwind of the coke ovens were heavily loaded samples and resembled the coal tar coke and oven condensate samples

Antioxidant and DPPH (1,1-diphenyl-2-picrylhydrazyl Free Radical Scavenging Activities of Boniger Acid and Calix[4]arene Derivative

Directory of Open Access Journals (Sweden)

E. ERDEM

2014-07-01

Full Text Available Diazonium derivative of calix[4]arene has been synthesized using three different synthetic steps. Initially p-tert-butylcalix[4]arene was synthesized with the condensation reaction of p-tert-butylphenol and formaldehyde in basic conditions. Calix[4]arene was obtained after the debutylation reaction of p-tert-butylcalix[4]arene with AlCl3. Calix[4]arene reacted with diazonium salt of Böniger acid to yield the 5,17-[(Bis(azo-bis(5-hydroxy-2,7-naphthalenedisulfonicacid]-25,26,27,28-tetrahydroxy calix[4]arene which has eight free phenolic hydroxyl group. Reaction steps were shown in Fig.1.2,7-naphthalenedisulfonicacid]-25,26,27,28-tetrahydroxy calix[4]arene The antioxidant activity of the Böniger acid and calix[4]aren derivative were determined using β-karotene-linoleic acid system. Moreover, the free radical scavenging activity values were tested with DPPH free radical. The two compounds showed strong antioxidant activity. Total antioxidant activity of Böniger acid and calix[4]aren derivative was determined using β–carotenelinoleic acid model system and was found the antioxidant activity of 84.00% and 85.60 % respectively. The free radical scavenging activities were determined as 83.05% and 84.69 %. Results show that, two compounds has the antioxidant activity. The calix[4]aren derivaties has more higher activity then Boniger acid because of calix[4]aren derivative has much hydroxl groups.

S,O-Ligand-Promoted Palladium-Catalyzed C-H Functionalization Reactions of Nondirected Arenes

NARCIS (Netherlands)

Naksomboon, K.; Valderas, C.; Gomez-Martinez, M.; Alvarez-Casao, Y.; Fernández Ibáñez, M.A.

Pd(II)-catalyzed C-H functionalization of non directed arenes has been realized using an inexpensive and easily accessible type of bidentate S,O-ligand. The catalytic system shows high efficiency in the C-H olefination reaction of electron-rich and electron-poor arenes. This methodology is

Synthesis of substituted Calix[6] arene and 18F labeling reaction as catalyst in preparation of 18F-FET

International Nuclear Information System (INIS)

Peng Cheng; Ma Yunchuan; Chen Xiaoxiao; Li Guixia; Li Shilei; Zhang Shuting; He Yong; Qi Chuanmin

2011-01-01

The phase transfer catalyst Substituted Calix[6] arene was prepared and it was used as catalyst to prepare the tumor diagnostic drug 18 F-FET. The results showed that para-sulfonated-calix[6] arene not only catalyzes 19 F substitution reaction, but also catalyzes 18 F labelling reaction with radiochemical yield of 11%. However, para-tert-butyl-calix[6] arene has no catalytic activity for the 19 F substitution reaction nor the 18 F labelling reaction of the precursor of FET. The catalyzing of para-sulfonated-calix[6]arene may be related to it's sulfonate groups, which participated in the coordination reaction and increased the polarity of calyx[6] arene and so on. Although radiochemical yield of the para-sulfonated-calix[6] arene catalyzed 18 F labeling of the precursor of FET was much lower than that obtained by Kryptofix 2. 2. 2, this study still has significant meaning for us to find better substituted Calix[6] arene catalysts by optimizing the reaction conditions. (authors)

Near-Infrared Fluorescence Detection of Acetylcholine in Aqueous Solution Using a Complex of Rhodamine 800 and p-Sulfonato-calix[8]arene

Science.gov (United States)

Jin, Takashi

2010-01-01

The complexing properties of p-sulfonatocalix[n]arenes (n = 4: S[4], n = 6: S[6], and n = 8: S[8]) for rhodamine 800 (Rh800) and indocyanine green (ICG) were examined to develop a near-infrared (NIR) fluorescence detection method for acetylcholine (ACh). We found that Rh800 (as a cation) forms an inclusion complex with S[n], while ICG (as a twitter ion) have no binding ability for S[n]. The binding ability of Rh800 to S[n] decreased in the order of S[8] > S[6] >> S[4]. By the formation of the complex between Rh800 and S[8], fluorescence intensity of the Rh800 was significantly decreased. From the fluorescence titration of Rh800 by S[8], stoichiometry of the Rh800-S[8] complex was determined to be 1:1 with a dissociation constant of 2.2 μM in PBS. The addition of ACh to the aqueous solution of the Rh800-S[8] complex caused a fluorescence increase of Rh800, resulting from a competitive replacement of Rh800 by ACh in the complex. From the fluorescence change by the competitive fluorophore replacement, stoichiometry of the Rh800-ACh complex was found to be 1:1 with a dissociation constant of 1.7 mM. The effects of other neurotransmitters on the fluorescence spectra of the Rh800-S[8] complex were examined for dopamine, GABA, glycine, and l-asparatic acid. Among the neurotransmitters examined, fluorescence response of the Rh800-S[8] complex was highly specific to ACh. Rh800-S[8] complexes can be used as a NIR fluorescent probe for the detection of ACh (5 × 10−4−10−3 M) in PBS buffer (pH = 7.2). PMID:22294934

PENGEMBANGAN WANA WISATA WATU SUMONG SEBAGAI KAWASAN EKOWISATA BERBASIS POHON AREN DAN PEMBERDAYAAN MASYARAKAT SECARA BERKELANJUTAN DI DESA PERON, LIMBANGAN, KENDAL

Directory of Open Access Journals (Sweden)

Eram Tunggul Pawenang

2015-12-01

Full Text Available Tujuan dari kegiatan ini adalah untuk memperdalam pengertian, penghayatan, dan pengalaman mahasiswa tentang cara berfikir dan bekerja interdisipliner pada lintas sektoral yaitu bidang ilmu Kesehatan Masyarakat, Hukum dan Akuntansi Manajemen, kegunaan hasil pendidikan dan penelitian bagi pembangunan pada umumnya dan pembangunan daerah pedesaan khususnya Desa Peron dalam membudidayakan pohon aren dalam fungsi konservasi dan pemberdayaan hasil pengolahan aren sebagai fungsi produksi, bagi perguruan tinggi dapat mengembangkan IPTEKS yang lebih bermanfaat dalam pengelolaan dan penyelesaian berbagai masalah pembangunan. Masalah utama yang ada di Desa Peron adalah petani aren dalam pemasaran hasil masih tergantung dengan tengkulak, kurangnya diversifikasi dari aren menjadi produk-produk yang lain, pengemasan hasil diversifikasi olahan aren kurang menarik konsumen, pemanfaatan ijuk, akar dan daun dari pohon aren yang tidak maksimal, potensi Wisata Watu Sumong yang belum dieksplorasi secara optimal serta kurangnya pengetahuan masyarakat tentang pengolahan limbah aren. Hasil dari kegiatan KKN PPM meliputi Program pengemasan gula aren dilaksanakan dengan 3 variasi bentuk pengemasan yaitu Gula aren cetak, Gula Semut dan Sirup Aren dengan label “Arenku” dan sedang dalam proses permintaan no PIRT. Program pemasaran gula aren telah terlaksana yaitu dengan memasarkan produk gula aren berupa gula semut aren, gula cetak dan sirup aren di beberapa tempat yaitu di KPRI Handayani, UNSEC UNNES, dan Sekatul. Kegiatan Pengenalan Watu Sumong telah dilaksanakan dan mendapat apresiasi positif dari Bupati Kendal dan Dinas Kebudayaan dan Pariwisata Kendal dan akan dikembangkan menjadi Desa Wisata. Pengenalan juga dilaksanakan pada saat Peron Expo dengan menampilkan Video dan Pemasangan papan sejarah Watu Sumong dan Denah Lokasi Wisata di Desa Peron. Pengembangan desa Wisata akan dilanjutkan oleh Kelompok sadar wisata “Wikir Sari”. Program

Photoinduced C-C Cross-Coupling of Aryl Chlorides and Inert Arenes

Directory of Open Access Journals (Sweden)

Lele Wang

2016-01-01

Full Text Available Here we report a facile, efficient, and catalyst-free method to realize C-C cross-coupling of aryl chlorides and inert arenes under UV light irradiation. The aryl radical upon homolytic cleavage of C-Cl bond initiated the nucleophilic substitution reaction with inert arenes to give biaryl products. This mild reaction mode can also be applied to other synthetic reactions, such as the construction of C-N bonds and trifluoromethylated compounds.

Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds**

Science.gov (United States)

Best, Daniel; Burns, David J; Lam, Hon Wai

2015-01-01

A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N—H groups are tolerated on the barbituric acid, with no complications arising from N—H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. PMID:25959544

CALIX[4]ARENE C-99 INHIBITS MYOSIN ATPase ACTIVITY AND CHANGES THE ORGANIZATION OF CONTRACTILE FILAMENTS OF MYOMETRIUM.

Science.gov (United States)

Labyntseva, R D; Bevza, A A; Lul'ko, A O; Cherenok, S O; Kalchenko, V I; Kosterin, S O

2015-01-01

Calix[4]arenes are cup-like macrocyclic (polyphenolic) compounds, they are regarded as promising molecular "platforms" for the design of new physiologically active compounds. We have earlier found that calix[4]arene C-99 inhibits the ATPase activity of actomyosin and myosin subfragment-1 of pig uterus in vitro. The aim of this study was to investigate the interaction of calix[4]arene C-99 with myosin from rat uterine myocytes. It was found that the ATPase activity of myosin prepared from pre-incubated with 100 mM of calix[4]arene C-99 myocytes was almost 50% lower than in control. Additionally, we have revealed the effect of calix[4]arene C-99 on the subcellular distribution of actin and myosin in uterus myocytes by the method of confocal microscopy. This effect can be caused by reorganization of the structure of the contractile smooth muscle cell proteins due to their interaction with calix[4]arene. The obtained results demonstrate the ability of calix[4]arene C-99 to penetrate into the uterus muscle cells and affect not only the myosin ATPase activity, but also the structure of the actin and myosin filaments in the myometrial cells. Demonstrated ability of calix[4]arene C-99 can be used for development of new pharmacological agents for efficient normalization of myometrial contractile hyperfunction.

Calix[4]arene C-99 inhibits myosin ATPase activity and changes the organization of contractile filaments of myometrium

Directory of Open Access Journals (Sweden)

R. D. Labyntseva,

2015-12-01

Full Text Available Calix[4]arenes are cup-like macrocyclic (polyphenolic compounds, they are regarded as promising molecular “platforms” for the design of new physiologically active compounds. We have earlier found that сalix[4]arenе C-99 inhibits the ATPase activity of actomyosin and myosin subfragment-1 of pig uterus іn vitro. The aim of this study was to investigate the interaction of calix[4]arene C-99 with myosin from rat uterine myocytes. It was found that the ATPase activity of myosin prepared from pre-incubated with 100 mM of calix[4]arene C-99 myocytes was almost 50% lower than in control. Additionally, we have revealed the effect of calix[4]arene C-99 on the subcellular distribution of actin and myosin in uterus myocytes by the method of confocal microscopy. This effect can be caused by reorganization of the structure of the contractile smooth muscle cell proteins due to their interaction with calix[4]arene. The obtained results demonstrate the ability of calix[4]arene C-99 to penetrate into the uterus muscle cells and affect not only the myosin ATPase activity, but also the structure of the actin and myosin filaments in the myometrial cells. Demonstrated ability of calix[4]arene C-99 can be used for development of new pharmacological agents for efficient normalization of myometrial contractile hyperfunction.

Arene ruthenium(II) complexes with 2-acetamidothiazole derived ligands: Synthesis, structural studies, antifouling and antibacterial properties

Digital Repository Service at National Institute of Oceanography (India)

Singh, K.S.; PrabhaDevi; Sawant, S.G.; Kaminsky, W.

. Habtemariam, P. J. Sadler, Chem. Commun. (2005) 4764. 11    [35] A. Habtemariam, M. Melchart, R. Fernández, S. Parsons, I. D. H. Oswald, A. Parkin, F. P. A. Fabbiani, J. E. Davidson, A. Dawson, R. E. Aird, D. I. Jodrell, P. J. Sadler, J. Med. Chem.49...-matrix least-squares on F 2 Data / restraints / parameters 4455 / 0 / 215 Goodness-of-fit on F2 1.038 Final R indices [I>2sigma(I)] R1 = 0.0202, wR2 = 0.0415 R indices (all data) R1 = 0.0261, wR2 = 0.0436 Largest diff. peak and hole 0.431 and -0.388 e...

Dual triggering of DNA binding and fluorescence via photoactivation of a dinuclear ruthenium(II) arene complex

Czech Academy of Sciences Publication Activity Database

Magennis, S.W.; Habtemariam, A.; Nováková, Olga; Henry, J.B.; Meier, S.; Parsons, S.; Oswald, D.H.; Brabec, Viktor; Sadler, P.J.

2007-01-01

Roč. 46, č. 12 (2007), s. 5059-5068 ISSN 0020-1669 R&D Projects: GA ČR(CZ) GA203/06/1239; GA ČR(CZ) GA305/05/2030; GA AV ČR(CZ) 1QS500040581; GA AV ČR(CZ) KAN200200651 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : DNA * ruthenium * fluorescence Subject RIV: BO - Biophysics Impact factor: 4.123, year: 2007

La mirada social en la prensa: Concepción Arenal

Directory of Open Access Journals (Sweden)

Simón Palmer, María del Carmen

2014-06-01

Full Text Available In La Voz de la Caridad Concepción Arenal set out her views on a series of social problems that remain current even today, although though they have not received as much attention as those relating to women, prisoners, or poverty.Concepción Arenal dejó en La Voz de la Caridad, sus opiniones sobre una serie de problemas sociales que, aún hoy, siguen de plena actualidad aunque no han merecido tanta atención como los referentes a la mujer, los presos o la pobreza.

Water-soluble resorcin[4]arene based cavitands

NARCIS (Netherlands)

Grote gansey, M.H.B.; Grote Gansey, Marcel H.B.; Bakker, Frank K.G.; Feiters, Martinus C.; Geurts, Hubertus P.M.; Verboom, Willem; Reinhoudt, David

1998-01-01

Water-soluble resorcin[4]arene based cavitands were obtained in good yields by reaction of bromomethylcavitands with pyridine. Their solubility was determined by conductometry. The behaviour in water depends on the alkyl chain length; the methylcavitand does not aggregate, whereas the pentyl- and

Synthesis and Characterization of Chitosan-p-t-Butylcalix[4]arene acid

Science.gov (United States)

Handayani, D. S.; Frimadasi, W.; Kusumaningsih, T.; Pranoto

2018-03-01

The synthesis of chitosan-p-t-butylcalix[4]arene acid was done with DIC (N, N’-diisopropylcarbodiimide) as the coupling agent. The structural analysis of the chitosan-p-t-butylcalix[4]arene acid was conducted by spectrophotometer Fourier Transform Infra Red (FTIR) and X-Ray Diffraction (XRD). Meanwhile, the surface area was investigated by Surface Area Analysis, the Scanning Electrone Microscope (SEM) analysed the surface morphology, and also the melting point temperature was determined. FTIR analysis on Chitosan-p-t-butylcalix[4]arene provides an overlapped absorption of -OH and -NH groups at 3438.26 cm-1. Meanwhile, a C = C aromatic bond present at 1480.43 cm-1. XRD analysis shows some broaden peaks due to the amorphous phase of the prepared material. The prepared material is a brownish yellow solid, odorless and porous. The melting point, surface area, and the average pore radius are above 300 °C, 9.42 m2 / g, and 52.5938 Å, respectively.

Multivalent calix[4]arene-based fluorescent sensor for detecting silver ions in aqueous media and physiological environment.

Science.gov (United States)

Lotfi, Behzad; Tarlani, Aliakbar; Akbari-Moghaddam, Peyman; Mirza-Aghayan, Maryam; Peyghan, Ali Ahmadi; Muzart, Jacques; Zadmard, Reza

2017-04-15

A new derivative of dipodal 1,3-calix[4]arene-based chemosensor (R), which was containing several binding sites have been synthesized and characterized by NMR, IR and LC-MS spectroscopic methods. The selectivity of Rhas been investigated in aqueous methanol, resulting in fluorescence shift and selective recognition of Ag + among 20 various alkali, alkaline earth and transition metal ions. Microstructural features of R and its complex with Ag + have been investigated by Atomic Force Microscopy (AFM). AFM images can clearly differentiate R from its complex of Ag + . Moreover; the complicated binding mode of metal-ligand complex has been explored by UV-Vis, LC-MS, FIR, Fluorescence titration, Job's plot method and theoretical approaches. Density functional theory (DFT) method at B3LYP/LANL2DZ level of theory was employed for computational studies. Theoretical calculations revealed that selectivity and specificity of R toward Ag + could be attributed to structural conformation of 1,3-alternate-calix[4]arene scaffold and molecular electrostatic potential of its surface. Furthermore; the competitive experiments were carried out to test sensor's ability for practical uses. Finally, the efficiency of R in matrix of physiological cations was examined and showed gradual emission enhancement which makes R an ideal candidate for monitoring of Ag + in physiological environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Unsaturated carbone and allenylidene ruthenium complexes from alkynes

International Nuclear Information System (INIS)

Bozek, Yu.L.; Diznev, P.A.

1995-01-01

The author's studies aimed at activation of terminal alkynes by metal complexes, reactivity patterns and selective preparations of unsaturated carbene, allenylidene and cumulenylidene derivatives of (arene)ruthenium complexes are reviewed. 48 refs

Ligand-accelerated non-directed C-H functionalization of arenes

Science.gov (United States)

Wang, Peng; Verma, Pritha; Xia, Guoqin; Shi, Jun; Qiao, Jennifer X.; Tao, Shiwei; Cheng, Peter T. W.; Poss, Michael A.; Farmer, Marcus E.; Yeung, Kap-Sun; Yu, Jin-Quan

2017-11-01

The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.

Dissymmetry effects on the laser spectroscopy of supersonically expanded rare gas/chiral arene heteroclusters.

Science.gov (United States)

Filippi, Antonello; Giardini, Anna; Marcantoni, Enrico; Paladini, Alessandra; Piccirillo, Susanna; Renzi, Gabriele; Rondino, Flaminia; Roselli, Graziella; Satta, Mauro; Speranza, Maurizio

2007-04-14

The R2PI-TOF spectra of supersonically expanded rare gas/chiral arene heteroclusters have been rationalized in terms of the distortion of the pi-electron density reflecting the different dipole and quadrupole momenta induced in the rare gas atoms by interaction with the opposite pi-faces of the chiral arene itself.

Research on Synthesis of New Azo Calix[4]arene and its Dyeing Properties

Directory of Open Access Journals (Sweden)

Tang Jun

2015-01-01

Full Text Available With the raw materials of calix[4]arene, benzocaine, tricaine and procaine hydrochloride, three new azo calix[4]arene derivatives—6a, 6b and 6c are synthesized by diazotization–coupling reaction of an aromatic amine, with its yield of 83%, 81% and 83% respectively. The structural characterization is in a way of IR, 1H NMR and elemental analysis. This paper investigates the spectral properties of azo calix[4]arene derivatives under different solution pH conditions through the UV–visible spectroscopy, and researches the dyeing properties through the dyeing curve, color yield test and fastness test. The results show that, with the increase of pH value, the azo calix[4]arene derivatives—6a, 6b and 6c form azo–hydrazone tautomeric isomers with the maximum absorption peak redshift; the dyeing effect of the compound is good, of which the dye–uptake rate of the compound 6a is as high as 78%; the surface depth of color yield is 2.798, and the dry and wet rubbing fastness and the soaping fastness are respectively 4, which is a better disperse dye.

Chemoselective hydrogenation of arenes by PVP supported Rh nanoparticles

DEFF Research Database (Denmark)

Ibrahim, Mahmoud; Poreddy, Raju; Philippot, Karine

2016-01-01

Polyvinylpyrrolidone-stabilized Rh nanoparticles (RhNPs/PVP) of ca. 2.2 nm in size were prepared by the hydrogenation of the organometallic complex [Rh(η3-C3H5)3] in the presence of PVP and evaluated as a catalyst in the hydrogenation of a series of arene substrates as well as levulinic acid...... for the hydrogenation of levulinic acid and methyl levulinate in water leading to quantitative formation of the fuel additive γ-valerolactone under moderate reaction conditions compared to previously reported catalytic systems....... and methyl levulinate. The catalyst showed excellent activity and selectivity towards aromatic ring hydrogenation compared to other reported transition metal-based catalysts under mild reaction conditions (room temperature and 1 bar H2). Furthermore, it was shown to be a highly promising catalyst...

Interaction of the cesium cation with calix[4]arene-bis(t-octylbenzo-18-crown-6): extraction and DFT study

Czech Academy of Sciences Publication Activity Database

Makrlík, E.; Toman, Petr; Vaňura, P.; Moyer, B. A.

2013-01-01

Roč. 1033, 6 February (2013), s. 14-18 ISSN 0022-2860 R&D Projects: GA ČR(CZ) GAP205/10/2280 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : cesium cation * calix[4]arene-bis(t-octylbenzo-18-crown-6) * complexation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.599, year: 2013

Light induced electron transfer reactions of metal complexes

International Nuclear Information System (INIS)

Sutin, N.; Creutz, C.

1980-01-01

Properties of the excited states of tris(2,2'-bipyridine) and tris(1,10-phenanthroline) complexes of chromium(III), iron(II), ruthenium(II), osmium(II), rhodium(III), and iridium(III) are described. The electron transfer reactions of the ground and excited states are discussed and interpreted in terms of the driving force for the reaction and the distortions of the excited states relative to the corresponding ground states. General considerations relevant to the conversion of light into chemical energy are presented and progress in the use of polypyridine complexes to effect the light decomposition of water into hydrogen and oxygen is reviewed

Synthesis and Characterization of a Heteroleptic Ru(II Complex of Phenanthroline Containing Oligo-Anthracenyl Carboxylic Acid Moieties

Directory of Open Access Journals (Sweden)

Peter A. Ajibade

2010-09-01

Full Text Available In an effort to develop new ruthenium(II complexes, this work describes the design, synthesis and characterization of a ruthenium(II functionalized phenanthroline complex with extended π-conjugation. The ligand were L1 (4,7-bis(2,3-dimethylacrylic acid-1,10-phenanthroline, synthesized by a direct aromatic substitution reaction, and L2 (4,7-bis(trianthracenyl-2,3-dimethylacrylic acid-1,10-phenanthroline, which was synthesized by the dehalogenation of halogenated aromatic compounds using a zero-valent palladium cross-catalyzed reaction in the absence of magnesium-diene complexes and/or cyclooctadienyl nickel (0 catalysts to generate a new carbon-carbon bond (C-C bond polymerized hydrocarbon units. The ruthenium complex [RuL1L2(NCS2] showed improved photophysical properties (red-shifted metal-to-ligand charge-transfer transition absorptions and enhanced molar extinction coefficients, luminescence and interesting electrochemical properties. Cyclic and square wave voltammetry revealed five major redox processes. The number of electron(s transferred by the ruthenium complex was determined by chronocoulometry in each case. The results show that processes I, II and III are multi-electron transfer reactions while processes IV and V involved one-electron transfer reaction. The photophysical property of the complex makes it a promising candidate in the design of chemosensors and photosensitizers, while its redox-active nature makes the complex a potential mediator of electron transfer in photochemical processes.

Two Discrete RuCp* (Cp*=Pentamethylcyclopentadienyl) Binding Modes of N-Confused Porphyrins: Peripheral π Complex and Sitting Atop Ruthenocenophane Complex by Skeletal Transformation.

Science.gov (United States)

Yamamoto, Takaaki; Mitsuno, Koki; Mori, Shigeki; Itoyama, Shuhei; Shiota, Yoshihito; Yoshizawa, Kazunari; Ishida, Masatoshi; Furuta, Hiroyuki

2018-05-07

Complexation of a RuCp* cation with N-confused tetraarylporphyrins (NCPs) forms directly bound ruthenium(II) pentamethylcyclopentadienyl (Cp*) π-complex on a specific meso-aryl group (e.g., phenyl) neighboring peripheral imino nitrogen of NCPs in high yields. In contrast, in the case of NCPs bearing bulky meso-substituents (e.g., 3,5-di-tert-butylphenyl), new ruthenocenophane-like complex embedded on an N-confused calix[4]phyrin was formed through multiple C-H bond activation of methyl groups of Cp* ligand. The mechanistic insight into the formation of the ruthenocenophane was derived from DFT calculations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ruthenium(η6,η1-arene-CH2-NHC Catalysts for Direct Arylation of 2-Phenylpyridine with (HeteroAryl Chlorides in Water

Directory of Open Access Journals (Sweden)

Nazan Kaloğlu

2018-03-01

Full Text Available A series of new benzimidazolium halides were synthesized in good yields as unsymmetrical N-heterocyclic carbene (NHC precursors containing the N–CH2–arene group. The benzimidazolium halides were readily converted into ruthenium(II–NHC complexes with the general formula [RuCl2(η6,η1–arene–CH2–NHC]. The structures of all new compounds were characterized by 1H NMR (Nuclear Magnetic Resonance, 13C NMR, FT-IR (Fourier Transform Infrared spectroscopy and elemental analysis techniques. The single crystal structure of one benzimidazole ruthenium complex, 2b, was determined. The complex is best thought of as containing an octahedrally coordinated Ru center with the arene residue occupying three sites, the remaining sites being occupied by a (carbeneC–Ru bond and two Ru–Cl bonds. The catalytic activity of [RuCl2(η6,η1–arene–CH2–NHC] complexes was evaluated in the direct (heteroarylation of 2-phenylpyridine with (heteroaryl chlorides in water as the nontoxic reaction medium. These results show that catalysts 2a and 2b were the best for monoarylation with simple phenyl and tolyl chlorides. For functional aryl chlorides, 2d, 2e, and 2c appeared to be the most efficient.

Accumulation of polycyclic arenes in Baltic Sea algae

Energy Technology Data Exchange (ETDEWEB)

Veldre, I.A.; Itra, A.R.; Paal' me, L.P.; Kukk, Kh.A.

1985-01-01

The paper presents data on the level of benzo(a)pyrene (BP) and some other polycyclic arenes in alga and phanerogam specimens from different gulfs of the Baltic Sea. Algae were shown to absorb BP from sea water. The mean concentration of BP in sea water was under 0.004 microgram/1, while in algae it ranged 0.1-21.2 micrograms/kg dry weight. Algae accumulate BP to a higher degree than phanerogams. The highest concentrations of BP were found in algae Enteromorpha while the lowest ones in Furcellaria. In annual green algae, BP level was higher in autumn, i. e. at the end of vegetation period, than in spring. Brown algae Fucus vesiculosus is recommended for monitoring polycyclic arene pollution in the area from Vormsi Island to Kaesmu and green algae Cladophora or Enteromorpha in the eastern part of the Finnish Gulf.

Ruthenium(II) tris(2,2'-bipyridine) chelate as a chemiluminophore in extrinsic lyoluminescences of aluminium and magnesium in aqueous solution

International Nuclear Information System (INIS)

Jiang Qinghong; Kotiranta, Miia; Langel, Kaarina; Suomi, Johanna; Hakansson, Markus; Spehar, Anna-Maria; Ala-Kleme, Timo; Eskola, Jarkko; Kulmala, Sakari

2005-01-01

Ruthenium(II) tris(2,2'-bipyridine) chelate shows chemiluminescence (CL) both during dissolution of metallic aluminium in alkaline conditions, and during dissolution of magnesium metal in acidic conditions. The presence of peroxodisulfate ions strongly enhances the CL. Magnesium system provides considerably better detectability of the present chelate giving linear calibration plot spanning over many orders of magnitude of concentration down to subnanomolar concentration levels. The possible primary species generated and luminescence mechanisms are shortly discussed

AREN has going into action for nuclear program in Romania

International Nuclear Information System (INIS)

Chirica, T.; Mauna, T.

2000-01-01

Romania has been a member of world nuclear power community since December 1996 when the first Candu type nuclear unit became fully in service in Cernavoda NPP. The nominal power rating of the Unit is 706 MWe, covering about 10% of country's annual consumption. Now, the major issues of the Romanian nuclear sector is to promote and develop the activities regarding completion of the second unit at the Cernavoda site, connected to the natural uranium chain and waste management. The Romanian 'Nuclear Energy' Association (AREN) operates as a non-governmental and non-profit organization member of the European Nuclear Society and has been involved since 1990 in the nuclear field as a professional society and members of Council of AREN work as volunteers. The main programs developed by AREN are: 1. Nuclear Energy Days, organized in the last i quarter of the year; 2. International Nuclear Energy Symposium - SIEN, organized every two years; 3. Round Tables dedicated to different aspects of the nuclear energy, mainly addressed to the specialists. The intention of this paper is to discuss the impact of the reduction of the Romanian nuclear program on the different categories of people and companies involved in nuclear field, including the difficult aspect of nuclear brain drain. (authors)

Synthesis, structural characterization and cytotoxic activity of two new organoruthenium(II complexes

Directory of Open Access Journals (Sweden)

SANJA GRGURIC-SIPKA

2008-06-01

Full Text Available Two new p-cymene ruthenium(II complexes containing as additional ligands N-methylpiperazine ([(η6-p-cymeneRuCl2(CH3NH(CH24NH]PF6, complex 1 or vitamin K3-thiosemicarbazone ([(η6-p-cymeneRuCl2(K3tsc], complex 2 were synthesized starting from [(η6-p-cymene2RuCl2]2 and the corresponding ligand. The complexes were characterized by elemental analysis, IR, electronic absorption and NMR spectroscopy. The X-ray crystal structure determination of complex 1 revealed “piano-stool” geometry. The differences in the cytotoxic activity of the two complexes are discussed in terms of the ligand present.

The thermodynamic effects of ligand structure on the molecular recognition of mononuclear ruthenium polypyridyl complexes with B-DNA

Science.gov (United States)

The ruthenium(II) polypyridyl complexes (RPCs), [(phen)2Ru(tatpp)]Cl2 (3Cl2) and [(phen)2Ru (tatpp)Ru(phen)2]Cl4 (4Cl4), containing the large planar and redox-active tetraazatetrapyrido- pentacene (tatpp) ligand, cleave DNA in the presence of reducing agents in cell-free assays and show significant...

Removal of uranyl ions by p-hexasulfonated calyx[6]arene acid

Energy Technology Data Exchange (ETDEWEB)

Popescu, Ioana-Carmen [R and D National Institute for Metals and Radioactive Resources–ICPMRR, B-dul Carol I No.70, Sector 2, Bucharest 020917 (Romania); Petru, Filip [“C.D. Nenitescu” Institute of Organic Chemistry, Splaiul Independentei 202B, Sector 6, Bucharest 71141 (Romania); Humelnicu, Ionel [“Al.I. Cuza” University of Iasi, The Faculty of Chemistry, Bd. Carol-I No. 11, Iasi 700506 (Romania); Mateescu, Marina [National R and D Institute for Chemistry and Petrochemistry, Splaiul Independenţei No. 202, Bucharest 060021 (Romania); Militaru, Ecaterina [R and D National Institute for Metals and Radioactive Resources–ICPMRR, B-dul Carol I No.70, Sector 2, Bucharest 020917 (Romania); Humelnicu, Doina, E-mail: doinah@uaic.ro [“Al.I. Cuza” University of Iasi, The Faculty of Chemistry, Bd. Carol-I No. 11, Iasi 700506 (Romania)

2014-10-15

Radioactive pollution is a significant threat for the people’s health. Therefore highly effective radioactive decontamination methods are required. Ion exchange, biotechnologies and phytoremediation in constructed wetlands have been used as radioactive decontamination technologies for uranium contaminated soil and water remediation. Recently, beside those classical methods the calix[n]arenic derivatives’ utilization as radioactive decontaminators has jogged attention. The present work aims to present the preliminary research results of uranyl ion sorption studies on the p-hexasulfonated calyx[6]arenic acid. The effect of temperature, contact time, sorbent amount and uranyl concentration variation on sorption efficiency was investigated. Isotherm models revealed that the sorption process fit better Langmuir isotherm.

Long synthetic nanotubes from calix[4]arenes.

Science.gov (United States)

Organo, Voltaire G; Sgarlata, Valentina; Firouzbakht, Farhood; Rudkevich, Dmitry M

2007-01-01

We report the synthesis and encapsulation properties of long (up to 5 nm) molecular nanotubes 1-4, which are based on calix[4]arenes and can be filled with multiple nitrosonium (NO(+)) ions upon reaction with NO(2)/N(2)O(4) gases. These are among the largest nanoscale molecular containers prepared to date and can entrap up to five guests. The structure and properties of tubular complexes 1(NO(+))(2)-4(NO(+))(5) were studied by UV/Vis, FTIR, and (1)H NMR spectroscopy in solution, and also by molecular modeling. Entrapment of NO(+) in 1(NO(+))(2)-4(NO(+))(5) is reversible, and addition of [18]crown-6 quickly recovers starting tubes 1-4. The FTIR and titration data revealed enhanced binding of NO(+) in longer tubes, which may be due to cooperativity. The described nanotubes may serve as materials for storing and converting NO(x) and also offer a promise to further develop supramolecular chemistry of molecular containers. These findings also open wider perspectives towards applications of synthetic nanotubes as alternatives to carbon nanotubes.

Selective production of arenes via direct lignin upgrading over a niobium-based catalyst

Science.gov (United States)

Shao, Yi; Xia, Qineng; Dong, Lin; Liu, Xiaohui; Han, Xue; Parker, Stewart F.; Cheng, Yongqiang; Daemen, Luke L.; Ramirez-Cuesta, Anibal J.; Yang, Sihai; Wang, Yanqin

2017-07-01

Lignin is the only large-volume renewable source of aromatic chemicals. Efficient depolymerization and deoxygenation of lignin while retaining the aromatic functionality are attractive but extremely challenging. Here we report the selective production of arenes via direct hydrodeoxygenation of organosolv lignin over a porous Ru/Nb2O5 catalyst that enabled the complete removal of the oxygen content from lignin. The conversion of birch lignin to monomer C7-C9 hydrocarbons is nearly quantitative based on its monomer content, with a total mass yield of 35.5 wt% and an exceptional arene selectivity of 71 wt%. Inelastic neutron scattering and DFT calculations confirm that the Nb2O5 support is catalytically unique compared with other traditional oxide supports, and the disassociation energy of Caromatic-OH bonds in phenolics is significantly reduced upon adsorption on Nb2O5, resulting in its distinct selectivity to arenes. This one-pot process provides a promising approach for improved lignin valorization with general applicability.

Direct Observation of a Nonheme Iron(IV)–Oxo Complex That Mediates Aromatic C–F Hydroxylation

OpenAIRE

Sahu, Sumit; Quesne, Matthew G.; Davies, Casey G.; Dürr, Maximilian; Ivanović-Burmazović, Ivana; Siegler, Maxime A.; Jameson, Guy N. L.; de Visser, Sam P.; Goldberg, David P.

2014-01-01

The synthesis of a pentadentate ligand with strategically designed fluorinated arene groups in the second coordination sphere of a nonheme iron center is reported. The oxidatively resistant fluorine substituents allow for the trapping and characterization of an FeIV(O) complex at −20 °C. Upon warming of the FeIV(O) complex, an unprecedented arene C–F hydroxylation reaction occurs. Computational studies support the finding that substrate orientation is a critical factor in the observed reactiv...

Los peligros volcánicos del Arenal

Directory of Open Access Journals (Sweden)

Sjöbohm Castillo, Linda Marie

2007-06-01

Full Text Available Este estudio fue realizado con el fin de establecer los riesgos asociados al volcán Arenal y la realización y utilización de los mapas de peligros volcánicos en la planificación de las áreas circundantes. Contiene información histórica de la actividad del volcán. Presenta los objetivos fundamentales de la producción de los mapas. Identifica los tipos de peligros que presenta el volcán en la actualidad y finalmente, informa sobre la construcción de los mapas de peligros volcánicos, tanto el de corto plazo como el de largo plazo This study was developed with the purpose of establishing the risks related to the Arenal Volcano and the development and use of volcanic danger maps in the planning of the areas around. It includes historic information about the volcano activity. It presents the main objective of doing the maps. It identifies the types of dangers the volcano presents in these days. Finally, it informs about the development of volcanic dangers maps, at short and long term

Valge villa / Karen Jagodin ; kommenteerinud Krista Aren, Emil Urbel

Index Scriptorium Estoniae

Jagodin, Karen, 1982-

2009-01-01

Villa (623 m² + kelder) Merirahu elamurajoonis Tallinnas. Arhitektid: Emil Urbel, Andrus Mark (AB Emil Urbel OÜ). Sisearhitektid: Krista Aren, Mati Veermets. Inseneriosad: AS Meistri Projekt. Haljastaja: Piret Kukk. Projekt: 2005-2008, valmis: 2009. Villa madalamat osa katab murtud pinnaga graniit, kõrgemat valge krohv

Impact of the uranium (VI) speciation in mineralised urines on its extraction by calix[6]arene bearing hydroxamic groups used in chromatography columns.

Science.gov (United States)

Baghdadi, S; Bouvier-Capely, C; Ritt, A; Peroux, A; Fevrier, L; Rebiere, F; Agarande, M; Cote, G

2015-11-01

Actinides determination in urine samples is part of the analyses performed to monitor internal contamination in case of an accident or a terrorist attack involving nuclear matter. Mineralisation is the first step of any of these analyses. It aims at reducing the sample volume and at destroying all organic compounds present. The mineralisation protocol is usually based on a wet ashing step, followed by actinides co-precipitation and a furnace ashing step, before redissolution and the quantification of the actinides by the appropriate techniques. Amongst the existing methods to perform the actinides co-precipitation, alkali-earth (typically calcium) precipitation is widely used. In the present work, the extraction of uranium(VI), plutonium(IV) and americium(III) from the redissolution solutions (called "mineralised urines") on calix[6]arene columns bearing hydroxamic groups was investigated as such an extraction is a necessary step before their determination by ICP-MS or alpha spectrometry. Difficulties were encountered in the transfer of uranium(VI) from raw to mineralised urines, with yield of transfer ranging between 0% and 85%, compared to about 90% for Pu and Am, depending on the starting raw urines. To understand the origin of such a difficulty, the speciation of uranium (VI) in mineralised urines was investigated by computer simulation using the MEDUSA software and the associated HYDRA database, compiled with recently published data. These calculations showed that the presence of phosphates in the "mineralised urines" leads to the formation of strong uranyl-phosphate complexes (such as UO2HPO4) which compete with the uranium (VI) extraction by the calix[6]arene bearing hydroxamic groups. The extraction constant of uranium (VI) by calix[6]arene bearing hydroxamic groups was determined in a 0.04 mol L(-1) sodium nitrate solution (logK=4.86±0.03) and implemented in an extraction model taking into account the speciation in the aqueous phase. This model allowed to

Rhodium Phosphine-π-Arene Intermediates in the Hydroamination of Alkenes

Science.gov (United States)

Liu, Zhijian; Yamamichi, Hideaki; Madrahimov, Sherzod T.; Hartwig, John F.

2011-01-01

A detailed mechanistic study of the intramolecular hydroamination of alkenes with amines catalyzed by rhodium complexes of a biaryldialkylphosphine are reported. The active catalyst is shown to contain the phosphine ligand bound in a κ1, η6 form in which the arene is π-bound to rhodium. Addition of deuterated amine to an internal olefin showed that the reaction occurs by trans addition of the N-H bond across the C=C bond, and this stereochemistry implies that the reaction occurs by nucleophilic attack of the amine on a coordinated alkene. Indeed, the cationic rhodium fragment binds the alkene over the secondary amine, and the olefin complex was shown to be the catalyst resting state. The reaction was zero-order in substrate, when the concentration of olefin was high, and a primary isotope effect was observed. The primary isotope effect, in combination with the observation of the alkene complex as the resting state, implies that nucleophilic attack of the amine on the alkene is reversible and is followed by turnover-limiting protonation. This mechanism constitutes an unusual pathway for rhodium-catalyzed additions to alkenes and is more closely related to the mechanism for palladium-catalyzed addition of amide N-H bonds to alkenes. PMID:21309512

Design and synthesis of new poly-phosphorylated upper-rim modified calix[4]arenes as potential and selective chelating agents of uranyl ion

International Nuclear Information System (INIS)

Migianu-Griffoni, E.; Mbemba, C.; Burgada, R.; Lecouvey, M.; Lecercle, D.; Taran, F.

2009-01-01

New upper-rim poly-phosphorylated calix[4]arenes were designed for decorporation of uranium in case of nuclear contamination. A ligand system containing four pre-organized 1-hydroxymethylene-1, 1-bisphosphonic acid moieties anchored onto a calix[4]arene platform has been developed. Three calix[4]-arene-bis-phosphonates were efficiently prepared in multi-step syntheses with a variable carbon chain length between the bis-phosphonate and the calix[4]arene. Affinity constants towards uranyl ion were determined and compared with those of bis(HEDP) and tris(HEDP) phosphonates, known as efficient ligands for uranyl. (authors)

CMPO-calix[4]arenes and the influence of structural modifications on the Eu(III), Am(III), Cm(III) separation

International Nuclear Information System (INIS)

Peters, C.; Braekers, D.; Desreux, J.F.; Kasyan, O.; Miroshnichenko, S.; Rudzevich, V.; Boehmer, V.

2008-01-01

The syntheses of new calix[4]arenes featuring CMPO groups on the wide rim are reported and the extraction of Am(III) and Eu(III) from concentrated HNO 3 aqueous phases are discussed with reference to the properties of the symmetric tetra-CMPO derivative 1. All extraction studies were conducted in the same experimental conditions which allows to directly compare the dependence of the distribution coefficients of various calixarenes on the acid concentration (0.1 M 3 ] < 5 M). Calix[4]arene 1 becomes a very poor extractant if the length of the aliphatic chain between the amide and phosphine oxide groups of CMPO is increased, if the bridging methylene groups are replaced by sulfur atoms or if the macrocyclic cavity size is increased. By contrast, mixed amide - CMPO calix[4]arenes are nearly as effective than 1. Moreover, Am(III)/Cm(III) separation coefficients between 1.5 and 3 have been obtained with unsymmetrical calix[4]arenes of type 1 with different aliphatic chains grafted on the narrow rim. Guidelines to anticipate the extraction ability of calix[4]arenes remain elusive because of the intricate solution behavior of these compounds. (orig.)

Light-Induced C-H Arylation of (Hetero)arenes by In Situ Generated Diazo Anhydrides.

Science.gov (United States)

Cantillo, David; Mateos, Carlos; Rincon, Juan A; de Frutos, Oscar; Kappe, C Oliver

2015-09-07

Diazo anhydrides (Ar-N=N-O-N=N-Ar) have been known since 1896 but have rarely been used in synthesis. This communication describes the development of a photochemical catalyst-free C-H arylation methodology for the preparation of bi(hetero)aryls by the one-pot reaction of anilines with tert-butyl nitrite and (hetero)arenes under neutral conditions. The key step in this procedure is the in situ formation and subsequent photochemical (>300 nm) homolytic cleavage of a transient diazo anhydride intermediate. The generated aryl radical then efficiently reacts with a (hetero)arene to form the desired bi(hetero)aryls producing only nitrogen, water, and tert-butanol as byproducts. The scope of the reaction for several substituted anilines and (hetero)arenes was investigated. A continuous-flow protocol increasing selectivity and safety has been developed enabling the experimentally straightforward preparation of a variety of substituted bi(hetero)aryls within 45 min of reaction time. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radiation stability of diglycolamide functionalized calix[4]arenes in ionic liquid: Solvent extraction, EPR and GC–MS studies

NARCIS (Netherlands)

Sengupta, A; Mohapatra, P.K.; Patil, A.B.; Kadam, R.M.; Verboom, Willem

2016-01-01

Ionic liquid-based solvent systems containing diglycolamide-functionalized calix[4]arenes (C4DGAs) are efficient for actinide ion extraction from nitric acid feeds. Therefore, the radiolytic stability of three C4DGAs (wide-rim, narrow-rim and both side DGA-functionalized calix[4]arenes) and TODGA

Bis(bipyridine)ruthenium(II) complexes with an aliphatic sulfinato donor: synthesis, characterization, and properties.

Science.gov (United States)

Tamura, Motoshi; Tsuge, Kiyoshi; Igashira-Kamiyama, Asako; Konno, Takumi

2011-06-06

Treatment of a thiolato-bridged Ru(II)Ag(I)Ru(II) trinuclear complex, [Ag{Ru(aet)(bpy)(2)}(2)](3+) (aet = 2-aminoethanthiolate; bpy = 2,2'-bipyridine), with NaI in aqueous ethanol under an aerobic condition afforded a mononuclear ruthenium(II) complex having an S-bonded sulfinato group, [1](+) ([Ru(aesi-N, S)(bpy)(2)](+) (aesi = 2-aminoethanesulfinate)). Similar treatment of optically active isomers of an analogous Ru(II)Ag(I)Ru(II) trinuclear complex, Δ(D)Δ(D)- and Λ(D)Λ(D)-[Ag{Ru(d-Hpen-O,S)(bpy)(2)}(2)](3+) (d-pen = d-penicillaminate), with NaI also produced mononuclear ruthenium(II) isomers with an S-bonded sulfinato group, Δ(D)- and Λ(D)-[2](+) ([Ru(d-Hpsi-O,S)(bpy)(2)](+) (d-psi = d-penicillaminesulfinate)), respectively, retaining the bidentate-O,S coordination mode of a d-Hpen ligand and the absolute configuration (Δ or Λ) about a Ru(II) center. On refluxing in water, the Δ(D) isomer of [2](+) underwent a linkage isomerization to form Δ(D)-[3] (+) ([Ru(d-Hpsi-N,S)(bpy)(2)](+)), in which a d-Hpsi ligand coordinates to a Ru(II) center in a bidentate-N,S mode. Complexes [1](+), Δ(D)- and Λ(D)-[2](+), and Δ(D)-[3](+) were fully characterized by electronic absorption, CD, NMR, and IR spectroscopies, together with single-crystal X-ray crystallography. The electrochemical properties of these complexes, which are highly dependent on the coordination mode of sulfinate ligands, are also described. © 2011 American Chemical Society

Lithium-ion induced conformational change of 5,17-bis(9-fluorenyl)-25,26,27,28-tetrapropoxy calix[4]arene resulting in an egg-shaped dimeric clathrate

DEFF Research Database (Denmark)

Faldt, A.; Krebs, Frederik C; Jørgensen, Mikkel

2000-01-01

Synthesis and structural investigation of a 5,17-bis(9-fluorenyl)-25,26,27,28-tetrapropoxy calix[4]arene and its lithium complex salt that forms a dimeric clathrate with a molecule of solvent inside a cavity. At least three different interactions were identified as being responsible for the forma...

Pyrazine-functionalized calix[4]arenes: synthesis by palladium-catalyzed cross-coupling with phosphorus pronucleophiles and metal ion extraction properties

NARCIS (Netherlands)

Nikishkin, N.; Huskens, Jurriaan; Ansari, S.A.; Mohapatra, P.K.; Verboom, Willem

2013-01-01

A series of pyrazine-based calix[4]arene extractants was prepared by a stepwise functionalization, comprising palladium-catalyzed exhaustive cross-coupling of di- and tetrasubstituted calix[4]arenes bearing chloropyrazine moieties. The extraction behavior of the synthesized ligands was studied on

Study on the inclusion behavior of p-sulfonatocalix[6]arene with propranolol by spectrofluorometry

Science.gov (United States)

Li, Hui; Song, Jin-Ping; Chao, Jian-Bin; Shuang, Shao-Min; Dong, Chuan

2012-11-01

The inclusion interaction between propranolol (PPL) and p-sulfonatocalix[6]arene (SCX6) was investigated by fluorescence and 1H NMR spectroscopy. Influences of pH, temperature, ionic strength and the concentration of SCX6 were examined in detail. In phosphate buffer solution with pH 7.5, the fluorescence of PPL dramatically quenched upon addition of SCX6 revealing the formation of inclusion complexes between PPL and SCX6. The stoichiometric ratio was verified to be 1:1 by the continuous variation method. The inclusion constant of PPL-SCX6 complexes was calculated as 2.2 × 104 L/mol by the nonlinear curve fitting method. 1H NMR titration spectra testified that the aliphatic chain of PPL may be partially penetrated into the hydrophobic cavity of SCX6. This was confirmed by molecular dynamics calculations.

Synthesis and Characterization of Two New p-tert-Butylcalix[4]-arene Schiff Bases

Directory of Open Access Journals (Sweden)

Saeed Taghvaee Ganjali

2001-03-01

Full Text Available Synthesis and characterization of two new Schiff bases of p-tertbuthylcalix[4]arene (H2L1 and HL2 is described. The synthesis of H2L1 and HL2 has been achieved by the condensation of salicylaldehyde with the amine group of upper rim monoamine p-tert-butylcalix[4]arene in ethanol. These compounds have been characterized on the basis of elemental analysis and spectral data. Solvatochromicity and fluorescence properties were observed and measured for H2L1 and HL2. Solvatochromicity of these ligands indicates their potential for NLO applications.

A New, Eco-Friendly Method for Iodination of Activated Arenes

Directory of Open Access Journals (Sweden)

R. Sathiyapriya

2006-01-01

Full Text Available An effective, eco-friendly method for iodination of arenes is presented. The reaction of activated aromatics with a mixture of sodium iodate and sodium sulphite in the presence of hydrochloric acid gives mono iodoarenes in high yields.

Self-assembled arene-ruthenium-based rectangles for the selective sensing of multi-carboxylate anions.

Science.gov (United States)

Vajpayee, Vaishali; Song, Young Ho; Lee, Min Hyung; Kim, Hyunuk; Wang, Ming; Stang, Peter J; Chi, Ki-Whan

2011-07-04

Novel arene-ruthenium [2+2] metalla-rectangles 4 and 5 have been synthesized by self-assembly using dipyridyl amide ligand 3 and arene-ruthenium acceptors (arene: benzoquinone (1), naphthacenedione (2)) and characterized by NMR spectroscopy and ESI-MS. The solid-state structure of 5 was determined by X-ray diffraction and shows encapsulated diethyl ether molecule in the rectangular cavity of 5. The luminescent 5 was further used for anion sensing with the amidic linkage serving as a hydrogen-bond donor site for anions and the ruthenium moiety serving as a signaling unit. A UV/Vis titration study demonstrated that although 5 interacts very weakly with common monoanions as well as with flexible dicarboxylate anions such as malonate and succinate, it displays significant binding affinity (K>10(3) in MeOH) for rigid multi-carboxylate anions such as oxalate, citrate, and tartrate, exhibiting a 1:1 stoichiometry. It has been suggested that 1:1 bidentate hydrogen bonding assisted by appropriate geometrical complementarity is mainly responsible for the increased affinity of 5 towards such anions. A fluorescence titration study revealed a large fluorescence enhancement of 5 upon binding to multi-carboxylate anions, which can be attributed to the blocking of the photoinduced electron-transfer process from the arene-Ru moiety to the amidic donor in 5 as a result of hydrogen bonding between the donor and the anion. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mulching An Arenic Hapludult In Southeastern Nigeria: Effects On ...

African Journals Online (AJOL)

A study was carried out over two cropping seasons at Umudike, southeastern Nigeria, to determine the type and quantity of mulch that would improve some selected physical properties of an Arenic Hapludult and optimize the rhizome yield of turmeric. Effects of mulch rate on bulk density (BD), total porosity (TP), ...

Mulching an Arenic Hapludult at Umudike: Effects on saturated ...

African Journals Online (AJOL)

A study was carried out over two cropping seasons on an Arenic Hapludult at Umudike, southeastern Nigeria, to investigate and determine the quantity and type of mulch material that would optimize the rhizome yield of turmeric (Curcuma longa Linn) and improve the saturated hydraulic conductivity of the soil. The turmeric ...

Synthesis of calix[4]arene-grafted magnetite nanoparticles and Evaluation of their arsenate as well as dichromate removal efficiency

Energy Technology Data Exchange (ETDEWEB)

Sayin, Serkan; Ozcan, Fatih; Yilmaz, Mustafa; Cengeloglu, Yunus [Department of Chemistry, Selcuk University, Konya (Turkey); Tor, Ali [Department of Environmental Engineering, Selcuk University, Konya (Turkey); Memon, Shahabuddin [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro (Pakistan)

2010-07-15

In this study, 5,17-bis-[(4-benzylpiperidine)methyl]-25,26,27,28-tetrahydroxy-calix[4]arene (3) has been prepared by the treatment of calix[4]arene with a secondary amine (4-benzylpiperidine) and formaldehyde by means of Mannich reaction. The prepared Mannich base (3) has been grafted onto [3-(2,3-epoxypropoxy)-propyl]-trimethoxysilane-modified Fe{sub 3}O{sub 4} magnetite nanoparticles (EPPTMS-MN) in order to obtain 5,17-bis-[(4-benzylpiperidine)methyl]-25,26,27,28-tetrahydroxy calix[4]arene-grafted EPPTMS-MN (BP-calix[4]arene-grafted Fe{sub 3}O{sub 4}). All new compounds were characterized by a combination of FTIR and {sup 1}H-NMR analyses. The morphology of the magnetic nanoparticles was examined by transmission electron microscopy. Moreover, the studies regarding the removal of arsenate and dichromate ions from the aqueous solutions were also carried out by using 5,17-bis-[(4-benzylpiperidine)methyl]-25,26,27,28-tetrahydroxy-calix[4]arene in liquid-liquid extraction and BP-calix[4]arene-grafted Fe{sub 3}O{sub 4} (4) in solid-liquid extraction experiments. The extraction results indicated that 3 is protonated at proton-switchable binding sites in acidic conditions. Hence, facilitating binding of arsenate and dichromate is resulted from both electrostatic interactions and hydrogen bonding. To understand the selectivity of 3, the retention of dichromate anions in the presence of Cl{sup -}, NO{sub 3}{sup -}, and SO{sub 4}{sup 2-} anions at pH 1.5 was also examined. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Binding of Coumarin 334 with β-Cyclodextrin and with C-Hexylpyrogallol[4]arene: Opposite Fluorescence Behavior

Directory of Open Access Journals (Sweden)

Chandrasekaran Sowrirajan

2013-01-01

Full Text Available We report here the structure of the host-guest complexes of Coumarin 334 (C334 with β-cyclodextrin (β-CD and with C-hexylpyrogallol[4]arene (C-HPA and the effect of acidity on the neutral-cation equilibrium of C334 in water and in the presence of the host molecules. The structures of the host-guest complexes are proposed on the basis of the change of fluorescence on the addition of β-CD or C-HPA to C334 and by 2D ROESY spectroscopy. Opposite fluorescence behaviors, that is, quenching of fluorescence in β-CD and enhancement of fluorescence in C-HPA are observed. Time-resolved fluorescence analysis is done for the complexation, and biexponential decay pattern is observed. The possible strong inclusion complexation with C-HPA is explained. The ground and the excited state pKa values for the protonation equilibrium of C334 in water and the difficulty of protonation in the presence of the host molecules are discussed.

Novel water-soluble b-cyclodextrin-calix[4]arene couples as fluorescent sensor molecules for the detection of neutral analytes

NARCIS (Netherlands)

Bugler, H.J.; Engbersen, Johannes F.J.; Reinhoudt, David

1998-01-01

The synthesis and the host-guest chemistry of two novel fluorescent B-cyclodextrin-calix[4]arene couples 1 and 2 is described. The compounds were prepared by coupling a B-cyclodextrin linked with an aminoxylyl spacer with two different calix[4]arene building blocks each bearing a fluorophore. The

Synthesis and characterization of poly(phenylacetylene)s with Ru(II) bis-terpyridine complexes in the side-chain.

Science.gov (United States)

Breul, Alexander M; Kübel, Joachim; Häupler, Bernhard; Friebe, Christian; Hager, Martin D; Winter, Andreas; Dietzek, Benjamin; Schubert, Ulrich S

2014-04-01

An alkyne-functionalized ruthenium(II) bis-terpyridine complex is directly copolymerized with phenylacetylene by alkyne polymerization. The polymer is characterized by size-exclusion chromatography (SEC), (1) H NMR spectroscopy, cyclic voltammetry (CV) measurements, and thermal analysis. The photophysical properties of the polymer are studied by UV-vis absorption spectroscopy. In addition, spectro-electrochemical measurements are carried out. Time-resolved luminescence lifetime decay curves show an enhanced lifetime of the metal complex attached to the conjugated polymer backbone compared with the Ru(tpy)2 (2+) model complex. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cobalt bis(dicarbollides)(1-) covalently attached to the calyx[4]arene platform: the first combination of organic bowl-shaped matrices and inorganic metallaborane cluster anions

NARCIS (Netherlands)

Grüner, Bohumír; Mikulasek, Libor; Baca, Jirí; Cisarova, Ivana; Böhmer, Volker; Danila, Crenguta; Reinoso garcia, M.M.; Verboom, Willem; Reinhoudt, David; Casnati, Alessandro; Ungaro, Rocco

2005-01-01

Various calix[4]arene and resorc[4]arene ionic compounds substituted by cobalt bis(dicarbollide) anions (1) have been prepared for the first time. From tBu-calix[4]arene (A) the complete series of mono-, di-, tri- and tetrasubstituted derivatives bearing one to four cluster anions on the lower rim

Experimental and DFT evaluation of the 1H and 13C NMR chemical shifts for calix[4]arenes

Science.gov (United States)

Guzzo, Rodrigo N.; Rezende, Michelle Jakeline Cunha; Kartnaller, Vinicius; Carneiro, José Walkimar de M.; Stoyanov, Stanislav R.; Costa, Leonardo Moreira da

2018-04-01

The density functional theory is employed to determine the efficiency of 11 exchange-correlation (XC) functionals to compute the 1H and 13C NMR chemical shifts of p-tert-butylcalix[4]arene (ptcx4, R1 = C(CH3)3) and congeners using the 6-31G(d,p) basis set. The statistical analysis shows that B3LYP, B3PW91 and PBE1PBE are the best XC functionals for the calculation of 1H chemical shifts. Moreover, the best results for the 13C chemical shifts are obtained using the LC-WPBE, M06-2X and wB97X-D functionals. The performance of these XC functionals is tested for three other calix[4]arenes: p-sulfonic acid calix[4]arene (sfxcx4 - R1 = SO3H), p-nitro-calix[4]arene (ncx4, R1 = NO2) and calix[4]arene (cx4 - R1 = H). For 1H chemical shifts B3LYP, B3PW91 and PBE1PBE yield similar results, although B3PW91 shows more consistency in the calculated error for the different structures. For 13C NMR chemical shifts, the XC functional that stood out as best is LC-WPBE. Indeed, the three functionals selected for each of 1H and 13C show good accuracy and can be used in future studies involving the prediction of 1H and 13C chemical shifts for this type of compounds.

NMR evidence for protonated tetraethyl p-tert-butylcalix[4]arene tetracacetate

Czech Academy of Sciences Publication Activity Database

Kříž, Jaroslav; Dybal, Jiří; Makrlík, E.; Vaňura, P.

2007-01-01

Roč. 81, č. 7 (2007), s. 1321-1326 ISSN 0137- 5083 Institutional research plan: CEZ:AV0Z40500505 Keywords : calix[4]arene * protonation * NMR * acetonitrile Subject RIV: CC - Organic Chemistry Impact factor: 0.483, year: 2007

The study of p-tert-butylcalix[n]arene on γ-radiation stabilization of polypropylene

International Nuclear Information System (INIS)

Feng Wen; Yuan Lihua; Zheng Shiyou; Huang Guanglin; Qiao Jinliang

2000-01-01

The γ-radiation effect of polyropylene was investigated in the presence of three kinds of p-tert-butylcalix[n]arene (n=4,6,8) in air or in vacuum at ambient temperature. The influence of radiation dose and store time upon the mechanical properties of the irradiated PP sheets were measured. The results showed that the radiation stabilization was reduced with the increase of the ring size of calixarenes. Based on the mass spectra and the analysis of post-irradiated product, the mechanism of radiation degradation of p-tert-butylcalix[4]arene has been proposed. (author)

Synthesis, Structure and Fluorescence Properties of 5,17-Distyryl-25,26,27,28-tetraproproxycalix[4]arenes in the Cone Conformation

DEFF Research Database (Denmark)

Larsen, Mogens; Krebs, Frederik C; Jørgensen, Mikkel

1998-01-01

The HWE (Horner-Wadsworth-Emmons) reaction performed on the easily obtainable 5,17-diformyl- calix[4]arenes (cone) with arylmethyl phosphorus ylides yielded 5,17-distyryl-25,26,27, 28-tetrapropoxycalix[4]arenes (cone) in high yield and purely in the E/E configuration. Compounds 2-5 were prepared...... this way containing bromine. Subsequent bromine-lithium exchange and reaction with trimethoxyborane yielded the boryl- substituted 5,17-distyrylcalix[4] arenes 6-7a. The structures of 3, 5, and 7a were determined by X-ray diffraction. The photophysical properties of 2 were established by absorption...

Alkenylation of Arenes and Heteroarenes with Alkynes.

Science.gov (United States)

Boyarskiy, Vadim P; Ryabukhin, Dmitry S; Bokach, Nadezhda A; Vasilyev, Aleksander V

2016-05-25

This review is focused on the analysis of current data on new methods of alkenylation of arenes and heteroarenes with alkynes by transition metal catalyzed reactions, Bronsted/Lewis acid promoted transformations, and others. The synthetic potential, scope, limitations, and mechanistic problems of the alkenylation reactions are discussed. The insertion of an alkenyl group into aromatic and heteroaromatic rings by inter- or intramolecular ways provides a synthetic route to derivatives of styrene, stilbene, chalcone, cinnamic acid, various fused carbo- and heterocycles, etc.

Control of the rheological properties of clay nanosheet hydrogels with a guanidinium-attached calix[4]arene binder.

Science.gov (United States)

Lee, Ji Ha; Kim, Chaelin; Jung, Jong Hwa

2015-10-21

A 1,3-alternate calix[4]arene derivative 1 possessing four guanidinium moieties was synthesized as a molecular binder. The clay nanosheet (CNS) hydrogels were prepared upon addition of 1 and sodium polyacrylate (ASSP), and their mechanical properties were measured by rheometry. CNS hydrogels prepared by combining calix[4]arene 1 with dispersed CNSs surrounded by ASSPs showed an enhancement of mechanical properties such as viscosity and elasticity.

Antioxidant and DPPH (1,1-diphenyl-2-picrylhydrazyl Free Radical Scavenging Activities of New the Calix[4]arene-bodipy Derivative

Directory of Open Access Journals (Sweden)

E. ERDEM

2014-07-01

Full Text Available p-tert-butylcalix[4]arene was synthesized with the condesation reaction of p-tert-butylphenol and formaldehyde in basic conditions and then has derivatized from the both of two hydroxyl position with chloride which is containing donor oxygen atoms. BODIPY compound (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene was synthesized with appropriate pyrrole and aldehyde compounds and then was bonded p-tert-butylcalix[4]arene derivative via lower rim hydroxyl groups.The antioxidant activity of the calix[4]arene-BODIPY compound were determined using β-karotene-linoleic acid system. Moreover, the free radical scavenging activity values were tested with DPPH free radical. The compound showed strong antioxidant activity.Total antioxidant activity of the compound was determined using β–carotenelinoleic acid model system and was found the antioxidant activity of 72,50%. The free radical scavenging activities were determined as 75.19%. Results show that, calix[4]arene-BODIPY compound has the antioxidant activity. 

Direct Synthesis of 5-Aryl Barbituric Acids by Rhodium(II)-Catalyzed Reactions of Arenes with Diazo Compounds.

Science.gov (United States)

Best, Daniel; Burns, David J; Lam, Hon Wai

2015-06-15

A commercially available rhodium(II) complex catalyzes the direct arylation of 5-diazobarbituric acids with arenes, allowing straightforward access to 5-aryl barbituric acids. Free N-H groups are tolerated on the barbituric acid, with no complications arising from N-H insertion processes. This method was applied to the concise synthesis of a potent matrix metalloproteinase (MMP) inhibitor. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Novel dansyl-appended calix[4]arene frameworks: fluorescence properties and mercury sensing.

Science.gov (United States)

Pandey, Shubha; Azam, Amir; Pandey, Siddharth; Chawla, H M

2009-01-21

Covalently-attached fluorophores may impart enhanced chemosensing capabilities to calixarene frameworks. Synthesis and characterization of six novel dansyl-appended calix[4]arenes, namely, H/Dan4, NO2/Dan4, H/(OH)2Dan2, H/(Ester)2(Dan)2, t-Bu/(OH)2Dan2, and t-Bu/(Ester)2Dan2, containing two or four dansyl moieties are reported. Among these, fluorescence intensity of NO2/Dan4 is observed to decrease significantly in the presence Hg2+ in the solution. Based on the decrease in fluorescence, a limit of detection for Hg2+ of 20 ppb is obtained. NO2/Dan4 as a chemosensing agent for Hg2+ shows excellent selectivity and adequate reversibility. Complexation of NO2/Dan4 with Hg2+ is investigated using fluorescence spectroscopy and is observed to be 2:1. The formation constant of (NO2/Dan4)2Hg2+ is estimated to be 5.2(+/- 0.8) x 10(10) M(-2) at ambient conditions. These observations are traced to the fact that while all other dansyl-appended calix[4]arenes show cone conformation in the solution, NO2/Dan4 is in the 1,3-alternate conformation. Stokes shift versus solvent orientational polarizability for NO2/Dan4 also indicates the difference in the ground- to excited-state dipole moment of this compound to be the maximum among all six, rendering it most sensitive to its environment. Fluorescence emission of NO2/Dan4 in nonpolar chloroform, polar-aprotic acetonitrile, and polar-protic ethanol is observed to be different than that of the rest of the dansyl-appended compounds as well.

Uranyl complexes formed with a para-t-butylcalix[4]arene bearing phosphinoyl pendant arms on the lower rim. Solid and solution studies

Energy Technology Data Exchange (ETDEWEB)

Ramirez, F. de M. [Instituto Nacional de Investigaciones Nucleares, La Marquesa, Ocoyoacac (Mexico). Dept. de Quimica; Varbanov, S. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Organic Chemistry with Center of Phytochemistry; Buenzli, J.C.G. [Ecole Polytechnique Federale de Lausanne (EPFL) (Switzerland). Inst. of Chemical Sciences and Engineering; Rivas-Silva, J.F.; Ocana-Bribiesca, M.A. [Instituto de Fisica de la BUAP, Puebla (Mexico); Cortes-Jacome, M.A.; Toledo-Antonio, J.A. [Instituto Mexicano del Petroleo/Programa de Ingenieria Molecular (Mexico)

2012-07-01

The current interest in functionalized calixarenes with phosphorylated pendant arms resides in their coordination ability towards f elements and capability towards actinide/rare earth separation. Uranyl cation forms 1:1 and 1:2 (M:L) complexes with a tetra-phosphinoylated p-tert-butylcalix[4]arene, B{sub 4}bL{sup 4}: UO{sub 2}(NO{sub 3}){sub 2}(B{sub 4}bL{sup 4}){sub n} . xH{sub 2}O (n = 1, x = 2, 1; n = 2, x = 6, 2). Spectroscopic data point to the inner coordination sphere of 1 containing one monodentate nitrate anion, one water molecule and the four phosphinoylated arms bound to UO{sub 2}{sup 2+} while in 2, uranyl is only coordinated to calixarene ligands. In both cases the U(VI) ion is 8-coordinate. Uranyl complexes display enhanced metal-centred luminescence due to energy transfer from the calixarene ligands; the luminescence decays are bi-exponential with associated lifetimes in the ranges 220 {mu}s < {tau}{sub s} < 250 {mu}s and 630 {mu}s < {tau}{sub L} < 640 {mu}s, pointing to the presence of two species with differently coordinated calixarene, as substantiated by a XPS study of U(4f{sub 5/2,7/2}), O(1s) and P(2p) levels on solid state samples. The extraction study of UO{sub 2}{sup 2+} cation and trivalent rare-earth (Y, La, Eu) ions from acidic nitrate media by B{sub 4}bL{sup 4} in chloroform shows the uranyl cation being much more extracted than rare earths. (orig.)

Photoreactions of ruthenium(II) and osmium(II) complexes with deoxyribonucleic acid (DNA).

Science.gov (United States)

Moucheron, C; Kirsch-De Mesmaeker, A; Kelly, J M

1997-09-01

The design of Ru(II) and Os(II) complexes which are photoreactive with deoxyribonucleic acid (DNA) represents one of the main targets for the development of novel molecular tools for the study of DNA and, in the future, for the production of new, metal-based, anti-tumor drugs. In this review, we explain how it is possible to make a complex photoreactive with nucleobases and nucleic acids. According to the photophysical behaviour of the Ru(II) compounds, two types of photochemistry are expected: (1) photosubstitution of a ligand by a nucleobase and another monodentate ligand, which takes place from the triplet, metal-centred (3MC) state; this state is populated thermally from the lowest lying triplet metal to ligand charge transfer (3MLCT) state; (2) photoreaction from the 3MLCT state, corresponding to photoredox processes with DNA bases. The two photoreactivities are in competition. By modulating appropriately the redox properties of the 3MLCT state, an electron transfer process from the base to the excited complex takes place, and is directly correlated with DNA cleavage or the formation of an adduct of the complex to DNA. In this adduct, guanine is linked by N2 to the alpha-position of a non-chelating nitrogen of the polyazaaromatic ligand without destruction of the complex. Different strategies are explained which increase the affinity of the complexes for DNA and direct the complex photoreactivity to sites of special DNA topology or targeted sequences of bases. Moreover, the replacement of the Ru(II) ion by the Os(II) ion in the photoreactive complexes leads to an increased specificity of photoreaction. Indeed, only one type of photoreactivity (from the 3MLCT state) is present for the Os(II) complexes because the 3MC state is too high in energy to be populated at room temperature.

Synthesis of Novel p-tert-Butylcalix[4]arene Derivative: Structural Characterization of a Methanol Inclusion Compound

Directory of Open Access Journals (Sweden)

Silvana Moris

2016-09-01

Full Text Available A p-tertbutylcalix[4]arene derivative was synthesized from a reaction of the diisothiocyanate p-tertbutylcalix[4]arene, obtaining crystals that were then characterized by mass spectroscopy, Raman spectroscopy, and single-crystal X-ray diffraction. The molecule presents two acid carbamothioic-n-ethoxy-methyl-ester substituent groups. Through crystallization of this compound, it was also found that it includes a methanol molecule within the aromatic cavity. The inclusion of the methanol molecule is due to favorable CH∙∙∙π interactions.

Arenal-type pyroclastic flows: A probabilistic event tree risk analysis

Science.gov (United States)

Meloy, Anthony F.

2006-09-01

A quantitative hazard-specific scenario-modelling risk analysis is performed at Arenal volcano, Costa Rica for the newly recognised Arenal-type pyroclastic flow (ATPF) phenomenon using an event tree framework. These flows are generated by the sudden depressurisation and fragmentation of an active basaltic andesite lava pool as a result of a partial collapse of the crater wall. The deposits of this type of flow include angular blocks and juvenile clasts, which are rarely found in other types of pyroclastic flow. An event tree analysis (ETA) is a useful tool and framework in which to analyse and graphically present the probabilities of the occurrence of many possible events in a complex system. Four event trees are created in the analysis, three of which are extended to investigate the varying individual risk faced by three generic representatives of the surrounding community: a resident, a worker, and a tourist. The raw numerical risk estimates determined by the ETA are converted into a set of linguistic expressions (i.e. VERY HIGH, HIGH, MODERATE etc.) using an established risk classification scale. Three individually tailored semi-quantitative risk maps are then created from a set of risk conversion tables to show how the risk varies for each individual in different areas around the volcano. In some cases, by relocating from the north to the south, the level of risk can be reduced by up to three classes. While the individual risk maps may be broadly applicable, and therefore of interest to the general community, the risk maps and associated probability values generated in the ETA are intended to be used by trained professionals and government agencies to evaluate the risk and effectively manage the long-term development of infrastructure and habitation. With the addition of fresh monitoring data, the combination of both long- and short-term event trees would provide a comprehensive and consistent method of risk analysis (both during and pre-crisis), and as such

Field reconnaissance of the effects of the earthquake of April 13, 1973, near Laguna de Arenal, Costa Rica

Science.gov (United States)

Plafker, George

1973-01-01

At about 3:34 a.m. on April 13, 1973, a moderate-sized, but widely-felt, earthquake caused extensive damage with loss of 23 lives in a rural area of about 150 km2 centered just south of Laguna de Arenal in northwestern Costa Rica (fig. 1). This report summarizes the results of the writer's reconnaissance investigation of the area that was affected by the earthquake of April 13, 1973. A 4-day field study of the meizoseismal area was carried out during the period from April 28 through May 1 under the auspices of the U.S. Geological Survey. The primary objective of this study was to evaluate geologic factors that contributed to the damage and loss of life. The earthquake was also of special interest because of the possibility that it was accompanied by surface faulting comparable to that which occurred at Managua, Nicaragua, during the disastrous earthquake of December 23, 1972 (Brown, Ward, and Plafker, 1973). Such earthquake-related surface faulting can provide scientifically valuable information on active tectonic processes at shallow depths within the Middle America arc. Also, identification of active faults in this area is of considerable practical importance because of the planned construction of a major hydroelectrical facility within the meizoseismal area by the Instituto Costarricense de Electricidad (I.C.E.). The project would involve creation of a storage reservoir within the Laguna de Arenal basin and part of the Río Arenal valley with a 75 m-high earthfill dam across Río Arenal at a point about 10 km east of the outlet of Laguna de Arenal.

Interaction of acridine-calix[4]arene with DNA at the electrified liquid liquid interface

International Nuclear Information System (INIS)

Kivlehan, Francine; Lefoix, Myriam; Moynihan, Humphrey A.; Thompson, Damien; Ogurtsov, Vladimir I.; Herzog, Gregoire; Arrigan, Damien W.M.

2010-01-01

The behaviour of an acridine-functionalised calix[4]arene at the interface between two immiscible electrolyte solutions (ITIES) is reported. Molecular modelling showed that the acridine-calix[4]arene has regions of significant net positive charge spread throughout the protonated acridine moieties, consistent with it being able to function as an anion ionophore. The presence of this compound in the organic phase facilitated the transfer of aqueous phase electrolyte ions. Upon addition of double stranded DNA to the aqueous phase, the transfer of electrolyte anions was diminished, due to DNA binding to the acridine moiety at the ITIES. The behaviour provides a basis for DNA hybridization detection using electrochemistry at the ITIES.

Calix[6]arene bypasses human pancreatic cancer aggressiveness: downregulation of receptor tyrosine kinases and induction of cell death by reticulum stress and autophagy.

Science.gov (United States)

Pelizzaro-Rocha, Karin Juliane; de Jesus, Marcelo Bispo; Ruela-de-Sousa, Roberta Regina; Nakamura, Celso Vataru; Reis, Fabiano Souza; de Fátima, Angelo; Ferreira-Halder, Carmen Veríssima

2013-12-01

Pancreatic cancer ranks fourth among cancer-related causes of death in North America. Minimal progress has been made in the diagnosis and treatment of patients with late-stage tumors. Moreover, pancreatic cancer aggressiveness is closely related to high levels of pro-survival mediators, which can ultimately lead to rapid disease progression, resistance and metastasis. The main goal of this study was to define the mechanisms by which calix[6]arene, but not other calixarenes, efficiently decreases the aggressiveness of a drug resistant human pancreas carcinoma cell line (Panc-1). Calix[6]arene was more potent in reducing Panc-1 cell viability than gemcitabine and 5-fluorouracil. In relation to the underlying mechanisms of cytotoxic effects, it led to cell cycle arrest in the G0/G1 phase through downregulation of PIM1, CDK2, CDK4 and retinoblastoma proteins. Importantly, calix[6]arene abolished signal transduction of Mer and AXL tyrosine kinase receptors, both of which are usually overexpressed in pancreatic cancer. Accordingly, inhibition of PI3K and mTOR was also observed, and these proteins are positively modulated by Mer and AXL. Despite decreasing the phosphorylation of AKT at Thr308, calix[6]arene caused an increase in phosphorylation at Ser473. These findings in conjunction with increased BiP and IRE1-α provide a molecular basis explaining the capacity of calix[6]arene to trigger endoplasmic reticulum stress and autophagic cell death. Our findings highlight calix[6]arene as a potential candidate for overcoming pancreatic cancer aggressiveness. Importantly, we provide evidence that calix[6]arene affects a broad array of key targets that are usually dysfunctional in pancreatic cancer, a highly desirable characteristic for chemotherapeutics. © 2013.

Am(m)ines make the difference: organoruthenium am(m)ine complexes and their chemistry in anticancer drug development.

Science.gov (United States)

Babak, Maria V; Meier, Samuel M; Legin, Anton A; Adib Razavi, Mahsa S; Roller, Alexander; Jakupec, Michael A; Keppler, Bernhard K; Hartinger, Christian G

2013-03-25

With the aim of systematically studying fundamental structure-activity relationships as a basis for the development of Ru(II) arene complexes (arene = p-cymene or biphenyl) bearing mono-, bi-, or tridentate am(m)ine ligands as anticancer agents, a series of ammine, ethylenediamine, and diethylenetriamine complexes were prepared by different synthetic routes. Especially the synthesis of mono-, di-, and triammine complexes was found to be highly dependent on the reaction conditions, such as stoichiometry, temperature, and time. Hydrolysis and protein-binding studies were performed to determine the reactivity of the compounds, and only those containing chlorido ligands undergo aquation or form protein adducts. These properties correlate well with in vitro tumor-inhibiting potency of the compounds. The complexes were found to be active in anticancer assays when meeting the following criteria: stability in aqueous solution and low rates of hydrolysis and binding to proteins. Therefore, the complexes least reactive to proteins were found to be the most cytotoxic in cancer cells. In general, complexes with biphenyl as arene ligand inhibited the growth of tumor cells more effectively than the cymene analogues, consistent with the increase in lipophilicity. This study highlights the importance of finding a proper balance between reactivity and stability in the development of organometallic anticancer agents. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterisation of the ester-substituted products of the reaction of p-t-butyl calix[4]arene and ethyl bromoacetate using LC-UV-MS and LC-DAD.

Science.gov (United States)

McMahon, Gillian; Wall, Rachel; Nolan, Kieran; Diamond, Dermot

2002-07-19

A series of derivatisation reactions between p-t-butyl calix[4]arene and ethyl bromoacetate were carried out in order to prepare 1,3 diester substituted calix[4]arene. Mass spectral data, obtained from direct injection of samples, indicated that the reactions were rich in the desired product. Since the ultra violet (UV) spectra of the desired product and possible impurities are very similar, liquid chromatography (LC) chromatographic data seemed to corroborate these results. However, when on-line LC-UV-MS was carried out and each LC peak subjected to MS analysis as it eluted, a very different picture emerged. It was found that many of these reactions actually contained high levels of the monoester product which, having less affinity for sodium in the MS, is therefore seriously underestimated in any direct injection assay. LC-diode array detection (DAD) methods were also used to help successfully identify and characterise the compounds being formed in these complex reactions. The overall results obtained in this paper allowed the optimal reaction conditions to be determined for this reaction. LC-MS analysis of the chromatographic peaks also identified the presence of two isomers of the diester substituted calix[4]arene (1,3 and 1,2 diesters). The combination of LC and UV/MS detection is required for accurate analysis of the products of such reactions.

Zn2+ -Ion Sensing by Fluorescent Schiff Base Calix[4]arene Macrocycles.

Science.gov (United States)

Ullmann, Steve; Schnorr, René; Handke, Marcel; Laube, Christian; Abel, Bernd; Matysik, Jörg; Findeisen, Matthias; Rüger, Robert; Heine, Thomas; Kersting, Berthold

2017-03-17

A macrocyclic ligand (H 2 L) containing two o,o'-bis(iminomethyl)phenol and two calix[4]arene head units has been synthesized and its coordination chemistry towards divalent Ni and Zn investigated. The new macrocycle forms complexes of composition [ML] (M=Zn, M=Ni) and [ZnL(py) 2 ], which were characterized by elemental analysis; IR, UV/Vis, and NMR spectroscopy; electrospray ionization mass spectrometry (ESI-MS); and X-ray crystallography (for [ZnL(py) 2 ] and [NiL]). H 2 L allows the sensitive optical detection of Zn 2+ among a series of biologically relevant metal ions by a dual fluorescence enhancement/quenching effect in solution. The fluorescence intensity of the macrocycle increases by a factor of ten in the presence of Zn 2+ with a detection limit in the lower nanomolar region. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Host-Guest Interaction between Corona[n]arene and Bisquaternary Ammonium Derivatives for Fabricating Supra-Amphiphile.

Science.gov (United States)

Zeng, Lingda; Guo, Qing-Hui; Feng, Yuanning; Xu, Jiang-Fei; Wei, Yuhan; Li, Zhibo; Wang, Mei-Xiang; Zhang, Xi

2017-06-13

The interactions between a host, water-soluble corona[n]arene (S6-CAP), and a series of guests, bisquaternary ammonium derivatives (CnDAs), in water, were investigated. The host and guest can form 1:1 host-guest complex. Their binding constants decrease as the alkyl length of CnDAs increases, which can be tunable ranging from 10 3 to 10 6 M -1 . The binding processes are mainly entropy-driven, while the enthalpy changes also play an important role in enhancing the host-guest interactions. In addition, a supra-amphiphile was fabricated with S6-CAP and a normal surfactant bearing bisquaternary ammonium (C4R). The S6-CAP·C4R complex forms micellar aggregates in water, and the system possesses better assembling activity and dilution stability than its building block C4R. This study enriches the families of supra-amphiphiles with a new architecture, and employing such a supra-amphiphile in biofunctional materials is highly anticipated.

Nitrosonium complexation by the tetraphosphonate cavitand 5,11,17,23-tetramethyl-6,10:12,16:18,22:24,4-tetrakis(phenylphosphonato-κ2O,Oresorcin(4arene

Directory of Open Access Journals (Sweden)

Roberta Pinalli

2017-12-01

Full Text Available The crystal structure of a new supramolecular complex between the tetraphosphonate cavitand 5,11,17,23-tetramethyl-6,10:12,16:18,22:24,4-tetrakis(phenylphosphonato-κ2O,O′resorcin(4arene and the nitrosyl cation NO+, as the BF4− salt, is reported. The complex, of general formula [(C56H44P4O12(NO]BF4·CH2Cl2 or NO@Tiiii[H, CH3, C6H5] BF4·CH2Cl2, crystallizes in the space group P-1. The nitrosyl cation is disordered over two equivalent positions, with occupancies of 0.503 (2 and 0.497 (2, and interacts with two adjacent P=O groups at the upper rim of the cavitand through dipole–charge interactions. In the lattice, the cavitands are connected through a series of C—H...π interactions involving the methyl and methylenic H atoms and the aromatic rings of the macrocycle. The structure is further stabilized by the presence of C—H...F interactions between the hydrogen atoms of the cavitands and the F atoms of the tetrafluoridoborate anion. As a result of the disorder, the lattice dichloromethane molecules could not be modelled in terms of atomic sites, and were treated using the PLATON SQUEEZE procedure [Spek (2015. Acta Cryst. C71, 9–18]. The complexation process has also been studied in solution through NMR titrations.

Binding behaviors of p-sulfonatocalix[4]arene with gemini guests.

Science.gov (United States)

Zhao, Hong-Xia; Guo, Dong-Sheng; Liu, Yu

2013-02-14

A dozen of homoditopic cations, possessing different spacer lengths and rigidities, as well as sizes, shapes, and charges of terminal groups, were synthesized as candidate gemini guests for the complexation of p-sulfonatocalix[4]arenes (SC4A). The 12 gemini guests are divided into five species according to the different terminal groups: imidazolium (G1-G3), pyridinium (G4-G6), quinolinium (G7), viologen (G8-G11), and 1,4-diazabicyclo[2.2.2]octane (DBO, G12). Their binding structures and stoichiometries with SC4A were examined by NMR spectroscopy, which is helpful to construct diverse highly ordered assemblies. The obtained results show that the length of the linkers, as well as the charge numbers on the end groups have a pronounced effect on the binding stoichiometry, whereas the size and shape of the terminal groups have no significant influence. Furthermore, both the stability constants and thermodynamic parameters of SC4A with the terminal subunits were determined by the isothermal titration calorimetry experiments, which are valuable to understand the binding behavior, giving quantitatively deep insight.

Calix[4]arene-Based Enantioselective Fluorescent Sensors for the Recognition of N-Acetyl-aspartate

Institute of Scientific and Technical Information of China (English)

QING Guang-Yan; CHEN Zhi-Hong; WANG Feng; YANG Xi; MENG Ling-Zhi; HE Yong-Bing

2008-01-01

Two-armed chiral anion receptors (1 and 2), calix[4]arenes bearing dansyl fluorophore and (1R,2R)- or(1S,2S)-1,2-diphenylethylenediamine binding sites, were prepared and examined for their chiral amino acid anion binding abilities by the fluorescence spectra in dimethylsulfoxide (DMSO). The results of non-linear curve fitting indicate that 1 or 2 forms a 1 : 1 stoichiometry complex with N-acetyl-L-or D-aspartate by multiple hydrogen bonding interactions, exhibiting good enantioselective fluorescent recognition for the enantiomers of N-acetyl-as-partate, [receptor 1: Kass(D)/Kass(L)=6.74; receptor 2: Kass(L)/Kass(D)=6.48]. The clear fluorescent response difference indicates that receptors 1 and 2 could be used as a fluorescent chemosensor for N-Acetyl-aspartate.

An Integrated approach (thermodynamic, structural, and computational) to the study of complexation of alkali-metal cations by a lower-rim calix[4]arene amide derivative in acetonitrile.

Science.gov (United States)

Horvat, Gordan; Stilinović, Vladimir; Hrenar, Tomica; Kaitner, Branko; Frkanec, Leo; Tomišić, Vladislav

2012-06-04

The calix[4]arene secondary-amide derivative L was synthesized, and its complexation with alkali-metal cations in acetonitrile (MeCN) was studied by means of spectrophotometric, NMR, conductometric, and microcalorimetric titrations at 25 °C. The stability constants of the 1:1 (metal/ligand) complexes determined by different methods were in excellent agreement. For the complexation of M(+) (M = Li, Na, K) with L, both enthalpic and entropic contributions were favorable, with their values and mutual relations being quite strongly dependent on the cation. The enthalpic and overall stability was the largest in the case of the sodium complex. Molecular and crystal structures of free L, its methanol and MeCN solvates, the sodium complex, and its MeCN solvate were determined by single-crystal X-ray diffraction. The inclusion of a MeCN molecule in the calixarene hydrophobic cavity was observed both in solution and in the solid state. This specific interaction was found to be stronger in the case of metal complexes compared to the free ligand because of the better preorganization of the hydrophobic cone to accept the solvent molecule. Density functional theory calculations showed that the flattened cone conformation (C(2) point group) of L was generally more favorable than the square cone conformation (C(4) point group). In the complex with Na(+), L was in square cone conformation, whereas in its adduct with MeCN, the conformation was slightly distorted from the full symmetry. These conformations were in agreement with those observed in the solid state. The classical molecular dynamics simulations indicated that the MeCN molecule enters the L hydrophobic cavity of both the free ligand and its alkali-metal complexes. The inclusion of MeCN in the cone of free L was accompanied by the conformational change from C(2) to C(4) symmetry. As in solution studies, in the case of ML(+) complexes, an allosteric effect was observed: the ligand was already in the appropriate square cone

Ruthenium-complex catalyzed N-(cyclo)alkylation of aromatic amines with diols. Selective synthesis of N-(n-hydroixyalkyl)anilines of type PhNH(CH2)nOH and of some bioactive arylpiperazines,

NARCIS (Netherlands)

Koten, G. van; Abbenhuis, R.A.T.M.; Boersma, J.

1998-01-01

A new class of well-defined neutral mono-, and dicationic ruthenium(II) complexes containing a neutral terdentate donor system [C5H3N(CH2E)(2)-2,6] (E = PPh2 (PNP) or NMe2 (NN'N)) has been found effective as catalyst precursor in N-(cyclo)alkylation reactions of aromatic amines with diols

mPW1PW91 Calculated Conformational Study of Calix[n]arene (n = 4,5,6): Hydrogen Bond

International Nuclear Information System (INIS)

Kim, Kwang Ho; Choe, Jong In

2009-01-01

We have performed mPW1PW91 calculations to investigate the conformational characteristics and hydrogen bonds of p-tert-butylcalix[4]arene, p-tert-butylcalix[5]arene, calix[6]arene and p-tertbutylcalix[ 6]arene. The structures of the different conformers of 1-3 were optimized by using mPW1PW91/ 6-31+G(d,p) method. The relative stability of the four conformers of 1 is in the following order: cone (most stable) > partial-cone > 1,2-alternate > 1,3-alternate. The relative stability of the conformers of 2 is in the following order: cone (most stable) > 1,2-alternate > partial-cone > 1,3-alternate. The relative stability of the various conformers of 3 is in the following order: cone (pinched: most stable) > partial-cone > cone (winged) ∼ 1,2-alternate ∼ 1,2,3-alternate > 1,4-alternate > 1,3-alternate > 1,3,5-alternate. The structures of the various conformers of 4 were optimized by using the mPW1PW91/6-31G(d,p) method followed by single point calculation of mPW1PW91/6-31+G(d,p). The relative stability of the conformers of 4 is in the following order: cone (pinched) > 1,2-alternate > cone (winged) > 1,4-alternate ∼ partial-cone > 1,2,3-alternate > 1,3,5-alternate > 1,3-alternate

Depositional setting and early diagenesis of the dinosaur eggshell-bearing Aren Fm at Bastus, Late Campanian, south-central Pyrenees

OpenAIRE

Díaz Molina, Margarita; Kälin, Otto; Benito Moreno, María Isabel; López Martínez, Nieves; Vicens, Enric

2007-01-01

The Late Cretaceous Aren Fm exposed north of Bastus in the Tremp Basin (south-central Pyrenees) preserves an excellent record of dinosaur eggs laid in a marine littoral setting. Different from other cases reported in literature, at the Bastus site the preferential nesting ground was original beach sand. The coastal deposits of Aren Fm can be grouped into four facies assemblages, representing respectively shoreface, beachface, beach ridge plain and backbarrier lagoon environments. Shoreface de...

Electrochemical Reduction and Intramolecular Electron Communication of Nitro Substituted Thiacalix[4]arenes

Czech Academy of Sciences Publication Activity Database

Liška, Alan; Lhoták, P.; Ludvík, Jiří

2016-01-01

Roč. 28, č. 11 (2016), s. 2861-2865 ISSN 1040-0397 R&D Projects: GA ČR GA13-21704S Institutional support: RVO:61388955 Keywords : 1,3-alt-thiacalix[4]arenes * nitro substituents * polarography Subject RIV: CG - Electrochemistry Impact factor: 2.851, year: 2016

Organic chemistry in ambient temperature chloroaluminate melts. I. Protonation of arenes

International Nuclear Information System (INIS)

Dworkin, A.S.; Smith, G.P.; ZIngg, S.P.; Pagni, R.M.

1987-01-01

Acidic chloroaluminates are the quintessential Friedel-Crafts catalysts. Many of the reactions that they activate are of the carbenium-ion-chain type. In the case of arene (ArH) substrates a key step is the partial protonation of ArH by a protic acid (HB) as shown in Eq. 1 , where B- is a generic base and ArH/sub 2//sup +/ is the protonated arene or arenium ion. The apparent role of the acidic chloroaluminate is the ArH + HB ↔ ArH/sub 2//sup +/ + B/sup -/. Enhancement of the protonating strength of HB through the reaction of acidic chloroaluminate species, such as Al/sub 2/Cl/sub 6/, Al/sub 3/Cl/sub 7/- or Al/sub 3/Cl/sub 10-/., with the base B/sub -/. The simplest example of HB is HCl for which the overall protonating reaction is given in Eq. 2, where ArH + HCl + Al/sub 2/Cl/sub 7/- ↔ ArH/sub 2/+ + 2AlCl/sub 4/- Al/sub 2/Cl/sub 7/- represents the acidic chloroalmuniate

Crystal structures of two thiacalix[4]arene derivatives anchoring four ...

Indian Academy of Sciences (India)

Administrator

Abstract. The crystal structures of two thiacalixarene derivatives anchoring thiadiazole functional groups at lower rim, C60H72O4S12N8 (1), C64H80O4S12N8 (2), have been determined by single crystal X-ray diffraction. The thiacalix[4]arene framework in both 1 and 2 adopts the 1,3-alternate conformation. Com- pound 1 ...

Copper-catalyzed oxidative Heck reactions between alkyltrifluoroborates and vinyl arenes.

Science.gov (United States)

Liwosz, Timothy W; Chemler, Sherry R

2013-06-21

We report herein that potassium alkyltrifluoroborates can be utilized in oxidative Heck-type reactions with vinyl arenes. The reaction is catalyzed by a Cu(OTf)2/1,10-phenanthroline with MnO2 as the stoichiometric oxidant. In addition to the alkyl Heck, amination, esterification, and dimerization reactions of alkyltrifluoroborates are demonstrated under analogous reaction conditions. Evidence for an alkyl radical intermediate is presented.

Controlling the photochemical reaction of an azastilbene derivative in water using a water-soluble pillar[6]arene.

Science.gov (United States)

Xia, Danyu; Wang, Pi; Shi, Bingbing

2017-09-20

Photochemistry plays an important role in our lives. It has also been a common tool in the laboratory to construct complicated systems from small molecules. Supramolecular chemistry provides an opportunity to solve some of the problems in controlling photochemical reactions via non-covalent interactions. By using confining media and weak interactions between the medium and the reactant molecule, the excited state behavior of molecules has been successfully manipulated. Pillararenes, a new class of macrocyclic hosts, have rarely been used in the field of photochemical investigations, such as the controlling of photo-induced reactions. Herein, we explore a synthetic macrocyclic host, a water-soluble pillar[6]arene, as a controlling tool to manipulate the photo-induced reactions (hydration) in water. A host-guest system in water based on a water-soluble pillar[6]arene and an azastilbene derivative, (E)-4,4'-dimethyl-4,4'-diazoniastilbene diiodide, has been constructed. Then this water-soluble pillar[6]arene was successfully employed to control the photohydration of the azastilbene derivative in water as a "protective agent".

Uranium(III)-carbon multiple bonding supported by arene δ-bonding in mixed-valence hexauranium nanometre-scale rings.

Science.gov (United States)

Wooles, Ashley J; Mills, David P; Tuna, Floriana; McInnes, Eric J L; Law, Gareth T W; Fuller, Adam J; Kremer, Felipe; Ridgway, Mark; Lewis, William; Gagliardi, Laura; Vlaisavljevich, Bess; Liddle, Stephen T

2018-05-29

Despite the fact that non-aqueous uranium chemistry is over 60 years old, most polarised-covalent uranium-element multiple bonds involve formal uranium oxidation states IV, V, and VI. The paucity of uranium(III) congeners is because, in common with metal-ligand multiple bonding generally, such linkages involve strongly donating, charge-loaded ligands that bind best to electron-poor metals and inherently promote disproportionation of uranium(III). Here, we report the synthesis of hexauranium-methanediide nanometre-scale rings. Combined experimental and computational studies suggest overall the presence of formal uranium(III) and (IV) ions, though electron delocalisation in this Kramers system cannot be definitively ruled out, and the resulting polarised-covalent U = C bonds are supported by iodide and δ-bonded arene bridges. The arenes provide reservoirs that accommodate charge, thus avoiding inter-electronic repulsion that would destabilise these low oxidation state metal-ligand multiple bonds. Using arenes as electronic buffers could constitute a general synthetic strategy by which to stabilise otherwise inherently unstable metal-ligand linkages.

Ruthenium(II) pincer complexes with oxazoline arms for efficient transfer hydrogenation reactions

KAUST Repository

Chen, Tao

2012-08-01

Well-defined P NN CN pincer ruthenium complexes bearing both strong phosphine and weak oxazoline donors were developed. These easily accessible complexes exhibit significantly better catalytic activity in transfer hydrogenation of ketones compared to their PN 3P analogs. These reactions proceed under mild and base-free conditions via protonation- deprotonation of the \\'NH\\' group in the aromatization-dearomatization process. © 2012 Elsevier Ltd. All rights reserved.

Cobalt(III), nickel(II) and ruthenium(II) complexes of 1,10 ...

Indian Academy of Sciences (India)

Co(II) and Ru(II) complexes investigated in this study effect photocleavage of the supercoiled ... DNA is related to their utility in the design and development of synthetic restriction ..... ∗Quasi-reversible/irreversible (electrochemical behaviour of ...

Investigation on the inclusion interaction of 4-sulfonatocalix[n]arenes with 1-(4-nitrophenyl)piperazine

Science.gov (United States)

Zhang, Yongbin; Chao, Jianbin; Zhao, Shuhui; Xu, Penghao; Wang, Hongfang; Guo, Zhiqiang; Liu, Diansheng

2014-11-01

The inclusion behaviors of 4-Sulfonatocalix[n]arenes (SCXn) (n = 4, 6, 8) with 1-(4-nitrophenyl)piperazine (NPP) were investigated by UV spectroscopy and fluorescence spectroscopy at different pH values (pH = 3.05, 6.50, 8.40). The UV absorption and fluorescence intensity of NPP remarkably increased in presence of SCXn revealing formation of the inclusion complexes between NPP and SCXn. Moreover, the formation constants (K) of inclusion complexes were also determined by the non-linear fitting method, and the obtained data showed that the formation constants decreased gradually with the increasing of the pH value. When the pH value was 3.05, the formation constant of NPP with SCX8 reached a maximum of 1.7 × 107 L mol-1. The stoichiometric ratio was verified to be 1:1 by the continuous variation method. Meanwhile FT-IR and DSC analysis also indicated that NPP could form the inclusion complex with SCXn. In order to explore the inclusion mechanism of NPP with SCXn, 1H NMR and molecular modeling studies were carried out and experimental results showed that the part of benzene ring of NPP penetrated into the hydrophobic cavity of SCXn.

Electron transfer reactions of ruthenium(II) complexes with polyphenolic acids in micelles

Energy Technology Data Exchange (ETDEWEB)

Rajeswari, Angusamy [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Department of Chemistry, Fatima College, Madurai 625 018 (India); Ramdass, Arumugam [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Research Department of Chemistry, Aditanar College of Arts and Science, Tiruchendur 628 216 (India); Muthu Mareeswaran, Paulpandian [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India); Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Rajagopal, Seenivasan, E-mail: rajagopalseenivasan@yahoo.com [School of Chemistry, Madurai Kamaraj University, Madurai 625 021 (India)

2016-02-15

The electron transfer in a microhetrogeneous system is a perfect mimic of biological electron transfer. The electron transfer between biologically important phenolic acids and ruthenium (II) complexes is systematically studied in the presence of anionic and cationic micelles. The photophysical properties of these ruthenium (II) complexes with anionic and cationic micelles and their binding abilities with these two type of micelles are also studies using absorption, emission and excited state lifetime spectral techniques. Pseudophase Ion Exchange (PIE) Model is applied to derive mechanism of electron transfer in two types of micelles. - Highlights: • Effect of microhetrogeneous system is studied using ruthenium (II) complexes and gallic acid is studied. • Pseudophase Ion exchange model is applied to derive the mechanism. • Binding constants are in the range of 10{sup 2}–10{sup 4} M{sup −1}.

From simple rings to one-dimensional channels with calix[8]arenes, water clusters, and alkali metal ions

OpenAIRE

Bergougnant, Rémi D.; Robin, Adeline Y.; Fromm, Katharina M.

2007-01-01

The macrocycle 4-tert-butylcalix[8]arene (L) was reacted with alkali metal carbonates (Li₂CO₃, Na₂CO₃, K₂CO₃, Rb₂CO₃, and Cs₂CO₃) at the interface of a biphasic THF/water system. Needle-like crystals with a general formula [Ax(4-tert-butylcalix[8]arene-xH)(THF)y(H₂O)z] (with A=Li, Na, K, Rb, Cs, x=1, 2, y=4, 5, 8, and z=6, 7) were thereby obtained. The solid state structures were investigated by X-ray diffraction of single crystals and by TGA measurements. They do not appear to be maintained ...

Preparation of Different Substitued Polypyridine Ligands, Ruthenium(II)-Bridged Complexes and Spectoscopıc Studies.

Science.gov (United States)

Obali, Aslihan Yilmaz; Ucan, Halil Ismet

2016-09-01

Novel different substitued polypyridine ligands 4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzaldehyde (BA-PPY), (E)-N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzylidene)-pyrene-4-amine (PR-PPY), (E)-N-(4-((4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-yl)phenoxy)methyl)benzylidene)-1,10-phenanthroline-5amine (FN-PPY), 2-(4-(bromomethyl)phenyl)-1H-imidazo[4,5-f][1,10] phenanthroline (BR-PPY), 2-(4-(azidomethyl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (N3-PPY) and triazole containing polypyridine ligand 3,4-bis[(4-(metoxy)-1,2,3-triazole)1-methylphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)] benzaldehyde (BA-DIPPY) and Ruthenium(II) complexes were synthesized and characterized. Their photopysical properties were investigated. The complexes RuP(PR-PPY), RuB(PR-PPY, RuP(FN-PPY) and RuB(FN-PPY) exhibited a broad absorption bands at 485, 475, 476, and 453 nm, respectively, assignable to the spin-allowed MLCT (dπ-π*) transition. The emission maxima of the pyrene-appended polypyridine ligand PR-PPY was observed at λems = 616 nm and the phenanthroline-appended polypyridine ligand FN-PPY was observed at λems = 668 nm. And the emission maxima of the complexes RuP(PR-PPY), RuB(PR-PPY), RuP(FN-PPY) and RuB(FN-PPY) were observed at λems = 646, 646, 685 and 685 nm, respectively. As seen in fluorescence spectra, the fluorescence intensities of the ligands are higher than their metal complexes. This is because of quenching effect of Ruthenium(II) metal on chromophore groups.

Investigation of the inclusion behavior between p-sulfoniccalix[8]arene and norfloxacin by fluorescence spectroscopy

International Nuclear Information System (INIS)

Wang Xueying; Luo Chuannan; Lv Zhen; Lu Fuguang

2011-01-01

The host-guest complexation between p-sulfoniccalix[8]arene (SC 8 A) and norfloxacin (NFLX) in aqueous solution was investigated by fluorescence spectroscopy. Strong fluorescence intensity of the NFLX aqueous solution alone and obvious fluorescence quenching of NFLX solution in the presence of SC 8 A were observed. The fluorescence lifetimes of NFLX and SC 8 A-NFLX inclusion complex were determined and the effect of temperature on SC 8 A-NFLX inclusion complex was studied. The static quenching of the inclusion was obtained, that is the SC 8 A can form a nonfluorescent ground-state inclusion complex with NFLX. As the results show, the combined ratio (n) was 1:1 and association constant K was 1.17x10 5 L/mol. Based on the experimental results, the mechanism of the inclusion complex was explored. The space matching, electrostatic force and hydrogen bond play important effects in the inclusion process. Subsequently, the addition of bovine serum albumin (BSA) solution led to the recovery of fluorescence intensity. It is indicated that BSA can liberate the NFLX into the solution by destructing the SC 8 A-NFLX inclusion complex. Hence SC 8 A may be used for controlled-release drug delivery in the pharmaceutical industry. - Highlights: → Fluorescence lifetimes of NFLX and SC8A-NFLX inclusion complex were determined. → Mechanism of the SC8A-NFLX inclusion complex was explored. → It is proved that SC8A can form a nonfluorescent ground-state inclusion complex with NFLX.

Development of the chromatographic partitioning of cesium and strontium utilizing two macroporous silica-based calix[4]arene-crown and amide impregnated polymeric composites: PREC partitioning process.

Science.gov (United States)

Zhang, Anyun; Kuraoka, Etsushu; Kumagai, Mikio

2007-07-20

To partition effectively Cs(I) and Sr(II), two harmful heat emitting nuclides, from a highly active liquid waste by extraction chromatography, two kinds of macroporous silica-based polymeric materials, Calix[4]arene-R14/SiO(2)-P and TODGA/SiO(2)-P, were synthesized. Two chelating agents, 1,3-[(2,4-diethyl-heptylethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14), an excellent supramolecular compound having molecular recognition ability for Cs(I), and N,N,N',N'-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) were impregnated and immobilized into the pores of SiO(2)-P particles support by a vacuum sucking technique. The loading and elution of 11 typical simulated fission and non-fission products from 4.0M or 2.0M HNO(3) were performed at 298K. It was found that in the first column packed with the Calix[4]arene-R14/SiO(2)-P, all of the simulated elements were separated effectively into two groups: (1) Na(I), K(I), Sr(II), Fe(III), Ba(II), Ru(III), Pd(II), Zr(IV), and Mo(VI) (noted as Sr-group); (2) Cs(I)-Rb(I) (Cs-group) by eluting with 4.0M HNO(3) and distilled water, respectively. The harmful element Cs(I) flowed into the second group along with Rb(I) because of their close sorption and elution properties towards Calix[4]arene-R14/SiO(2)-P, while Sr(II) showed no sorption and flowed into Sr-containing group. In the second column packed with TODGA/SiO(2)-P, the Sr-group was separated into (1) Ba(II), Ru(III), Na(I), K(I), Fe(III), and Mo(VI) (non-sorption group); (2) Sr(II); (3) Pd(II); and (4) Zr(IV) by eluting with 2.0M HNO(3), 0.01M HNO(3), 0.05M DTPA-pH 2.5, and 0.5M H(2)C(2)O(4), respectively. Sr(II) adsorbed towards TODGA/SiO(2)-P flowed into the second group and showed the excellent separation efficiency from others. Based on the elution behavior of the tested elements, an advanced PREC (Partitioning and Recovery of two heat generators from an acidic HLW (high activity liquid waste) by Extraction Chromatography) process was proposed.

Calix[6]arene mono-diazonium salt synthesis and covalent immobilization onto glassy carbon electrodes

International Nuclear Information System (INIS)

Cannizzo, Caroline; Jasmin, Jean-Philippe; Vautrin-Ul, Christine; Chausse, Annie; Wagner, Mathieu; Doizi, Denis; Lamouroux, Christine

2014-01-01

This Letter describes the fast synthesis of a mono-aminated calix[6]arene. The immobilization of this macrocycle onto glassy carbon electrodes via diazonium salt chemistry and the electrochemical characterization of the grafted organic layer are also reported. (authors)

Potential Eye Drop Based on a Calix[4]arene Nanoassembly for Curcumin Delivery: Enhanced Drug Solubility, Stability, and Anti-Inflammatory Effect.

Science.gov (United States)

Granata, Giuseppe; Paterniti, Irene; Geraci, Corrada; Cunsolo, Francesca; Esposito, Emanuela; Cordaro, Marika; Blanco, Anna Rita; Cuzzocrea, Salvatore; Consoli, Grazia M L

2017-05-01

Curcumin is an Indian spice with a wide spectrum of biological and pharmacological activities but poor aqueous solubility, rapid degradation, and low bioavailability that affect medical benefits. To overcome these limits in ophthalmic application, curcumin was entrapped in a polycationic calix[4]arene-based nanoaggregate by a simple and reproducible method. The calix[4]arene-curcumin supramolecular assembly (Calix-Cur) appeared as a clear colloidal solution consisting in micellar nanoaggregates with size, polydispersity index, surface potential, and drug loading percentage meeting the requirements for an ocular drug delivery system. The encapsulation in the calix[4]arene nanoassembly markedly enhanced the solubility, reduced the degradation, and improved the anti-inflammatory effects of curcumin compared to free curcumin in both in vitro and in vivo experiments. Calix-Cur did not compromise the viability of J774A.1 macrophages and suppressed pro-inflammatory marker expression in J774A.1 macrophages subjected to LPS-induced oxidative stress. Histological and immunohistochemical analyses showed that Calix-Cur reduced signs of inflammation in a rat model of LPS-induced uveitis when topically administrated in the eyes. Overall, the results supported the calix[4]arene nanoassembly as a promising nanocarrier for delivering curcumin to anterior ocular tissues.

Reactivity and selectivity of arenes in reactions with ozone

International Nuclear Information System (INIS)

Vysotskii, Yu.B.; Mestechkin, M.M.; Sivyakova, L.N.; Tyupalo, N.F.

1987-01-01

The reactions of arenes with ozone, distinguished by the variety of products (quinones, aldehydes, acids), are of interest not only from the theoretical standpoint but also are of preparative value in the case of polycyclic hydrocarbons. In this work a quantitative treatment of this reaction is given on the basis of direct kinetic measurements and simple quantum chemical means, permitting its rate constants and the yield of the products to be related to the elements of electronic structure readily subject to quantum mechanical calculation

Microwave-assisted facile and rapid Friedel-Crafts benzoylation of arenes catalysed by bismuth trifluoromethanesulfonate

DEFF Research Database (Denmark)

Tran, Phoung Hoang; Hansen, Poul Erik; Pham, Thuy Than

2014-01-01

The catalytic activity of metal triflates was investigated in Friedel–Crafts benzoylation under microwave irradiation. Friedel–Crafts benzoylation with benzoyl chloride of a variety of arenes containing electron-rich and electron-poor rings using bismuth triflate under microwave irradiation is de...

Mono and dinuclear arene ruthenium(II) triazoles by 1,3-dipolar cycloadditions to a coordinated azide in ruthenium(II) compounds

Digital Repository Service at National Institute of Oceanography (India)

Singh, K.S.; Svitlyk, V.; Mozharivskyj, Y.

= Me, 3 or Et, 4). In contrast, a similar 1,3-dipolar cycloaddition reaction of (((Eta sup(6)-C sub(6)Me sub(6))Ru(L sub(2))N sub(3))) (2) (where; L sub(2) = tropolone) with acetylene yielded the monomeric triazole compound ((Eta sup(6)-C sub(6)Me sub(6...

Rhodium-catalyzed C-H alkynylation of arenes at room temperature.

Science.gov (United States)

Feng, Chao; Loh, Teck-Peng

2014-03-03

The rhodium(III)-catalyzed ortho C-H alkynylation of non-electronically activated arenes is disclosed. This process features a straightforward and highly effective protocol for the synthesis of functionalized alkynes and represents the first example of merging a hypervalent iodine reagent with rhodium(III) catalysis. Notably, this reaction proceeds at room temperature, tolerates a variety of functional groups, and more importantly, exhibits high selectivity for monoalkynylation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A calix[4]arene derivative and its selective interaction with drugs (clofibric acid, diclofenac and aspirin).

Science.gov (United States)

Danil de Namor, Angela F; Al Nuaim, Maan; Villanueva Salas, Jose A; Bryant, Sophie; Howlin, Brendan

2017-03-30

The synthesis and characterisation of a partially substituted calix[4]arene, namely, 5,11,17,23-tetra-tert-butyl,25,27-bis[aminoethoxy] 26,28-dihydroxycalix[4]arene are reported. Its interaction with commonly used pharmaceuticals (clofibric acid, diclofenac and aspirin) was investigated by spectroscopic ( 1 H NMR and UV), electrochemical (conductance measurements) and thermal (titration calorimetry) techniques. It is concluded on the basis of the experimental work and molecular simulation studies that the receptor interacts selectively with these drugs. Preliminary studies on the selective extraction of these pharmaceuticals from water by the calix receptor are reported and the potential for a carrier mediated sensor based on this ligand for 'on site' monitoring of pharmaceuticals is discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Opciones para la prevención: el caso del Volcán Arenal

Directory of Open Access Journals (Sweden)

Esquivel Valverde, Lidier

2004-05-01

Full Text Available El presente artículo analiza una serie de aspectos relacionados con la actividad del volcán Arenal y su repercusión la zona. Como tema principal, explica ampliamente la propuesta Uso de suelos en los alrededores del volcán, creada por el Comité Asesor Técnico en Vulcanología, integrada por el Observatorio Vulcanológico y Sismológico de Costa Rica de la Universidad Nacional (OVSICORI, la Red Sismológica Nacional de la Universidad de Costa Rica (RSN y el Área de Amenaza y Auscultación Sísmica y Volcánica del Instituto Costarricense de Electricidad (ICE, la cual estipula las zonas de restricción para el uso de suelo, dividida en dos niveles de restricción y cuatro sub áreas. El artículo incluye un Mapa de restricciones de uso del suelo, tránsito de personas y ubicación de los proyectos de desarrollo más importantes en los alrededores del volcán Arenal. Las conclusiones exponen los motivos que propiciaron la creación de la propuesta y su aplicación, así como algunos puntos deficitarios con respecto a la participación de otros actores This article analyses a series of aspects related to the activity of the Arenal Volcano and its repercussion in the zone. The main topic broadly explains the proposal about soil use around the Volcano, created by the Technical Advisor Committee in Volcanology, composed by the Volcanological and Seismological Observatory of the Costa Rica, National University (Observatorio Vulcanológico y Sismológico de Costa Rica de la Universidad Nacional - OVSICORI, the National Seismic Network of the University of Costa Rica (Red Sismológica Nacional de la Universidad de Costa Rica - RSN and the Threat Area and Seismic Auscultation of the Costa Rican Electricity Institute (Área de Amenaza y Auscultación Sísmica y Volcánica del Instituto Costarricense de Electricidad - ICE that includes the restricted zones for soil use, divided in two levels of restriction and four sub areas. The article includes a

Enhanced catalysis and enantioselective resolution of racemic naproxen methyl ester by lipase encapsulated within iron oxide nanoparticles coated with calix[8]arene valeric acid complexes.

Science.gov (United States)

Sayin, Serkan; Akoz, Enise; Yilmaz, Mustafa

2014-09-14

In this study, two types of nanoparticles have been used as additives for the encapsulation of Candida rugosa lipase via the sol-gel method. In one case, the nanoparticles were covalently linked with a new synthesized calix[8]arene octa valeric acid derivative (C[8]-C4-COOH) to produce new calix[8]arene-adorned magnetite nanoparticles (NP-C[8]-C4-COOH), and then NP-C[8]-C4-COOH was used as an additive in the sol-gel encapsulation process. In the other case, iron oxide nanoparticles were directly added into the sol-gel encapsulation process in order to interact electrostatically with both C[8]-C4-COOH and Candida rugosa lipase. The catalytic activities and enantioselectivities of two novel encapsulated lipases (Enc-NP-C[8]-C4-COOH and Enc-C[8]-C4-COOH@Fe3O4) in the hydrolysis reaction of racemic naproxen methyl ester were evaluated. The results showed that the activity and enantioselectivity of the lipase were improved when the lipase was encapsulated in the presence of calixarene-based additives. Indeed, the encapsulated lipases have an excellent rate of enantioselectivity, with E = 371 and 265, respectively, as compared to the free enzyme (E = 137). The lipases encapsulated with C[8]-C4-COOH and iron oxide nanoparticles (Enc-C[8]-C4-COOH@Fe3O4) retained more than 86% of their initial activities after 5 repeated uses and 92% with NP-C[8]-C4-COOH.

Grafting of Oligo(ethylene glycol) Functionalized Calix[4]arene-tetra-diazonium Salts for Antifouling Germanium and Gold Surfaces.

Science.gov (United States)

Blond, Pascale; Mattiuzzi, Alice; Valkenier, Hennie; Troian-Gautier, Ludovic; Bergamini, Jean-François; Doneux, Thomas; Goormaghtigh, Erik; Raussens, Vincent; Jabin, Ivan

2018-05-03

Biosensors that can determine protein concentration and structure are highly desired for biomedical applications. For the development of such biosensors, the use of Fourier transformed infra-red (FTIR) spectroscopy with the attenuated internal total reflection (ATR) configuration is particularly attractive but it requires appropriate surface functionalization of the ATR optical element. Indeed, the surface has to specifically interact with a target protein in close contact with the optical element and must display antifouling properties to prevent nonspecific adsorption of other proteins. We here report robust monolayers of calix[4]arenes bearing oEGs chains, which were grafted on germanium and gold surfaces via their tetra-diazonium salts. The formation of monolayers of oEGylated calix[4]arenes was confirmed by AFM, IR and contact angle measurements. The antifouling properties of these modified surfaces were studied by ATR-FTIR spectroscopy and fluorescence microscopy and the non-specific absorption of BSA was found to be reduced by 85% compared to non-modified germanium. In other words, the organic coating by oEGylated calix[4]arenes provides remarkable antifouling properties, opening the way to the design of germanium- and gold-based biosensors.

Excited-state dynamics of a ruthenium(II) catalyst studied by transient photofragmentation in gas phase and transient absorption in solution

Energy Technology Data Exchange (ETDEWEB)

Imanbaew, D.; Nosenko, Y. [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Forschungszentrum OPTIMAS, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany); Kerner, C. [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Chevalier, K.; Rupp, F. [Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany); Riehn, C., E-mail: riehn@chemie.uni-kl.de [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Forschungszentrum OPTIMAS, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany); Thiel, W.R. [Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 52–54, 67663 Kaiserslautern (Germany); Diller, R. [Fachbereich Physik, Technische Universität Kaiserslautern, Erwin-Schrödinger-Str. 46, 67663 Kaiserslautern (Germany)

2014-10-17

Graphical abstract: - Highlights: • Ultrafast dynamics of new Ru(II) catalysts investigated in gas phase and solution. • Catalyst activation (HCl loss) achieved in ion trap by UV photoexcitation. • Electronic relaxation proceeds by IVR and IC followed by ground state dissociation. • No triplet formation in contrast to other Ru-polypyridine complexes. • Solvent prohibits catalyst activation in solution by fast vibrational cooling. - Abstract: We report studies on the excited state dynamics of new ruthenium(II) complexes [(η{sup 6}-cymene)RuCl(apypm)]PF{sub 6} (apypm=2-NR{sub 2}-4-(pyridine-2-yl)-pyrimidine, R=CH{sub 3} (1)/H (2)) which, in their active form [1{sup +}-HCl] and [2{sup +}-HCl], catalyze the transfer hydrogenation of arylalkyl ketones in the absence of a base. The investigations encompass femtosecond pump–probe transient mass spectrometry under isolated conditions and transient absorption spectroscopy in acetonitrile solution, both on the cations [(η{sup 6}-cymene)RuCl(apypm)]{sup +} (1{sup +}, 2{sup +}). Gas phase studies on mass selected ions were performed in an ESI ion trap mass spectrometer by transient photofragmentation, unambiguously proving the formation of the activated catalyst species [1{sup +}-HCl] or [2{sup +}-HCl] after photoexcitation being the only fragmentation channel. The primary excited state dynamics in the gas phase could be fitted to a biexponential decay, yielding time constants of <100 fs and 1–3 ps. Transient absorption spectroscopy performed in acetonitrile solution using femtosecond UV/Vis and IR probe laser pulses revealed additional deactivation processes on longer time scales (∼7–12 ps). However, the formation of the active catalyst species after photoexcitation could not be observed in solution. The results from both studies are compared to former CID investigations and DFT calculations concerning the activation mechanism.

Calix[4]arene supported clusters: a dimer of [Mn(III)Mn(II)] dimers

DEFF Research Database (Denmark)

Taylor, Stephanie M; McIntosh, Ruaraidh D; Beavers, Christine M

2011-01-01

Phosphinate ligands allow for the transformation of a calix[4]arene supported [Mn(III)(2)Mn(II)(2)] tetramer cluster motif into an unusual [Mn(III)Mn(II)](2) dimer of dimers; the clusters self-assemble in the crystal to form bi-layer arrays reminiscent of the typical packing of calixarene solvates....

Polymethylated [Fe(η6-arene)2]2+ dications: methyl-group rearrangements and application of the EINS mechanism.

Science.gov (United States)

Štíbr, Bohumil; Bakardjiev, Mario; Hájková, Zuzana; Holub, Josef; Padělková, Zdenka; Růžička, Aleš; Kennedy, John D

2011-06-14

Reactions between the methylated arenes ArMe(n) [where ArMe(n) = C(6)Me(n)H((6-n)), and n = 1-6] and FeCl(2) in heptane at 90 °C in the presence of anhydrous AlCl(3) give, for the arenes with n = 1-5, extensive isomerisations and disproportionations involving the methyl groups on the arene rings, and the formation of mixtures of [Fe(ArMe(n))(2)](2+) dications that defy separation into pure species. GC-MS studies of AlCl(3)/mesitylene and AlCl(3)/durene reactions in the absence of FeCl(2) (90 °C, 2 h) allow quantitative assessments of the rearrangements, and the EINS mechanism (electrophile-induced nucleophilic substitution) is applied to rationalise the phenomena. By contrast, ArMe(n) / FeCl(2) /AlCl(3) reactions in heptane for 24-36 h at room-temperature proceed with no rearrangements, allowing the synthesis of the complete series of pure [Fe(ArMen)](2+) cations in yields of 48-71%. The pure compounds are characterised by (1)H NMR spectroscopy and electrospray-ionization mass-spectrometry (ESI-MS), and the structures of [Fe(m-xylene)(2)][PF(6)](2) and [Fe(durene)(2)][PF(6)](2) are established by single-crystal X-ray diffraction analyses.

(II) complexes as sensitizers for dye sensitized solar cells

Indian Academy of Sciences (India)

dimethyl-3-propyl-1 H-imidazol-3-ium iodide (DMPII),. 4-tert-butyl-pyridine (TBP) and ... cymene) ruthenium(II) dimer was synthesized according to the reported ... saturated ammonium chloride (200 ml) solution was added to decompose the ...

Synthesis of cationic diphosphine ruthenium complexes with nido-dicarbaundecaborate anions. Molecular structure of [RuCl(dppe)2]+[7,8-nido-C2B9H12]-

International Nuclear Information System (INIS)

Cheredilin, D.N.; Dolgushin, F.M.; Balagurova, E.V.; Godovikov, I.A.; Chizhevskij, I.T.

2004-01-01

Five new diphosphine ruthenium(II) complexes with nido-dicarbaundecaborate anions were synthesized. The composition and structure of the complexes were confirmed by data of 1 H, 31 P{ 1 H} NMR and elementary analysis. The crystal and molecular structure of solvated complex [RuCl(dppe) 2 + [7,8-nido-C 2 B 9 H 12 ] - ·CH 2 Cl 2 was ascertained by the method of X-ray diffraction analysis. It is shown that coordination sphere of ruthenium atom in the complex cation is a distorted trigonal bipyramid. The distances from ruthenium atom to phosphorus atoms are 2.398(1) and 2.391(1) A, while the angle P-Ru-P equals 175.85(5) Deg [ru

RutheniumII Complexes bearing Fused Polycyclic Ligands: From Fundamental Aspects to Potential Applications

Directory of Open Access Journals (Sweden)

Ludovic Troian-Gautier

2014-04-01

Full Text Available In this review, we first discuss the photophysics reported in the literature for mononuclear ruthenium complexes bearing ligands with extended aromaticity such as dipyrido[3,2-a:2',3'-c]phenazine (DPPZ, tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]-phenazine (TPPHZ,  tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]acridine (TPAC, 1,10-phenanthrolino[5,6-b]1,4,5,8,9,12-hexaazatriphenylene (PHEHAT 9,11,20,22-tetraaza- tetrapyrido[3,2-a:2',3'-c:3'',2''-l:2''',3'''-n]pentacene (TATPP, etc. Photophysical properties of binuclear and polynuclear complexes based on these extended ligands are then reported. We finally develop the use of binuclear complexes with extended π-systems for applications such as photocatalysis.

Characterization of an azo-calix[4]arene-based optical sensor for Europium (III) ions

International Nuclear Information System (INIS)

Echabaane, M.; Rouis, A.; Bonnamour, I.; Ouada, H. Ben

2012-01-01

Selective and sensitive optical sensor membranes (optodes) were elaborated to detect cations in aqueous solutions. The sensing films are based on chromogenic calix[4]arene derivatives. The optode membranes were studied using UV/Vis absorption spectroscopy measurements. The sensitivity of the optode has been tested for Pb 2+ , Cd 2+ , Mg 2+ and Eu 3+ ions at pH 6.8. The results showed a good selectivity response towards Eu 3+ . Low selectivity coefficients were observed for Cd 2+ and Mg 2+ where Pb 2+ can be considered as interfering ions. The characteristics of this optode such as response time, regeneration, reproducibility and lifetime are discussed. - Highlights: ► We report optical sensing studies of chromogenic calixarene derivatives. ► We investigate optical interaction between azo-calix[4]arene and Eu 3+ . ► We study sensitivity and selectivity of optode films. ► We describe characteristics of optode films for determination of europium traces.

Upper-rim CMPO-substituted calix[6]- and calix[8]arene extractants for the An3+/Ln3+ separation from radioactive waste

International Nuclear Information System (INIS)

Sansone, F.; Ungaro, R.; Casnati, A.; Galletta, M.; Macerata, E.; Trivellone, E.; Giola, M.; Mariani, M.; Boehmer, V.

2008-01-01

Two new ligands (1 and 2) for actinide/lanthanide separation derived from calix[6]- and calix[8]arenes functionalised at the upper rim with six or eight CMPO binding units were synthesised. These ligands, having a methoxy group at the lower rim, are conformationally mobile in solution at room temperature. Extraction data from water to a NPHE/n-octanol (90/10) solution of ligands 1 and 2, in the presence of bromo-cosan as synergist, show that these derivatives are less efficient and selective than the previously reported homologues derived from calix[4]arenes or from the lower rim CMPO calix[6]- and calix[8]arenes, especially at high nitric acid concentrations. However, although compound 1 and 2 do not appear promising for the actinide/lanthanide separation from high acidity radioactive waste, the results obtained in this work disclose some important structural results which can be useful for the design of new efficient and selective polytopic ligands. (orig.)

Immobilization of Chlorosulfonyl-Calix[4]arene onto the surface of silica gel through the directly estrification

Science.gov (United States)

Taghvaei-Ganjali, Saeed; Zadmard, Reza; Saber-Tehrani, Mandana

2012-06-01

For the first time Chlorosulfonyl-Calix[4]arene has been chemically bonded to silica gel through the directly estrification without silane coupling agent to prepare Chlorosulfonyl-Calix[4]arene-bonded silica gel. Sample characterization was performed by various techniques such as elemental analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), powder X-ray diffraction (XRD), N2 adsorption-desorption, thermal gravimetric analysis (TGA), 29Si CP/MAS spectroscopy and acid-base titration. All data approve the successful incorporation of organic group via covalent bond. From the comparison between sulfur content determined by elemental analysis and the number of H+ determined by acid-base titration, it was shown that two ester units took place onto the new synthesized sample and two acidic sites exist on the surface.

Three-dimensional tetranuclear Cd(II) coordination network based on a 1,3-alternate calix[4]arene derivative

International Nuclear Information System (INIS)

Lee, Eun Ji; Ju, Hui Yeong; Park, Ki Min; Moon, ASuk Hee; Kang, Young Jin

2015-01-01

Polynuclear coordination polymers can exhibit more intriguing network topologies and better functionalities than those of common complexes because they have metal-cluster nodes for the construction of multidimensional frameworks and the potential applications induced by collaborative activities between metal ions. New tetranuclear Cd(II) coordination polymer 1 based on 1,3-alternate calix arene derivative (H_4 CTA) with four carboxyl pendant arms has been synthesized by the solvo thermal reaction at 110 .deg. C for 2 days. Compound 1 shows a 3-D framework consisting of tetranuclear Cd(II) cluster core as a metal-cluster node and 1,3-alternate H_4CTA as a multidentate linker. The coordination polymer 1 displays intense blue emission, implying that this tetranuclear Cd(II) coordination polymer could be a suitable material in the area of luminescence research

Cadmium-sensitive electrode based on tetracetone derivatives of p-tert-butylcalix[8]arene

Energy Technology Data Exchange (ETDEWEB)

Dernane, C. [Université de Jijel, Laboratoire de Matériaux: Elaborations-Propriétés-Applications, BP 98, Ouled Aissa, 18000 Jijel (Algeria); Zazoua, A., E-mail: azazoua@yahoo.fr [Université de Jijel, Laboratoire de Matériaux: Elaborations-Propriétés-Applications, BP 98, Ouled Aissa, 18000 Jijel (Algeria); Kazane, I. [Université de Jijel, Laboratoire de Matériaux: Elaborations-Propriétés-Applications, BP 98, Ouled Aissa, 18000 Jijel (Algeria); Jaffrezic-Renault, N. [Université de Lyon, LSA-UMR 5180 CNRS, Université Claude Bernard Lyon 1, 69622 Villeurbanne cedex (France)

2013-10-15

The performance of a cadmium-sensitive electrode based on the tetracetone derivatives of p-tert butylcalix[8]arene was investigated. The ion-sensitivity of the calix[8]arene was examined via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectrometry, UV/Vis spectroscopy and FT-IR spectroscopy. The sensitive membrane containing the active ionophore was cast onto the surface of a gold electrode. The electrode exhibited a linear relationship between the charge transfer resistance (R{sub ct}) and the logarithm of the detected ion concentration. The cathodic peak at a potential of 0.56 V increased linearly as the Cd{sup 2+} ion concentration increased. The detection limit of the device reached 10{sup −7} M with high sensitivity toward cadmium. - Highlights: • The performances of cadmium-sensitive electrode were investigated. • The sensitive membrane was casted on the surface of a gold electrode. • The electrode showed a linear relationship between the R{sub ct} and the ion concentration. • The detection limit of the device was 10{sup −7} M with high sensitivity toward cadmium.

Propyl phthalimide-modified thiacalixphenyl[4]arene as a “turn on” chemosensor for Hg(II) ions

Energy Technology Data Exchange (ETDEWEB)

Modi, Krunal; Panchal, Urvi; Mehta, Viren; Panchal, Manthan; Kongor, Anita; Jain, V.K., E-mail: drvkjain@hotmail.com

2016-11-15

Thiacalixphenyl[4]arene tetra N-(3-propyl) phthalimide (TPTN3PPh), a novel thiacalixarene bearing a N-(3-bromopropyl) phthalimide group, was synthesized and characterized by Electrospray Ionization Mass Spectrometry (ESI-MS) and NMR. The ability of TPTN3PPh to recognize the cations Fe(III), Cu(II), Cd(II), Zn(II), Cr(II), Ca(II), Co(II), Mg(II), Ag(I), Pb(II), Sr(II), Hg (II), Th(II), Ba(II), Bi(II), K(I), and Na(I) was evaluated. Only Hg(II) was selectively and sensitively detected using a spectrofluorimetric method, with a detection limit as low as 3.10×10{sup −9} M. Analysis of the binding behavior of TPTN3PPh with Hg(II) revealed 1:2 complex formation. Real sample analysis detected nano levels of mercury ions in a waste water samples.

Sorption of CO ₂ in a hydrogen-bonded diamondoid network of sulfonylcalix[4]arene

Energy Technology Data Exchange (ETDEWEB)

Sinnwell, Michael A. [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, WA, USA; Atwood, Jerry L. [Department of Chemistry, University of Missouri-Columbia, Columbia, MO, USA; Thallapally, Praveen K. [Physical and Computational Science Directorate, Pacific Northwest National Laboratory, Richland, WA, USA

2018-02-08

An organic material, p-tert-butyltetrasulfonylcalix[4]arene, self-assembles via hydrogen bonding to form a diamondoid supramolecular network. Possessing discrete, zero-dimensional (0D) microcavities, the thiacalixarene derivative adsorbs CO2 at high pressures

Porphyrinic supramolecular daisy chains incorporating pillar[5]arene-viologen host-guest interactions

KAUST Repository

Fathalla, Maher; Strutt, Nathan; Srinivasan, Sampath; Katsiev, Khabiboulakh; Hartlieb, Karel J.; Bakr, Osman; Stoddart, J. Fraser

2015-01-01

A porphyrin functionalised with pillar[5]arene and a viologen at its 5- and 15-meso positions assembles in a head-to-tail manner, producing linear supramolecular daisy chains in dichloromethane. At high concentrations, it forms an organogel which has been investigated by electron microscopy and rheological measurements, paving the way for the preparation of other functional supramolecular assemblies which harness viologen"⊂" pillararene host-guest interactions.

Porphyrinic supramolecular daisy chains incorporating pillar[5]arene-viologen host-guest interactions

KAUST Repository

Fathalla, Maher

2015-05-18

A porphyrin functionalised with pillar[5]arene and a viologen at its 5- and 15-meso positions assembles in a head-to-tail manner, producing linear supramolecular daisy chains in dichloromethane. At high concentrations, it forms an organogel which has been investigated by electron microscopy and rheological measurements, paving the way for the preparation of other functional supramolecular assemblies which harness viologen"⊂" pillararene host-guest interactions.

Kinetic enantioselectivity of a protonated bis(diamido)-bridged basket resorcin[4]arene towards alanine peptides.

Science.gov (United States)

Fraschetti, C; Montagna, M; Crestoni, M E; Calcaterra, A; Aiello, F; Santi, L; Filippi, A

2017-02-01

Efficient enantiodiscrimination of some alanine-containing di- and tri-peptides by using chiral protonated bis(diamido)-bridged basket resorcin[4]arenes depends on several factors, including the basicity of the amino acid residues at the C- and N-termini of the peptide.

Immobilization of Chlorosulfonyl-Calix[4]arene onto the surface of silica gel through the directly estrification

Energy Technology Data Exchange (ETDEWEB)

Taghvaei-Ganjali, Saeed, E-mail: S-taghvaei@IAU-tnb.ac.ir [Chemistry Department, Islamic Azad University, North Tehran Branch, Postal Code: 1913674711, Tehran (Iran, Islamic Republic of); Zadmard, Reza [Chemistry and Chemical Engineering Research Center of Iran, Postal Code: 1496813151, Tehran (Iran, Islamic Republic of); Saber-Tehrani, Mandana [Chemistry Department, Islamic Azad University, North Tehran Branch, Postal Code: 1913674711, Tehran (Iran, Islamic Republic of)

2012-06-01

For the first time Chlorosulfonyl-Calix[4]arene has been chemically bonded to silica gel through the directly estrification without silane coupling agent to prepare Chlorosulfonyl-Calix[4]arene-bonded silica gel. Sample characterization was performed by various techniques such as elemental analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), powder X-ray diffraction (XRD), N{sub 2} adsorption-desorption, thermal gravimetric analysis (TGA), {sup 29}Si CP/MAS spectroscopy and acid-base titration. All data approve the successful incorporation of organic group via covalent bond. From the comparison between sulfur content determined by elemental analysis and the number of H{sup +} determined by acid-base titration, it was shown that two ester units took place onto the new synthesized sample and two acidic sites exist on the surface.

Sweetening ruthenium and osmium: organometallic arene complexes containing aspartame.

Science.gov (United States)

Gray, Jennifer C; Habtemariam, Abraha; Winnig, Marcel; Meyerhof, Wolfgang; Sadler, Peter J

2008-09-01

The novel organometallic sandwich complexes [(eta(6)-p-cymene)Ru(eta(6)-aspartame)](OTf)(2) (1) (OTf = trifluoromethanesulfonate) and [(eta(6)-p-cymene)Os(eta(6)-aspartame)](OTf)(2) (2) incorporating the artificial sweetener aspartame have been synthesised and characterised. A number of properties of aspartame were found to be altered on binding to either metal. The pK(a) values of both the carboxyl and the amino groups of aspartame are lowered by between 0.35 and 0.57 pH units, causing partial deprotonation of the amino group at pH 7.4 (physiological pH). The rate of degradation of aspartame to 3,6-dioxo-5-phenylmethylpiperazine acetic acid (diketopiperazine) increased over threefold from 0.12 to 0.36 h(-1) for 1, and to 0.43 h(-1) for 2. Furthermore, the reduction potential of the ligand shifted from -1.133 to -0.619 V for 2. For the ruthenium complex 1 the process occurred in two steps, the first (at -0.38 V) within a biologically accessible range. This facilitates reactions with biological reductants such as ascorbate. Binding to and activation of the sweet taste receptor was not observed for these metal complexes up to concentrations of 1 mM. The factors which affect the ability of metal-bound aspartame to interact with the receptor site are discussed.

Constructing Multiply Substituted Arenes Using Sequential Pd(II)-Catalyzed C–H Olefination**

Science.gov (United States)

Engle, Keary M.; Wang, Dong-Hui; Yu, Jin-Quan

2011-01-01

Complementary catalytic systems have been developed in which the reactivity/selectivity balance in Pd(II)-catalyzed ortho-C–H olefination can be modulated through ligand control. This allows for sequential C–H functionalization for the rapid preparation of 1,2,3-trisubstituted arenes. Additionally, a rare example of iterative C–H activation, in which a newly installed functional group directs subsequent C–H activation has been demonstrated. PMID:20632344

Access to the meta position of arenes through transition metal catalysed C-H bond functionalisation: a focus on metals other than palladium.

Science.gov (United States)

Mihai, Madalina T; Genov, Georgi R; Phipps, Robert J

2018-01-02

The elaboration of simple arenes in order to access more complex substitution patterns is a crucial endeavor for synthetic chemists, given the central role that aromatic rings play in all manner of important molecules. Classical methods are now routinely used alongside stoichiometric organometallic approaches and, most recently, transition metal catalysis in the range of methodologies that are available to elaborate arene C-H bonds. Regioselectivity is an important consideration when selecting a method and, of all those available, it is arguably those that target the meta position that are fewest in number. The rapid development of transition metal-catalysed C-H bond functionalisation over the last few decades has opened new possibilities for meta-selective C-H functionalisation through the diverse reactivity of transition metals and their compatibility with a wide range of directing groups. The pace of discovery of such processes has grown rapidly in the last five years in particular and it is the purpose of this review to examine these but in doing so to place the focus on metals other than palladium, the specific contributions of which have been very recently reviewed elsewhere. It is hoped this will serve to highlight to the reader the breadth of current strategies and mechanisms that have been used to tackle this challenge, which may inspire further progress in the field.

Preparation of Langmuir–Blodgett thin films of calix[6]arenes and p-tert butyl group effect on their gas sensing properties

Energy Technology Data Exchange (ETDEWEB)

Ozmen, Mustafa, E-mail: musozmen@gmail.com [Department of Chemistry, University of Selcuk, 42075 Konya (Turkey); Ozbek, Zikriye, E-mail: zikriye@comu.edu.tr [Department of Bioengineering, University of Canakkale Onsekiz Mart, 17100 Canakkale (Turkey); Bayrakci, Mevlut [Department of Bioengineering, University of Karamanoglu Mehmetbey, 70200 Karaman (Turkey); Ertul, Seref; Ersoz, Mustafa [Department of Chemistry, University of Selcuk, 42075 Konya (Turkey); Capan, Rifat [Department of Physics, University of Balikesir, 10145 Balikesir (Turkey)

2015-12-30

Graphical abstract: - Highlights: • In this work, we prepared Langmuir–Blodgett films of calix[6]arene derivatives. • Then LB films of calixarene compounds were characterized. • Organic vapor sensing properties of prepared LB films were investigated. - Abstract: Organic vapor sensing properties of Langmuir–Blodgett (LB) thin films of p-tert-butyl calix[6]arene and calix[6]arene, and their certain characterization are reported in this work. LB films of these calixarenes have been characterized by contact angle measurement, quartz crystal microbalance (QCM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). QCM system was used for the measurement of sensor response against chloroform, benzene, toluene and ethanol vapors. Forming of stable monolayers was observed at the water surface using surface pressure–area isotherm graph. The results indicate that good quality, uniform LB films can be prepared with a transfer ratio of over 0.95. Due to the adsorption of vapors into the LB film structures; they yield a response to all vapors as of large, fast, and reproducible.

Three-dimensional tetranuclear Cd(II) coordination network based on a 1,3-alternate calix[4]arene derivative

Energy Technology Data Exchange (ETDEWEB)

Lee, Eun Ji; Ju, Hui Yeong; Park, Ki Min [Dept. of Chemistry and Research Institute of Natural Science, Gyeongsang National University, Jinju (Korea, Republic of); Moon, ASuk Hee [Dept. of Food and Nutrition, Kyungnam College of Inform ation and Technology, Busan (Korea, Republic of); Kang, Young Jin [Div. of cience Education, Kangwon National University, Chuncheon (Korea, Republic of)

2015-08-15

Polynuclear coordination polymers can exhibit more intriguing network topologies and better functionalities than those of common complexes because they have metal-cluster nodes for the construction of multidimensional frameworks and the potential applications induced by collaborative activities between metal ions. New tetranuclear Cd(II) coordination polymer 1 based on 1,3-alternate calix arene derivative (H{sub 4} CTA) with four carboxyl pendant arms has been synthesized by the solvo thermal reaction at 110 .deg. C for 2 days. Compound 1 shows a 3-D framework consisting of tetranuclear Cd(II) cluster core as a metal-cluster node and 1,3-alternate H{sub 4}CTA as a multidentate linker. The coordination polymer 1 displays intense blue emission, implying that this tetranuclear Cd(II) coordination polymer could be a suitable material in the area of luminescence research.

Depositional setting and early diagenesis of the dinosaur eggshell-bearing Aren Fm at Bastus, Late Campanian, south-central Pyrenees

Science.gov (United States)

Díaz-Molina, Margarita; Kälin, Otto; Benito, M. Isabel; Lopez-Martinez, Nieves; Vicens, Enric

2007-07-01

The Late Cretaceous Aren Fm exposed north of Bastus in the Tremp Basin (south-central Pyrenees) preserves an excellent record of dinosaur eggs laid in a marine littoral setting. Different from other cases reported in literature, at the Bastus site the preferential nesting ground was original beach sand. The coastal deposits of Aren Fm can be grouped into four facies assemblages, representing respectively shoreface, beachface, beach ridge plain and backbarrier lagoon environments. Shoreface deposits include fine- to coarse-grained hybrid arenites and subordinate quartz-dominated conglomerates with ripple structures of wave and wave-current origin. Beachface deposits are mainly storm beach conglomerates, but parallel-laminated foreshore arenites locally occur. Backbarrier lagoon deposits comprise of washover sandy conglomerates that grade laterally into sandy lime mudstones, biomicrites and marls. Beach ridge sediment, wherein the bulk of dinosaur eggs and eggshell debris occurs, predominantly is a reddish hybrid arenite that has undergone a complex early diagenetic evolution, including marine and meteoric cementation followed by soil development. The reddish arenites overlie wave-dominated shoreface deposits and in places pass laterally into lagoonal deposits. They originally formed shore ridges, that became stabilized during progradational episodes by pedogenesis (beach ridge, sensu [Otvos, E.G., 2000. Beach ridges—definitions and significance. Geomorphology 32, 83-108.]), which also affected the dinosaur eggs. The eggshell-bearing beach ridge arenites are typically preserved at the top of parasequences forming the systems tracts of a third-order sequence. Thick packages of this facies resulted from aggradation of barrier/beach ridge deposits, whose preservation below surfaces of transgressive erosion was favoured by incipient lithification.

A water-soluble pillar[5]arene as a new carrier for an old drug.

Science.gov (United States)

Barbera, Lucia; Franco, Domenico; De Plano, Laura M; Gattuso, Giuseppe; Guglielmino, Salvatore P P; Lentini, Germana; Manganaro, Nadia; Marino, Nino; Pappalardo, Sebastiano; Parisi, Melchiorre F; Puntoriero, Fausto; Pisagatti, Ilenia; Notti, Anna

2017-04-11

The remarkable affinity of deca-carboxylatopillar[5]arene WP5 towards the aminoglycoside antibiotic, amikacin, in aqueous media is reported; in vitro studies on Gram-positive bacteria (Staphylococcus aureus) show that drug entrapment inside WP5 also takes place in the presence of the microrganisms, thus pointing to WP5 as an appealing carrier for amikacin targeted delivery.

A new ion selective electrode for cesium (I) based on calix[4]arene-crown-6 compounds.

Science.gov (United States)

Ramanjaneyulu, P S; Kumar, Abha Naveen; Sayi, Y S; Ramakumar, K L; Nayak, S K; Chattopadhyay, S

2012-02-29

A polyvinylchloride (PVC) based liquid membrane ion selective electrode (ISE) for cesium has been developed. 25,27-Dihydroxycalix[4]arene-crown-6 (L1), 5,11,17,23-tetra-tert-butyl-25,27-dimethoxycalix[4]arene-crown-6 (L2) and 25,27-bis(1-octyloxy)calix[4]arene-crown-6 (L3) were investigated for their use as ionophores. The cation exchange resin DOWEX-50W was used to maintain low activity Cs+ in inner filling solution to improve the performance. The best response for cesium was observed with L3 along with optimized membrane constituents and composition. Excellent Nernstian response (56.6 mV/decade of Cs(I)) over the concentration range 10(-7) to 10(-2)M of Cs(I) was obtained with a fast response time of less than 10s. Detection limit for Cs(I) using the present ISE is 8.48×10(-8) M Cs(I). Separate solution method (SSM) was applied to ascertain the selectivity for Cs(I) over alkali, alkaline earth and transition metal ions. The response of ISE for Cs(I) was fairly constant over the pH range of 4-11. The lifetime of the electrode is 10 months which is the highest life for any membrane based Cs-ISE so far developed. The concentration of cesium ion in two simulated high level active waste streams was determined and results agreed well with those obtained independently employing AAS. Copyright © 2011 Elsevier B.V. All rights reserved.

Formation and proof of stable bi-, tri- and tetraradical polyanions during the electrochemical reduction of cone-polynitrocalix[4]arenes. An ESR-UV-vis spectroelectrochemical study

International Nuclear Information System (INIS)

Liška, Alan; Rosenkranz, Marco; Klíma, Jiří; Dunsch, Lothar; Lhoták, Pavel; Ludvík, Jiří

2014-01-01

Graphical abstract: - Abstract: The first intermediates of electrochemical reduction of nitro compounds in nonaqueous DMF are stable radical anions. In the series of mono-, di-, tri- and tetranitro calix[4]arenes each nitro group represents a reduction center, therefore the question about the spin state of intermediary anions arises. In this communication, the voltammetric and coulometric investigation of these compounds is performed together with the spectral measurements (ESR and UV-vis). The in-situ spectroelectrochemical approach proved that during reduction, in all polynitro radicalic intermediates the electrons remain unpaired and thus relatively stable mono-, di-, tri- and tetraradical mono-, di-, tri- and tetraanions, respectively, can be electrochemically generated in aprotic DMF from polynitrocalix[4]arenes. This finding confirms that the nitrophenyl units in polynitrocalix[4]arenes are completely independent and no mutual electronic communication takes place among them

Spectrofluorimetric study on the inclusion interaction between vitamin K3 with p-(p-sulfonated benzeneazo)calix[6]arene and determination of VK3.

Science.gov (United States)

Zhou, Yunyou; Xu, Hongwei; Wu, Lian; Liu, Chun; Lu, Qin; Wang, Lun

2008-11-15

The characteristics of host-guest complexation between p-(p-sulfonated benzeneazo) calix[6]arene (SBC6A) and vitamin K3 (VK3) were investigated by fluorescence spectrometry. A 1:1 stoichiometry for the complexation was established and was verified by Job's plot. An association constant of 4.95 x 10(3)L mol(-1) at 20 degrees C was calculated by applying a deduced equation. The interaction mechanism of the inclusion complex was discussed. It was found that the fluorescence of SBC6A could be remarkably quenched by an appropriate amount of VK3 especially when non-ionic surfactant Triton X-100 existed. According to the obtained results, a novel sensitive spectrofluorimetric method for the determination of VK3 based on supramolecular complex was developed with a linear range of 5.0 x 10(-7) -3.0 x 10(-5)mol L(-1) and a detection limit of 2.0 x 10(-7)mol L(-1). The proposed method was used to determine VK3 in commercial preparations with satisfactory results.

Spectrofluorimetric study on the inclusion interaction between vitamin K 3 with p-( p-sulfonated benzeneazo)calix[6]arene and determination of VK 3

Science.gov (United States)

Zhou, Yunyou; Xu, Hongwei; Wu, Lian; Liu, Chun; Lu, Qin; Wang, Lun

2008-11-01

The characteristics of host-guest complexation between p-( p-sulfonated benzeneazo) calix[6]arene (SBC6A) and vitamin K 3 (VK 3) were investigated by fluorescence spectrometry. A 1:1 stoichiometry for the complexation was established and was verified by Job's plot. An association constant of 4.95 × 10 3 L mol -1 at 20 °C was calculated by applying a deduced equation. The interaction mechanism of the inclusion complex was discussed. It was found that the fluorescence of SBC6A could be remarkably quenched by an appropriate amount of VK 3 especially when non-ionic surfactant Triton X-100 existed. According to the obtained results, a novel sensitive spectrofluorimetric method for the determination of VK 3 based on supramolecular complex was developed with a linear range of 5.0 × 10 -7-3.0 × 10 -5 mol L -1 and a detection limit of 2.0 × 10 -7 mol L -1. The proposed method was used to determine VK 3 in commercial preparations with satisfactory results.

Calix[4]arenes Containing a Ureido Functionality on the Lower Rim as Highly Efficient Receptors for Anion Recognition.

Czech Academy of Sciences Publication Activity Database

Klejch, T.; Slavíček, J.; Hudeček, O.; Eigner, V.; Gutierrez, Natalia Andrea; Cuřínová, Petra; Lhoták, P.

2016-01-01

Roč. 40, č. 9 (2016), s. 7935-7942 ISSN 1144-0546 Institutional support: RVO:67985858 Keywords : calix[4]arene * anion recognition * receptors Subject RIV: CC - Organic Chemistry Impact factor: 3.269, year: 2016

A new and general method for the preparation of novel II-heterocyclic derivatives of ruthenium [C5Me5Ru (η6-arene)]X (arene = benzene, thiophene, 3-methylthiophene, benzothiophene, pyridine, 2.6 and 3.5-lutidine, quinoline, acridine). X-ray crystal structure of [(C5Me5)2Ru2Cl2(pyridine)2] PF6

International Nuclear Information System (INIS)

Chaudret, B.; Jalon, F.; Perez-Manrique, M.; Lahoz, F.; Plou, F.J.

1990-01-01

Zinc reduction of (Cp*RuCl 2 ) n (Cp* = C 5 Me 5 ) in acetone or THF followed by addition of 1 equivalent of an arene or aromatic heterocycle leads to compounds of general formulation [Cp* Ru(arene)]X (X = Cl, BF 4 ). Coordination of benzene is rapid and competes successfully with any other arene. Thiophene and 3-methylthiophene give stable π adducts whereas benzothiophene is coordinated through the benzene not through the heterocyclic ring. 2.6 and 3.5-lutidine coordinate through the ring, thus demonstrating an electronic rather than steric stabilization. Again, quinoline and acridine coordinate through the benzene ring. Pyridine gives an unstable π adduct in THF. A paramagnetic mixed-valence species, byproduct of the reaction in THF, has been characterized by an X-ray crystal structure determination. Crystals are triclinic, space group P-1

SUBJECT INDEX

Indian Academy of Sciences (India)

Unknown

Electrochemical behaviour of alkaline copper complexes. 543 ... Kinetic investigation of the oxidation of N- alkyl anilines by ... Catalytic combustion of methane. A method for increasing ... Cobalt(III), nickel(II) and ruthenium(II) complexes of 1 ...

Remediation of cadmium-contaminated soil by extraction with para-sulphonato-thiacalix[4]arene, a novel supramolecular receptor.

Science.gov (United States)

Li, Yushuang; Hu, Xiaojun; Song, Xueying; Sun, Tieheng

2012-08-01

Batch extractions were conducted to evaluate the performance of para-sulphonato-thiacalix[4]arene (STC[4]A), a novel supramolecular receptor, for removing cadmium (Cd) from soil. The extraction mechanism was investigated by determination of the conditional stability constants (log K) of the STC[4]A-Cd complex. The influences of various variables were examined, including pH, contact time, and extractant concentration. The Cd extraction efficiency increased with increasing pH, reaching the maximum at pH 11 and then declining at higher pH values. This pH dependence was explained by the variation in the log K value of the STC[4]A-Cd complex along with pH change. When the STC[4]A dose was increased to an STC[4]A:Cd molar ratio of 2.5:1, Cd was exhaustively removed (up to 96.8%). The comparison experiment revealed that the Cd extraction performance of STC[4]A was almost equivalent to that of EDTA and significantly better than that of natural organic acids. STC[4]A extraction could efficiently prevent co-dissolution of soil minerals. Copyright © 2012 Elsevier Ltd. All rights reserved.

Evaluation of calix[4]arene tethered Schiff bases for anion recognition

International Nuclear Information System (INIS)

Chawla, H.M.; Munjal, Priyanka

2016-01-01

Two calix[4]arene tethered Schiff base derivatives (L1 and L2) have been synthesized and their ion recognition capability has been evaluated through NMR, UV–vis and fluorescence spectroscopy. L1 interacts with cyanide ions very selectively to usher a significant change in color and fluorescence intensity. On the other hand L2 does not show selectivity for anion sensing despite having the same functional groups as those present in L1. The differential observations may be attributed to plausible stereo control of anion recognition and tautomerization in the synthesized Schiff base derivatives.

Evaluation of calix[4]arene tethered Schiff bases for anion recognition

Energy Technology Data Exchange (ETDEWEB)

Chawla, H.M., E-mail: hmchawla@chemistry.iitd.ac.in; Munjal, Priyanka

2016-11-15

Two calix[4]arene tethered Schiff base derivatives (L1 and L2) have been synthesized and their ion recognition capability has been evaluated through NMR, UV–vis and fluorescence spectroscopy. L1 interacts with cyanide ions very selectively to usher a significant change in color and fluorescence intensity. On the other hand L2 does not show selectivity for anion sensing despite having the same functional groups as those present in L1. The differential observations may be attributed to plausible stereo control of anion recognition and tautomerization in the synthesized Schiff base derivatives.

Synthesis, DNA-binding and photocleavage studies of [Ru(phen)2(pbtp)]2+ and [Ru(bpy)2(pbtp)]2+ (phen=1,10-phenanthroline; bpy=2,2'-bipyridine; pbtp=4,5,9,11,14-pentaaza-benzo[b]triphenylene).

Science.gov (United States)

Tan, Lifeng; Xiao, Yue; Liu, Xiaohua; Zhang, Sheng

2009-09-01

Based on the ligand dppz (dppz=dipyrido-[3,2-a:2',3'-c]phenazine), a new ligand pbtp (pbtp=4,5,9,11,14-pentaaza-benzo[b]triphenylene) and its polypyridyl ruthenium(II) complexes [Ru(phen)(2)(pbtp)](2+) (1) (phen=1,10-phenanthroline and [Ru(bpy)(2)(pbtp)](2+) (2) (bpy=2,2'-bipyridine) have been synthesized and characterized by elemental analysis, ES-MS and (1)H NMR spectroscopy. The DNA-binding of these complexes were investigated by spectroscopic methods and viscosity measurements. The experimental results indicate that both complexes 1 and 2 bind to CT-DNA in classical intercalation mode, and can enantioselectively interact with CT-DNA. It is interesting to note that the pbtp ruthenium(II) complexes, in contrast to the analogous dppz complexes, do not show fluorescent behavior when intercalated into DNA. When irradiated at 365 nm, both complexes promote the photocleavage of pBR 322 DNA.

Session 6: Catalytic hydro-dehalogenation as a remediation methodology: a consideration of Pd and Ni activity and halo-arene reactivity

Energy Technology Data Exchange (ETDEWEB)

Keane, M.A.; Amorim, C. [Kentucky Univ., Dept. of Chemical and Materials Engineering (United States); Patterson, P.M. [Kentucky Univ., Center for Applied Energy Research, Lexington, KY (United States)

2004-07-01

In this presentation, we consider the action of Ni/SiO{sub 2} and Pd/SiO{sub 2} bearing the same (ca. 5% w/w) metal loading and probe the intrinsic activity/selectivity of the metal site. Characterization pre- and post- reaction has drawn on HRTEM-EDX, SEM, XRD, TPR, H{sub 2} chemisorption/TPD. Reduction of Pd/SiO{sub 2} is far more facile than that of Ni/SiO{sub 2} to generate a narrower distribution of smaller Pd particles that exhibit significantly (up to three orders of magnitude) higher specific hydro-dehalogenation activities. The latter is manifest in a predominant complete dehalogenation of poly-halogenated aromatics. The role of the support in modifying the hydro-dehalogenation activity of the metal site will be addressed by considering carbon supported Pd and Ni, employing graphite, activated carbon and carbon nano-fibers as substrates. While the use of carbon nano-fibers/nano-tubes as metal supports is attracting the interest of the catalysis community, their application in halo-arene hydro-dehalogenation has yet to be reported in the literature. Carbon nano-fibers offer a high aspect ratio surface on which to disperse the active metal phase, as is illustrated by the representative TEM. The highly crystalline faceted Pd phase is a morphological feature that is consistent with a strong interaction between the metal particles and the support medium. This translates into high specific hydro-dehalogenation activities that are maintained over prolonged reaction cycles, a feature that will be discussed. The conversion of a range of halo-arenes (mono-, di- and tri- chloro-, bromo-, fluoro and iodo- benzenes, phenols and toluenes) under clearly defined reaction conditions will be presented where the differences in halo-arene reactivity are identified. Halo-arene reactivity is determined by inductive and steric effects, the former evident in the enhancement of hydro-dehalogenation by electron donating (-OH and -CH{sub 3}) substituents, the latter in the

Crystal structure and physical properties of a ruthenium(II) bipyridine dimethylsulfoxide complex

International Nuclear Information System (INIS)

Wang, Y.; Eichhorn, D.M.; Goswami, N.; Zhao, Q.; Rillema, D.P.

1999-01-01

The complex [Ru(bpy) 2 (DMSO)C1]PF 6 , where bpy is 2,2prime-bipyridine and DMSO is dimethyl-sulfoxide, crystallizes in the triclinic space group Pbar 1 (number s ign2) with a = 8.873 (2), b = 12.805 (4), c = 12.864 (4) angstrom, α = 97.76(3), β = 106.45(2), γ = 107.88(2); Z = 2, and d calc = 1.75 mg/m 3 . The coordination geometry is that of a distorted octahedron with a cis-RuN 4 SCl arrangement of coordinating atoms. The four Ru-N distances to the bpy ligands are 2.082(5), 2.092(4), 2.044(4), and 2.078(5) angstrom. The Ru-Cl distance is 2.421(2) angstrom and the Ru-S distance to DMSO is 2.260(1) angstrom. The Ru-N bond distance trans to Cl is the shortest; the Ru-N bond distance trans to S is the longest. The complex is oxidized and reduced reversibly at 1.13 and minus1.37 V vs. SSCE, respectively. It displays electronic absorptions at 515, 480 (1.5 x 10 4 ), 342 (1.5 X 10 4 ), 292 (1.2 X 10 5 ), and 240 nm (6.2 x 10 4 ) and has a broad emission band centered at 607 nm at 77 K in a 4:1 ethanol/methanol glass. The emission lifetime at room temperature is less than the pulse width of the laser, τ < 20 ns

Aqua(μ-cone-26,28-dibutoxy-25,27-bis{N-[5-(dimethylaminonaphthalene-1-sulfonyl]carbamoylmethoxy}-5,11,17,23-tetrakis(1,1-dimethylethylcalix[4]arene(2−disodium acetonitrile tetrasolvate

Directory of Open Access Journals (Sweden)

Pogisego Dinake

2012-04-01

Full Text Available The structure of the title complex, [Na2(C80H98N4O10S2(H2O]·4CH3CN, obtained after crystallization from acetonitrile, contains two formula units in the asymmetric unit (Z′ = 2 and an estimated four molecules of acetonitrile per calixarene moiety. It is unusual for two Na+ ions to occupy the lower rims of the cone calix[4]arene, as in this case, with one Na+ ion forming two O→ Na+ coordinate bonds with the two butoxy groups and four such bonds with the two N-dansyl carboxamide groups, forming six dative bonds between Na+ and O. On the other hand, the other Na+ ion forms only five O→Na+ coordinate bonds on the far end of the calix[4]arene lower rim, bringing the two dansyl groups in close proximity with each other. There also appears to be an O→Na+ coordination coming from a dangling water molecule. The structure contained both resolved and poorly resolved solvent molecules. The latter were treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

Facial One-Pot Synthesis of D 3h Symmetric Bicyclocalix[2]arene[2]triazines and Their Layered Comb Self-Assembly

KAUST Repository

Chen, Yin

2017-11-23

A number of D3h symmetric bicyclocalix[2]arene[2]triazine core compounds were synthesized via a general and good-yielding (43-48% yield) facile protocol starting from cyanuric halides, phloroglucinol and K2CO3 under very mild reaction conditions. These cage-like compounds are tolerate with different reaction conditions and can be derived with other functional groups in high yield. The X-ray crystal structures show these compounds have slightly distorted D3h symmetric structures. Due to the unique molecular topological structure, bicyclocalix[2]arene[2]triazine molecules form unique layered comb networks when hydrogen bond groups exist (such as CO2H, B(OH)2), which represent a new kind of building block unit for supramolecular architectures.

Ground- and excited-state pinched cone equilibria in calix[4]arenes bearing two perylene bisimide dyes

NARCIS (Netherlands)

Hippius, C.; van Stokkum, I.H.M.; Zangrando, E.; Williams, R.M.; Wykes, M.; Beljonne, D.; Wurthner, F.

2008-01-01

We report on a series of bis-chromophoric compounds o2c, g2c, and r2c, afforded by linking two identical orange, green, or red perylene bisimide (PBI) units, respectively, through a calix[4]arene spacer unit. The PBI units are characterized by their increasing sterical demand from a planar

Ground- and excited-state pinched cone equilibria in calix[4]arenes bearing two perylene bisimide dyes

NARCIS (Netherlands)

Hippius, C.; van Stokkum, I.H.M.; Zangrando, E.; Williams, R.M.; Wykes, M.; Beljonne, D.; Würthner, F.

2008-01-01

We report oil a series of bis-chromophoric compounds o2c, g2c, and r2c, afforded by linking two identical orange, green, or red perylene bisimide (PBI) units, respectively, through a calix[4]arene spacer unit. The PBI units are characterized by their increasing sterical demand from a planar

Cobalt(III)-catalyzed alkenylation of arenes and 6-arylpurines with terminal alkynes: efficient access to functional dyes.

Science.gov (United States)

Wang, Shan; Hou, Ji-Ting; Feng, Mei-Lin; Zhang, Xiao-Zhuan; Chen, Shan-Yong; Yu, Xiao-Qi

2016-02-14

Alkenylation of unactivated arenes and 6-arylpurines with terminal alkynes in high yields using Cp*Co(CO)I2 as catalyst under mild conditions is described. This method shows outstanding functional group compatibility and can be applied in the design of a mitochondria-targeted imaging dye.

A Polyoxovanadate-Resorcin[4]arene-Based Porous Metal-Organic Framework as an Efficient Multifunctional Catalyst for the Cycloaddition of CO2 with Epoxides and the Selective Oxidation of Sulfides.

Science.gov (United States)

Lu, Bing-Bing; Yang, Jin; Liu, Ying-Ying; Ma, Jian-Fang

2017-10-02

In this work, we report a new polyoxovanadate-resorcin[4]arene-based metal-organic framework (PMOF), [Co 2 L 0.5 V 4 O 12 ]·3DMF·5H 2 O (1), assembled with a newly functionalized wheel-like resorcin[4]arene ligand (L). 1 features an elegant porous motif and represents a rare example of PMOFs composed of both a resorcin[4]arene ligand and polyoxovanadate. Remarkably, 1 shows open V sites in the channel, which makes 1 an efficient heterogeneous Lewis acid catalyst for the cycloaddition of carbon dioxide to epoxides with high conversion and selectivity. Strikingly, 1 also exhibits high catalytic activity for the heterogeneous oxidative desulfurization of sulfides. Particularly, the heterogeneous catalyst 1 can be easily separated and reused with good catalytic activity.

α-Diazo-β-ketonitriles: uniquely reactive substrates for arene and alkene cyclopropanation.

Science.gov (United States)

Nani, Roger R; Reisman, Sarah E

2013-05-15

An investigation of the intramolecular cyclopropanation reactions of α-diazo-β-ketonitriles is reported. These studies reveal that α-diazo-β-ketonitriles exhibit unique reactivity in their ability to undergo arene cyclopropanation reactions; other similar acceptor-acceptor-substituted diazo substrates instead produce mixtures of C-H insertion and dimerization products. α-Diazo-β-ketonitriles also undergo highly efficient intramolecular cyclopropanation of tri- and tetrasubstituted alkenes. In addition, the α-cyano-α-ketocyclopropane products are demonstrated to serve as substrates for SN2, SN2', and aldehyde cycloaddition reactions.

NMR analysis of t-butyl-catalyzed deuterium exchange at unactivated arene localities.

Science.gov (United States)

Stack, Douglas E; Eastman, Rachel

2016-10-01

Regioselective labelling of arene rings via electrophilic exchange is often dictated by the electronic environment caused by substituents present on the aromatic system. Previously, we observed the presence of a t-butyl group, either covalently bond or added as an external reagent, could impart deuterium exchange to the unactivated, C1-position of estrone. Here, we provide nuclear magnetic resonance analysis of this exchange in a solvent system composed of 50:50 trifluoroacetic acid and D 2 O with either 2-t-butylestrone or estrone in the presence of t-butyl alcohol has shed insights into the mechanism of this t-butyl-catalyzed exchange. Fast exchange of the t-butyl group concurrent with the gradual reduction of the H1 proton signal in both systems suggest a mechanism involving ipso attack of the t-butyl position by deuterium. The reversible addition/elimination of the t-butyl group activates the H1 proton towards exchange by a mechanism of t-butyl incorporation, H1 activation and exchange, followed by eventual t-butyl elimination. Density functional calculations are consistent with the observation of fast t-butyl exchange concurrent with slower H1 exchange. The σ-complex resulting from ipso attack of deuterium at the t-butyl carbon was 6.6 kcal/mol lower in energy than that of the σ-complex resulting from deuterium attack at C1. A better understanding of the t-butyl-catalyzed exchange could help in the design of labelling recipes for other phenolic metabolites. Copyright © 2016 The Authors. Journal of Labelled Compounds and Radiopharmaceuticals published by John Wiley & Sons, Ltd.

New methods of arene iodination and functional transformation of multiple bonds in organic compounds

International Nuclear Information System (INIS)

Filimonov, V.D.; Chajkovskij, V.K.; Krasnokutskaya, E.A.

2000-01-01

The review summarizes the latest results of organic chemistry and technology of organic synthesis department of Tomsk polytechnical university concerning iodination of arenes and chemical transformations of unsaturated compounds. Preparative possibilities of the new reactions and reagents for iodination, oxidation of alkenes and alkynes to 1,2- and bis-1,2-dicarbonyl compounds, iodonitration of alkynes, and reaction of oxidative dimerization of the terminal alkynes to unsaturated δ-sultones are discussed [ru

Oxidant-free Rh(III)-catalyzed direct C-H olefination of arenes with allyl acetates.

Science.gov (United States)

Feng, Chao; Feng, Daming; Loh, Teck-Peng

2013-07-19

Rh(III)-catalyzed direct olefination of arenes with allyl acetate via C-H bond activation is described using N,N-disubstituted aminocarbonyl as the directing group. The catalyst undergoes a redox neutral process, and high to excellent yields of trans-products are obtained. This protocol exhibits a wide spectrum of functionality compatibility because of the simple reaction conditions employed and provides a highly effective synthetic method in the realm of C-H olefination.

Eco-friendly Oxidative Iodination of Various Arenes with Sodium Percarbonate as the Oxidantâ€

Directory of Open Access Journals (Sweden)

Lech Skulski

2005-10-01

Full Text Available Six easy laboratory procedures are presented for the oxidative iodination ofvarious aromatics, mostly arenes, with either molecular iodine or potassium iodide (usedas the sources of iodinating species, I or I3 , in the presence of sodium percarbonate(SPC, a stable, cheap, easy to handle, and eco-friendly commercial oxidant.

Computations between metallocalix(4)arene host and a series of four oil-based fuel pollutant guests

International Nuclear Information System (INIS)

Pathak, D.A.; Street, N.C.

2006-01-01

Calculations using PM3 and mechanics methods on metallocalix(4)arene hosts (1-10) and substituted dibenzothiophene guests (A-D), which are generally known as oil-based fuel pollutants, show that host-guest formation is energetically favored. Calculations have been carried out for both 1/1 and 1/4 ratios of host/guest. There is no direct bonding between the metal center of the host and the sulfur of the guest in the host-guest complex. Sterically hundered dibenzothiophene guests show similar energies to the unhindered analogs. For calix(4)arenas (5-10) in partial cone conformations and having hydrogen rather than p-tert-butyl groups on the wide rim, host-guest formation occurs within the narrow rim rather than the wide rim. Host-guest association appears to occur via Pie-Pie interactions between host and guest phenyl groups rather than via metal-sulfur bonding. The study has importance especially in oil refining to obtain environmentally safe fuel oils and help supramolecular chemists in designing and synthesizing more sophisticated host molecules for the removal of sulfur from crude oil / refinery oil. (author)

Design and reactivity of mono- and polymetallic complexes of low valent f-elements

OpenAIRE

Camp , Clément

2013-01-01

Beyond its importance in nuclear industry the redox chemistry uranium is attracting increasinginterest because complexes of low-valent uranium can promote unusual reductive chemistrythrough unusual reaction pathways, including attractive examples of CO, CO2, N2, arenes andazides activation in mild condition. Due to the unique coordination and bonding properties ofuranium, its compounds could provide an attractive alternative to transition metals for thecatalytic transformation of small molecu...

Some mixed ligand hydridocarbonyl and hydridophosphine complexes of ruthenium(II) and iridium(III)

International Nuclear Information System (INIS)

Pandey, R.N.; Kumar, Sunil; Kumar, Arun; Kumar, S.K.

1993-01-01

Mixed-ligand hydridocarbonyl and hydridophosphine complexes of Ru II and Ir III have been isolated from the displacement reaction of [RuH(CO)(Pφ 3 ) 3 Cl] with ligand isonicotinic acid hydrazide (INAH) in benzene medium. Most probable structures are assigned on the basis of elemental analysis, electronic, infrared and far-infrared spectral studies. In all cases bonding of INAH occurs through amino nitrogen of hydrazine residue. (author). 15 refs., 1 tab

5,11,17,23-Tetra-tert-butyl-25,26,27,28-tetrapropynyloxy-2,8,14,20-tetrathiacalix[4]arene

Directory of Open Access Journals (Sweden)

Xiang-Gao Meng

2009-12-01

Full Text Available The title compound [systematic name: 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrapropynyloxy-2,8,14,20-tetrathiacalix[4]arene], C52H56O4S4, is an alkylated product bearing four propyne groups at the lower rim of a 5,11,17,23-tetra-tert-butyl-tetrathiacalix[4]arene. The molecule is located on a crystallographic twofold rotation axis, running through two S atoms and perpendicular to the long axis of the molecule. The four propyne groups, located in an alternate fashion above and below the mean plane of the four S atoms, are almost parallel to the calixarene long axis. The dihedral angle between the two crystallographically independent benzene rings is 86.77 (14°. Two tert-butyl groups are disordered over two positions with site occupancies of 0.59 (2 and 0.41 (2.

Synthesis of phosphorylated calix[4]arene derivatives for the design of solid phases immobilizing uranyl cations

International Nuclear Information System (INIS)

Maroun, E.B.; Hagege, A.; Asfari, Z.; Basset, CH.; Quemeneur, E.; Vidaud, C.

2009-01-01

With the aim of developing supports for uranyl cations immobilisation, new 1, 3-alternate calix[4]arenes bearing both phosphonic acid functions as chelating sites and N-succinimide-4-oxa-butyrate as the anchoring arm were synthesised in good yields. The coupling of such calixarenes to a gel was performed and a successful immobilisation of uranyl cations was obtained. (authors)

Synthesis of phosphorylated calix[4]arene derivatives for the design of solid phases immobilizing uranyl cations

Energy Technology Data Exchange (ETDEWEB)

Maroun, E.B.; Hagege, A.; Asfari, Z. [Laboratoire de Chimie Analytique et Minerale, UMR 7178 ULP/CNRS/IN2P3 LC4, ECPM, Strasbourg Cedex (France); Basset, CH.; Quemeneur, E.; Vidaud, C. [CEA IBEB, SBTN, Centre de Marcoule, Bagnols-sur-Ceze (France)

2009-07-01

With the aim of developing supports for uranyl cations immobilisation, new 1, 3-alternate calix[4]arenes bearing both phosphonic acid functions as chelating sites and N-succinimide-4-oxa-butyrate as the anchoring arm were synthesised in good yields. The coupling of such calixarenes to a gel was performed and a successful immobilisation of uranyl cations was obtained. (authors)

Topotactic intercalation of a bulky organic anion (thiacalix[4]arene) into LDH through an osmotic swelling/restoration reaction in formamide.

Science.gov (United States)

Huang, Gailing; Ma, Shulan; Zhao, Xinhua; Yang, Xiaojing; Ooi, Kenta

2009-01-21

Utilizing the osmotic swelling of LDH in formamide, for the first time, the bulky thiacalix[4]arene anion is introduced, leading to the recovery of LDH layers, and the hexagonal prism morphology of the precursor is well retained.

Direct synthesis of metal complexes starting from zero-valent metals

Energy Technology Data Exchange (ETDEWEB)

Gojon-Zorrilla, Gabriel; Kharisov, Boris I. [Universidad Autonoma de Nuevo Leon, Monterrey, Nuevo Leon (Mexico); Garnovskii, Alexander D. [Institute of Physical and Organic Chemistry (Russian Federation)

1996-06-01

The recent (1980-1994) literature on metal-vapor synthesis of coordination and organometallic compounds is reviewed. An account is given of the high-and low-temperature reactions between free metal atoms and a large variety of substrates, mainly alkenes, alkynes, dienes, arenes, funtionalized arenes, alkyl halides {beta}-diketones and simple inorganic molecules. The main experimental methods are described, as well as the results obtained thereby. It is shown that in many instances these methods present significant advantages over conventional synthetic procedures, offering unique access to some metal complexes. [Spanish] Se reviso la literatura reciente (1980-1994) sobre la sintesis de compuestos de coordinacion y compuestos organometalicos a partir de vapores metalicos. Se examinan las reacciones de los atomos metalicos libres con una gran variedad de substratos, principalmente alquenos, alquinos, dienos, hidrocarburos aromaticos y sus derivados, haluros de alquilo y arilo, {beta}-dicetonas y moleculas inorganicas simples. Se presentan los principales metodos experimentales, asi como los resultados obtenidos; se concluye que la crisintesis presenta en muchos casos ventajas significativas sobre los procedimientos sinteticos tradicionales, constituyendo frecuentemente la unica opcion disponible.

Removal of lindane from an aqueous solution by using aminopropyl silica gel-immobilized calix[6]arene.

Science.gov (United States)

Tor, Ali; Aydin, Mehmet Emin; Aydin, Senar; Tabakci, Mustafa; Beduk, Fatma

2013-11-15

An aminopropyl silica gel-immobilized calix[6]arene (C[6]APS) has been used for the removal of lindane from an aqueous solution in batch sorption technique. The C[6]APS was synthesized with p-tert-butylcalix[6]arene hexacarboxylate derivative and aminopropyl silica gel in the presence of N,N'-diisopropyl carbodiimide coupling reagent. The sorption study was carried out as functions of solution pH, contact time, initial lindane concentration, C[6]APS dosage and ionic strength of solution. The matrix effect of natural water samples on the sorption efficiency of C[6]APS was also investigated. Maximum lindane removal was obtained at a wide pH range of 2-8 and sorption equilibrium was achieved in 2h. The isotherm analysis indicated that the sorption data can be represented by both Langmuir and Freundlich isotherm models. Increasing ionic strength of the solutions increased the sorption efficiency and matrix of natural water samples had no effect on the sorption of lindane. By using multilinear regression model, regression equation was also developed to explain the effects of the experimental variables. Copyright © 2013 Elsevier B.V. All rights reserved.

Why Aren't We There Yet? Taking Personal Responsibility for Creating an Inclusive Campus. An ACPA Publication

Science.gov (United States)

Arminio, Jan, Ed.; Torres, Vasti, Ed.; Pope, Raechele L., Ed.

2012-01-01

Despite seeming endless debate and public attention given to the issue for several decades, those committed to creating welcoming and engaging campus environments for all students recognize that there is considerably more work to be done, and ask "Why aren't we there yet, and when will we be done?" While our campuses have evolved from being…

Decompression Induced Crystallization of Basaltic Andesite Magma: Constraints on the Eruption of Arenal Volcano, Costa Rica.

Science.gov (United States)

Szramek, L. A.; Gardner, J. E.; Larsen, J. F.

2004-12-01

Arenal Volcano is a small stratovolcano located 90 km NW of San Jose, Costa Rica. In 1968 current activity began with a Plinian phase, and has continued to erupt lava flows and pyroclastic flows intermittently since. Samples from the Plinian, pyroclastic flow, strombolian, and effusive phases have been studied texturally. Little variation in crystallinity occurs amongst the different phases. Number density of crystals, both 2D and 3D are 50-70 mm-2 and 30,000-50,000 mm-3 in the Plinian sample, compared to the lesser values in other eruptive types. Characteristic crystal size also increases as explosivity decreases. Two samples, both lava flows collected while warm, overlap with the Plinian sample. This suggests that the variations seen may be a result of cooling history. Plagioclase differs between the Plinian sample, in which they are only tabular in shape, and the other eruptive types, which contain both tabular and equant crystals. To link decompression paths of the Arenal magma to possible pre-eruptive conditions, we have carried out hydrothermal experiments. The experiments were preformed in TZM pressure vessels buffered at a fugacity of Ni-NiO and water saturation. Phase equilibria results in conjunction with mineral compositions and temperature estimates by previous workers from active lava flows and two-pyroxene geothermometry, constrain the likely pre-eruptive conditions for the Arenal magma to 950-1040° C with a water pressure of 50-80 MPa. Samples that started from conditions that bracket our estimated pre-eruptive conditions were decompressed in steps of 5-30 MPa and held for various times at each step until 20 MPa was reached, approximating average decompression rates of 0.25, 0.025, 0.0013 MPa/s. Comparison of textures found in the natural samples to the experimentally produced textures suggest that the Plinian eruption likely was fed by magma ascending at 0.05-1 m/s, whereas the less explosive phases were fed by magma ascending at 0.05 m/s or less.

Facial One-Pot Synthesis of D 3h Symmetric Bicyclocalix[2]arene[2]triazines and Their Layered Comb Self-Assembly

KAUST Repository

Chen, Yin; Jiahui, Wang; Xu, Hai; Qianqian, Li; Jing, Jiang

2017-01-01

A number of D3h symmetric bicyclocalix[2]arene[2]triazine core compounds were synthesized via a general and good-yielding (43-48% yield) facile protocol starting from cyanuric halides, phloroglucinol and K2CO3 under very mild reaction conditions

A mixed ruthenium polypyridyl complex containing a PEG-bipyridine macroligand

Energy Technology Data Exchange (ETDEWEB)

Marin, Veronica; Holder, Elisabeth; Meier, Michael A.R.; Hoogenboom, Richard; Schubert, Ulrich S. [Laboratory of Macromolecular Chemistry and Nanoscience, Eindhoven University of Technology and Dutch Polymer Institute (DPI), P. O. Box 513, 5600 MB Eindhoven (Netherlands)

2004-04-06

An amino-functionalized bipyridine ligand was prepared in order to serve as a bridging unit to an activated low-molecular-weight monomethyl ether of poly(ethylene glycol) (PEG). Coordination of a ruthenium(II) phenantroline precursor onto the formed PEG-containing bipyridine ligand yielded a metal-containing polymer which shows interesting properties for solar cell applications. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

Oxidation of Bromide to Bromine by Ruthenium(II) Bipyridine-Type Complexes Using the Flash-Quench Technique.

Science.gov (United States)

Tsai, Kelvin Yun-Da; Chang, I-Jy

2017-07-17

Six ruthenium complexes, [Ru(bpy) 3 ] 2+ (1), [Ru(bpy) 2 (deeb)] 2+ (2), [Ru(deeb) 2 (dmbpy)] 2+ (3), [Ru(deeb) 2 (bpy)] 2+ (4), [Ru(deeb) 3 ] 2+ (5), and [Ru(deeb) 2 (bpz)] 2+ (6) (bpy: 2,2'-bipyridine; deeb: 4,4'-diethylester-2,2'-bipyridine; dmbpy: 4,4'-dimethyl-2,2'-bipyridine, bpz: 2,2'-bipyrazine), have been employed to sensitize photochemical oxidation of bromide to bromine. The oxidation potential for complexes 1-6 are 1.26, 1.36, 1.42, 1.46, 1.56, and 1.66 V vs SCE, respectively. The bimolecular rate constants for the quenching of complexes 1-6 by ArN 2 + (bromobenzenediazonium) are determined as 1.1 × 10 9 , 1.6 × 10 8 , 1.4 × 10 8 , 1.2 × 10 8 , 6.4 × 10 7 , and 8.9 × 10 6 M -1 s -1 , respectively. Transient kinetics indicated that Br - reacted with photogenerated Ru(III) species at different rates. Bimolecular rate constants for the oxidation of Br - by the Ru(III) species derived from complexes 1-5 are observed as 1.2 × 10 8 , 1.3 × 10 9 , 4.0 × 10 9 , 4.8 × 10 9 , and 1.1 × 10 10 , M -1 s -1 , respectively. The last reaction kinetics observed in the three-component system consisting of a Ru sensitizer, quencher, and bromide is shown to be independent of the Ru sensitizer. The final product was identified as bromine by its reaction with hexene. The last reaction kinetics is assigned to the disproportionation reaction of Br 2 -• ions, for which the rate constant is determined as 5 × 10 9 M -1 s -1 . Though complex 6 has the highest oxidation potential in the Ru(II)/Ru(III) couple, its excited state fails to react with ArN 2 + sufficiently for subsequent reactions. The Ru(III) species derived from complex 1 reacts with Br - at the slowest rate. Complexes 2-5 are excellent photosensitizers to drive photooxidation of bromide to bromine.

Synthesis, Photophysical and Electrochemical Properties of a Mixed Bipyridyl-Phenanthrolyl Ligand Ru(II Heteroleptic Complex Having trans-2-Methyl-2-butenoic Acid Functionalities

Directory of Open Access Journals (Sweden)

Adewale O. Adeloye

2011-09-01

Full Text Available In this work, two ligands: 4-(trans-2-Methyl-2-butenoic acid-2,2'-bipyridine (L1 and 5-(trans-2-methyl-2-butenoic acid-1,10-phenanthroline (L2, with the corresponding mixed-ligand heteroleptic Ru(II complex were synthesized and characterized by FT-IR, 1H-, 13C-NMR spectroscopy and elemental analysis. The influence of the mixed functionalized polypyridyl ruthenium(II complex on the photophysical and electrochemical properties were investigated and compared to individual single-ligand homoleptic complexes. Interestingly, the mixed-ligand complex formulated as [RuL1L2(NCS2] exhibits broad and intense metal-to-ligand charge transfer (MLCT absorption with a high molar extinction coefficient (λmax = 514 nm, ε = 69,700 M−1 cm−1, better than those of individual single-ligand complexes, [Ru(L12(NCS2] and [Ru(L22(NCS2], and a strong photoluminescence intensity ratio in the red region at λem = 686 nm. The electrochemical properties of the complex indicated that the redox processes are ligand-based.

Mono and dinuclear rhodium, iridium and ruthenium complexes containing chelating 2,2´-bipyrimidine ligands: Synthesis, molecular structure, electrochemistry and catalytic properties

Czech Academy of Sciences Publication Activity Database

Govindaswamy, P.; Canivet, J.; Therrien, B.; Süss-Fink, G.; Štěpnička, P.; Ludvík, Jiří

2007-01-01

Roč. 692, č. 17 (2007), s. 3664-3675 ISSN 0022-328X R&D Projects: GA MŠk(CZ) LC06070 Institutional research plan: CEZ:AV0Z40400503 Keywords : arene ligands * electrochemistry * dinuclear complexes * transfer hydrogenation Subject RIV: CG - Electrochemistry Impact factor: 2.168, year: 2007

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

High spectral response heteroleptic ruthenium (II) complexes as sensitizers for dye sensitized solar cells · M Chandrasekharam Ch Srinivasarao T Suresh M Anil Reddy M Raghavender G Rajkumar M Srinivasu P Yella Reddy · More Details Abstract Fulltext PDF. Heteroleptic ruthenium(II) bipyridyl complex, cis-Ru(II)(4 ...

CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonding: Effect of local rigidification on solvent extraction toward f-block elements

International Nuclear Information System (INIS)

Chu, Hongzhu; He, Lutao; Jiang, Qian; Fang, Yuyu; Jia, Yiming; Yuan, Xiangyang; Zou, Shuliang; Li, Xianghui; Feng, Wen; Yang, Yuanyou; Liu, Ning; Luo, Shunzhong; Yang, Yanqiu; Yang, Liang; Yuan, Lihua

2014-01-01

Highlights: • Three CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonds were designed and synthesized. • The influence of local rigidification caused by intramolecular hydrogen bonds upon extraction of f-elements was investigated. • Selective extraction is realized via tuning local chelating surroundings by aid of intramolecular hydrogen bonds. -- Abstract: To understand intramolecular hydrogen bonding in effecting liquid–liquid extraction behavior of CMPO-calixarenes, three CMPO-modified calix[4]arenes (CMPO-CA) 5a–5c with hydrogen-bonded spacer were designed and synthesized. The impact of spacer rotation that is hindered by introduction of intramolecular hydrogen bonding upon extraction of La 3+ , Eu 3+ , Yb 3+ , Th 4+ , and UO 2 2+ has been examined. The results show that 5b and 5c containing only one hydrogen bond with a less hindered rotation spacer extract La 3+ more efficiently than 5a containing two hydrogen bonds with a more hindered rotation spacer, demonstrating the importance of local rigidification of spacer in the design of extractants in influencing the coordination environment. The large difference in extractability between La 3+ and Yb 3+ (or Eu 3+ ) by 5b (or 5c), and the small difference by 5a, suggests intramolecular hydrogen bonding do exert pronounced influence upon selective extraction of light and heavy lanthanides. Log–log plot analysis indicates a 1:1, 2:1 and 1:1 stoichiometry (ligand/metal) for the extracted complex formed between 5b and La 3+ , Th 4+ , UO 2 2+ , respectively. Additionally, their corresponding acyclic analogs 7a–7c exhibit negligible extraction toward these metal ions. These results reveal the possibility of selective extraction via tuning local chelating surroundings of CMPO-CA by aid of intramolecular hydrogen bonding

Towards the Development of Functionalized PolypyridineLigands for Ru(II Complexes as Photosensitizers inDye-Sensitized Solar Cells (DSSCs

Directory of Open Access Journals (Sweden)

Adewale O. Adeloye

2014-08-01

Full Text Available A number of novel ruthenium(II polypyridine complexes have been designedand synthesized for use as photosensitizers in dye-sensitized solar cells (DSSCs due totheir rich photophysical properties such as intense absorption, long-lived lifetimes, highemission quantum yields and unique redox characteristics. Many of these complexesexhibit photophysical behavior that can be readily controlled through a careful choice ofligands and/or substituents. With this perspective, we review the design and general syntheticmethods of some polypyridine ligands based on bipyridine, phenanthroline, terpyridine andquaterpyridine with/without anchoring groups with a view to correlate functionality ofligand structures with the observed photophysical, electroredox and power conversionefficiency of some examples of Ru(II polypyridyl complexes that have been reported andparticularly used in the DSSCs applications. The main interest, however, is focused onshowing the development of new polypyridine ligand materials containing long-rangeelectron transfer motifs such as the alkenyl, alkynyl and polyaromatic donor functionalities.

A simple and rapid creatinine sensing via DLS selectivity, using calix[4]arene thiol functionalized gold nanoparticles.

Science.gov (United States)

Sutariya, Pinkesh G; Pandya, Alok; Lodha, Anand; Menon, Shobhana K

2016-01-15

A new, simple, ultra-sensitive and selective approach has been reported for the "on spot" colorimetric detection of creatinine based on calix[4]arene functionalized gold nanoparticles (AuNPs) with excellent discrimination in the presence of other biomolecules. The lower detection limit of the method is 2.16nM. The gold nanoparticles and p-tert-butylcalix[4]arene were synthesized by microwave assisted method. Specifically, in our study, we used dynamic light scattering (DLS) which is a powerful method for the determination of small changes in particle size, improved selectivity and sensitivity of the creatinine detection system over colorimetric method. The nanoassembly is characterized by Transmission electron microscopy (TEM), DLS, UV-vis and ESI-MS spectroscopy, which demonstrates the binding affinity due its ability of hydrogen bonding and electrostatic interaction between -NH group of creatinine and pSDSC4. It exhibits fast response time (creatinine and has long shelf-life (>5 weeks). The developed pSDSC4-AuNPs based creatinine biosensor will be established as simple, reliable and accurate tool for the determination of creatinine in human urine samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Cell cycle, apoptosis, cellular uptake and whole-transcriptome microarray gene expression analysis of HeLa cells treated with a ruthenium(II)-arene complex with an isoquinoline-3-carboxylic acid ligand.

Science.gov (United States)

Jovanović, Katarina K; Tanić, Miljana; Ivanović, Ivanka; Gligorijević, Nevenka; Dojčinović, Biljana P; Radulović, Siniša

2016-10-01

Ruthenium(II)-arene complexes are promising drug candidates for the therapy of solid tumors. In previous work, seven new compounds of the general formula [Ru(η 6 -p-cymene)(L 1-7 )Cl] were synthesized and characterized, of which the complex with L=isoquinoline-3-carboxylic acid (RuT 7 ) was two times as active on HeLa cells compared to normal cell line MRC-5, as indicated by IC 50 values determined after 48h of incubation (45.4±3.0 vs. 84.2±5.7μM, respectively). In the present study, cell cycle analysis of HeLa cells treated with RuT 7 showed S phase arrest and an increase in sub-G1 population. The apoptotic potential of the title compound was confirmed with the Annexin V-FITC/PI assay together with a morphological evaluation of cells using fluorescent microscopy. Analysis of the intracellular accumulation of ruthenium showed 8.9ng Ru/10 6 cells after 6h of incubation. To gain further insight in the molecular mechanism of action of RuT 7 on HeLa cells, a whole-transcriptome microarray gene expression analysis was performed. Analysis of functional categories and signaling and biochemical pathways associated with the response of HeLa cells to treatment with RuT 7 showed that it leads the cells through the intrinsic (mitochondrial) apoptotic pathway, via indirect DNA damage due to the action of reactive oxygen species, and through direct DNA binding of RuT 7 . Statistical analysis for enrichment of gene sets associated with known drug-induced toxicities identified fewer associated toxicity profiles in RuT 7 -treated cells compared to cisplatin treatment. Altogether these results provide the basis for further development of RuT 7 in animal and pre-clinical studies as a potential drug candidate. Copyright © 2016 Elsevier Inc. All rights reserved.

Design and reactivity of mono- and polymetallic complexes of low valent f-elements

International Nuclear Information System (INIS)

Camp, Clement

2013-01-01

Beyond its importance in nuclear industry the redox chemistry uranium is attracting increasing interest because complexes of low-valent uranium can promote unusual reductive chemistry through unusual reaction pathways, including attractive examples of CO, CO 2 , N 2 , arenes and azides activation in mild condition. Due to the unique coordination and bonding properties of uranium, its compounds could provide an attractive alternative to transition metals for the catalytic transformation of small molecules. However, metal-based multi-electron processes remain uncommon in uranium chemistry especially in comparison with the d-block metals, the chemistry of low-valent uranium being dominated by single-electron transfers. In this context, the first aim of this project was to investigate the association of low-valent uranium to a non-innocent ligand acting as an independent electron reservoir at a same molecule. Accordingly, we interrogated the use of highly p-delocalized Schiff bases ligands for supporting low-valent uranium chemistry. This led to the isolation of electron-rich complexes which are stabilized by storing electrons on the ligands through the formation of C-C bonds. Interestingly, these C-C bonds can be cleaved by oxidizing agents and the electrons released to participate in multi-electron redox reactions. This process was observed within different Schiff-base ligand scaffolds, allowing a tuning of the properties of the compounds. The second part of this work was dedicated to the synthesis of novel trivalent uranium complexes supported by siloxy ligands and the study of their redox reactivity and coordination properties. Novel dinuclear highly-reactive low-valent uranium assemblies were developed. The study of their limited stability revealed that these compounds are spontaneously decomposing through the cleavage of tBu groups from the supporting ligands resulting in the formation of U(IV) species. In parallel, a mononuclear trivalent uranium complex was

Spectrophotometric and electrochemical study for metal ion binding of azocalix[4]arene bearing p-ethylester group

Science.gov (United States)

Kim, Tae Hyun

2017-05-01

The complexation behavior of diazophenylcalix[4]arene bearing para-ethylester group (p-EAC) for alkali, alkaline earth, various heavy and transition metal ions (Li+, Na+, K+, Rb+, Cs+, Mg2 +, Ca2 +, Sr2 +, Ba2 +, Cr3 +, Fe2 +, Co2 +, Ni2 +, Cu2 +, Zn2 +, Pb2 +) was investigated by spectrophotometric and electrochemical methods in CH3CN. p-EAC exhibits decreased absorbance at 353 nm in the presence of Cr3 +, Fe2 +, Pb2 +, and Cu2 +. The spectra of p-EAC showed bathochromic shift in absorption maximum on the addition of Cr3 +, Fe2 +, or Pb2 + with decreasing order of absorbance (Cr3 + > Fe2 + > Pb2 +), and on the other hand, hypsochromic shift on the addition of Cu2 +. This leads to the selective coloration from light green to orange and colorless for Cr3 + and Cu2 + that can be detected by the naked eye, respectively. In electrochemistry experiments, p-EAC also showed two different types of voltammetric changes toward Cr3 +, Fe2 +, or Pb2 +, and toward Cu2 +, whereas no significant changes occurred in the presence of the other metal ions. Nonlinear fitting curve procedure was used to determine a logarithmic value of 5.20, 4.92, 3.54 and 4.80 for the stability constants of the complex of p-EAC with Cr3 +, Fe2 +, Pb2 +, and Cu2 +, respectively.

Amidines for versatile ruthenium(II)-catalyzed oxidative C-H activations with internal alkynes and acrylates.

Science.gov (United States)

Li, Jie; John, Michael; Ackermann, Lutz

2014-04-25

Cationic ruthenium complexes derived from KPF6 or AgOAc enabled efficient oxidative CH functionalizations on aryl and heteroaryl amidines. Thus, oxidative annulations of diversely decorated internal alkynes provided expedient access to 1-aminoisoquinolines, while catalyzed C-H activations with substituted acrylates gave rise to structurally novel 1-iminoisoindolines. The powerful ruthenium(II) catalysts displayed a remarkably high site-, regio- and, chemoselectivity. Therefore, the catalytic system proved tolerant of a variety of important electrophilic functional groups. Detailed mechanistic studies provided strong support for the cationic ruthenium(II) catalysts to operate by a facile, reversible C-H activation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ruthenium(II) bipyridine complexes bearing new keto-enol azoimine ligands: synthesis, structure, electrochemistry and DFT calculations.

Science.gov (United States)

Al-Noaimi, Mousa; Awwadi, Firas F; Mansi, Ahmad; Abdel-Rahman, Obadah S; Hammoudeh, Ayman; Warad, Ismail

2015-01-25

The novel azoimine ligand, Ph-NH-N=C(COCH3)-NHPh(C≡CH) (H2L), was synthesized and its molecular structure was determined by X-ray crystallography. Catalytic hydration of the terminal acetylene of H2L in the presence of RuCl3·3H2O in ethanol at reflux temperature yielded a ketone (L1=Ph-N=N-C(COCH3)=N-Ph(COCH3) and an enol (L2=Ph-N=N-C(COCH3)=N-PhC(OH)=CH2) by Markovnikov addition of water. Two mixed-ligand ruthenium complexes having general formula, trans-[Ru(bpy)(Y)Cl2] (1-2) (where Y=L1 (1) and Y=L2 (2), bpy is 2.2'-bipyrdine) were achieved by the stepwise addition of equimolar amounts of (H2L) and bpy ligands to RuCl3·3H2O in absolute ethanol. Theses complexes were characterized by elemental analyses and spectroscopic (IR, UV-Vis, and NMR (1D (1)H NMR, (13)C NMR, (DEPT-135), (DEPT-90), 2D (1)H-(1)H and (13)C-(1)H correlation (HMQC) spectroscopy)). The two complexes exhibit a quasi-reversible one electron Ru(II)/Ru(III) oxidation couple at 604 mV vs. ferrocene/ferrocenium (Cp2Fe(0/+)) couple along with one electron ligand reduction at -1010 mV. The crystal structure of complex 1 showed that the bidentate ligand L1 coordinates to Ru(II) by the azo- and imine-nitrogen donor atoms. The complex adopts a distorted trans octahedral coordination geometry of chloride ligands. The electronic spectra of 1 and 1+ in dichloromethane have been modeled by time-dependent density functional theory (TD-DFT). Copyright © 2014 Elsevier B.V. All rights reserved.

JCSC_128_11_1725_1735_SI.docx

Indian Academy of Sciences (India)

Windows7

Ruthenium(II) complexes bearing pyridine-functionalized N-heterocyclic carbene ligands: Synthesis, structure and catalytic application over amide synthesis. MUTHUKUMARAN NIRMALA and PERIASAMY VISWANATHAMURTHI*. Department of Chemistry, Periyar University, Salem, Tamil Nadu 636 011, India. e-mail: ...

SINTESIS 4,10,16,22-TETRAMETOKSIKALIKS[4] ARENA DARI MINYAK ADAS (SYNTHESIS OF 4,10,16,22-TETRAMETHOXYCALIX [4] ARENE FROM ANISE OIL

Directory of Open Access Journals (Sweden)

Ratna Ningsih S

2015-01-01

Full Text Available One kind of calixarenes, i.e. 4,10,16,22-tetramethoxycalix[4]arene (4, has been synthesized from anethole (1, which was isolated from anise oil. The synthesis of 4 was carried out via acid-catalyzed procedure. The reaction route consists of three stages, i.e. (i oxidation of 1 with KMnO4 at 40oC for 15 minutes, (ii reduction p-anisaldehyde (2 with NaBH4 at 76oC for 3 hours, and  (iii cyclotetramerization of p-anisilalcohol (3 with AlCl3 at 20oC for 2 hours. Oxidation of 1 produced 2 in 77%, whereas reduction of 2 gave 3 in 55 %. The cyclotetramerization of 3 yielded 4 in 95 %.  Key Words: 4,10,16,22-tetramethoxycalix[4]arene, Anise Oil, Anethole

Rhodium-catalyzed annulation of arenes with alkynes through weak chelation-assisted C-H activation.

Science.gov (United States)

Yang, Yudong; Li, Kaizhi; Cheng, Yangyang; Wan, Danyang; Li, Mingliang; You, Jingsong

2016-02-18

The purpose of this article is to give a brief review of weak chelation-assistance as a powerful means for the rhodium-catalyzed annulation of arenes with alkynes. The use of commonly occurring functional groups (e.g., ketones, aldehydes, carboxylic acids and alcohols) as the directing groups enriches the versatility of auxiliary ligands and extends the scope of products. This short article offers an overview on emerging procedures, highlights their advantages and limitations, and covers the latest progress in the rapid synthesis of organic functional materials and natural products.

A Smart Europium-Ruthenium Complex as Anticancer Prodrug: Controllable Drug Release and Real-Time Monitoring under Different Light Excitations.

Science.gov (United States)

Li, Hongguang; Xie, Chen; Lan, Rongfeng; Zha, Shuai; Chan, Chi-Fai; Wong, Wing-Yan; Ho, Ka-Lok; Chan, Brandon Dow; Luo, Yuxia; Zhang, Jing-Xiang; Law, Ga-Lai; Tai, William C S; Bünzli, Jean-Claude G; Wong, Ka-Leung

2017-11-09

A unique, dual-function, photoactivatable anticancer prodrug, RuEuL, has been tailored that features a ruthenium(II) complex linked to a cyclen-europium chelate via a π-conjugated bridge. Under irradiation at 488 nm, the dark-inactive prodrug undergoes photodissociation, releasing the DNA-damaging ruthenium species. Under evaluation-window irradiation (λ irr = one-photon 350 nm or two-photon 700 nm), the drug delivery process can be quantitatively monitored in real-time because of the long-lived red europium emission. Linear relationships between released drug concentration and ESI-MS or luminescence responses are established. Finally, the efficiency of the new prodrug is demonstrated both in vitro RuEuL anticancer prodrug over some existing ones and open the way for decisive improvements in multipurpose prodrugs.

A non-symmetric pillar[5]arene based on triazole-linked 8-oxyquinolines as a sequential sensor for thorium(IV) followed by fluoride ions.

Science.gov (United States)

Fang, Yuyu; Li, Caixia; Wu, Lei; Bai, Bing; Li, Xing; Jia, Yiming; Feng, Wen; Yuan, Lihua

2015-09-07

A novel non-symmetric pillar[5]arene bearing triazole-linked 8-oxyquinolines at one rim was synthesized and demonstrated as a sequential fluorescence sensor for thorium(iv) followed by fluoride ions with high sensitivity and selectivity.

Asymmetric Ruthenium(II and Osmium(II Complexes with New Bidentate Polyquinoline Ligands. Synthesis and NMR Characterization

Directory of Open Access Journals (Sweden)

Antonino Mamo

2010-03-01

Full Text Available A series of Ru(II and Os(II tris-chelate complexes with new bidentate 2-pyridylquinoline ligands have been synthesized and fully characterized by EA,1H-NMR and FAB-MS techniques. The new ligands are: L1 = 4-p-methoxyphenyl-6-bromo-2-(2′- pyridylquinoline (mphbr-pq and L2 = 4-p-hydroxyphenyl-6-bromo-2-(2′-pyridyl-quinoline (hphbr-pq. The complexes studied are: [Ru(bpy2L1](PF62 (C1, [Ru(bpy2L2](PF62 (C2, [Os(bpy2L1](PF62 (C3, [Os(bpy2L2](PF62 (C4 (bpy = 2,2′-bipyridine, [Ru(dmbpy2L1](PF62 (C5, [Ru(dmbpy2L2](PF62 (C6, [Os(dmbpy2L1](PF62 (C7, and [Os(dmbpy2L2](PF62 (C8 (dmbpy = 4,4′-dimethyl-2,2′-bipyridine. Moreover, new functionalized complexes C9-C12 were obtained by the basecatalyzed direct alkylation of C2, C4, C6, and C8 with 6-bromo-1-hexene. The complete assignment of the 1H-NMR spectra for the two new ligands (L1 and L2, and their Ru(II or Os(II complexes has been accomplished using a combination of one- and two-dimensional NMR techniques. The JH,H values have been determined for the majority of the resonances.

Asymmetric oxidation of vinyl- and ethynyl terthiophene ligands in triruthenium complexes.

Science.gov (United States)

Zhang, Jing; Sun, Chao-Fang; Zhang, Ming-Xing; Hartl, František; Yin, Jun; Yu, Guang-Ao; Rao, Li; Liu, Sheng Hua

2016-01-14

A series of ruthenium(ii) complexes [{RuCl(CO)(PMe3)3(-CH[double bond, length as m-dash]CH-)}nX], (: n = 3, X = 3,3''-dimethyl-2,2':3',2''-terthiophene; : n = 2, X = 2,2'-bithiophene; : n = 2, X = 2,3-bis(3-methylthiophen-2-yl)benzothiophene) and [{Cp*(dppe)2Ru(-C[triple bond, length as m-dash]C-)}3X], (X = 3,3''-dimethyl-2,2':3',2''-terthiophene), were prepared and characterized by (1)H, (13)C and (31)P NMR. Their redox, spectroscopic and bonding properties were studied with a range of spectro-electrochemical methods in combination with density functional theory calculations. The first two anodic steps observed for and are largely localized on the lateral frameworks of the molecular triangle, the direct conjugation between them being precluded due to the photostable open form of the dithienyl ethene moiety. The third anodic step is then mainly localized on the centerpiece of the triangular structure, affecting both bithiophene laterals. The experimental IR and UV-vis-NIR spectroelectrochemical data and, largely, also DFT calculations account for this explanation, being further supported by direct comparison with the anodic behavior of reference diruthenium complexes and .

Hydrogenation of imines catalysed by ruthenium(II) complexes based on lutidine-derived CNC pincer ligands.

Science.gov (United States)

Hernández-Juárez, Martín; Vaquero, Mónica; Álvarez, Eleuterio; Salazar, Verónica; Suárez, Andrés

2013-01-14

The preparation of new Ru(II) complexes incorporating fac-coordinated lutidine-derived CNC ligands is reported. These derivatives are selectively deprotonated by (t)BuOK at one of the methylene arms of the pincer, leading to catalytically active species in the hydrogenation of imines.

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

International Nuclear Information System (INIS)

Ke, Hanzhong; Ma, Wanpeng; Wang, Hongda; Cheng, Guoe; Yuan, Han; Wong, Wai-Kwok; Kwong, Daniel W.J.; Tam, Hoi-Lam; Cheah, Kok-Wai; Chan, Chi-Fai; Wong, Ka-Leung

2014-01-01

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 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 2 =391 GM). • The TTP–Ru exhibits a substantial 1 O 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

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: kehanz@163.com [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: wkwong@hkbu.edu.hk [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)

2014-10-15

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.

Ruthenium(II) chloro-bis(bipyridyl) complexes with substituted pyridine ligands: interpretation of their electronic absorption spectra

International Nuclear Information System (INIS)

Sizova, O.V.; Ershov, A.Yu.; Ivanova, N.V.; Shashko, A.D.; Kutejkina-Teplyakova, A.V.

2003-01-01

A number of complexes cis-[Ru(Bipy) 2 (L)(Cl)](BF 4 ), where Bipy-2,2'-bipyridine, L-pyridine, 4-aminopyridine, 4-picoline, nicotinamide, isonicotinamide, 3- and 4-cyanopyridine, 4,4'-bipyridine, trans-1,2-bis(4-pyridyl)ethylene, 4,4'-azopyridine, pyrazine, imidazole and NH 3 , were prepared. Using the CINDO-CI semiempirical method the energies and intensities of transition in electronic absorption spectra (EAS) of the complexes were calculated. It is shown that major differences in EAS of the compounds stem from position of transitions with charge transfer d π (Ru)→π*(L) [ru

Interaction of In(I) and Tl(I) cations with 2,6-diaryl pyridine ligands: cation encapsulation within a very weakly interacting N/arene host environment.

Science.gov (United States)

Mansaray, Hassanatu B; Tang, Christina Y; Vidovic, Dragoslav; Thompson, Amber L; Aldridge, Simon

2012-12-03

The interaction of 2,6-dimesitylpyridine with Tl(I) and In(I) cations has been investigated with a view to developing tractable molecular M(I) compounds which are soluble in organic media. In stark contrast to isosteric and isoelectronic terphenyl systems, complexes featuring the [(2,6-Mes(2)py)M](+) fragment feature very weak metal-ligand interactions in the solid state, as revealed by M-N distances of the order of 2.45 Å (M = In) and 2.64 Å (M = Tl). While additional weak π interactions are observed with arene solvate molecules in these systems, the related 2:1 complex [(2,6-Mes(2)py)(2)In][BAr(f)(4)] features an In(I) center wholly encapsulated by the bulky Mes(2)py donors, and even longer In-N distances [2.586(6) and 2.662(5) Å]. These contacts are about 0.5 Å greater than the sum of the respective covalent radii (2.13 Å) and provide evidence for an effectively "naked" In(I) cation stabilized to a minor extent by orbital interactions.

The coordination chemistry of dipyridylbenzene: N-deficient terpyridine or panacea for brightly luminescent metal complexes?

Science.gov (United States)

Williams, J A Gareth

2009-06-01

1,3-Di(2-pyridyl)benzene (dpybH) structurally resembles the widely-used ligand terpyridine (tpy), with which it is isoelectronic. In this critical review, following a brief overview of synthetic strategies for dpybH and derivatives, we survey the different types of complex that are possible with these ligands. Whilst metals such as ruthenium(ii), osmium(ii) and platinum(ii) give a terdentate N--C--N binding mode in which cyclometallation occurs at C(2), the ions iridium(iii), rhodium(iii) and palladium(ii) favour C(4) metallation. The latter process can be blocked by appropriate ligand modification, to allow the N--C--N mode to be accessed with these metal ions too. The luminescence properties of the complexes are discussed. A huge range of emission efficiencies are encountered amongst Ir(iii) complexes containing dpyb derivatives, according to the other ligands present. Trends can be rationalised with the aid of simple frontier-orbital considerations. The Pt(ii) complexes of dipyridylbenzenes are also intensely luminescent. Their application to contemporary organic light-emitting device (OLED) technology is discussed, including white light emitters exploiting excimer emission. Their potential as cell imaging agents amenable to time-resolved detection procedures on the microsecond timescale has also been demonstrated (118 references).

Metal–Organic Frameworks Stabilize Mono(phosphine)–Metal Complexes for Broad-Scope Catalytic Reactions

Energy Technology Data Exchange (ETDEWEB)

Sawano, Takahiro; Lin, Zekai; Boures, Dean; An, Bing; Wang, Cheng; Lin, Wenbin (UC); (Xiamen)

2016-08-10

Mono(phosphine)–M (M–PR3; M = Rh and Ir) complexes selectively prepared by postsynthetic metalation of a porous triarylphosphine-based metal–organic framework (MOF) exhibited excellent activity in the hydrosilylation of ketones and alkenes, the hydrogenation of alkenes, and the C–H borylation of arenes. The recyclable and reusable MOF catalysts significantly outperformed their homogeneous counterparts, presumably via stabilizing M–PR3 intermediates by preventing deleterious disproportionation reactions/ligand exchanges in the catalytic cycles.

Redox and catalytic properties of new polypyrrole modified electrodes functionalized by [Ru(bpea)(bpy)H{sub 2}O]{sup 2+} complexes; bpea=N,N'-bis(2-pyridylmethyl)ethylamine, bpy=2,2'-bipyridine

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, Montserrat; Romero, Isabel; Sens, Cristina; Llobet, Antoni; Deronzier, Alain

2003-04-05

New ruthenium(II) complexes containing one or two pyrrole-functionalized polypyridylic ligands have been prepared in order to study their electrochemical behaviour in heterogeneous phase, after anodic polymerization from CH{sub 2}Cl{sub 2} solution on an electrode surface. Complexes containing one pyrrole unit have general formula [Ru(bpea-pyr)(bpy)(L)]{sup 2+} (bpea-pyr=N-[3-bis(2-pyridylmethyl)aminopropyl]pyrrole, bpy=2,2'-bipyridine, L=Cl, complex 3, or L=H{sub 2}O, complex 1), whereas compounds having two pyrrole units correspond to [Ru(bpea-pyr)(bpy-pyr)(L)]{sup 2+} (bpy-pyr=4-methyl-4'-pyrrolylbutyl-2,2'-bipyridine, L=Cl, complex 4, or L=H{sub 2}O, complex 2). Upon oxidative polymerization, all complexes form highly stable polypyrrolic films on a graphite disk electrode surface. An electrode modified with complex 2 polypyrrole coating film, C/poly-2, has been tested as heterogeneous catalyst for the oxidation of benzyl alcohol, showing a remarkably high efficiency and notably improving the results obtained with analogous complexes in homogeneous phase.

Pengaruh Asam Kuat, Pengamplasan, Dan Lama Perendaman Terhadap Laju Imbibisi Dan Perkecambahan Biji Aren (Arenga pinnata

Directory of Open Access Journals (Sweden)

Marina Silalahi

2017-08-01

Full Text Available Abstrak Biji Arenga pinnata memiliki kulit biji  keras dan berlignin sehingga menghambat masuknya air ke dalam biji. Lapisan lignin pada kulit biji dapat didegradasi melalui reaksi kimia maupun perlakuan fisik. Perendaman biji aren dengan asam kuat (HNO3, H2SO4, dan HCl dan pengamplasan akan mempengaruhi laju imbibisi air melewati kulit biji. Variabel bebas dalam penelitian ini adalah konsentrasi asam kuat (HNO3, H2SO4, dan HCl, luas pengamplasan, air panas, lama perendaman, sedangkan variabel terikat laju imbibisi pada biji aren. Konsentrasi asam kuat yang digunakan adalah 1M dan 0,5M untuk masing-masing HNO3, H2SO4, dan HCl. Pengamplasan dilakukan di bagian pangkal biji, dan luas pengamplasan bervariasi (tanpa amplas, amplas ½ bagian, dan amplas keseluruhan. Setiap perlakuan direndam selama 18, 24 dan 36 jam. Biji aren yang diberi perlakuan fisik maupun kimia mengalami pengelupasan kulit biji. Laju imbibisi biji pada perendaman 24 jam lebih tinggi dibandingkan dengan lama perendaman 18 maupun 36 jam. Laju imbibisi tertinggi terjadi pada waktu perendaman 1M HCl dan amplas penuh dengan lama perendaman 24 jam sebesar 0,038 ± 0,002 mL/jam dan 0,038 ± 0,007 mL/jam . Biji aren yang diberi perlakuan fisik dan kimia mulai berkecambah 7 minggu setelah tanam dengan daya kecambah tertinggi pada pemberian HNO3 dan lama perendaman 18 jam.Abstract Arenga pinnata seed has a hard seed coat and lignin that inhibit the absorption of water into the seed. The lignin in the seed coat can be degraded by chemical or physical treatments. Soaking of the palm seeds into strong acids (HNO3, H2SO4, or HCl and sanding may affect the imbibition rate. The research was conducted to investigate the effect of a strong acid, sanding, and soaking time to the imbibition rate of A. pinnata seed. The independent variables in this research are concentration of the strong acids HNO3, H2SO4, and HCl; sanding, and soaking time, while the dependent variable is the rate of imbibition

Methodology for estimating aquifer recharge direct mfisurado system by the method of ripple of free (WTF) surface Mina Arenal departamento de Rivera

International Nuclear Information System (INIS)

Iardino, G.; González, G.; Montaño, J.

2010-01-01

The study area is framed in the so-called Crystal Island Rivera region of economic importance to Uruguay considering the gold occurrences . The company Uruguay Mineral Exploration Inc. (UME ) develops prospective exploration projects in the region since 1997 The discovery of a deposit of gold ore results in the opening of the Arenal mine near the town of Minas de Corrales, Department Rivera .Income groundwater to the quarry would affect the progress of the mineral extractive work to control this situation and monitors the evolution of a monitoring program is established with the potentiometric measurement levels and hydrological variables meteorelógicas.The data obtained allowed to estimate the direct recharge of the aquifer system in the area comprising the operational work of the Arenal mine, by applying the method of free surface fluctuation (WTF ) .The WTF method provides an estimate of groundwater recharge by analyzing water level fluctuations in observation wells

Highly potent extranuclear-targeted luminescent iridium(III) antitumor agents containing benzimidazole-based ligands with a handle for functionalization

Czech Academy of Sciences Publication Activity Database

Yellol, J.; Perez, S.A.; Yellol, G.; Zajac, Juraj; Donaire, A.; Vigueras, G.; Novohradský, Vojtěch; Janiak, C.; Brabec, Viktor; Ruiz, J.A.

2016-01-01

Roč. 52, č. 98 (2016), s. 14165-14168 ISSN 1359-7345 R&D Projects: GA ČR(CZ) GA14-21053S Institutional support: RVO:68081707 Keywords : anticancer * complexes * ruthenium(ii) Subject RIV: BO - Biophysics Impact factor: 6.319, year: 2016

Iron(II) supramolecular helicates interfere with the HIV-1 Tat-TAR RNA interaction critical for viral replication

Czech Academy of Sciences Publication Activity Database

Malina, Jaroslav; Hannon, Michael J.; Brabec, Viktor

2016-01-01

Roč. 6, JUL2016 (2016) ISSN 2045-2322 R&D Projects: GA ČR(CZ) GA16-03517S Institutional support: RVO:68081707 Keywords : DINUCLEAR RUTHENIUM(II) COMPLEX * METALLOSUPRAMOLECULAR CYLINDERS * BIOLOGICAL EVALUATION Subject RIV: BO - Biophysics Impact factor: 4.259, year: 2016

Actinide complexes of the calixarenes: Pt. 2

International Nuclear Information System (INIS)

Harrowfield, J.M.; Ogden, M.I.; White, A.H.

1990-01-01

The synthesis and room-temperature single-crystal X-ray structure determination of a novel tetranuclear thorium complex with p-tert-butylcalix [8] arene, H 8 L, has been achieved, the stoichiometry being assigned as [Th 4 (HL)(H 2 L)(dmso) 4 (OH) 3 (OH 2 )].dmso. 2H 2 O (dmso = Me 2 SO). Crystals of the complex are triclinic. Each calixarene unit, one with approximate 2 and the other approximate mm symmetry, is co-ordinated to two thorium atoms, the environment of each thorium comprising five ligand phenolic oxygen atoms; three being 'monodentate' and two bridging, with a monodentate O-bonded dmso entering through each cup of each ligand, and hydroxide groups variously bridging to the other thorium within the same ligand, and binding the two Th 2 L systems together. The 1 H NMR spectrum has been rationalised in terms of the X-ray structure. (author)

Ruthenium(II) Complexes Containing Lutidine-Derived Pincer CNC Ligands: Synthesis, Structure, and Catalytic Hydrogenation of C-N bonds.

Science.gov (United States)

Hernández-Juárez, Martín; López-Serrano, Joaquín; Lara, Patricia; Morales-Cerón, Judith P; Vaquero, Mónica; Álvarez, Eleuterio; Salazar, Verónica; Suárez, Andrés

2015-05-11

A series of Ru complexes containing lutidine-derived pincer CNC ligands have been prepared by transmetalation with the corresponding silver-carbene derivatives. Characterization of these derivatives shows both mer and fac coordination of the CNC ligands depending on the wingtips of the N-heterocyclic carbene fragments. In the presence of tBuOK, the Ru-CNC complexes are active in the hydrogenation of a series of imines. In addition, these complexes catalyze the reversible hydrogenation of phenantridine. Detailed NMR spectroscopic studies have shown the capability of the CNC ligand to be deprotonated and get involved in ligand-assisted activation of dihydrogen. More interestingly, upon deprotonation, the Ru-CNC complex 5 e(BF4 ) is able to add aldimines to the metal-ligand framework to yield an amido complex. Finally, investigation of the mechanism of the hydrogenation of imines has been carried out by means of DFT calculations. The calculated mechanism involves outer-sphere stepwise hydrogen transfer to the C-N bond assisted either by the pincer ligand or a second coordinated H2 molecule. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unusual stoichiometry of urea-derivatized calix[4]arenes induced by anion complexation

Czech Academy of Sciences Publication Activity Database

Lang, Kamil; Cuřínová, P.; Dudič, M.; Prošková, P.; Stibor, I.; Šťastný, V.; Lhoták, P.

2005-01-01

Roč. 46, č. 26 (2005), s. 4469-4472 ISSN 0040-4039 R&D Projects: GA ČR(CZ) GA203/03/0926 Keywords : calixarene * anion complexation * dimerization Subject RIV: CA - Inorganic Chemistry Impact factor: 2.477, year: 2005

Pengembangan dan Implementasi Aplikasi Pengawasan Ternak Berbasis Android di Peternakan Bukit Aren Farm Majalengka

Directory of Open Access Journals (Sweden)

Faraj Faraj

2015-10-01

Full Text Available Bukit Aren Farm located in Majalengka, West Java is a company specialized in the broiler of the agriculture industry, farming broiler performed in different places and every breeding cattle carried monitored by the supervisory staff. Every day, staf record information manually about the animal in the cage that data will be used as a performance evaluation of animal production. The livestock management personnel encountered problems when running calculations of the evaluation product and efficiency livestock because the calculation process can be done if the existing data stored carefully and systematically, in particular the data recorded cattle in significant quantities, it would require much time for staff supervision to determine the level of production performance. Application developed using waterfall method. The waterfall model is composed of: requirements, design, implementation, verification, maintenance. To begin the design steps required observations or interviews to determine the needs of the system under design. Applications developed using CodeIgniter framework, angularjs and ionic based architecture. Results of the project is the application mobile livestock monitoring data storage that can serve the number of deaths, data on the number quarantine of chicken, and the amount of data that then feed use these data will generate a data value prices and feed consumption levels of livestock mortality information for the evaluation process in the livestock in line with the business processes of Bukit Aren Farm. The application has been tested by using black box method and the results of these tests indicate that all functions in the system has been well running on the Android operating system from version 4.1.

Dynamic NMR studies of restricted arene rotation in the chromiu tricarbonyl thiophene and selenophene complexes

Energy Technology Data Exchange (ETDEWEB)

Sanger, Michael J. [Iowa State Univ., Ames, IA (United States)

1994-05-27

This thesis contains the results of organometallic studies of thiophene and selenophene coordination in transition metal complexes. Chromium tricarbonyl complexes of thiophene, selenophene, and their alkyl-substituted derivatives were prepared and variable-temperature ¹³C NMR spectra of these complexes were recorded in dimethyl ether. Bandshape analyses of these spectra yielded activation parameters for restricted rotation of the thiophene and selenophene ligands in these complexes. Extended Hueckel molecular orbital calculations (EHMO) of the free thiophene and selenophene ligands and selected chromium tricarbonyl thiophene complexes were performed to better explain the activation barriers of these complexes. The structure of Cr(CO)₃(η⁵-2,5-dimethylthiophene) was established by a single crystal X-ray diffraction study.

Electron transport properties of some new 4-tert-butylcalix[4]arene derivatives in thin films

Energy Technology Data Exchange (ETDEWEB)

Leontie, Liviu, E-mail: lleontie@uaic.ro [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, B-dul Carol I, Nr. 11, 700506 Iasi (Romania); Danac, Ramona [Faculty of Chemistry, Alexandru Ioan Cuza University of Iasi, B-dul Carol I, Nr. 11, 700506 Iasi (Romania); Girtan, Mihaela [Laboratoire LPhiA, Angers University, 2, Bd. Lavoisier, 49045, Angers (France); Carlescu, Aurelian; Rambu, Alicia Petronela; Rusu, Gheorghe I. [Faculty of Physics, Alexandru Ioan Cuza University of Iasi, B-dul Carol I, Nr. 11, 700506 Iasi (Romania)

2012-07-16

Temperature dependences of electric conductivity and thermoelectric power of some recently synthesized organic compounds, 4-tert-butylcalix[4]arene derivatives, are studied. Thin-film samples (d = 0.10-0.40 {mu}m) spin-coated from chloroform solutions onto glass substrates were used. Organic films with reproducible electron transport properties can be obtained if, after deposition, they are submitted to a heat treatment within temperature range of 295-575 K. The studied polycrystalline compounds show typical p-type semiconductor behavior. The activation energy of the electric conduction ranges between 0.82 and 1.12 eV, while the ratio of charge carrier mobilities was found in the range of 0.83-0.94. Some correlations between semiconducting parameters and molecular structure of the organic compounds have been discussed. In the higher temperature ranges (T > 420 K), the electron transport in examined compounds can be interpreted in terms of the band gap representation model, while in the lower temperature range, the Mott's variable-range hopping conduction model was found to be appropriate. The investigated compounds hold promise for thermistor applications. - Highlights: Black-Right-Pointing-Pointer 4-tert-butylcalix(4)arene derivatives in thin films are p-type semiconductors. Black-Right-Pointing-Pointer The electron transfer is favored by their extended conjugation and packing capacity. Black-Right-Pointing-Pointer The band gap representation is suitable in the higher temperature range. Black-Right-Pointing-Pointer The Mott's VRH conduction model may be applied in the lower temperature range. Black-Right-Pointing-Pointer As-prepared organic compounds are promising for thermistor applications.

Electron transport properties of some new 4-tert-butylcalix[4]arene derivatives in thin films

International Nuclear Information System (INIS)

Leontie, Liviu; Danac, Ramona; Girtan, Mihaela; Carlescu, Aurelian; Rambu, Alicia Petronela; Rusu, Gheorghe I.

2012-01-01

Temperature dependences of electric conductivity and thermoelectric power of some recently synthesized organic compounds, 4-tert-butylcalix[4]arene derivatives, are studied. Thin-film samples (d = 0.10–0.40 μm) spin-coated from chloroform solutions onto glass substrates were used. Organic films with reproducible electron transport properties can be obtained if, after deposition, they are submitted to a heat treatment within temperature range of 295–575 K. The studied polycrystalline compounds show typical p-type semiconductor behavior. The activation energy of the electric conduction ranges between 0.82 and 1.12 eV, while the ratio of charge carrier mobilities was found in the range of 0.83–0.94. Some correlations between semiconducting parameters and molecular structure of the organic compounds have been discussed. In the higher temperature ranges (T > 420 K), the electron transport in examined compounds can be interpreted in terms of the band gap representation model, while in the lower temperature range, the Mott's variable-range hopping conduction model was found to be appropriate. The investigated compounds hold promise for thermistor applications. - Highlights: ► 4-tert-butylcalix(4)arene derivatives in thin films are p-type semiconductors. ► The electron transfer is favored by their extended conjugation and packing capacity. ► The band gap representation is suitable in the higher temperature range. ► The Mott's VRH conduction model may be applied in the lower temperature range. ► As-prepared organic compounds are promising for thermistor applications.

Amphiphilic brushes from metallo-supramolecular block copolymers

NARCIS (Netherlands)

Guillet, P.; Fustin, C.A.; Wouters, D.; Höppener, S.; Schubert, U.S.; Gohy, J.M.W.

2009-01-01

A novel strategy to control the formation of amphiphilic brushes from metallo-supramol. block copolymers is described. The investigated copolymer consists of a polystyrene block linked to a poly(ethylene oxide) one via a charged bis-terpyridine ruthenium(ii) complex (PS-[Ru]-PEO). The initial

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 123; Issue 5 ... to study the decay of the excited states and the fast reactions of photo produced ... Ruthenium(II) carbonyl complexes containing chalconates and triphenylphosphine/arsine ..... Diversity in electrochemical oxidation of dihydroxybenzenes in the presence ...

Self-Assembly of Calix[4]arene-Based Amphiphiles Bearing Polyethylene Glycols: Another Example of "Platonic Micelles".

Science.gov (United States)

Yoshida, Kenta; Fujii, Shota; Takahashi, Rintaro; Matsumoto, Sakiko; Sakurai, Kazuo

2017-09-12

The aggregation number of classical micelles exhibits a certain distribution, which is a recognizable feature of conventional micelles. However, we recently identified perfectly monodisperse calix[4]arene-based micelles whose aggregation numbers agree with the vertex numbers of regular polyhedra, that is, Platonic solids, and thus they are named "Platonic micelles". Regarding our hypothesis of the formation mechanism of Platonic micelles, both repulsive interactions including steric hindrance and electrostatic repulsions among the headgroups are important for determining their aggregation number; however, neither of these is necessarily needed to consider. In this study, we employed polyethylene glycols (PEGs) as the nonionic headgroup of calix[4]arene-based amphiphiles to study the effects of only repulsive interactions caused by steric hindrance on the formation of Platonic micelles. The amphiphiles containing relatively low-molecular-weight PEGs (550 or 1000 g mol -1 ) form dodecamer or octamer micelles, respectively, with no variation in the aggregation number. However, relatively high-molecular-weight PEGs (2000 g mol -1 ) produce polydispersed micelles with a range of aggregation number. PEG 2000 exhibits a greater affinity for water than PEG 550 and 1000, resulting in fewer hydrophobic interactions in micelle formation, as indicated by the drastic increase of the critical micelle concentration (CMC) value in the PEG 2000 system. The instability of the structure of PEG 2k CaL5 micelles might contribute to the higher mobility of PEG in the micellar shell, resulting in a non-Platonic aggregation number with polydispersity.

Ruthenium(II) complexes containing bidentate Schiff bases and ...

Indian Academy of Sciences (India)

Unknown

triphenylphosphine or triphenylarsine. P VISWANATHAMURTHIa ... catalytic activities in the oxidation of benzyl alcohol to benzaldehyde. Keywords. Monobasic ... primarily because of the fascinating electron-transfer, photochemical and cata-.

Interaction of the thallium cation with 1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown-6: experimental and theoretical study

Czech Academy of Sciences Publication Activity Database

Makrlík, E.; Dybal, Jiří; Vaňura, P.

2013-01-01

Roč. 1042, 24 June (2013), s. 73-77 ISSN 0022-2860 R&D Projects: GA ČR GA203/09/1478 Institutional support: RVO:61389013 Keywords : thallium cation * substituted calix[4]arene-crown-6 * compound Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.599, year: 2013

LATEGLACIAL BATS FROM THE “M” LAYERS OF THE ARENE CANDIDE CAVE (LIGURIA, ITALY

Directory of Open Access Journals (Sweden)

LEONARDO SALARI

2010-03-01

Full Text Available The Arene Candide Cave (Finale Ligure, Northern Italy is considered one of the most important prehistoric site in Italy. The archaeological excavations conducted by the “Istituto Italiano di Paleontologia Umana” of Rome revealed 3 different horizons: an upper horizon with Holocene human presence dated from the Neolithic to the Byzantine period, and two underlying Pleistocene horizons with Gravettian and Epigravettian lithic artefacts. The stratigraphical sequence of the upper Palaeolithic is divided in two groups of strata separated by a depositional gap: the “P” complex, divided in 13 layers, dated from 25,620 to 18,560 years BP, and the 5 “M” layers dated between 11,750 and 9,980 years BP (14C non-calibrated dating.In this paper the fossil bone remains of bats from “M” layers are described. Fifteen taxa, divided into 3 families and 6 genera have been identified: Rhinolophus ferrumequinum, R. mehelyi, R. euryale, R. hipposideros, Myotis myotis, M. blythii, M. capaccinii, M. emarginatus, M. mystacinus s.l., Myotis sp. (small sized, Plecotus auritus s.l., Nyctalus lasiopterus, N. noctula, Barbastella barbastellus and Miniopterus schreibersii. Comments for each of these taxa on current ecological and geographical distributions are presented, together with some osteometric measures and recent data referred to Late Pleistocene fossils bats in Italy. Finally, the value of this bat tanathocoenoses as a microclimatic, environmental, and human activity indicators is discussed. SHORT NOTE

Modulation of ICT probability in bi(polyarene)-based O-BODIPYs: towards the development of low-cost bright arene-BODIPY dyads.

Science.gov (United States)

Gartzia-Rivero, Leire; Sánchez-Carnerero, Esther M; Jiménez, Josue; Bañuelos, Jorge; Moreno, Florencio; Maroto, Beatriz L; López-Arbeloa, Iñigo; de la Moya, Santiago

2017-09-12

We report the synthesis, and spectroscopic and electrochemical properties of a selected library of novel spiranic O-BODIPYs bearing a phenol-based bi(polyarene) unit tethered to the boron center through oxygen atoms. These dyes constitute an interesting family of arene-BODIPY dyads useful for the development of photonic applications due to their synthetic accessibility and tunable photonic properties. It is demonstrated that the electron-donor capability of the involved arene moiety switches on a non-emissive intramolecular charge transfer (ICT) state, which restricts the fluorescence efficiency of the dyad. Interestingly, the influence of this non-radiative deactivation channel can be efficiently modulated by the substitution pattern, either at the dipyrrin ligand or at the polyarene moiety. Thus, dyads featuring electron-rich dipyrrin and electron-poor polyarene show lower or almost negligible ICT probability, and hence display bright fluorescence upon dual excitation at far-away spectral regions. This synthetic approach has allowed the easy development of low-cost efficient ultraviolet-absorbing visible-emitting cassettes by selecting properly the substitution pattern of the involved key units, dipyrrin and bi(polyarene), to modulate not only absorption and emission wavelengths, but also fluorescence efficiencies.

Supramolecular Drug Delivery Systems Based on Water-Soluble Pillar[n]arenes.

Science.gov (United States)

Wu, Xuan; Gao, Lei; Hu, Xiao-Yu; Wang, Leyong

2016-06-01

Supramolecular drug delivery systems (SDDSs), including various kinds of nanostructures that are assembled by reversible noncovalent interactions, have attracted considerable attention as ideal drug carriers owing to their fascinating ability to undergo dynamic switching of structure, morphology, and function in response to various external stimuli, which provides a flexible and robust platform for designing and developing functional and smart supramolecular nano-drug carriers. Pillar[n]arenes represent a new generation of macrocyclic hosts, which have unique structures and excellent properties in host-guest chemistry. This account describes recent progress in our group to develop pillararene-based stimuli-responsive supramolecular nanostructures constructed by reversible host-guest interactions for controllable anticancer drug delivery. The potential applications of these supramolecular drug carriers in cancer treatment and the fundamental questions facing SDDSs are also discussed. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spectrofluorimetric determination of benzoimidazolic pesticides: Effect of p-sulfonatocalix[6]arene and cyclodextrins

International Nuclear Information System (INIS)

Pacioni, Natalia L.; Sueldo Occello, Valeria N.; Lazzarotto, Marcio; Veglia, Alicia V.

2008-01-01

The effect of the addition of a macrocyclic host (H) such as p-sulfonatocalix[6]arene (C6S), native and modified cyclodextrins (CDs), on the fluorescence of benzoimidazolic fungicides (P), like Benomyl (BY) and Carbendazim (CZ), has been studied. The fluorescence of BY in water at pH 1.000 and 25.0 deg. C was increased in the presence of C6S, αCD and hydroxypropyl-β-CD (HPCD). The association constants determined by fluorescence enhancement showed weak interactions (K A ∼ 10 1 to 10 2 M -1 ) between the fungicide with both CDs, whereas they were stronger with C6S (K A ∼ 10 5 M -1 ). Molecular recognition of BY for C6S was mainly attributed to electrostatic interactions, and for CDs to the hydrophobic effect and hydrogen bond formation. On the other hand, the fluorescent behaviour of CZ in the presence of C6S at pH 6.994 was interpreted as the formation of two complexes with 1:1 (P:H) and 1:2 (P:H 2 ) stoichiometry, the latter being less fluorescent than the free analyte. Relative fluorescence quantum yield ratios between the complexed and free BY (φ P:H /φ P ) were 2.00 ± 0.05, 1.40 ± 0.03 and 2.8 ± 0.4 for C6S, αCD and HPCD, respectively. The analytical parameters improved in the presence of C6S and CDs. The best limit of detection (L D , ng mL -1 ) was 17.4 ± 0.8 with HPCD. The proposed method with C6S and HPCD was successfully applied to fortified samples of tap water and orange flesh extract with good recoveries (91-106%) and R.S.D. (≤2%) by triplicate analysis. The method is rapid, direct and simple and needs no previous degradation or derivatization reaction

Spectrofluorimetric determination of benzoimidazolic pesticides: Effect of p-sulfonatocalix[6]arene and cyclodextrins

Energy Technology Data Exchange (ETDEWEB)

Pacioni, Natalia L.; Sueldo Occello, Valeria N. [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Lazzarotto, Marcio [Departamento de Quimica Organica, Instituto de Quimica, Universidade Federal do Rio Grande do Sul-UFRGS, 15003 Porto Alegre, R.S. (Brazil); Veglia, Alicia V. [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)], E-mail: aveglia@fcq.unc.edu.ar

2008-08-22

The effect of the addition of a macrocyclic host (H) such as p-sulfonatocalix[6]arene (C6S), native and modified cyclodextrins (CDs), on the fluorescence of benzoimidazolic fungicides (P), like Benomyl (BY) and Carbendazim (CZ), has been studied. The fluorescence of BY in water at pH 1.000 and 25.0 deg. C was increased in the presence of C6S, {alpha}CD and hydroxypropyl-{beta}-CD (HPCD). The association constants determined by fluorescence enhancement showed weak interactions (K{sub A} {approx} 10{sup 1} to 10{sup 2} M{sup -1}) between the fungicide with both CDs, whereas they were stronger with C6S (K{sub A} {approx} 10{sup 5} M{sup -1}). Molecular recognition of BY for C6S was mainly attributed to electrostatic interactions, and for CDs to the hydrophobic effect and hydrogen bond formation. On the other hand, the fluorescent behaviour of CZ in the presence of C6S at pH 6.994 was interpreted as the formation of two complexes with 1:1 (P:H) and 1:2 (P:H{sub 2}) stoichiometry, the latter being less fluorescent than the free analyte. Relative fluorescence quantum yield ratios between the complexed and free BY ({phi}{sup P:H}/{phi}{sup P}) were 2.00 {+-} 0.05, 1.40 {+-} 0.03 and 2.8 {+-} 0.4 for C6S, {alpha}CD and HPCD, respectively. The analytical parameters improved in the presence of C6S and CDs. The best limit of detection (L{sub D}, ng mL{sup -1}) was 17.4 {+-} 0.8 with HPCD. The proposed method with C6S and HPCD was successfully applied to fortified samples of tap water and orange flesh extract with good recoveries (91-106%) and R.S.D. ({<=}2%) by triplicate analysis. The method is rapid, direct and simple and needs no previous degradation or derivatization reaction.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 128; Issue 1 ... Ruthenium(II) complexes (1-3) bearing bis-phenolate--heterocyclic carbene ligand were synthesized in good yields by the reaction of imidazolinium proligand (HL) with ... Department of Chemistry, Periyar University, Salem 636 011, Tamil Nadu, India ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. V Gopal Reddy. Articles written in Journal of Chemical Sciences. Volume 123 Issue 4 July 2011 pp 371-378. Synthesis and photoelectrochemical characterization of a high molar extinction coefficient heteroleptic ruthenium(II) complex · L Giribabu Vrun Kumar Singh M ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 123; Issue 4. Issue front cover thumbnail. Volume 123, Issue 4. July 2011, pages 371-524. pp 371-378. Synthesis and photoelectrochemical characterization of a high molar extinction coefficient heteroleptic ruthenium(II) complex · L Giribabu Vrun Kumar Singh M ...

Multilayer membranes of p-sulfonato-calix[8]arene and polyvinylamine and their use for selective enrichment of rare earth metal ions

Energy Technology Data Exchange (ETDEWEB)

Toutianoush, Ali [Institut fuer Physikalische Chemie der Universitaet zu Koeln, Luxemburger Str. 116, D-50939 Cologne (Germany); El-Hashani, Ashraf [Institut fuer Physikalische Chemie der Universitaet zu Koeln, Luxemburger Str. 116, D-50939 Cologne (Germany); Schnepf, Judit [Institut fuer Physikalische Chemie der Universitaet zu Koeln, Luxemburger Str. 116, D-50939 Cologne (Germany); Tieke, Bernd [Institut fuer Physikalische Chemie der Universitaet zu Koeln, Luxemburger Str. 116, D-50939 Cologne (Germany)]. E-mail: Tieke@Uni-Koeln.de

2005-06-30

Using alternating electrostatic layer-by-layer assembly of p-octasulfonato-calix[8]arene and polyvinylamine, multilayer assemblies were built up on porous polymer supports. The resulting composite membranes with ultrathin separation layer were studied on their permeability for various metal chloride salts in aqueous solution. The membranes were permeable for sodium chloride, but much less permeable for divalent metal chlorides such as magnesium and zinc chloride, the theoretical separation factors {alpha} (NaCl/MgCl{sub 2}) and {alpha} (NaCl/ZnCl{sub 2}) being 43 and 20. Rare earth metal chlorides LnCl{sub 3} with Ln being La, Ce, Pr and Sm and the related YCl{sub 3} were strongly rejected from the membrane, the theoretical separation factors {alpha} (NaCl/LaCl{sub 3}) and {alpha} (NaCl/YCl{sub 3}) being 138 and 160, for example. Possible origins for the selective ion transport are discussed in terms of Donnan rejection of the highly charged ions and complex formation of the rare earth metal ions with the p-sulfonato-calixarene units in the membrane.

Multilayer membranes of p-sulfonato-calix[8]arene and polyvinylamine and their use for selective enrichment of rare earth metal ions

International Nuclear Information System (INIS)

Toutianoush, Ali; El-Hashani, Ashraf; Schnepf, Judit; Tieke, Bernd

2005-01-01

Using alternating electrostatic layer-by-layer assembly of p-octasulfonato-calix[8]arene and polyvinylamine, multilayer assemblies were built up on porous polymer supports. The resulting composite membranes with ultrathin separation layer were studied on their permeability for various metal chloride salts in aqueous solution. The membranes were permeable for sodium chloride, but much less permeable for divalent metal chlorides such as magnesium and zinc chloride, the theoretical separation factors α (NaCl/MgCl 2 ) and α (NaCl/ZnCl 2 ) being 43 and 20. Rare earth metal chlorides LnCl 3 with Ln being La, Ce, Pr and Sm and the related YCl 3 were strongly rejected from the membrane, the theoretical separation factors α (NaCl/LaCl 3 ) and α (NaCl/YCl 3 ) being 138 and 160, for example. Possible origins for the selective ion transport are discussed in terms of Donnan rejection of the highly charged ions and complex formation of the rare earth metal ions with the p-sulfonato-calixarene units in the membrane

Deuterium isotope effects during formation of phenols by hepatic monoxygenases. Evidence for an alternative to the arene oxide pathway

International Nuclear Information System (INIS)

Tomaszewski, J.E.; Jerina, D.M.; Daly, J.W.

1975-01-01

The in vivo and in vitro metabolisms of normal and deuterated aromatic substrates have been investigated in rats. Significant isotope effects (k/ sub H//k/sub D/ equals 1.3-1.75) were associated with in vivo formation of meta-hydroxylated metabolites from 1:1 mixtures of normal and perdeuterio-(arylring) nitrobenzene, methyl phenyl sulfide, and methyl phenyl sulfone. Since isotope effects of this magnitude are incompatible with arene oxides as intermediates in the formation of phenols, the results provide evidence that multiple pathways are responsible for the formation of phenols in mammals. Significant isotope effects were not associated with the formation of the other phenolic isomers of nitrobenzene, methyl phenyl sulfone, or methyl phenyl sulfide or with the formation of phenolic products from anisole, bromobenzene, chlorobenzene, fluorobenzene, benzonitrile, naphthalene, zoxazolamine, acetanilide, biphenyl, diphenylhydantoin, benzene, o- and p-xylene, toluene, and mesitylene. Significant isotope effects might not be observable with the latter substrates if the kinetic parameters for oxidation of substrate change or if the arene oxide pathway greatly predominates. Furthermore, extensive in vivo metabolism of any substrate would make isotope effects unobservable by the procedure employed, namely the analysis of isotope content in metabolites formed from 1:1 mixtures of normal and deuterated substrates. (U.S.)

Male and mosquito larvae survey at the Arenal-Tempisque irrigation project, Guanacaste, Costa Rica

Directory of Open Access Journals (Sweden)

Mario Vargas V

2003-09-01

Full Text Available A monitoring of male and larvae of mosquitoes was conducted during 1991-1994, at the Irrigation Project in Arenal-Tempisque, Guanacaste, Costa Rica. CDC CO2 -baited traps were used to collect adults of mosquitoes and dips were used for immatures of culicids. A total of 1 480 larvae and 1 129 males of culicids were identified resulting in, Aedes with 6 species, Anopheles, Mansonia and Psorophora with 2 species, Culex with 21 species and Haemagogus, Limatus, Toxorhynchites and Uranotaenia with only one species each. The results indicate that, as occurred in other countries, irrigation projects must be under strict monitoring programs to prevent and control possible health problems in which mosquitoes act as vectorsSe realizó un monitoreo de machos y larvas de mosquitos durante los años 1991 a 1994 en el Proyecto de Riego Arenal-Tempisque, Guanacaste, Costa Rica. Los especímenes fueron colectados en 32 giras de cuatro días cada una y cada 15 días. La colecta de adultos se hizo mediante trampas tipo CDC y la de larvas con la técnica estándar del cucharón. Se identificaron un total de 1 480 larvas y 1 129 machos de culícidos, correspondientes a 21 especies de Culex, 6 especies de Aedes, 2 especies de Anopheles, Mansonia, y Psorophora y una especie de Haemagogus, Limatus, Toxorhynchites y Uranotaenia. Los resultados indican que tal y como ha ocurrido en proyectos de riego en otros países, se deben mantener estrictos programas de monitoreo con el fin de prevenir y controlar posibles problemas de salud humana y animal, en los cuales los mosquitos actúen como vectores

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Y Soujnya. Articles written in Journal of Chemical Sciences. Volume 123 Issue 4 July 2011 pp 371-378. Synthesis and photoelectrochemical characterization of a high molar extinction coefficient heteroleptic ruthenium(II) complex · L Giribabu Vrun Kumar Singh M Srinivasu Ch ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

pp 1-17 Inorganic and Analytical. Cobalt(III), nickel(II) and ruthenium(II) complexes of 1,10-phenanthroline family of ligands: DNA binding and photocleavage studies · S Arounaguiri D Easwaramoorthy A Ashokkumar Aparna Dattagupta Bhaskar G Maiya · More Details Abstract Fulltext PDF. DNA binding and photocleavage ...

Highly efficient and stable cyclometalated ruthenium(II) complexes as sensitizers for dye-sensitized solar cells

International Nuclear Information System (INIS)

Huang, Jian-Feng; Liu, Jun-Min; Su, Pei-Yang; Chen, Yi-Fan; Shen, Yong; Xiao, Li-Min; Kuang, Dai-Bin; Su, Cheng-Yong

2015-01-01

Highlights: • Four novel thiocyanate-free cyclometalated ruthenium sensitizer were conveniently synthesized. • The D-CF 3 -sensitized DSSCs show higher efficiency compared to N719 based cells. • The DSSCs based on D-CF 3 and D-bisCF 3 sensitizers exhibit excellent long-term stability. • The diverse cyclometalated Ru complexes can be developed as high-performance sensitizers for use in DSSC. - Abstract: Four novel thiocyanate-free cyclometallted Ru(II) complexes, D-bisCF 3 , D-CF 3 , D-OMe, and D-DPA, with two 4,4′-dicarboxylic acid-2,2′-bipyridine together with a functionalized phenylpyridine ancillary ligand, have been designed and synthesized. The effect of different substituents (R = bisCF 3 , CF 3 , OMe, and DPA) on the ancillary C^N ligand on the photophysical properties and photovoltaic performance is investigated. Under standard global AM 1.5 solar conditions, the device based on D-CF 3 sensitizer gives a higher conversion efficiency of 8.74% than those based on D-bisCF 3 , D-OMe, and D-DPA, which can be ascribed to its broad range of visible light absorption, appropriate localization of the frontier orbitals, weak hydrogen bonds between -CF 3 and -OH groups at the TiO 2 surface, moderate dye loading on TiO 2 , and high charge collection efficiency. Moreover, the D-bisCF 3 and D-CF 3 based DSSCs exhibit good stability under 100 mW cm −2 light soaking at 60 °C for 400 h

Theoretical study of X⁻ · 1 · YF (1 = triazine, X = Cl, Br and I, Y = H, Cl, Br, I, PH₂ and AsH₂): noncovalently electron-withdrawing effects on anion-arene interactions.

Science.gov (United States)

Chen, Yishan; Yao, Lifeng

2014-01-01

The ternary complexes X(-) · 1 · YF (1 = triazine, X = Cl, Br and I, Y = H, Cl, Br, I, PH2 and AsH2) have been investigated by MP2 calculations to understand the noncovalently electron-withdrawing effects on anion-arene interactions. The results indicate that in binary complexes (1 · X(-)), both weak σ-type and anion-π complexes can be formed for Cl(-) and Br(-), but only anion-π complex can be formed for I(-). Moreover, the hydrogen-bonding complex is the global minimum for all three halides in binary complexes. However, in ternary complexes, anion-π complex become unstable and only σ complex can retain in many cases for Cl(-) and Br(-). Anion-π complex keeps stable only when YF = HF. In contrast with binary complexes, σ complex become the global minimum for Cl(-) and Br(-) in ternary complexes. These changes in binding mode and strength are consistent with the results of covalently electron-withdrawing effects. However, in contrast with the covalently electron-withdrawing substituents, Cl(-) and Br(-) can attack the aromatic carbon atom to form a strong σ complex when the noncovalently electron-withdrawing effect is induced by halogen bonding. The binding behavior for I(-) is different from that for Cl(-) and Br(-) in two aspects. First, the anion-π complex for I(-) can also keep stable when the noncovalent interaction is halogen bonding. Second, the anion-π complex for I(-) is the global minimum when it can retain as a stable structure.

Palladium(II)-Catalyzed meta-C-H Olefination: Constructing Multisubstituted Arenes through Homo-Diolefination and Sequential Hetero-Diolefination.

Science.gov (United States)

Bera, Milan; Maji, Arun; Sahoo, Santosh K; Maiti, Debabrata

2015-07-13

Divinylbenzene derivatives represent an important class of molecular building blocks in organic chemistry and materials science. Reported herein is the palladium-catalyzed synthesis of divinylbenzenes by meta-C-H olefination of sulfone-based arenes. Successful sequential olefinations in a position-selective manner provided a novel route for the synthesis of hetero-dialkenylated products, which are difficult to access using conventional methods. Additionally, 1,3,5-trialkenylated compounds can be generated upon successful removal of the directing group. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Arene-Inserted Extended Germa[n]pericyclynes: Synthesis, Structure, and Phosphorescence Properties.

Science.gov (United States)

Tanimoto, Hiroki; Mori, Junta; Ito, Shunichiro; Nishiyama, Yasuhiro; Morimoto, Tsumoru; Tanaka, Kazuo; Chujo, Yoshiki; Kakiuchi, Kiyomi

2017-07-26

This report describes the synthesis and characterization of arene-inserted extended (ArEx) germa[n]pericyclynes composed of germanium and 1,4-diethynylbenzene units. These novel cyclic germanium-π unit materials were synthesized with diethynylbenzene and germanium dichloride. X-ray crystallographic analysis revealed their structures, and the planar conformation of ArEx germa[4]pericyclyne along with the regular aromatic rings. UV/Vis absorption spectra and fluorescence emission spectra showed considerably unique and highly improved character compared to previously reported germa[n]pericyclynes. Even in the absence of transition metal components, phosphorescence emissions were observed, and the emission lifetimes were dramatically improved. ArEx germa[n]pericyclynes showed high photoluminescence quantum yields, whereas low photoluminescence quantum yields were observed for acyclic compounds. Density functional theory calculations show delocalized orbitals between skipped alkyne units through a germanium tether, and an increase in the HOMO energy level, leading to a small HOMO-LUMO energy gap. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chelation of heavy group 2 (radio)metals by p-tert-butylcalix[4]arene-1,3-crown-6 and logK determination via NMR

Science.gov (United States)

Bauer, David; Gott, Matthew; Steinbach, Jörg; Mamat, Constantin

2018-06-01

A crown-bridged calix[4]arene scaffold was investigated as lead compound for the ligation of heavy alkaline earth metals such as strontium and barium, which appear to be useful for radiopharmaceutical applications in diagnosis as well as in radiotherapy. In particular barium, due to its chemical similarities, could serve as a surrogate for radium, a metal of high radiopharmaceutical interest. The ability of p-tert-butylcalix[4]arene-1,3-crown-6 (1) in particular to chelate cations, such as group 1 and 2 metal ions or ammonium ions is well known. Also, the manifold possibilities of structural modification on the upper- and lower-rim as well as on the crown itself produce properties that may lead to a highly selective and effective chelating agent. In this work, titration experiments of the perchlorate salts of Ba2+, Sr2+ and Pb2+ with ligand 1 were performed to determine their stability constants (logK = 4.7, 4.3, and 3.3, respectively) by 1H NMR measurements in acetonitrile-d3.

[The calix[4]arene C-107 is highly effective supramolecular inhibitor of the Na+,K(+)-ATPase of plasma membranes].

Science.gov (United States)

Bevza, O V; Veklich, T O; Shkrabak, O A; Rodik, R V; Kal'chenko, V I; Kosterin, S O

2013-01-01

The inhibition of the Na+,K(+)-ATPase activity of the myometrium cell plasma membranes with calixarene C-107 (5,17-diamino(2-pyridyl) methylphosphono-11,23-di-tret-butyl-26,28-dihydroxy-25,27-dipropoxycalix[4]arene) was investigated. It has been shown that calixarene C-107 reduced the Na+,K(+)-ATPase activity more efficiently than ouabain did, while it did not practically influence the "basal" Mg(2+)-ATPase activity of the same membrane. The magnitude of the cofficient of inhibition I0.5 was 33 +/- 4 nM, Hill coefficient was 0.38 +/- 0.06. The model calixarene C-150--the calixarene "scaffold" (26,28-dihydroxy-25,27-dipropoxycalix[4]arene), and the model compound M-3 (4-hydroxyaniline(2-pyridine)methylphosphonic acid)--a fragment of the calixarene C-107, had practically no influence on the enzymatic activity of Na+,K(+)-ATPase and Mg(2+)-ATPase. We carried out the computer simulation of interaction of calixarenes C-107 and the mentioned model compound with ligand binding sites of the Na+,K(+)-ATPase of plasma membrane and structure foundation of their intermolecular interaction was found out. The participation of hydrogen, hydrophobic, electrostatic and pi-pi (stacking) interaction between calixarene and enzyme aminoacid residues, some of which are located near the active center of Na+,K(+)-ATPase, was discussed.

Incorporation of amphiphilic ruthenium(II) ammine complexes into Langmuir-Blodgett thin films with switchable quadratic nonlinear optical behavior.

Science.gov (United States)

Boubekeur-Lecaque, Leïla; Coe, Benjamin J; Harris, James A; Helliwell, Madeleine; Asselberghs, Inge; Clays, Koen; Foerier, Stijn; Verbiest, Thierry

2011-12-19

Nine nonlinear optical (NLO) chromophores with pyridinium electron acceptors have been synthesized by complexing new proligands with {Ru(II)(NH(3))(5)}(2+) electron-donor centers. The presence of long alkyl/fluoroalkyl chain substituents imparts amphiphilic properties, and these cationic complexes have been characterized as their PF(6)(-) salts by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. Each complex shows three reversible/quasireversible redox processes; a Ru(III/II) oxidation and two ligand-based reductions. The energies of the intense visible d → π* metal-to-ligand charge-transfer (MLCT) absorptions correlate to some extent with the ligand reduction potentials. (1)H NMR spectroscopy also provides insights into the relative electron-withdrawing strengths of the new ligands. Single crystal X-ray structures have been determined for two of the proligand salts and one complex salt, [Ru(II)(NH(3))(5)(4-C(16)H(33)PhQ(+))]Cl(3)·3.25H(2)O (PhQ(+) = N-phenyl-4,4'-bipyridinium), showing centrosymmetric packing structures in each case. The PF(6)(-) analogue of the latter complex has been used to deposit reproducibly high-quality, multilayered Langmuir-Blodgett (LB) thin films. These films show a strong second harmonic generation (SHG) response from a 1064 nm laser; their MLCT absorbance increases linearly with the number of layers (N) and I(2ω)/I(ω)(2) (I(2ω) = intensity at 532 nm; I(ω) = intensity at 1064 nm) scales quadratically with N, consistent with homogeneous deposition. LB films on indium tin oxide (ITO)-coated glass show electrochemically induced switching of the SHG response, with a decrease in activity of about 50% on Ru(II) → Ru(III) oxidation. This effect is reversible, but reproducible over only a few cycles before the signal from the Ru(II) species diminishes. This work extrapolates our original solution studies (Coe, B. J. et al. Angew. Chem., Int. Ed.1999, 38, 366) to the first demonstration of

Conception et réactivité de complexes mono- et polymétalliques d'éléments f en bas degré d'oxydation

OpenAIRE

Camp , Clément

2013-01-01

Beyond its importance in nuclear industry the redox chemistry uranium is attracting increasinginterest because complexes of low-valent uranium can promote unusual reductive chemistrythrough unusual reaction pathways, including attractive examples of CO, CO2, N2, arenes andazides activation in mild condition. Due to the unique coordination and bonding properties ofuranium, its compounds could provide an attractive alternative to transition metals for thecatalytic transformation of small molecu...

Functional microporous materials of metal carboxylate: Gas-occlusion properties and catalytic activities

International Nuclear Information System (INIS)

Mori, Wasuke; Sato, Tomohiko; Ohmura, Tesushi; Nozaki Kato, Chika; Takei, Tohru

2005-01-01

Copper(II) terephthalate is the first transition metal complex found capable of adsorbing gases. This complex has opened the new field of adsorbent complex chemistry. It is recognized as the lead complex in the construction of microporous complexes. This specific system has been expanded to a systematic series of derivatives of other isomorphous transition metals, molybdenum(II), ruthenium(II, III), and rhodium(II). These complexes with open frameworks are widely recognized as very useful materials for applications to catalysis, separation at molecular level, and gas storage. - Graphical abstract: Novel microporous intramolecular reaction systems

Triphenylsilane-substituted arenes as host materials for use in green phosphorescent organic light emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Kim, Jwajin; Lee, Kum Hee; Kim, Young Seok; Lee, Hyun Woo [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Ho Won [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of); Kim, Young Kwan, E-mail: kimyk@hongik.ac.kr [Department of Information Display, Hongik University, Seoul 121-791 (Korea, Republic of); Yoon, Seung Soo, E-mail: ssyoon@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2016-03-15

We demonstrated triphenylsilane-substituted arenes (1–4) as host materials for green phosphorescent organic light-emitting diodes. Particularly, a device using 9,9-dimethyl-2-(triphenylsilyl)-7-[4-(triphenylsilyl)phenyl]-9H-fluorene (compound 4) as the host material with the green phosphorescence dopant bis[2-(1,1′,2′,1′′-terphen-3-yl)pyridinato-C,N]iridium(III) (acetylacetonate) showed the efficient green emission with an external quantum efficiency of 4.64%, a power efficiency of 7.2 lm/W and luminous efficiency of 16.6 cd/A at 20 mA/cm{sup 2}, respectively, with the Commission International de L’Eclairage chromaticity coordinates of (0.33, 0.59) at 8.0 V.

A solution for cesium removal from high-salinity acidic or alkaline liquid waste: The crown calix[4]arenes

International Nuclear Information System (INIS)

Dozol, J.F.; Simon, N.; Lamare, V.; Rouquette, H.; Eymard, S.; Tournois, B.; Marc, D. de; Macias, R.M.

1999-01-01

Calix[4]arenes monocrown or biscrown, blocked in 1,3 alternative cone conformation, display an exceptional efficiency for cesium extraction, even from very acid or alkaline media. Moreover, they possess an important selectivity for cesium over sodium that makes possible the extraction of cesium from media containing high sodium nitrate loadings. Another advantage, since the extraction of cesium is reversible, is that the stripping of cesium can be carried out in deionized water, a property which leads to very high concentration factors. 79 refs., 10 figs., 6 tabs

Solid structures of the stepwise self-assembled copillar[5]arene-based supramolecular polymers

International Nuclear Information System (INIS)

Park, Yeon Sil; Hwang, Seong Min; Shin, Jae Yeon; Paek, Kyung Soo

2016-01-01

Development of supramolecular polymer has attracted much interest because of their interesting properties such as stimuli-responsiveness, recycling, self-healing and degradability, and their consequential applications. The essential feature of this class of polymers is the self-assembly of discrete monomeric subunits via non-covalent interactions or dynamic covalent bonds. Among the many monomeric subunits, pillar[n]arenes have been ideal building blocks for the fabrication of polymeric supramolecules because of their intrinsic characteristics. The ring-shaped morphologies in supramolecular polymer P are probably due to the tendency of the end-to-end connection in the solid state of long flexible supramolecular chains. The size increase of nano-rings as the stepwise addition increases might be due to the fact that the linear supramolecular polymer P in solution seems to be maintained until the nano-ring formation by solidification

Solid structures of the stepwise self-assembled copillar[5]arene-based supramolecular polymers

Energy Technology Data Exchange (ETDEWEB)

Park, Yeon Sil; Hwang, Seong Min; Shin, Jae Yeon; Paek, Kyung Soo [Dept. of Chemistry, Soongsil University, Seoul (Korea, Republic of)

2016-10-15

Development of supramolecular polymer has attracted much interest because of their interesting properties such as stimuli-responsiveness, recycling, self-healing and degradability, and their consequential applications. The essential feature of this class of polymers is the self-assembly of discrete monomeric subunits via non-covalent interactions or dynamic covalent bonds. Among the many monomeric subunits, pillar[n]arenes have been ideal building blocks for the fabrication of polymeric supramolecules because of their intrinsic characteristics. The ring-shaped morphologies in supramolecular polymer P are probably due to the tendency of the end-to-end connection in the solid state of long flexible supramolecular chains. The size increase of nano-rings as the stepwise addition increases might be due to the fact that the linear supramolecular polymer P in solution seems to be maintained until the nano-ring formation by solidification.

A Biscalix[4]arene-based Ditopic Hard/Soft Receptor for K+/Ag+ Complexation

Czech Academy of Sciences Publication Activity Database

Budka, J.; Lhoták, P.; Stibor, I.; Michlová, V.; Sýkora, Jan; Císařová, I.

2002-01-01

Roč. 43, č. 15 (2002), s. 2857-2861 ISSN 0040-4039 R&D Projects: GA ČR GA104/00/1722; GA ČR GA203/99/M037 Keywords : silver(i) complexes * ion-binding sites * polycyclic aromatic compounds Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.357, year: 2002

Rhodium catalyzed regioselective arene homologation of aryl urea via double C-H bond activation and migratory insertion of alkyne

Institute of Scientific and Technical Information of China (English)

Yan Wang; Hao Zhou; Ke Xu; Mei-Hua Shen; Hua-Dong Xu

2017-01-01

A convenient rhodium catalyzed oxidative arene homologation of aniline derivatives with symmetrical or unsymmetrical alkynes using Cu(OAc)2 as oxidant is described.Urea group is shown to be effective as a directing group for initial ortho C-H activation.Two migratory insertion events of alkyne into Rh-C bond occur successively,both with complete regioselectivity.This method is particularly useful for synthesis of polyarenes with different substituents,which has not been reported with conventional protocol.A mechanism has been proposed to explain the observed data.

Ground vs. excited state interaction in ruthenium-thienyl dyads : implications for through bond interactions in multicomponent systems

NARCIS (Netherlands)

Henry, William; Browne, Wesley R.; Ronayne, Kate L.; O’Boyle, Noel M.; Vos, Johannes G.; McGarvey, John J.

2005-01-01

The vibrational and photophysical properties of mononuclear ruthenium(II) and ruthenium(III) polypyridyl complexes based on the, ligands 2-(5-(pyridin-2"-yl)-1'H-1',2',4'-triaz-3'-yl)-thiophene, 2-(5-(pyrazin-2"-yl)-1'H-1',2,4-triaz-3'-yl)-thiophene, are reported. The effect of the introduction of

Helquat Dyes: Helicene-like Push-Pull Systems with Large Second-Order Nonlinear Optical Responses

Czech Academy of Sciences Publication Activity Database

Coe, B. J.; Rusanova, D.; Joshi, Vishwas; Sánchez, S.; Vávra, Jan; Khobragade, Dushant; Severa, Lukáš; Císařová, I.; Šaman, David; Pohl, Radek; Clays, K.; Depotter, G.; Brunschwig, B. S.; Teplý, Filip

2016-01-01

Roč. 81, č. 5 (2016), s. 1912-1920 ISSN 0022-3263 R&D Projects: GA ČR GA13-19213S Grant - others:AV ČR(CZ) M200551208 Institutional support: RVO:61388963 Keywords : hyper-Rayleigh scattering * organic THz generator * ruthenium(II) complexes Subject RIV: CC - Organic Chemistry Impact factor: 4.849, year: 2016

Separation of uranium from aqueous solutions using calix[6]arenes in liquid-liquid extraction as well as solid phase extraction

International Nuclear Information System (INIS)

Schmeide, K.; Geipel, G.; Bernhard, G.

2004-11-01

The suitability of different calyx[n] arene types for uranyl extraction from liquid solutions was examined by means of liquid-liquid extraction using aqueous phases and organic solvents of varying compositions. It was found that COOH-derivatised calyx[6] arenes have good extraction properties and can even be used in the acid pH range. The use of calixarene-modified fleeces for the separation of uranyl from aqueous phases was examined in batch experiments with pH and uranyl concentration as variables and in the presence or absence of competing ions. The results showed that calixarene-modified fleeces can be used for uranium separation starting from pH 4. At pH 5, up to a maximum of 7.6 x 10 -7 mol uranium can be bound per 1 g of calixarene-modified fleece. The separation of uranyl from synthetic pit waters was examined as a means of testing the separation capacity of calixarene-modified fleeces in environmentally sensitive waters. Studies on the reversibility of uranium bonding to calixarene-treated polyester fleeces have shown that under environmentally realistic conditions (neutral pH range) the uranium is firmly bound to the calixarene-modified fleeces and cannot be mobilised. By contrast, in acidic environments calixarene-modified fleeces are capable of near-complete regeneration. Such regenerated textile filter materials can then be used for further uranium separation cycles [de

Spectroscopic and DFT studies of calix[4]arene: time-dependent DFT calculations for elucidating the variation in the excitation energies with geometry

Energy Technology Data Exchange (ETDEWEB)

Boo, Bong Hyun; Kwak, Hae Ran; Hong, Seung Ki [Chungnam National University, Daejeon (Korea, Republic of); Park, Chan Jo [Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of); No, Kwang Hyun [Sookmyung Womens University, Seoul (Korea, Republic of)

2010-08-15

We have searched low-lying conformers of calix[4]arene and found one global minimum having a cone shape, together with three conformers such as partial cone-shape conformers. We then elucidated the thermodynamics for the conformational changes by performing density-functional theory (DFT) calculations. The time-dependent DFT calculation enabled us to assign the absorption spectrum and to reveal a variation of the excitation energies with geometry.

The non-planarity of the benzene molecule in the X-ray structure of the chelated bismuth(III) heteroboroxine complex is not supported by quantum mechanical calculations

Czech Academy of Sciences Publication Activity Database

Fanfrlík, Jindřich; Sedlák, Robert; Pecina, Adam; Rulíšek, Lubomír; Dostál, L.; Moncól, J.; Růžička, A.; Hobza, Pavel

2016-01-01

Roč. 45, č. 2 (2016), s. 462-465 ISSN 1477-9226 R&D Projects: GA ČR GBP208/12/G016; GA ČR(CZ) GA14-31419S Institutional support: RVO:61388963 Keywords : crystal structures * arene complexes * sigma hole Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.029, year: 2016 http://pubs.rsc.org/en/content/articlepdf/2016/dt/c5dt04381f

Crystallization and Melt Removal at Arenal Volcano, Polytopic Vector Analysis

Science.gov (United States)

Hidalgo, P. J.; Vogel, T. A.; Bolge, L. L.; Ehrlich, R.; Alvarado, G. E.

2007-12-01

Tephra sequences ET3 and ET4 from Arenal volcano in Costa Rica have recently been interpreted to be a product of crystal fractionation by Bolge and coworkers in a series of papers (2004, 2006). The two tephra units are part of a sequence of 22 tephra units that represent a 7000 year span of the Arenal volcano activity. The tephro- stratigraphy has been described extensively by Melson (1982; 1994). The ET3 and ET4 tephras were interpreted (based on major- and trace-element, isotopic analyses of whole rocks and microchemical analyses of individual phases) as clear evidence of crystal separation by gravity settling (Bolge et al., 2004, 2006). The lower ET4 tephra sequence (andesitic and crystal poor) and the upper ET3 tephra (basaltic and crystal rich) represent an inverted snapshot of the magma chamber with contrasting geochemical properties. The ET3 sequence (deeper part of the magma chamber) has nearly constant composition with only a few elements varying stratigraphically (best represented by CaO). This is consistent with gradually decreasing amounts of melt in the upper part of ET3. The lower ET4 tephra (upper part of the magma chamber) contains large chemical gradients in both incompatible and compatible elements. In the present study we use whole-rock geochemical data from the recent tephra sequences ET3 and ET4 as inputs to Polytopic Vector Analysis (PVA) (for a review of this method see Vogel and coworkers, in press). With this method we produce a three end member solution that is consistent with crystallization of Olivine, plagioclase and pyroxene from the most mafic end member (EM1) resulting in a crystal rich mush zone. As crystallization progresses the compositions of the liquids are driven towards an intermediate end member (EM3), which has an intermediate composition liquid. At EM3 composition, rapid depletion of FeO, MgO and TiO2 by crystallization of Fe-Ti oxides, rapidly drives the liquid composition towards the silicic EM1 (incompatible element

New selective ligands for caesium. Application to Cs+/Na+ separation by nano-filtration-complexation in aqueous phase

International Nuclear Information System (INIS)

Pellet-Rostaing, S.; Chitry, F.; Lemaire, M.; Guy, A.; Foos, J.

2000-01-01

Separating traces of caesium from aqueous medium containing high sodium concentration is a harsh problem because caesium and sodium have a similar behaviour in aqueous medium. The aim of our study was to select a highly caesium-selective ligand in a nano-filtration-complexation process in order to achieve Cs + /Na + separation. This process involve a nano-filtration step combined with a preliminary complexation step. Caesium complexes are retained by the nano-filtration membrane whereas free sodium cations pass through it. We tried to find a relation between the ligands structure and their activity towards caesium-complexation. Among the synthesized receptors, Tetra-hydroxylated bis-crown-6 calix[4]arene was found to be the more caesium-selective ligand (S=β(Cs + )/β(Na+)=6600). Combined with a nano-filtration process, this ligand helped reaching 90% caesium retention in a highly concentrated aqueous medium ([NaNO 3 ] = 3 mol/L). (authors)

[Comparative investigation of the effect of calix[4]arene C-99 and its analogs on Na+,K(+)-ATPase activity of uterus myocite plasma membrane].

Science.gov (United States)

Veklich, T O; Shkrabak, O A; Cherenok, S O; Kal'chenko, V I; Kosterin, S O

2012-01-01

The aim of our investigation was to determine structural features of calix[4]arene C-99 which are important for its inhibition properties relative to Na+,K(+)-ATPase of uterus myocite plasma membrane. Therefore we studied the effect of calix[4]arenes C-296, C-297, C-424, C-425, C-426, C-427, which are structurally similar to this inhibitor, on the mentioned enzyme activity. We have shown that calixarenes C-296 and C-297 which have two additional propoxy groups on the lower rim of macrocycle are less effective inhibitors of Na+,K(+)-ATPase relative to calixarene C-99. Calixarenes C-425 and C-427 which have on the upper rim of macrocycle three and four phosponic residues, respectively, also inhibit Na+,K(+)-ATPase activity less effectively as compared to calixarene C-99. Both calixarenes: C-424, which has only two carbonate residues on the upper rim, and C-426, which has on the upper rim ketomethilphosphonate residues instead of hydroxymethilphosphonate residues of calixarene C-99, do not affect Na+,K(+)-ATPase activity. We have made respective conclusions concerning the role of certain chemical groups of calixarene C-99 during its interaction with Na+,K(+)-ATPase.

Uranium electrocatalysis: The secret is in the ring

Science.gov (United States)

Mazzanti, Marinella

2018-03-01

An arene-anchored uranium complex has recently been shown to serve as efficient electrocatalyst for the conversion of water into dihydrogen. Now, the crucial role of the arene moiety in enabling catalytic activity -- unusual for uranium -- has been explored, providing important insight for the design of improved electrocatalysts.

DNA interactions of dinuclear RuII arene antitumor complexes in cell-free media

Czech Academy of Sciences Publication Activity Database

Nováková, Olga; Nazarov, A.A.; Hartinger, Ch.G.; Keppler, B.K.; Brabec, Viktor

2009-01-01

Roč. 77, č. 3 (2009), s. 364-374 ISSN 0006-2952 R&D Projects: GA MŠk(CZ) LC06030; GA MŠk(CZ) ME08017; GA MŠk(CZ) OC08003; GA AV ČR(CZ) 1QS500040581; GA AV ČR(CZ) KAN200200651 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : dinuclear ruthenium complex * DNA * cross-links Subject RIV: BO - Biophysics Impact factor: 4.254, year: 2009

Electron localization in a mixed-valence diniobium benzene complex.

Science.gov (United States)

Gianetti, Thomas L; Nocton, Grégory; Minasian, Stefan G; Kaltsoyannis, Nikolas; Kilcoyne, A L David; Kozimor, Stosh A; Shuh, David K; Tyliszczak, Tolek; Bergman, Robert G; Arnold, John

2015-02-01

Reaction of the neutral diniobium benzene complex {[Nb(BDI)N t Bu] 2 (μ-C 6 H 6 )} (BDI = N , N '-diisopropylbenzene-β-diketiminate) with Ag[B(C 6 F 5 ) 4 ] results in a single electron oxidation to produce a cationic diniobium arene complex, {[Nb(BDI)N t Bu] 2 (μ-C 6 H 6 )}{B(C 6 F 5 ) 4 }. Investigation of the solid state and solution phase structure using single-crystal X-ray diffraction, cyclic voltammetry, magnetic susceptibility, and multinuclear NMR spectroscopy indicates that the oxidation results in an asymmetric molecule with two chemically inequivalent Nb atoms. Further characterization using density functional theory (DFT) calculations, UV-visible, Nb L 3,2 -edge X-ray absorption near-edge structure (XANES), and EPR spectroscopies supports assignment of a diniobium complex, in which one Nb atom carries a single unpaired electron that is not largely delocalized on the second Nb atom. During the oxidative transformation, one electron is removed from the δ-bonding HOMO, which causes a destabilization of the molecule and formation of an asymmetric product. Subsequent reactivity studies indicate that the oxidized product allows access to metal-based chemistry with substrates that did not exhibit reactivity with the starting neutral complex.

Synthesis of 4‧-substituted-2,2‧;6‧,2″-terpyridine Ru(II) complexes electrochemical, fluorescence quenching and antibacterial studies

Science.gov (United States)

Ezhilarasu, Tamilarasu; Sathiyaseelan, Anbazhagan; Kalaichelvan, Pudupalayam Thangavelu; Balasubramanian, Sengottuvelan

2017-04-01

Three new Ru(II) terpyridine complexes viz. [Ru(BBtpy)2](PF6)2 [Ru(L1)] (BBtpy = 4‧-(4-benzyloxybenzaldehyde)-2,2‧:6‧,2″-terpyridine), [Ru(BMBtpy)2](PF6)2 [Ru(L2)] (BMBtpy = 4‧-(4-benzyloxy-3-methoxybenzaldehyde)-2,2‧:6‧,2″-terpyridine) and [Ru(BEBtpy)2](PF6)2 [Ru(L3)] (BEBtpy = 4‧-(4-benzyloxy-3-ethoxybenzaldehyde)-2,2‧:6‧,2″-terpyridine) have been synthesized and characterized. The MALDI-TOF/MS fragmentation pattern of [Ru(BMBtpy)2](PF6)2 complex exhibits a molecular ion peak at m/z = 987.09 [M-2PF6]2+ fragment. These Ru(II) complexes are redox active, show both metal centered oxidation and ligand centered reduction processes. The peak potential and peak current Ipa and Ipc also undergo definite shift and increase with increase in the scan rate (20-120 mV/s). The fluorescence of Ru(II) complexes [Ru(L1)], [Ru(L2)] and [Ru(L3)] are effectively quenched by 1,4-benzoquinone and 1,4-naphthoquinone in acetonitrile. The antibacterial activity of ruthenium(II) complexes were screened against four human pathogens both gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus) and gram negative bacteria (Escherichia coli, Klebsiella pneumonia) by the well diffusion method. The antibacterial activity of Ru(II) complexes is comparable to that of standard antibiotics like tetracycline.

Electrochemistry and spectroelectrochemistry of tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine, Lu2Pc4 and dimeric lutetium(III) phthalocyanine, Lu2Pc2(OAc)2

International Nuclear Information System (INIS)

Koca, Atif; Ceyhan, Tanju; Erbil, Mehmet K.; Ozkaya, Ali Riza; Bekaroglu, Ozer

2007-01-01

In this study, electrochemical, electrochromic and spectroelectrochemical properties of a tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine (Lu 2 Pc 4 2) were investigated explicitly as compared with a tert-butylcalix[4]arene bridged dimeric lutetium(III) phthalocyanine [Lu 2 Pc 2 (OAc) 2 1]. Distinctive differences between electrochemical and electrochromic properties of 1 and 2 were detected. Moreover, the properties of 1 and 2 were compared with previously reported S 4 (CH 2 ) 4 bridged Lu 2 Pc 2 (OAc) 2 and Lu 2 Pc 4 . The calixarene bridged phthalocyanine (Pc) compounds, 1 and 2 showed well-defined electrochromic behaviour with green-blue and blue-purple colour transitions. The enhanced electrochromic properties of 2, as compared to 1, were attributed to its double-decker structure, probably allowing the formation of suitable ion channels for the counter ion movement in the solid film

Aquation Is a Crucial Activation Step for Anticancer Action of Ruthenium(II) Polypyridyl Complexes to Trigger Cancer Cell Apoptosis.

Science.gov (United States)

Li, Meng; Lai, Lanhai; Zhao, Zhennan; Chen, Tianfeng

2016-01-01

Aquation has been proposed as crucial chemical action step for ruthenium (Ru) complexes, but its effects on the action mechanisms remain elusive. Herein, we have demonstrated the aquation process of a potent Ru polypyridyl complex (RuBmp=[Ru(II) (bmbp)(phen)Cl]ClO4 , bmbp=2,6-bis(6-methylbenzimidazol-2-yl) pyridine, phen=phenanthroline) with a chloride ligand, and revealed that aquation of RuBmp effectively enhanced its hydrophilicity and cellular uptake, thus significantly increasing its anticancer efficacy. The aquation products (H-RuBmp=[Ru(II) (bmbp)(phen)Cl]ClO4 , [Ru(II) (bmbp)(phen)(H2 O)]ClO4 , bmbp) exhibited a much higher apoptosis-inducing ability than the intact complex, with involvement of caspase activation, mitochondria dysfunction, and interaction with cell membrane death receptors. H-RuBmp demonstrated a higher interaction potency with the cell membrane and induced higher levels of ROS overproduction in cancer cells to regulate the AKT, MAPK, and p53 signaling pathways. Taken together, this study could provide useful information for fine-tuning the rational design of next-generation metal medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tunable blue organic light emitting diode based on aluminum calixarene supramolecular complex

Science.gov (United States)

Legnani, C.; Reyes, R.; Cremona, M.; Bagatin, I. A.; Toma, H. E.

2004-07-01

In this letter, the results of supramolecular organic light emitting diodes using a calix[4] arene complex thin film as emitter and electron transporting layer are presented. The devices were grown onto glass substrates coated with indium-tin-oxide layer and aluminum thick (150nm) cathode. By applying a dc voltage between the device electrodes in forward bias condition, a blue light emission in the active area of the device was observed. It was found that the electroluminescent emission peak can be tuned between 470 and 510nm changing the applied voltage bias from 4.3 to 5.4V. The observed tunable emission can be associated with an energy transfer from the calixarene compound.

ESI MS/MS Study of Calix[4]arene Derivatives and their Metal Complexes

OpenAIRE

Benković, Tomislav; Tomišić, Vladislav; Frkanec, Leo; Galić, Nives

2012-01-01

The peptidocalixarenes 1–3 bearing tryptophan, phenylglycine and leucil units at the lower rim and their complexes with alkali-metal (Li+, Na+, K+, Rb+, Cs+) and selected lanthanide cations (La3+, Ce3+, Eu3+, Yb3+) were analyzed by ESI MS. The influences of the solvent (acetonitrile, methanol, addition of formic acid or sodium acetate) and the calixarene:cation molar ratio on signal intensities were investigated. Comprehensive MS/MS analyses were performed of all singly and doubly charged ion...

Linked supramolecular building blocks for enhanced cluster formation

DEFF Research Database (Denmark)

McLellan, Ross; Palacios, Maria A.; Beavers, Christine M.

2015-01-01

the complex assembly process. The ability to covalently link calix[4]arenes at the methylene bridge provides significantly improved control over the introduction of different metal centres to resulting cluster motifs. Clusters assembled from bis-calix[4]-arenes and transition metal ions or 3d-4 f combinations......(Figure Presented). Methylene-bridged calix[4]arenes have emerged as extremely versatile ligand supports in the formation of new polymetallic clusters possessing fascinating magnetic properties. Metal ion binding rules established for this building block allow one to partially rationalise...

The effects of linear assembly of two carbazole groups on acid-base and DNA-binding properties of a ruthenium(II) complex

Science.gov (United States)

Chen, Xi; Xue, Long-Xin; Ju, Chun-Chuan; Wang, Ke-Zhi

2013-07-01

A novel Ru(II) complex of [Ru(bpy)2(Hbcpip)](ClO4)2 {where bpy = 2,2-bipyridine, Hbcpip = 2-(4-(9H-3,9'-bicarbazol-9-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline} is synthesized and characterized. Calf-thymus DNA-binding properties of the complex were studied by UV-vis absorption and luminescence titrations, steady-state emission quenching by [Fe(CN)6]4-, DNA competitive binding with ethidium bromide, thermal denaturation and DNA viscosity measurements. The results indicate that the complex partially intercalated into the DNA with a binding constant of (5.5 ± 1.4) × 105 M-1 in buffered 50 mM NaCl. The acid-base properties of the complex were also studied by UV-visible and luminescence spectrophotometric pH titrations, and ground- and excited-state acidity ionization constant values were derived.

Energy Flexibility from Large Prosumers to Support Distribution System Operation—A Technical and Legal Case Study on the Amsterdam ArenA Stadium

Directory of Open Access Journals (Sweden)

Dirk Kuiken

2018-01-01

Full Text Available To deal with the rising integration of stochastic renewables and energy intensive distributed energy resources (DER to the electricity network, alternatives to expensive network reinforcements are increasingly needed. An alternative solution often under consideration is integrating flexibility from the consumer side to system management. However, such a solution needs to be contemplated from different angles before it can be implemented in practice. To this end, this article considers a case study of the Amsterdam ArenA stadium and its surrounding network where flexibility is expected to be available to support the network in the future. The article studies the technical aspects of using this flexibility to determine to what extent, despite the different, orthogonal goals, the available flexibility can be used by various stakeholders in scenarios with a large load from electric vehicle charging points. Furthermore, a legal study is performed to determine the feasibility of the technical solutions proposed by analysing current European Union (EU and Dutch law and focusing on the current agreements existing between the parties involved. The article shows that flexibility in the network provided by Amsterdam ArenA is able to significantly increase the number of charging points the network can accommodate. Nonetheless, while several uses of flexibility are feasible under current law, the use of flexibility provided by electric vehicles specifically faces several legal challenges in current arrangements.

Determination of Benzo[α]pyrene in Edible Oil Using Tetraoxocalix[2]arene[2]triazine Bonded Silica SPE Sorbent.

Science.gov (United States)

Guo, Yun; Zhao, Wen-Jie; Deng, Zhi-Fen; Hongbo, Wang; Peng, Bin; Ma, Xue; Lan, Chen; Zhang, Shu-Sheng

2018-06-01

Benzo[α]pyrene (BaP) is a well-known carcinogen in edible oil. In this study, a method combined solid-phase extraction (SPE) with fluorescent detection was developed using tetraoxocalix[2]arene[2]triazine sorbent (SiO 2 -OCA) for the clean-up and enrichment of BaP. The interaction between SiO 2 -OCA and BaP involves a donor-acceptor complex mechanism. The experimental procedure was as follows: BaP was extracted from edible oil with DMF/H 2 O (9:1, v/v). Then, the ratio of DMF/H 2 O was adjusted to 1:2 prior to SPE. The final concentrate was analyzed using a fluorescence detector at excitation and emission wavelengths of 255 and 420 nm. The method was fully validated. The linearity was in the range of 0.1-100 μg kg -1 with a coefficient of 0.999. The limits of detection and quantification were 0.03 and 0.1 μg kg -1 , respectively. The average recoveries were in the range of 88.0-122.3%. The intraday and interday precisions were 6.8% and 9.2%, respectively. Compared with other methods, the method reported in this article shows a good detection limit, high reproducibility and recovery, and linearity over a broad concentration range. This established method was also applied to evaluate real samples. The concentration of six tested samples was below 5 μg kg -1 .

Sensing parts per million levels of gaseous NO2 by a optical fiber transducer based on calix[4]arenes.

Science.gov (United States)

Ohira, Shin-Ichi; Wanigasekara, Eranda; Rudkevich, Dmitry M; Dasgupta, Purnendu K

2009-03-15

Calixarenes are interesting building blocks in supramolecular receptor design. They can be easily functionalized to give the desired guest binding and sequestration properties. We demonstrate here the use of simple alkylated calixarenes as novel NO(2) sensors. Upon reacting with gaseous NO(2), alkylated calixarenes form stable calixarene-NO(+) (nitrosonium) complexes that have a deep purple color. This specific and selective formation of the colored complex was used to develop a fiber optic based colorimetric NO(2) sensor. Several alkylated calixarenes are used and tested as sensing materials. The calixarene compound was immobilized on a fine mesh silica-gel coated thin layer chromatography plate. The sensing plate was coupled with a fiber optic based photodetector. Gas samples were sampled in a manner where they impinged on the surface of sensing plate. The light transmission through the plate was continuously monitored. For a 5 min sample, the limit of detection was 0.54 ppmv with 1,3-alternate O-hexyl calix[4]arene (1a). There were no significant response differences between different conformations of calixarenes such as 1,3-alternate or cone. This chemistry can form the basis of a colorimetric sensor that relies on extant filter tape technology. With calixarenes however, such a reaction is potentially reversible - color formed upon reaction with NO(2) can be reversed by flushing the sensing plate by purified air. While we found that the removal of the developed color can be accelerated by simultaneous heating and suction, permitting the reuse of the same sensing area multiple times, we also observed that the sensitivity gradually decreased. The nitrosonium calixarene derivative tends to transform to the nitrated form; this process is catalyzed by light. Several methylated calixarenes were synthesized and tested but a fully satisfactory solution has proven elusive.

A low frequency infrared study of ruthenium(II) complexes with 1,8-naphthyridines and 2,2'-bipyridine

International Nuclear Information System (INIS)

Staniewicz, R.J.; Hendricker, D.G.; Griffiths, P.R.

1977-01-01

A report is presented on the synthesis and characterization of [Ru(napy) 4 ](PF 6 ) 2 , [Ru(2-mnapy) 4 ] (PF 6 ) 2 , [Ru(2,7-dmnapy) 3 ] (PF 6 ) 2 and [Ru(bipy) 3 ] (PF 6 ) 2 ; where (napy) = 1,8-naphthyridine; (2,7-dmnapy) = 2,7-dimethyl-1, 8-naphthyridine; (2-mnapy) = 2-methyl-1, 8-naphthyridine, and (bipy) = bipyridine. The complexes were prepared as previously reported (Staniewicz et al., (J.Am.Chem.Soc., in the press)). Low frequency infrared spectra were measured using a Digilab FTS-14 Fourier transform spectrophotometer. The results are discussed. Molecular structures are proposed. (U.K.)

Solvent extraction of Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ and Ni2+ into nitrobenzene using strontium dicarbol-lylcobaltate and tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate

Directory of Open Access Journals (Sweden)

E. MAKRLÍK

2008-12-01

Full Text Available The exchange extraction constants corresponding to the general equilibrium M2+(aq + SrL2+(nb D ML2+ (nb + Sr2+ (aq occurring in the two-phase water–nitrobenzene system (M2+ = Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Mn2+, Co2+ or Ni2+; L = tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate; aq = aqueous phase; nb = nitrobenzene phase were evaluated from extraction experiments and -activity measurements. Furthermore, the stability constants of the ML2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Ba2+ < Mn2+ < Pb2+, Co2+ < Cu2+, Zn2+ < Cd2+, Ni2+ < UO22+ < Ca2+.

Synthesis and conformational studies of a series of 5,17-bis-aryl-25,26,27,28-tetrapropoxycalix[4]arenes: The influence of π-π interactions on the molecular structure

DEFF Research Database (Denmark)

Larsen, M.; Krebs, Frederik C; Harrit, N.

1999-01-01

Four 5,17-bis-aryl-25,26,27,28-tetrapropoxycalix[4]arenes were prepared via Negishi, Suzuki and Ullman type couplings [aryl = phenyl (1), 3-bromophenyl (2), 1-naphthyl (3) and carbazol-9-yl (4)]. The influence of the aryl groups on the structure was studied by X-ray crystallography, NMR, electron...

Strategic planning model for achieving stakeholder involvement in environmental at DOE weapons complex sites

International Nuclear Information System (INIS)

Weber, G.

1994-01-01

Within today's reality a public manager often needs to develop cooperative relationships among a number of individual, program, and organizational stakeholders to accomplish particular projects, programs, or policies. A DOE site manager charged with accomplishing environmental restoration and conversion at former weapons production sites is no exception. Important reasons for this include the technical and political complexity of the clean-up problem; limits on the funding, authority, and other resources available to DOE; authority, responsibilities, and interests of other stakeholders; and the ever present potential for conflict among stakeholders, and power of any one to hinder, if not halt, the clean-up process if conflicts aren't managed and cooperative relationships established and maintained

Removal of Parathion from Aqueous Media Through p-tert-Butylcalix[4]arene Based Modified Silica

Directory of Open Access Journals (Sweden)

Sibghatullah Memon

2013-12-01

Full Text Available This study explores, adsorption efficiency of p-tert-butylcalix[4]arene based modified silica to remove parathion from aqueous environment. The adsorption parameters, i.e. pH, concentration of pesticide solution, contact time and adsorbent dosage were optimized, as 10, 1 mg L-1, 40 min and 0.04 g, respectively. Langmuir, Freundlich and Dubinin-Radushkevich (D-R isotherm models were used to evaluate the adsorption mechanism. Adsorption constants values of these models suggest that the adsorption of parathion is favorable and were found to be best fit with Freundlich isotherm. From the kinetic study it can be predicted that adsorption of parathion follows Ho and McKay model (pseudo-second order. Thermodynamic parameters, enthalpy (ΔH, entropy (ΔS and Gibbs free energy (ΔG have also been evaluated and were found as -132.25, 0.45, -4.14 Jmol-1, respectively.

New mixed ligand complexes of ruthenium(II) that incorporate a ...

Indian Academy of Sciences (India)

Unknown

infrared, UV-Vis, steady-state emission and 1H NMR spectroscopic methods. Results ... Deionised, triply distilled water was used for preparing various buffers. .... 259 nm in CH3CN containing a drop of HCl (acid was added to ensure complete.

A High Molar Extinction Coefficient Ru(II Complex Functionalized with cis-Dithiocyanato-bis-(9-anthracenyl-10-(2-methyl-2-butenoic acid-1,10-phenanthroline: Potential Sensitizer for Stable Dye-Sensitized Solar Cells

Directory of Open Access Journals (Sweden)

Adewale O. Adeloye

2014-01-01

Full Text Available New heteroleptic ruthenium(II complex was formulated as [Ru(L12(NCS2], where L1 = 9-anthracenyl-10-(2-methyl-2-butenoic acid-1,10-phenanthroline was synthesized and its photophysical properties were studied and compared to previously reported analogue complex containing no anthracene moiety [Ru(L22(NCS2], L2 = (2-methyl-2-butenoic acid-1,10-phenanthroline. The two complexes though exhibit very strong molar extinction coefficient values; however, [Ru(L12(NCS2] shows better characteristic broad and intense metal-to-ligand charge transfer (MLCT absorption band and higher molar absorptivity coefficient at (λmax=522 nm, ε=6.60×104 M−1 cm−1 than that of [Ru(L22(NCS2] complex, (λmax=446 nm, ε=4.82×104 M−1 cm−1. At room temperature, long wavelength emissions with strong intensity ratio centered at 660 nm were recorded for [Ru(L12(NCS2] complex with a bathochromic shift (λem=700 nm for [Ru(L22(NCS2] complex. It was shown that the luminescence wavelength characteristic of the complexes may be a function relating to the increasing length of π-conjugation and/or molecular weight. A preliminary cyclic voltammetry of [Ru(L12(NCS2] complex also exhibits good electroredox activity with oxidation potential of about 1.04 V, significantly better than other Ru(II polypyridine complexes containing bidentate ligands.

Origin of the {sup 238}U-{sup 230}Th disequilibrium in magmas from subduction zones: the Arenal example; Origine du desequilibre {sup 238}U-{sup 230}TH dans les magmas des zones de subduction: exemple de l`Arenal

Energy Technology Data Exchange (ETDEWEB)

Villemant, B [Paris-6 Univ., 75 (France)

1997-12-31

The existence in some volcanic products of strong excess of {sup 238}U with respect to {sup 230}Th is one of the characteristics of volcanic arc magmas. These excesses are generally attributed to fluid additions inside mantellic sources before magma segregation, differentiation and eruption. These fluids should be linked to the dehydration of the subducted rocks. These hypotheses are essentially based on correlations between {sup 10}Be, {sup 87}Sr anomalies, Ba/La ratios and on the distribution of volcanic centers with respect to the subduction zone. Recent studies suggest an evolution of the composition of volcanic sources in Central America from a depleted mantle type (MORB) in the North (Nicaragua) to a less transformed enriched type (OIB) in the South (Costa Rica). The Arenal volcano belongs to a transition zone between these two types. The preliminary study of trace elements and {sup 238}U-{sup 230}Th disequilibria in recent volcanic products (1968-1993) indicates a more complex situation. At least two different mantle sources were successively involved characterized by different Th/La and La/Yb ratios and very different to the OIB type. Also most lavas are in equilibrium with {sup 238}U/{sup 232}Th ratios of about 1.2 to 1.3. However, in eruptive cycle, some lavas are characterized by a strong {sup 238}U excess with respect to {sup 230}Th with cannot be linked to the sources, even when modified by fluids in depth. These results are interpreted in terms of heterogeneities of mantle sources and low depths late interactions with hydrothermal fluids during eruptions. Abstract only. (J.S.). 2 refs.

Origin of the {sup 238}U-{sup 230}Th disequilibrium in magmas from subduction zones: the Arenal example; Origine du desequilibre {sup 238}U-{sup 230}TH dans les magmas des zones de subduction: exemple de l`Arenal

Energy Technology Data Exchange (ETDEWEB)

Villemant, B. [Paris-6 Univ., 75 (France)

1996-12-31

The existence in some volcanic products of strong excess of {sup 238}U with respect to {sup 230}Th is one of the characteristics of volcanic arc magmas. These excesses are generally attributed to fluid additions inside mantellic sources before magma segregation, differentiation and eruption. These fluids should be linked to the dehydration of the subducted rocks. These hypotheses are essentially based on correlations between {sup 10}Be, {sup 87}Sr anomalies, Ba/La ratios and on the distribution of volcanic centers with respect to the subduction zone. Recent studies suggest an evolution of the composition of volcanic sources in Central America from a depleted mantle type (MORB) in the North (Nicaragua) to a less transformed enriched type (OIB) in the South (Costa Rica). The Arenal volcano belongs to a transition zone between these two types. The preliminary study of trace elements and {sup 238}U-{sup 230}Th disequilibria in recent volcanic products (1968-1993) indicates a more complex situation. At least two different mantle sources were successively involved characterized by different Th/La and La/Yb ratios and very different to the OIB type. Also most lavas are in equilibrium with {sup 238}U/{sup 232}Th ratios of about 1.2 to 1.3. However, in eruptive cycle, some lavas are characterized by a strong {sup 238}U excess with respect to {sup 230}Th with cannot be linked to the sources, even when modified by fluids in depth. These results are interpreted in terms of heterogeneities of mantle sources and low depths late interactions with hydrothermal fluids during eruptions. Abstract only. (J.S.). 2 refs.

Ru/Fe bimetallic complexes: Synthesis, characterization, cytotoxicity and study of their interactions with DNA/HSA and human topoisomerase IB.

Science.gov (United States)

Takarada, Jessica E; Guedes, Adriana P M; Correa, Rodrigo S; Silveira-Lacerda, Elisângela de P; Castelli, Silvia; Iacovelli, Federico; Deflon, Victor Marcelo; Batista, Alzir Azevedo; Desideri, Alessandro

2017-12-15

Three ruthenium/iron-based compounds, 1: [Ru(MIm)(bipy)(dppf)]PF 6 (MIm = 2-mercapto-1-methylimidazole anion), 2: [RuCl(Im)(bipy)(dppf)]PF 6 (Im = imidazole), and 3: [Ru(tzdt)(bipy)(dppf)]PF 6 (tzdt = 1,3-thiazolidine-2-thione anion) (dppf = 1,1'-bis(diphenylphosphine)ferrocene and bipy = 2,2'-bipyridine), were synthesized, and characterized by elemental analyses, conductivity, UV/Vis, IR, 1 H, 13 C and 31 P{1H} NMR spectroscopies, and by electrochemical technique. The complex 3 was also characterized by single-crystal X-ray. The three ruthenium(II) complexes show cytotoxicity against DU-145 (prostate carcinoma cells) and A549 (lung carcinoma cells) tumor cells. The free ligands do not exhibit any cytotoxic activity, such as evident by the IC 50 values higher than 200 μM. UV/Vis and viscosity experiments showed that the complexes interact weakly with the DNA molecule, via electrostatic forces. The interaction of the complexes 1-3 with the HSA is moderate, with K b values in range of 10 5 -10 7  M -1 , presenting a static mechanism of interaction stabilized by hydrophobic. Complexes 2 and 3 showed high affinity for the FA7 HSA site as evidenced by fluorescence spectroscopy and molecular docking. Complexes 1-3 were tested as potential human Topoisomerase IB inhibitors by analysing the different steps of the enzyme catalytic cycle. The results indicate that all compounds efficiently inhibit the DNA relaxation and the cleavage reaction, in which the effect increases upon pre-incubation. Complexes 1 and 2 are also able to slow down the religation reaction. Copyright © 2017 Elsevier Inc. All rights reserved.

Expeditious Entry to Novel 2-Methylene-2,3-dihydrofuro[3,2-c] chromen-2-ones from 6-Chloro-4-hydroxychromen-2-one and Propargylic Alcohols

Directory of Open Access Journals (Sweden)

Josefina Díez

2011-08-01

Full Text Available A catalytic system consisting of the ruthenium(II complex [Ru(η3-2-C3H4Me(CO(dppf][SbF6] (dppf = 1,1’-bis(diphenylphosphinoferrocene and trifluoroacetic acid has been used to promote the coupling of secondary propargylic alcohols with 6-chloro-4-hydroxychromen-2-one. The reactions afforded unusual 2-methylene-2,3-dihydrofuro[3,2-c]chromen-2-ones in good yields.

Reactions of N,3-diarylpropiolamides with arenes under superelectrophilic activation: synthesis of 4,4-diaryl-3,4-dihydroquinolin-2(1H-ones and their derivatives

Directory of Open Access Journals (Sweden)

Larisa Yu. Gurskaya

2016-05-01

Full Text Available The reaction of 3-aryl-N-(arylpropiolamides with arenes in TfOH at room temperature for 0.5 h led to 4,4-diaryl-3,4-dihydroquinolin-2-(1H-ones in yields of 44–98%. The obtained dihydroquinolinones were further transformed into the corresponding N-acyl or N-formyl derivatives. For the latter, the superelectrophilic activation of the N-formyl group by TfOH in the reaction with benzene resulted in the formation of N-(diphenylmethyl-substituted dihydroquinolinones.

Ruthenium dioxide nanoparticles in ionic liquids: synthesis, characterization and catalytic properties in hydrogenation of olefins and arenes

International Nuclear Information System (INIS)

Rossi, Liane M.; Dupont, Jairton; Machado, Giovanna; Fichtner, Paulo F.P.; Radtke, Claudio; Baumvol, Israel J.R.; Teixeira, Sergio R.

2004-01-01

The reaction of NaBH 4 with RuCl 3 dissolved in 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMI.PF 6 ) ionic liquid is a simple and reproducible method for the synthesis of stable RuO 2 nanoparticles with a narrow size distribution within 2-3 nm. RuO 2 nanoparticles were characterized by XRD, XPS, EDS and TEM. These nanoparticles showed high catalytic activity either in the solventless or liquid-liquid biphasic hydrogenation of olefins and arenes under mild reaction conditions. Hg(0) and CS 2 poisoning experiments and XRD and TEM analysis of particles isolated after catalysis indicated the formation of Ru(0) nanoparticles. The nanoparticles could be re-used in solventless conditions up to 10 times in the hydrogenation of 1-hexene yielding a total turnover number for exposed Ru atoms of 175,000. (author)

Evolución metamórfica de los gabros coroníticos de El Arenal, faja máfica-ultramáfica El Destino-Las Águilas, sierra de San Luis Metamorphic evolution of the coronitic gabbrons of the El Arenal, El Destino-Las Aguilas, mafic-ultramafic belt, Sierra de San Luis

OpenAIRE

N. Brogioni; G. Cruciani; M. Franceschelli; O. Vaselli

2007-01-01

Las meta-melagabronoritas coroníticas se localizan en uno de los cuerpos de El Arenal, pertenecientes a la faja máfica-ultramáfica El Destino-Las Aguilas del flanco oriental de la sierra de San Luis. Son rocas de grano fino y representan fraccionados poco evolucionados, con alto contenido de Cr-Ni y [Mg/Mg+FeT++] comprendidas entre 0,72 y 0,75, derivados de un magma toleítico olivínico de bajo Ti, cuyo emplazamiento precedió a la deformación penetrativa y metamorfismo famatinianos. Las microe...

Electrochemistry and spectroelectrochemistry of tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine, Lu{sub 2}Pc{sub 4} and dimeric lutetium(III) phthalocyanine, Lu{sub 2}Pc{sub 2}(OAc){sub 2}

Energy Technology Data Exchange (ETDEWEB)

Koca, Atif [Chemical Engineering Department, Engineering Faculty, Marmara University, TR34722 Goeztepe, Istanbul (Turkey); Ceyhan, Tanju; Erbil, Mehmet K. [Department of Biochemistry, Division of Organic Chemistry, Guelhane Medical Academy (GATA), Ankara (Turkey); Ozkaya, Ali Riza [Department of Chemistry, Marmara University, TR34722 Goeztepe, Istanbul (Turkey)], E-mail: aliozkaya@marmara.edu.tr; Bekaroglu, Ozer [Department of Chemistry, Technical University of Istanbul, TR34469 Maslak, Istanbul (Turkey)], E-mail: obek@itu.edu.tr

2007-11-09

In this study, electrochemical, electrochromic and spectroelectrochemical properties of a tert-butylcalix[4]arene bridged bis double-decker lutetium(III) phthalocyanine (Lu{sub 2}Pc{sub 4}2) were investigated explicitly as compared with a tert-butylcalix[4]arene bridged dimeric lutetium(III) phthalocyanine [Lu{sub 2}Pc{sub 2}(OAc){sub 2}1]. Distinctive differences between electrochemical and electrochromic properties of 1 and 2 were detected. Moreover, the properties of 1 and 2 were compared with previously reported S{sub 4}(CH{sub 2}){sub 4} bridged Lu{sub 2}Pc{sub 2}(OAc){sub 2} and Lu{sub 2}Pc{sub 4}. The calixarene bridged phthalocyanine (Pc) compounds, 1 and 2 showed well-defined electrochromic behaviour with green-blue and blue-purple colour transitions. The enhanced electrochromic properties of 2, as compared to 1, were attributed to its double-decker structure, probably allowing the formation of suitable ion channels for the counter ion movement in the solid film.

CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonding: effect of local rigidification on solvent extraction toward f-block elements.

Science.gov (United States)

Chu, Hongzhu; He, Lutao; Jiang, Qian; Fang, Yuyu; Jia, Yiming; Yuan, Xiangyang; Zou, Shuliang; Li, Xianghui; Feng, Wen; Yang, Yuanyou; Liu, Ning; Luo, Shunzhong; Yang, Yanqiu; Yang, Liang; Yuan, Lihua

2014-01-15

To understand intramolecular hydrogen bonding in effecting liquid-liquid extraction behavior of CMPO-calixarenes, three CMPO-modified calix[4]arenes (CMPO-CA) 5a-5c with hydrogen-bonded spacer were designed and synthesized. The impact of spacer rotation that is hindered by introduction of intramolecular hydrogen bonding upon extraction of La(3+), Eu(3+), Yb(3+), Th(4+), and UO2(2+) has been examined. The results show that 5b and 5c containing only one hydrogen bond with a less hindered rotation spacer extract La(3+) more efficiently than 5a containing two hydrogen bonds with a more hindered rotation spacer, demonstrating the importance of local rigidification of spacer in the design of extractants in influencing the coordination environment. The large difference in extractability between La(3+) and Yb(3+) (or Eu(3+)) by 5b (or 5c), and the small difference by 5a, suggests intramolecular hydrogen bonding do exert pronounced influence upon selective extraction of light and heavy lanthanides. Log-log plot analysis indicates a 1:1, 2:1 and 1:1 stoichiometry (ligand/metal) for the extracted complex formed between 5b and La(3+), Th(4+), UO2(2+), respectively. Additionally, their corresponding acyclic analogs 7a-7c exhibit negligible extraction toward these metal ions. These results reveal the possibility of selective extraction via tuning local chelating surroundings of CMPO-CA by aid of intramolecular hydrogen bonding. Copyright © 2013 Elsevier B.V. All rights reserved.

The сalix[4]arene C-107 is highly effective supramolecular inhibitor of the Na(+,K(+-АТРase of plasmatic membrane

Directory of Open Access Journals (Sweden)

O. V. Bevza

2013-04-01

Full Text Available The inhibition of the Na+,K+-АТРase activity of the myometrium cell plasma membranes with calixarene С-107 (5,17-diamino(2-pyridylmethylphosphono-11,23-di-tret-butyl-26,28-dihydroxy-25,27-dipropoxycalix[4]arene was investigated. It has been shown that calixarene С-107 reduced the Na+,K+-АТРase activity more efficiently than ouabain did, while it did not practically influence the “basal” Mg2+-АТРase activity of the same membrane. The magnitude of the cofficient of inhibition I0.5 was 33 ± 4 nМ, Hill coefficient was 0.38 ± 0.06. The model calixa­rene C-150 – the calixarene “scaffold” (26,28-dihydroxy-25,27-dipropoxycalix[4]arene, and the model compound М-3 (4-hydroxyaniline(2-pyridinemethylphosphonic acid – a fragment of the calixarene С-107, had practically no influence on the enzymatic activity of Na+,K+-АТРase and Mg2+-АТРаse. We carried out the computer simulation of interaction of calixarenes C-107 and the mentioned model compound with ligand binding sites of the Na+,K+-АТРase of plasma membrane and structure foundation of their intermolecular interaction was found out. The participation of hydrogen, hydrophobic, electrostatic and π-π (stacking interaction between calixarene and enzyme aminoacid residues, some of which are located near the active center of Na+,K+-АТРase, was discussed.

Study of the ion-channel behavior on glassy carbon electrode supported bilayer lipid membranes stimulated by perchlorate anion

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhiquan; Shi, Jun; Huang, Weimin, E-mail: huangwm@jlu.edu.cn

2015-10-01

In this paper, a kind of didodecyldimethylammonium bromide (DDAB) layer membranes was supported on a glassy carbon electrode (GCE). We studied the ion channel behavior of the supported bilayer lipid membrane by scanning electrochemical microscopy (SCEM) in tris(2,2′-bipyridine) ruthenium(II) solution. Perchlorate anion was used as a presence of stimulus and ruthenium(II) complex cations as the probing ions for the measurement of SECM, the lipid membrane channel was opened and exhibited the behavior of distinct SECM positive feedback curve. The channel was in a closed state in the absence of perchlorate anions while reflected the behavior of SECM negative feedback curve. The rates of electron transfer reaction in the lipid membranes surface were detected and it was dependant on the potential of SECM. - Highlights: • The rates of electron transfer reaction in the lipid membranes surface were detected. • Dynamic investigations of ion-channel behavior of supported bilayer lipid membranes by scanning electrochemical microscopy • A novel way to explore the interaction between molecules and supported bilayer lipid membranes.

The antimalarial activity of Ru-chloroquine complexes against resistant Plasmodium falciparum is related to lipophilicity, basicity, and heme aggregation inhibition ability near water/n-octanol interfaces.

Science.gov (United States)

Martínez, Alberto; Rajapakse, Chandima S K; Jalloh, Dalanda; Dautriche, Cula; Sánchez-Delgado, Roberto A

2009-08-01

We have measured water/n-octanol partition coefficients, pK(a) values, heme binding constants, and heme aggregation inhibition activity of a series of ruthenium-pi-arene-chloroquine (CQ) complexes recently reported to be active against CQ-resistant strains of Plasmodium falciparum. Measurements of heme aggregation inhibition activity of the metal complexes near water/n-octanol interfaces qualitatively predict their superior antiplasmodial action against resistant parasites, in relation to CQ; we conclude that this modified method may be a better predictor of antimalarial potency than standard tests in aqueous acidic buffer. Some interesting tendencies emerge from our data, indicating that the antiplasmodial activity is related to a balance of effects associated with the lipophilicity, basicity, and structural details of the compounds studied.

Anion complexation by calix[4]arene–TTF conjugates

Czech Academy of Sciences Publication Activity Database

Flídrová, K.; Tkadlecová, M.; Lang, Kamil; Lhoták, P.

2012-01-01

Roč. 92, č. 1 (2012), s. 668-673 ISSN 0143-7208 R&D Projects: GA ČR GA203/09/0691 Institutional research plan: CEZ:AV0Z40320502 Keywords : calix[4]arene * tetrathiafulvalene * anion recognition * receptor * NMR titration * UV/vis spectroscopy Subject RIV: CA - Inorganic Chemistry Impact factor: 3.532, year: 2012

3-(Dicyanomethylidene)indan-1-one-Functionalized Calix[4]arene-Calix[4]pyrrole Hybrid: An Ion-Pair Sensor for Cesium Salts.

Science.gov (United States)

Yeon, Yerim; Leem, Soojung; Wagen, Corin; Lynch, Vincent M; Kim, Sung Kuk; Sessler, Jonathan L

2016-09-02

A chromogenic calix[4]arene-calix[4]pyrrole hybrid ion pair receptor bearing an indane substituent at a β-pyrrolic position has been prepared. On the basis of solution-phase UV-vis spectroscopic analysis and (1)H NMR spectroscopic studies carried out in 10% methanol in chloroform, receptor 1 is able to bind only cesium ion pairs (e.g., CsF, CsCl, and CsNO3) but not the constituent cesium cation (as its perchlorate salt) or the F(-), Cl(-), or NO3(-) anions (as the tetrabutylammonium salts). It thus displays rudimentary AND logic gate behavior. Receptor 1 shows a colorimetric response to cesium ion pairs under conditions of solid-liquid (nitrobenzene) and liquid-liquid (D2O-nitrobenzene-d5) extraction.

Dye Sensitized Solar Cell, DSSC

Directory of Open Access Journals (Sweden)

Pongsatorn Amornpitoksuk

2003-07-01

Full Text Available A dye sensitized solar cell is a new type of solar cell. The operating system of this solar cell type is similar to plant’s photosynthesis process. The sensitizer is available for absorption light and transfer electrons to nanocrystalline metal oxide semiconductor. The ruthenium(II complexes with polypyridyl ligands are usually used as the sensitizers in solar cell. At the present time, the complex of [Ru(2,2',2'’-(COOH3- terpy(NCS3] is the most efficient sensitizer. The total photon to current conversion efficiency was approximately 10% at AM = 1.5.

Ultrabright planar optodes for luminescence life-time based microscopic imaging of O₂ dynamics in biofilms

DEFF Research Database (Denmark)

Staal, Marc Jaap; Borisov, S M; Rickelt, L F

2011-01-01

New transparent optodes for life-time based microscopic imaging of O2 were developed by spin-coating a µm-thin layer of a highly luminescent cyclometalated iridium(III) coumarin complex in polystyrene onto glass cover slips. Compared to similar thin-film O2 optodes based on a ruthenium(II) polypy......New transparent optodes for life-time based microscopic imaging of O2 were developed by spin-coating a µm-thin layer of a highly luminescent cyclometalated iridium(III) coumarin complex in polystyrene onto glass cover slips. Compared to similar thin-film O2 optodes based on a ruthenium...

Transfer Hydro-dehalogenation of Organic Halides Catalyzed by Ruthenium(II) Complex.

Science.gov (United States)

You, Tingjie; Wang, Zhenrong; Chen, Jiajia; Xia, Yuanzhi

2017-02-03

A simple and efficient Ru(II)-catalyzed transfer hydro-dehalogenation of organic halides using 2-propanol solvent as the hydride source was reported. This methodology is applicable for hydro-dehalogenation of a variety of aromatic halides and α-haloesters and amides without additional ligand, and quantitative yields were achieved in many cases. The potential synthetic application of this method was demonstrated by efficient gram-scale transformation with catalyst loading as low as 0.5 mol %.

Pincer-CNC mononuclear, dinuclear and heterodinuclear Au(III) and Pt(II) complexes supported by mono- and poly-N-heterocyclic carbenes: synthesis and photophysical properties.

Science.gov (United States)

Gonell, S; Poyatos, M; Peris, E

2016-04-07

A family of cyclometallated Au(iii) and Pt(ii) complexes containing a CNC-pincer ligand (CNC = 2,6-diphenylpyridine) supported by pyrene-based mono- or bis-NHC ligands have been synthesized and characterized, together with the preparation of a Pt-Au hetero-dimetallic complex based on a Y-shaped tris-NHC ligand. The photophysical properties of all the new species and of two related Ru(ii)-arene complexes were studied and compared. Whereas the pyrene-based complexes only exhibit emission in solution, those containing the Y-shaped tris-NHC ligand are only luminescent when dispersed in poly(methyl methacrylate) (PMMA). In particular, the pyrene-based complexes were found to be emissive in the range of 373-440 nm, with quantum yields ranging from 3.1 to 6.3%, and their emission spectra were found to be almost superimposable, pointing to the fluorescent pyrene-centered nature of the emission. This observation suggests that the emission properties of the pyrene fragment may be combined with some of the numerous applications of NHCs as supporting ligands allowing, for instance, the design of biological luminescent agents.

ANÁLISE ESPACIAL DA EVOLUÇÃO DO USO E COBERTURA DA TERRA NA SUB-BACIA HIDROGRÁFICA DO ARROIO ARENAL, SANTA MARIA/RS

OpenAIRE

Ana Caroline Paim Benedetti

2006-01-01

Este trabalho investiga a dinâmica das classes de uso e cobertura da terra na subbacia hidrográfica do Arroio Arenal RS, através da representação de processos espaço-temporais. Por meio de um conjunto de imagens multi-sensores, realizou-se a análise espacial de uma série temporal distinta entre as datas de outubro de 1995, maio de 2000 e janeiro de 2005, gerando informações representativas da paisagem e relacionando-as a diferentes aspectos sócio-econômicos, políticos e ambientais inerentes ...

Malonamide, phosphine oxide and calix[4]arene functionalized ionic liquids: synthesis and extraction of actinides and lanthanides

International Nuclear Information System (INIS)

Ternova, Dariia

2014-01-01

Radioactive waste treatment is a crucial problem nowadays. This work was dedicated to the development of the new extracting systems for radionuclides on the basis of 'green' solvents Ionic Liquids (Ils). For this purpose Ils were functionalized with various extracting patterns: phosphine oxide, carbamoyl phosphine oxide groups and malonamide fragment. Also the calix[4]arene platforms were used for the synthesis of functionalized ionic liquids (Fils) and their precursors. The Fils of both types cationic and anionic have been obtained. The synthesized Fils were tested for the liquid-liquid extraction of radionuclides. lt was found that extraction well occurs due to the extracting patterns, however a charge of a modified ion influences extraction.The various extracting experiments and mathematical modelling have been performed to determine the mechanisms of extraction. These studies showed that each extracting system is characterized by a different set of extracting equilibria, based mostly on cationic exchange. (author)

Bis(arene) actinide sandwich complexes, (η6-C6H3R3)2An: Linear or bent?

International Nuclear Information System (INIS)

Li, J.; Bursten, B.E.

1999-01-01

The syntheses of the sandwich complexes ferrocene, (η 5 -C 5 H 5 ) 2 -Fe, in 1951 and uranocene, (η 8 -C 8 H 8 ) 2 U, in 1968 ushered in the modern eras of organotransition metal and organoactinide chemistry, respectively. Ferrocene and uranocene are examples of linear sandwich complexes, that is, those in which the (ring centroid)-M-(ring centroid) angle (denoted θ) is 180 degree. In the case of (η 5 -C 5 H 5 ) 2 M chemistry, a number of bent (θ 2 An (An = Th-Am) and (η 6 -C 6 H 3 R 3 ) 2 An (An = Th, U, Pu; R = Me, t Bu) obtained by using local density approximation (LDA) and Perdew-Wang (PW91) gradient-corrected relativistic density functional theory (DFT) methods. These DFT methods are found to be able to reproduce the experimental geometries and vibrational frequencies of organoactinide complexes with satisfactory accuracy. The (TTB) 2 An calculations that are reported here are, to date, the largest full geometry optimizations to be carried out on an actinide system

PENGARUH UMUR TUMBUHAN AREN TERHADAP PRODUKSI NIRA DI DESA MURUNG A KECAMATAN BATU BENAWA KABUPATEN HULU SUNGAI TENGAH KALIMANTAN SELATAN

Directory of Open Access Journals (Sweden)

Fatriani Fatriani

2016-08-01

Full Text Available This study aims to determine the effect of age on the sap of palm plants produced from A Murung Village, Sub Batu Benawa Hulu Sungai Tengah District, South Kalimantan. Based on simple linear regression analysis it can be seen the following equation: Y = 12.6612 - 0.2625999 * age plant. Sap production varies inversely with the mean age of palm plants with increasing age, the more little palm plant sap produced. F hit (15.24> F tab (9:07 means that age has a significant influence on the production of palm juice either at the level of confidence of 5% or 1% of the above regression equation can be estimated (predicted by age palm juice production plant . The results of the calculation of the correlation coefficient (r indicates the closeness of the relationship between age with the production of palm juice, this is indicated by r values of -0.734597 (close to -1, mean age of palm plants have a very close correlation with the production of palm juice, while based on the coefficient of determination (R2 known value is 53.9632%, means the production of palm juice is influenced by the age factor while the remaining 53.96% influenced by other factors. Age factor has a strong relationship with the production of palm wine (the correlation coefficient of -0.734597. Age factor is inversely proportional to the roduction of palm juice, palm sugar The older age of the plants produced less sap, Age 11 years generating plants aren aren at most ( 10.68 liters while the lowest is 30 years old (2.34 liters, Need palm cultivation in the area within the framework of sustainability brown sugar.Technic tapping sugar production in order to maximize the production of palm juice should really be considered, Ways to maximize production Nira through efforts to extend the period of tapping palm bunches of flowers should also be noted. Keywords :Age plants, production, Nira

Structural study of the uranyl and rare earth complexation functionalized by the CMPO; Etude structurale de la complexation de l'uranyle et des ions lanthanides par des calixarenes fonctionnalises par le CMPO

Energy Technology Data Exchange (ETDEWEB)

Cherfa, S

1998-12-10

In view of reducing the volume of nuclear waste solutions, a possible way is to extract simultaneously actinide and lanthanide ions prior to their ulterior separation.. Historically, the two extractant families used for nuclear waste reprocessing are the phosphine oxides and the CMPO (Carbamoyl Methyl Phosphine Oxide). For a better understanding of the complexes formed during extraction, we undertook structural studies of the complexes formed between uranyl and lanthanide (III) ions and the two classes of ligands cited above. These studies have been performed by X-ray diffraction on single crystals. Recently, a new type of extractants of lanthanide (III) and actinide (III) ions has been developed. When the Organic macrocycle called calixarene (an oligomeric compound resulting from the poly-condensation of phenolic units) is functionalized by a CMPO ligand, the extracting power, in terms of yield and selectivity towards lightest lanthanides, is greatly enhanced compared to the one measured for the single CMPO. Our X-ray diffraction studies allowed us to characterise, in terms of stoichiometry and monodentate or bidentate coordination mode of the CMPO functions, the complexes of calix[4]arene-CMPO (with four phenolic units) with lanthanide nitrates and uranyl. These different steps of characterisation enabled us to determine the correlation between the structures of the complexes and both selectivity and exacerbation of the extracting power measured in the liquid phase. (author)

Systematic method for the incorporation of the {(eta(6)-arene)Fe} fragment into carborane cages via [(eta(6)-arene)Fe](2+) dications. A series of [3-(eta(6)-arene)-closo-3,1,2-FeC2B9H11] complexes. Reliable synthesis of polymethylated [(eta(6)-arene)(2)Fe](2+) cations

Czech Academy of Sciences Publication Activity Database

Štíbr, Bohumil; Bakardjiev, Mario; Holub, Josef; Růžička, A.; Kvíčalová, Magdalena

2009-01-01

Roč. 48, č. 23 (2009), s. 10904-10906 ISSN 0020-1669 R&D Projects: GA MŠk LC523 Institutional research plan: CEZ:AV0Z40320502 Keywords : organotransition-metal matallacarborane * magnetic-resonance spectroscopy * iron complexes Subject RIV: CA - Inorganic Chemistry Impact factor: 4.657, year: 2009

A general approach to intermolecular carbonylation of arene C-H bonds to ketones through catalytic aroyl triflate formation

Science.gov (United States)

Garrison Kinney, R.; Tjutrins, Jevgenijs; Torres, Gerardo M.; Liu, Nina Jiabao; Kulkarni, Omkar; Arndtsen, Bruce A.

2018-02-01

The development of metal-catalysed methods to functionalize inert C-H bonds has become a dominant research theme in the past decade as an approach to efficient synthesis. However, the incorporation of carbon monoxide into such reactions to form valuable ketones has to date proved a challenge, despite its potential as a straightforward and green alternative to Friedel-Crafts reactions. Here we describe a new approach to palladium-catalysed C-H bond functionalization in which carbon monoxide is used to drive the generation of high-energy electrophiles. This offers a method to couple the useful features of metal-catalysed C-H functionalization (stable and available reagents) and electrophilic acylations (broad scope and selectivity), and synthesize ketones simply from aryl iodides, CO and arenes. Notably, the reaction proceeds in an intermolecular fashion, without directing groups and at very low palladium-catalyst loadings. Mechanistic studies show that the reaction proceeds through the catalytic build-up of potent aroyl triflate electrophiles.

Fundamental Factors Impacting the Stability of Phosphonate-Derivatized Ruthenium Polypyridyl Sensitizers Adsorbed on Metal Oxide Surfaces.

Science.gov (United States)

Raber, McKenzie; Brady, Matthew David; Troian-Gautier, Ludovic; Dickenson, John; Marquard, Seth L; Hyde, Jacob; Lopez, Santiago; Meyer, Gerald J; Meyer, Thomas J; Harrison, Daniel P

2018-06-08

A series of 18 ruthenium(II) polypyridyl complexes were synthesized and evaluated under electrochemically oxidative conditions, which generates the Ru(III) oxidation state and mimics the harsh conditions experienced during the kinetically-limited regime that can occur in dye-sensitized solar cells (DSSCs) and dye-sensitized photoelectrosynthesis cells (DSPECs), to further develop fundamental insights into the factors governing molecular sensitizer surface stability in aqueous 0.1 M HClO4 (aq). Both desorption and oxidatively induced ligand substitution were observed on planar fluorine doped tin oxide, FTO, electrodes, with a dependence on the E1/2 Ru(III/II) redox potential dictating the comparative ratios of the processes. Complexes such as RuP4OMe (E1/2 = 0.91 vs Ag/AgCl) displayed virtually only desorption, while complexes such as RuPbpz (E1/2 > 1.62 V vs Ag/AgCl) displayed only chemical decomposition. Comparing isomers of 4,4'- and 5,5-disubstituted-2,2'-bipyridine ancillary polypyridyl ligands, a dramatic increase in the rate of desorption of the Ru(III) complexes was observed for the 5,5'-ligands. Nanoscopic indium doped tin oxide thin films, nanoITO, were also sensitized and analyzed with cyclic voltammetry, UV-Vis absorption spectroscopy, and XPS, allowing for further distinction of desorption versus ligand substitution processes. Desorption loss to bulk solution associated with the planar surface of FTO is essentially non-existent on nanoITO, where both desorption and ligand substitution are shut down with RuP4OMe. These results revealed that minimizing time spent in the oxidized form, incorporating electron donating groups, maximizing hydrophobicity, and minimizing molecular bulk near the adsorbed ligand are critical to optimizing the performance of ruthenium(II) polypyridyl complexes in dye-sensitized solar cell devices.

Enhanced free energy of extraction of Eu3+ and Am3+ ions towards diglycolamide appended calix[4]arene: insights from DFT-D3 and COSMO-RS solvation models.

Science.gov (United States)

Ali, Sk Musharaf

2017-08-22

Density functional theory in conjunction with COSMO and COSMO-RS solvation models employing dispersion correction (DFT-D3) has been applied to gain an insight into the complexation of Eu 3+ /Am 3+ with diglycolamide (DGA) and calix[4]arene appended diglycolamide (CAL4DGA) in ionic liquids by studying structures, energetics, thermodynamics and population analysis. The calculated Gibbs free energy for both Eu 3+ and Am 3+ ions with DGA was found to be smaller than that with CAL4DGA. The entropy of complexation was also found to be reduced to a large extent with DGA compared to complexation with CAL4DGA. The solution phase free energy was found to be negative and was higher for Eu 3+ ion. The entropy of complexation was not only found to be further reduced but also became negative in the case of DGA alone. Though the entropy was found to be negative it could not outweigh the high negative enthalpic contribution. The same trend was observed in the solution where the free energy of extraction, ΔG, for Eu 3+ ions was shown to be higher than that for Am 3+ ions towards free DGA. But the values of ΔG and ΔΔG(= ΔG Eu -ΔG Am ) were found to be much higher with CAL4DGA (-12.58 kcal mol -1 ) in the presence of nitrate ions compared to DGA (-1.69 kcal mol -1 ) due to enhanced electronic interaction and positive entropic contribution. Furthermore, both the COSMO and COSMO-RS models predict very close values of ΔΔΔG (= ΔΔG CAL4DGA - ΔΔG nDGA ), indicating that both solvation models could be applied for evaluating the metal ion selectivity. The value of the reaction free energy was found to be higher after dispersion correction. The charge on the Eu and Am atoms for the complexes with DGA and CAL4DGA indicates the charge-dipole type interaction leading to strong binding energy. The present theoretical results support the experimental findings and thus might be of importance in the design of functionalized ligands.

Density functionalized [RuII(NO)(Salen)(Cl)] complex: Computational photodynamics and in vitro anticancer facets.

Science.gov (United States)

Mir, Jan Mohammad; Jain, N; Jaget, P S; Maurya, R C

2017-09-01

Photodynamic therapy (PDT) is a treatment that uses photosensitizing agents to kill cancer cells. Scientific community has been eager for decades to design an efficient PDT drug. Under such purview, the current report deals with the computational photodynamic behavior of ruthenium(II) nitrosyl complex containing N, N'-salicyldehyde-ethylenediimine (SalenH 2 ), the synthesis and X-ray crystallography of which is already known [Ref. 38,39]. Gaussian 09W software package was employed to carry out the density functional (DFT) studies. DFT calculations with Becke-3-Lee-Yang-Parr (B3LYP)/Los Alamos National Laboratory 2 Double Z (LanL2DZ) specified for Ru atom and B3LYP/6-31G(d,p) combination for all other atoms were used using effective core potential method. Both, the ground and excited states of the complex were evolved. Some known photosensitizers were compared with the target complex. Pthalocyanine and porphyrin derivatives were the compounds selected for the respective comparative study. It is suggested that effective photoactivity was found due to the presence of ruthenium core in the model complex. In addition to the evaluation of theoretical aspects in vitro anticancer aspects against COLO-205 human cancer cells have also been carried out with regard to the complex. More emphasis was laid to extrapolate DFT to depict the chemical power of the target compound to release nitric oxide. A promising visible light triggered nitric oxide releasing power of the compound has been inferred. In vitro antiproliferative studies of [RuCl 3 (PPh 3 ) 3 ] and [Ru(NO)(Salen)(Cl)] have revealed the model complex as an excellent anticancer agent. From IC 50 values of 40.031mg/mL in former and of 9.74mg/mL in latter, it is established that latter bears more anticancer potentiality. From overall study the DFT based structural elucidation and the efficiency of NO, Ru and Salen co-ligands has shown promising drug delivery property and a good candidacy for both chemotherapy as well as

Synthesis, spectral and structural studies of water soluble arene ruthenium (II) complexes containing 2,2′-dipyridyl-N-alkylimine ligand

Digital Repository Service at National Institute of Oceanography (India)

Singh, K.S.; Kaminsky, W.

of the complexes. A similar downfield of chemical shifts was also observed for the alkyl protons attached to the nitrogen. For instant, the methyl proton of dpNmei was observed as a singlet at around δ 4.05 in the complexes [1]PF 6 , [3]PF 6 and [5]PF 6 as 9...

Supramolecular Host-Guest System as Ratiometric Fe3+ Ion Sensor Based on Water-Soluble Pillar[5]arene.

Science.gov (United States)

Yao, Qianfang; Lü, Baozhong; Ji, Chendong; Cai, Yang; Yin, Meizhen

2017-10-18

Developing a specific, ratiometric, and reversible detection method for metal ions is significant to guard against the threat of metal-caused environmental pollution and organisms poisoning. Here a supramolecular host-guest system (WP5⊃G) based on water-soluble pillar[5]arene (WP5) and water-soluble quaternized perylene diimide derivative (G) was constructed. Morphological transformation was achieved during the process of adding WP5 into G aqueous solution, and a fluorescence "turn-off" phenomenon was observed which was caused by supramolecular photoinduced electron transfer (PET). Meanwhile, hydrophobic effect and electrostatic interaction played important roles in this supramolecular process, which was confirmed by isothermal titration calorimeter (ITC) and ζ potential experiments. Furthermore, the supramolecular host-guest system could be a "turn-on" fluorescent probe for Fe 3+ ion detection through the process of interdicting supramolecular PET. Moreover, the Fe 3+ ion detection showed specific, ratiometric, and reversible performances with a detection limit of 2.13 × 10 -7 M, which might have great potentials in biological and environmental monitoring.

Chemistry by nanocatalysis: First example of a solid-supported RAPTA complex for organic reactions in aqueous medium

KAUST Repository

García-Garrido, Sergio E.

2010-11-18

A ruthenium-arene-PTA (RAPTA) complex has been supported for the first time on an inorganic solid, that is, silica-coated ferrite nanoparticles. The resulting magnetic material proved to be a general, very efficient and easily reusable catalyst for three synthetically useful organic transformations; selective nitrile hydration, redox isomerization of allylic alcohols, and heteroannulation of (Z)-enynols. The use of low metal concentration, environmentally friendly water as a reaction medium, with no use at all of organic solvent during or after the reactions, and microwaves as an alternative energy source renders the synthetic processes reported herein "truly" green and sustainable. RAPTA\\'s delight: A nano-RAPTA complex supported on silica-coated ferrite nanoparticles proved to be a general, very efficient and easily reusable catalyst for three synthetically useful organic transformations; selective nitrile hydration, redox isomerization of allylic alcohols, and heteroannulation of (Z)-enynols. The use of low metal concentrations, water as a reaction medium, and microwaves as an energy source renders these processes green and sustainable. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Warm/cool-tone switchable thermochromic material for smart windows by orthogonally integrating properties of pillar[6]arene and ferrocene.

Science.gov (United States)

Wang, Sai; Xu, Zuqiang; Wang, Tingting; Xiao, Tangxin; Hu, Xiao-Yu; Shen, Ying-Zhong; Wang, Leyong

2018-04-30

Functional materials play a vital role in the fabrication of smart windows, which can provide a more comfortable indoor environment for humans to enjoy a better lifestyle. Traditional materials for smart windows tend to possess only a single functionality with the purpose of regulating the input of solar energy. However, different color tones also have great influences on human emotions. Herein, a strategy for orthogonal integration of different properties is proposed, namely the thermo-responsiveness of ethylene glycol-modified pillar[6]arene (EGP6) and the redox-induced reversible color switching of ferrocene/ferrocenium groups are orthogonally integrated into one system. This gives rise to a material with cooperative and non-interfering dual functions, featuring both thermochromism and warm/cool tone-switchability. Consequently, the obtained bifunctional material for fabricating smart windows can not only regulate the input of solar energy but also can provide a more comfortable color tone to improve the feelings and emotions of people in indoor environments.

Substituent Effects and Bonding Characteristics in o- Benzoquinonediiminebis(bipyrdine) Ruthenium(II) Complexes

Science.gov (United States)

1992-10-23

C.; Dei, A.; Gatteschi , D.; Pardi, L Inorg. Chem. 1989, 2L 1476; (b) Benel, C.; Dei, A.; Gatteschi , D.; Ckdel, H. U.; Pardi, L Inorg. Ckem. 1989, 28...3091; (c) Benelli, C.; Dei, A.; Gatteschi , D.; Pardi, L Inorg.Chem. 1990,2& 3409. 16. Bruni, S.; Cariati, F.; Dei, A.; Gatteschi , D. Inog Cbim. Ata...1991, 186 157. 17. Dei, A.; Gatteschi , D.; Pardi, L; Barra, A. L; Brunel, L C. Chem, Py. Lett.. 1990, 175. 589; Dei, A.; Pardi, L Inorg, Chim.Acta

Structural investigation of the complexation of uranyl and lanthanide ions by CMPO-functionalized calixarenes

International Nuclear Information System (INIS)

Cherfa, S.

1998-12-01

A way to reduce the volume of nuclear wastes is to make a simultaneous extraction of actinides and lanthanides for their ulterior separation. Historically, the two first series of extractants used for the reprocessing of these wastes are the phosphine oxides and the CMPO (carbamoyl methyl phosphine oxide). In order to better know the type of complexes formed during the extraction, have been carried out structural studies concerning these two series (uranyl complexes and lanthanide nitrates). These studies have been carried out by X-ray diffraction on monocrystals. More recently, a new series of extracting molecules of lanthanides (III) and actinides (III) have been developed. It has been shown that in functionalizing an organic macrocycle of calixarene type (cyclic oligomer resulting of the poly-condensation of phenolic units) by a ligand of CMPO type, the extracting power of these molecules in terms of yield and selectivity towards the lighter lanthanides was superior to those of the CMPO alone. This study, carried out by X-ray diffraction on monocrystals of complexes formed between these ligands calix[4]arenes-CMPO (with 4 phenolic units) with uranyl and lanthanides nitrates, has allowed to define the type of the formed complexes, that is to say to establish the stoichiometry and the coordination mode (monodentate or bidentate) of the CMPO functions. These different steps of characterization have allowed too to determine the correlations existing between the complexes structures in the one hand and the selectivity and the exacerbation of the extracting power measured in liquid phase on the other hand. (O.M.)

Additive Manufacture of Three Dimensional Nanocomposite Based Objects through Multiphoton Fabrication

Directory of Open Access Journals (Sweden)

Yaan Liu

2016-09-01

Full Text Available Three-dimensional structures prepared from a gold-polymer composite formulation have been fabricated using multiphoton lithography. In this process, gold nanoparticles were simultaneously formed through photoreduction whilst polymerisation of two possible monomers was promoted. The monomers, trimethylopropane triacrylate (TMPTA and pentaerythritol triacrylate (PETA were mixed with a gold salt, but it was found that the addition of a ruthenium(II complex enhanced both the geometrical uniformity and integrity of the polymerised/reduced material, enabling the first production of 3D gold-polymer structures by single step multiphoton lithography.

Evolución metamórfica de los gabros coroníticos de El Arenal, faja máfica-ultramáfica El Destino-Las Águilas, sierra de San Luis

OpenAIRE

N. Brogioni; G. Cruciani; M. Franceschelli; O. Vaselli

2007-01-01

Las meta-melagabronoritas coroníticas se localizan en uno de los cuerpos de El Arenal, pertenecientes a la faja máfica-ultramáfica El Destino-Las Aguilas del flanco oriental de la sierra de San Luis. Son rocas de grano fino y representan fraccionados poco evolucionados, con alto contenido de Cr-Ni y [Mg/Mg+FeT++] comprendidas entre 0,72 y 0,75, derivados de un magma toleítico olivínico de bajo Ti, cuyo emplazamiento precedió a la deformación penetrativa y metamorfismo famatinianos. Las microe...

Electronic optimization of heteroleptic Ru(II) bipyridine complexes by remote substituents: synthesis, characterization, and application to dye-sensitized solar cells.

Science.gov (United States)

Han, Won-Sik; Han, Jung-Kyu; Kim, Hyun-Young; Choi, Mi Jin; Kang, Yong-Soo; Pac, Chyongjin; Kang, Sang Ook

2011-04-18

We prepared a series of new heteroleptic ruthenium(II) complexes, Ru(NCS)(2)LL' (3a-3e), where L is 4,4'-di(hydroxycarbonyl)-2,2'-bipyridine and L' is 4,4'-di(p-X-phenyl)-2,2'-pyridine (X = CN (a), F (b), H (c), OMe (d), and NMe(2) (e)), in an attempt to explore the structure-activity relationships in their photophysical and electrochemical behavior and in their performance in dye-sensitized solar cells (DSSCs). When substituent X is changed from electron-donating NMe(2) to electron-withdrawing CN, the absorption and emission maxima reveal systematic bathochromic shifts. The redox potentials of these dyes are also significantly influenced by X. The electronic properties of the dyes were theoretically analyzed using density functional theory calculations; the results show good correlations with the experimental results. The solar-cell performance of DSSCs based on dye-grafted nanocrystalline TiO(2) using 3a-3e and standard N3 (bis[(4,4'-carboxy-2,2'-bipyridine)(thiocyanato)]ruthenium(II)) were compared, revealing substantial dependences on the dye structures, particularly on the remote substituent X. The 3d-based device showed the best performance: η = 8.30%, J(SC) = 16.0 mA·cm(-2), V(OC) = 717 mV, and ff = 0.72. These values are better than N3-based device.

Development of a pH sensing membrane electrode based on a new calix[4]arene derivative.

Science.gov (United States)

Kormalı Ertürün, H Elif; Demirel Özel, Ayça; Sayın, Serkan; Yılmaz, Mustafa; Kılıç, Esma

2015-01-01

A new pH sensing poly(vinyl chloride) (PVC) membrane electrode was developed by using recently synthesized 5,17-bis(4-benzylpiperidine-1-yl)methyl-25,26,27,28-tetrahydroxy calix[4]arene as an ionophore. The effects of membrane composition, inner filling solution and conditioning solution on the potential response of the proposed pH sensing membrane electrode were investigated. An optimum membrane composition of 3% ionophore, 67% o-nitrophenyl octyl ether (o-NPOE) as plasticizer, 30% PVC was found. The electrode exhibited a near-Nernstian slope of 58.7±1.1 mV pH(-1) in the pH range 1.9-12.7 at 20±1 °C. It showed good selectivity for H(+) ions in the presence of some cations and anions and a longer lifetime of at least 12 months when compared with the other PVC membrane pH electrodes reported in the literature. Having a wide working pH range, it was not only applied as a potentiometric indicator electrode in various acid-base titrations, but also successfully employed in different real samples. It has good reproducibility and repeatability with a response time of 6-7s. Compared to traditional glass pH electrode, it exhibited excellent potentiometric response after being used in fluoride-containing media. Copyright © 2014 Elsevier B.V. All rights reserved.

DNA interactions of monofuntional organometallic ruthenium(II) antitumor complexes in cell-free media

Czech Academy of Sciences Publication Activity Database

Nováková, Olga; Chen, H.; Vrána, Oldřich; Rodger, A.; Sadler, P. J.; Brabec, Viktor

2003-01-01

Roč. 42, č. 39 (2003), s. 11544-11554 ISSN 0006-2960 R&D Projects: GA ČR GA305/02/1552; GA ČR GA305/01/0418; GA AV ČR IAA5004101; GA MŠk OC D20.002; GA MŠk OC D20.005 Institutional research plan: CEZ:AV0Z5004920 Keywords : double-helical DNA * interstrand cross-links * biophysical analysis Subject RIV: BO - Biophysics Impact factor: 3.922, year: 2003

Spectroscopic investigations of Eu{sup 3+}-complexes with ligands containing multiple diglycolamide pendant arms in a room temperature ionic liquid

Energy Technology Data Exchange (ETDEWEB)

Sengupta, Arijit [Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Mohapatra, Prasanta K., E-mail: mpatra@barc.gov.in [Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Iqbal, Mudassir; Huskens, Jurriaan; Verboom, Willem [Laboratory of Molecular Nanofabrication, MESA" + Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede (Netherlands)

2014-10-15

Fluorescence spectroscopy was used to study the complexation of different ligands containing multiple diglycolamide (DGA) pendent arms such as T-DGA (tripodal diglycolamide), C4DGA (upper rim functionalized calix [4] arene with four DGA moieties), and C8DGA (both side functionalized calix [4] arene with eight DGA moieties) with Eu{sup 3+} in ionic liquids such as C{sub 4}mimNTf{sub 2} and C{sub 8}mimNTf{sub 2} (1-alkyl-3-methylimidazolium bis(trifluoromethylsulphonyl)imide). Mainly five sets of emission profiles were observed in all the spectra (1st set at∼580 nm assigned as the {sup 5}D{sub 0}→{sup 7}F{sub 0} transition, 2nd set at∼593 nm assigned as the {sup 5}D{sub 0}→{sup 7}F{sub 1} transition, 3rd set at∼613 nm assigned as the {sup 5}D{sub 0}→{sup 7}F{sub 2} transition, 4th set at∼650 nm assigned as the {sup 5}D{sub 0}→{sup 7}F{sub 3} transition, and 5th set at∼700 nm assigned as the {sup 5}D{sub 0}→{sup 7}F{sub 4} transition). The difference in the spectral features revealed that the nature of the complexes differs significantly from one another. Judd–Offelt constant Ω{sub 2}, which is a measure of the covalency of the metal–ligand bond, follows the order Eu{sup 3+}–C4DGA (C{sub 8}mimNTf{sub 2})>Eu{sup 3+}–C8DGA (C{sub 8}mimNTf{sub 2})>Eu{sup 3+}–TODGA (C{sub 4}mimNTf{sub 2})>Eu{sup 3+}–T-DGA (C{sub 4}mimNTf{sub 2})>Eu{sup 3+}{sub aq}. The high intensity of the {sup 5}D{sub 0}→{sup 7}F{sub 2} transitions in all complexes suggests that Eu{sup 3+} resides in a highly asymmetric environment. From the splitting patterns of the transitions, the local site symmetry around Eu{sup 3+} was found to be C{sub 2V} for the Eu{sup 3+}–T-DGA complex in both C{sub 4}mimNTf{sub 2} and a 1:5 acetonitrile–water mixture, C{sub 4V} for Eu{sup 3+}–C8DGA and Eu{sup 3+}–TODGA complexes, and either C{sub 1}, C{sub 2}, or C{sub S} for the Eu{sup 3+}–C4DGA complex. A linear relationship between the {sup 5}D{sub 0}–{sup 7}F{sub 1} splitting

Supramolecular solubilization of fullerenes and radio-fullerenes in aqueous media

International Nuclear Information System (INIS)

Braun, T.

1999-01-01

In this paper we are dealing with the supramolecular complexation of fullerenes C 60 , C 70 , some functionalized fullerenes and of the dumbbell structured C 120 dimer, with two host molecules, namely γ-cyclo-dextrin (GCD), and sulfocalix[8]arene in order to make them soluble in water. Previous investigations by others have shown that the reactions of some mentioned fullerenes and cyclo-dextrins and calixarenes are very slow and tedious in liquid phase as a result of solvatation effects. That we have decided to pursue the supramolecular complexation as solid-solid reactions by using mechanochemical activation in a ball mill. A mechanochemical treatment was used to enhance chemical reactivity in solid-solid reactions in which GCD give a complex with the C 60 as 2:1 host-guest complex. The calix[8]arene complex with C 60 molecule has been prepared. The sulfonated form of the host is well soluble in water. Endohedral radio-fullerenes of the XandC60 type (where * X is a rare gas, e.g. Ar, Xe, Kr, radionuclide) were prepared by nuclear recoil after neutron irradiation, a method developed by the author The endohedrally labelled fullerenes were then mechanochemically complexed into a labelled supramolecular complex with cyclo-dextrin and calixarene hosts. (author)

Palladium complexes with simple iminopyridines as catalysts for polyketone synthesis.

Science.gov (United States)

Rosar, V; Dedeic, D; Nobile, T; Fini, F; Balducci, G; Alessio, E; Carfagna, C; Milani, B

2016-10-07

Four iminopyridines (N-N') differing in the nature of the substituents on the iminic carbon and on the ortho positions of the aryl ring (H or CH3) on the iminic nitrogen were used for the synthesis of neutral and monocationic palladium(ii) complexes of general formulae [Pd(CH3)Cl(N-N')] and [Pd(CH3)(NCCH3)(N-N')][PF6]. The detailed NMR characterization in solution highlighted that: (i) for both series of complexes, the Pd-CH3 signal is progressively shifted to a lower frequency on increasing the number of methyl groups on the ligand skeleton; (ii) for the neutral derivatives, the chemical shift of the (15)N NMR signals, determined through {(1)H,(15)N}-HMBC spectra, is significantly affected by the coordination to palladium; (iii) the coordination induced shift (CIS) of the nitrogen atom trans to the CH3 ligand is smaller than the other. The structure in the solid state for the neutral derivatives with all the four ligands was solved, pointing out that: (iv) the Pd-C bond distance increases with the basicity of the nitrogen-donor ligand; (v) the Pd-N bond distance correlates well with the CIS value. The combining of the solution and solid state structural features allows stating that: (vi) the Pd-CH3 singlet is a good probe for the electron donor capability of the ligand; (vii) the CIS value might be used as a probe for the strength of the Pd-N bond. All monocationic complexes generated active catalysts for the CO/vinyl arene copolymerization, leading to prevailingly syndiotactic polyketones. The catalyst performances, both in terms of catalyst productivity and polymer molecular weight, correlate well with the precatalyst structural features.

Ruthenium complexes containing 2-(2-nitrosoaryl)pyridine: structural, spectroscopic, and theoretical studies.

Science.gov (United States)

Chan, Siu-Chung; Cheung, Ho-Yuen; Wong, Chun-Yuen

2011-11-21

Ruthenium complexes containing 2-(2-nitrosoaryl)pyridine (ON(^)N) and tetradentate thioether 1,4,8,11-tetrathiacyclotetradecane ([14]aneS4), [Ru(ON(^)N)([14]aneS4)](2+) [ON(^)N = 2-(2-nitrosophenyl)pyridine (2a), 10-nitrosobenzo[h]quinoline (2b), 2-(2-nitroso-4-methylphenyl)pyridine, (2c), 2-(2-nitrosophenyl)-5-(trifluoromethyl)pyridine (2d)] and analogues with the 1,4,7-trithiacyclononane ([9]aneS3)/tert-butylisocyanide ligand set, [Ru(ON(^)N)([9]aneS3)(C≡N(t)Bu)](2+) (4a and 4b), have been prepared by insertion of a nitrosonium ion (NO(+)) into the Ru-aryl bond of cyclometalated ruthenium(II) complexes. The molecular structures of the ON(^)N-ligated complexes 2a and 2b reveal that (i) the ON(^)N ligands behave as bidentate chelates via the two N atoms and the bite angles are 86.84(18)-87.83(16)° and (ii) the Ru-N(NO) and N-O distances are 1.942(5)-1.948(4) and 1.235(6)-1.244(5) Å, respectively. The Ru-N(NO) and N-O distances, together with ν(N═O), suggest that the coordinated ON(^)N ligands in this work are neutral moiety (ArNO)(0) rather than monoanionic radical (ArNO)(•-) or dianion (ArNO)(2-) species. The nitrosated complexes 2a-2d show moderately intense absorptions centered at 463-484 nm [ε(max) = (5-6) × 10(3) dm(3) mol(-1) cm(-1)] and a clearly discriminable absorption shoulder around 620 nm (ε(max) = (6-9) × 10(2) dm(3) mol(-1) cm(-1)), which tails up to 800 nm. These visible absorptions are assigned as a mixing of d(Ru) → ON(^)N metal-to-ligand charge-transfer and ON(^)N intraligand transitions on the basis of time-dependent density functional theory (TD-DFT) calculations. The first reduction couples of the nitrosated complexes range from -0.53 to -0.62 V vs Cp(2)Fe(+/0), which are 1.1-1.2 V less negative than that for [Ru(bpy)([14]aneS4)](2+) (bpy = 2,2'-bipyridine). Both electrochemical data and DFT calculations suggest that the lowest unoccupied molecular orbitals of the nitrosated complexes are ON(^)N-centered. Natural population

Study of reactivity of p-cymene ruthenium(II) dimer towards diphenyl ...

Indian Academy of Sciences (India)

Unknown

The reaction of [{(η6-p-cymene)Ru(µ-Cl)}2Cl2] with functionalized phosphine viz, diphenyl-. 2-pyridylphosphine ... ing from the displacement of the p-cymene ligand. ... The structures of complexes 1 and 2 have been confirmed by single crystal.

Synthesis and Characterization of Calixarene Tetraethers: An Exercise in Supramolecular Chemistry for the Undergraduate Organic Laboratory

Science.gov (United States)

Debbert, Stefan L.; Hoh, Bradley D.; Dulak, David J.

2016-01-01

In this experiment for an introductory undergraduate organic chemistry lab, students tetraalkylate tertbutylcalix[4]arene, a bowl-shaped macrocyclic oligophenol, and examine the supramolecular chemistry of the tetraether product by proton nuclear magnetic resonance (NMR) spectroscopy. Complexation with a sodium ion reduces the conformational…

Catalytic olefin polymerization with early transition metal compounds

OpenAIRE

Eshuis, Johan Jan Willem

1991-01-01

The catalysis of organic reactions by soluble metal complexes has become a major tool in synthesis, both in the laboratory and in the chemical industry. Processes catalyzed by transition metal complexes include carbonylation, olefin polymerization, olefin addition, olefin oxidation and alkane and arene oxidation. Traditionally, heterogeneous catalysts have been used for the production of large-scale commodity chemicals such as methanol and ammonia and in the production of high octane gasoline...

Studies of coupled chemical and catalytic coal conversion methods

Energy Technology Data Exchange (ETDEWEB)

Stock, L.M.

1990-01-01

This report concerns our research on base-catalyzed coal solubilization and a new approach for hydrogen addition. The work on base-catalyzed, chemical solubilization is continuing. this report is focused on the hydrogenation research. Specifically it deals with the use of arene chromium carbonyl complexes as reagents for the addition of dideuterium to coal molecules. In one phase of the work, he has established that the aromatic hydrocarbons in a representative coal liquid can be converted in very good yield to arene chromium carbonyl compounds. In a second phase of the work directly related to our objective of improved methods for catalytic hydrogenation, he has established that the aromatic constituents of the same coal liquid add dideuterium in the presence of added napththalene chromium carbonyl.

Studies of coupled chemical and catalytic coal conversion methods. Tenth quarterly report, January--March 1990

Energy Technology Data Exchange (ETDEWEB)

Stock, L.M.

1990-12-31

This report concerns our research on base-catalyzed coal solubilization and a new approach for hydrogen addition. The work on base-catalyzed, chemical solubilization is continuing. this report is focused on the hydrogenation research. Specifically it deals with the use of arene chromium carbonyl complexes as reagents for the addition of dideuterium to coal molecules. In one phase of the work, he has established that the aromatic hydrocarbons in a representative coal liquid can be converted in very good yield to arene chromium carbonyl compounds. In a second phase of the work directly related to our objective of improved methods for catalytic hydrogenation, he has established that the aromatic constituents of the same coal liquid add dideuterium in the presence of added napththalene chromium carbonyl.

Fluorinated arene, imide and unsaturated pyrrolidinone based donor acceptor conjugated polymers: Synthesis, structure-property and device studies

Science.gov (United States)

Liyanage, Arawwawala Don Thilanga

After the discovery of doped polyacetylene, organic semiconductor materials are widely studied as high impending active components in consumer electronics. They have received substantial consideration due to their potential for structural tailoring, low cost, large area and mechanically flexible alternatives to common inorganic semiconductors. To acquire maximum use of these materials, it is essential to get a strong idea about their chemical and physical nature. Material chemist has an enormous role to play in this novel area, including development of efficient synthetic methodologies and control the molecular self-assembly and (opto)-electronic properties. The body of this thesis mainly focuses on the substituent effects: how different substituents affect the (opto)-electronic properties of the donor-acceptor (D-A) conjugated polymers. The main priority goes to understand, how different alkyl substituent effect to the polymer solubility, crystallinity, thermal properties (e.g.: glass transition temperature) and morphological order. Three classes of D-A systems were extensively studied in this work. The second chapter mainly focuses on the synthesis and structure-property study of fluorinated arene (TFB) base polymers. Here we used commercially available 1,4-dibromo-2,3,5,6-tetrafluorobenzene (TFB) as the acceptor material and prepare several polymers using 3,3'-dialkyl(3,3'-R2T2) or 3,3'-dialkoxy bithiophene (3,3'-RO2T2) units as electron donors. A detail study was done using 3,3'-bithiophene donor units incorporating branched alkoxy-functionalities by systematic variation of branching position and chain length. The study allowed disentangling the branching effects on (i) aggregation tendency, intermolecular arrangement, (iii) solid state optical energy gaps, and (iv) electronic properties in an overall consistent picture, which might guide future polymer synthesis towards optimized materials for opto-electronic applications. The third chapter mainly focused on

Dam's design continues throughout construction

Energy Technology Data Exchange (ETDEWEB)

Lara E, R; Wulff, J G

1979-11-01

In spite of adverse site conditions, Arenal dam in Costa Rica was completed a year ahead of schedule. Historical data on local earthquake activity which was available in unusual detail reduced some uncertainties in design information. Other uncertainties regarding the complex foundation conditions were resolved as excavation and construction progressed.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

... copper(II)/copper(I) couple. The ancillary ligand plays a significant role in binding and cleavage activity. Volume 114 Issue 5 October 2002 pp 461-472 Inorganic and Analytical. Half-sandwich (-arene)ruthenium(II) chiral Schiff base complexes: Analysis of the diastereomeric mixtures in solution by 2D-NMR spectroscopy.

Calixarene methylene bisphosphonic acids as promising effectors of biochemical processes

Directory of Open Access Journals (Sweden)

S. V. Komisarenko

2013-12-01

Full Text Available This interdisciplinary study, performed with participation of research workers of Palladin Institute of Biochemistry and Institute of Organic Chemist­ry of NAS of Ukraine, is devoted to analysis of biochemical effects of some calixarene methylene bisphosphonic acids (cyclic phenol oligomers on two well-known biological phenomenons – Mg2+-dependent ATP hydrolysis (myosin subfragment-1 of myometrium smooth muscle was used as an example and fibrin polymerization. Calix[4]arene С-97 (calix[4]arene methylene bisphosphonic acids is a macrocyclic substance, which contains intramolecular highly ordered lipophilic cavity formed by four aromatic rings, one of which is functionalized at the upper rim with methylene bisphosphonic group. At concentration of 100 µM, this substance was shown to effectively inhibit ATPase activity of pig myometrium myosin subfragment-1 (inhibition coefficient І0.5 = 83 ± 7 µM. At the same time, this calix[4]arene causes significant (vs. control increase of myosin subfragment-1 hydrodynamic diameter, which may indicate formation of an intermolecular complex between calixa­rene and myosin head. Computer simulation methods (docking and molecular dynamics with addition of grid technologies enabled to elucidate the grounds of intermolecular interactions between calix[4]arene С-97 and myometrium myosin subfragment-1, that involve hydrophobic, electrostatic and π-π-stacking interactions, some of which are close to the ATPase active centre. In view of the ability of calixarenes to penetrate into the cell and their low toxicity, the results obtained may be used as a basis for further development of a new generation of supramolecular effectors (starting from the above mentioned substances, in particular calix[4]arene С-97 for regulation of smooth muscle contractile activity at the level of ATP dependent actin-myosin interaction. Calix[4]arenes bearing two or four methylenebisphosphonic acid groups at the macrocyclic upper

Competitive/co-operative interactions in acid base sandwich: role of cation vs. substituents.

Science.gov (United States)

Kalpana, Ayyavoo; Akilandeswari, Lakshminarayanan

2017-11-15

The cation-π interaction can be envisaged as a lewis acid base interaction, and it is in line with Pearson's acid base concept. The critical examination of interactions between the π-acids (alkali metal cations - Li + , Na + and alkaline earth metal cations Mg 2+ , Ca 2+ ) on one face and tripodal Cr(CO) 3 moiety on the other π face of substituted arenes demonstrates the role of cation and substitutents in manipulating the interactions between them. The interaction of the two π acids on both faces of arene is not expectedly additive, rather it shows either depreciation of interaction energy revealing the competition of acids toward the base or enhancement of interaction energy denoting a cooperative effect. Among the metal cations under study, Mg 2+ shows a cooperative gesture. Although the substituents play a meek role, they unfailingly exert their electronic effects and are amply documented by excellent correlation of various parameters with the Hammett constant σ m . The elusive switching of λ max from the UV to IR region on binding Mg 2+ with substituted arene-Cr(CO) 3 complex is a characteristic clue that TDDFT can help design the ionic sensors for Mg 2+ cations.

A New Homogeneous Catalyst for the Dehydrogenation of Dimethylamine Borane Starting with Ruthenium(III Acetylacetonate

Directory of Open Access Journals (Sweden)

Ebru Ünel Barın

2015-06-01

Full Text Available The catalytic activity of ruthenium(III acetylacetonate was investigated for the first time in the dehydrogenation of dimethylamine borane. During catalytic reaction, a new ruthenium(II species is formed in situ from the reduction of ruthenium(III and characterized using UV-Visible, Fourier transform infrared (FTIR, 1H NMR, and mass spectroscopy. The most likely structure suggested for the ruthenium(II species is mer-[Ru(N2Me43(acacH]. Mercury poisoning experiment indicates that the catalytic dehydrogenation of dimethylamine-borane is homogeneous catalysis. The kinetics of the catalytic dehydrogenation of dimethylamine borane starting with Ru(acac3 were studied depending on the catalyst concentration, substrate concentration and temperature. The hydrogen generation was found to be first-order with respect to catalyst concentration and zero-order regarding the substrate concentration. Evaluation of the kinetic data provides the activation parameters for the dehydrogenation reaction: the activation energy Ea = 85 ± 2 kJ·mol−1, the enthalpy of activation ∆H# = 82 ± 2 kJ·mol−1 and the entropy of activation; ∆S# = −85 ± 5 J·mol−1·K−1. The ruthenium(II catalyst formed from the reduction of ruthenium(III acetylacetonate provides 1700 turnovers over 100 hours in hydrogen generation from the dehydrogenation of dimethylamine borane before deactivation at 60 °C.

Nonlinear optical properties of systems based on ruthenium(II) tetra-15-crown-5-phthalocyaninate

International Nuclear Information System (INIS)

Grishina, A.D.; Gorbunova, Yu.G.; Enakieva, Yu.Yu.; Krivenko, T.V.; Savel'ev, V.V.; Vannikov, A.V.; Tsivadze, A.Yu.

2008-01-01

The third-order nonlinear optical properties of the ruthenium (II) complex with tetra-15-crown-5-phthalocyanine and axially coordinated triethylenediamine molecules (R 4 Pc)Ru(TED) 2 were analyzed by means of the z-scanning technique. A solution of (R 4 Pc)Ru(TED) 2 in tetrachloroethane was exposed to nanosecond laser pulses at a wavelength of 1064 nm. It was found that the third-order molecular polarizability of the Ru(II) complex is 4.5 x 10 -32 cm 4 /C (esu). The polarizability per molecule increases by a factor of 3.6 when the single molecule occurs in a supramolecular assembly of (R 4 Pc)Ru(TED) 2 complexes. The photoelectric and photorefractive properties at 1064 nm of polymer composites, determined by the supramolecular assemblies that exhibits optical absorption and photoelectric sensitivity in the near IR region, are reported [ru

para-Sulfonatocalix[6]arene-modified silver nanoparticles electrodeposited on glassy carbon electrode: preparation and electrochemical sensing of methyl parathion.

Science.gov (United States)

Bian, Yinghui; Li, Chunya; Li, Haibing

2010-05-15

In this paper, a new electrochemical sensor, based on modified silver nanoparticles, was fabricated using one-step electrodeposition approach. The para-sulfonatocalix[6]arene-modified silver nanoparticles coated on glassy carbon electrode (pSC(6)-Ag NPs/GCE) was characterized by attenuated total reflection IR spectroscopy (ATR-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), etc. The pSC(6) as the host are highly efficient to capture organophosphates (OPs), which dramatically facilitates the enrichment of nitroaromatic OPs onto the electrochemical sensor surface. The combination of the host-guest supramolecular structure and the excellent electrochemical catalytic activities of the pSC(6)-Ag NPs/GCE provides a fast, simple, and sensitive electrochemical method for detecting nitroaromatic OPs. In this work, methyl parathion (MP) was used as a nitroaromatic OP model for testing the proposed sensor. In comparison with Ag NPs-modified electrode, the cathodic peak current of MP was amplified significantly. Differential pulse voltammetry was used for the simultaneous determination of MP. Under optimum conditions, the current increased linearly with the increasing concentration of MP in the range of 0.01-80microM, with a detection limit of 4.0nM (S/N=3). The fabrication reproducibility and stability of the sensor is better than that of enzyme-based electrodes. The possible underlying mechanism is discussed.

Calixarenes, chemical chameleons

NARCIS (Netherlands)

van Dienst, E.S.; van Dienst, Erik; Iwema bakker, W.I.; Iwema Bakker, Wouter I.; Engbersen, Johannes F.J.; Verboom, Willem; Reinhoudt, David

1993-01-01

Methods for the synthesis of selectivety functionalized calix[4]arenes have been developed. These functionalized calix[4]arenes have been coupled to cavitands and cyclodextrins. A number of practical applications of calix[4]arenes are described.

1H and 13C NMR coordination-induced shifts in a series of tris(α-diimine)ruthenium(II) complexes containing pyridine, pyrazine, and thiazole moieties

International Nuclear Information System (INIS)

Orellana, G.; Ibarra, C.A.; Santoro, J.

1988-01-01

1 H and 13 C NMR chemical shifts of a series of ruthenium(II) tris chelates containing the heterocyclic ligands 2,2'-bipyridine, 2-(2-pyridyl)thiazole, 2-(2-pyrazyl)thiazole, and 2,2'-bithiazole are reported and compared to those of the corresponding free ligands. Calculated coordination-induced shifts (CIS, δ complexed - δ free ) range from +0.41 to -1.00 ppM for 1 H and from +5.8 to -3.7 ppM for 13 C nuclei. These values are discussed on the basis of the various effects (charge perturbation and field interactions) that arise upon chelation: electronic σ-donation to the metallic center via the nitrogen lone pair, d-π* back-donation to the ligand, van der Waals interactions, and magnetic anisotropy of the spectator ligands. Semiquantitative values of each effect at the different positions have been proposed, taking theoretical calculations of steric and anisotropic contributions as the starting point. Shielding van der Waals interaction between proximate atoms influences only the H(3') CIS of six-membered moieties, but to a very low extent (<0.15 ppM). Magnetic anisotropy of proximate ring currents practically determines the CIS of the α positions for all the complexed ligands examined (upfield shifts from -0.8 to -1.0 ppm), has a lower influence on external β positions (< 0.2 ppM), and is negligible for γ-protons. σ-donation deshields all the positions, its contribution increasing as protons separate from the coordinated nitrogen atom (up to 0.4 ppM). Π-back-bonding is a weaker effect (< 0.2 ppM upfield contribution) that operates mainly on the γ position of the pyridine and α and β positions of the pyrazine rings. 36 refs., 3 figs., 4 tabs

Synthesis and Biological Evaluation of Ru(II) and Pt(II) Complexes Bearing Carboxyl Groups as Potential Anticancer Targeted Drugs.

Science.gov (United States)

Martínez, Ma Ángeles; Carranza, M Pilar; Massaguer, Anna; Santos, Lucia; Organero, Juan A; Aliende, Cristina; de Llorens, Rafael; Ng-Choi, Iteng; Feliu, Lidia; Planas, Marta; Rodríguez, Ana M; Manzano, Blanca R; Espino, Gustavo; Jalón, Félix A

2017-11-20

The synthesis and characterization of Pt(II) (1 and 2) and Ru(II) arene (3 and 4) or polypyridine (5 and 6) complexes is described. With the aim of having a functional group to form bioconjugates, one uncoordinated carboxyl group has been introduced in all complexes. Some of the complexes were selected for their potential in photodynamic therapy (PDT). The molecular structures of complexes 2 and 5, as well as that of the sodium salt of the 4'-(4-carboxyphenyl)-2,2':6',2″-terpyridine ligand (cptpy), were determined by X-ray diffraction. Different techniques were used to evaluate the binding capacity to model DNA molecules, and MTT cytotoxicity assays were performed against four cell lines. Compounds 3, 4, and 5 showed little tendency to bind to DNA and exhibited poor biological activity. Compound 2 behaves as bonded to DNA probably through a covalent interaction, although its cytotoxicity was very low. Compound 1 and possibly 6, both of which contain a cptpy ligand, were able to intercalate with DNA, but toxicity was not observed for 6. However, compound 1 was active in all cell lines tested. Clonogenic assays and apoptosis induction studies were also performed on the PC-3 line for 1. The photodynamic behavior for complexes 1, 5, and 6 indicated that their nuclease activity was enhanced after irradiation at λ = 447 nm. The cell viability was significantly reduced only in the case of 5. The different behavior in the absence or presence of light makes complex 5 a potential prodrug of interest in PDT. Molecular docking studies followed by molecular dynamics simulations for 1 and the counterpart without the carboxyl group confirmed the experimental data that pointed to an intercalation mechanism. The cytotoxicity of 1 and the potential of 5 in PDT make them good candidates for subsequent conjugation, through the carboxyl group, to "selected peptides" which could facilitate the selective vectorization of the complex toward receptors that are overexpressed in

Laboratory scale investigations for testing the uptake potential of 1, 3 di octyloxy Calix(4)arene Crown 6 for separation of Cs from high level radioactive waste

International Nuclear Information System (INIS)

Thorat, Vidya; Soudamini, N.; Achare, Sanjay; Girisan, Prema; Mishra, R.K.; Kumar, Amar; Kaushik, C.P.; Banerjee, K.

2016-01-01

137 Cs one of the major beta gamma emitting fission products present in high level liquid waste (HLLW), which is generated during the reprocessing of spent nuclear fuel. Its separation will restrict the personal radiation exposure during the vitrification and prevents thermal deformation of conditioned waste matrix during storage. Separation will also reduce the volume of vitrified mass to be stored in repository. In addition 137 Cs has enormous applications as radiation sources in food preservation, sterilization of medical products, brachytherapy, blood irradiation, hygienization of sewage sludge etc. The use of 137 Cs (T 1/2 = 30 years) in place of 60 Co (T 1/2 = 5.2 years) will also reduce the shielding requirement, frequency of source replenishment and ease the handling/transportation of radioactive source. Present paper summarises experimental results pertaining to performance evaluation of indigenously synthesised 1, 3 di octyl oxy Calix(4) arene crown 6 (CC6) as extractant for recovery of caesium from HLLW

Amine-selective bioconjugation using arene diazonium salts.

Science.gov (United States)

Diethelm, Stefan; Schafroth, Michael A; Carreira, Erick M

2014-08-01

A novel bioconjugation strategy is presented that relies on the coupling of diazonium terephthalates with amines in proteins. The diazonium captures the amine while the vicinal ester locks it through cyclization, ensuring no reversibility. The reaction is highly efficient and proceeds under mild conditions and short reaction times. Densely functionalized, complex natural products were directly coupled to proteins using low concentrations of coupling partners.

JW Steed and DA Tocher

Indian Academy of Sciences (India)

LeBozec et al 1989), give rise to bis(cyclohexadienyl) complexes even when one of the arenes is the sterically congested 1,3,5-triisopropylbenzene ligand (Neto and ... It is also noteworthy that Boekelheide (Swann et al 1986) has demonstrated that the action of the hydride source red-Al upon Ru(n-2:2) paracyclophane)(n-.

Antiplasmodial activity of iron(II and ruthenium(II organometallic complexes against Plasmodium falciparum blood parasites

Directory of Open Access Journals (Sweden)

Nicolli Bellotti de Souza

2015-01-01

Full Text Available This work reports the in vitro activity against Plasmodium falciparumblood forms (W2 clone, chloroquine-resistant of tamoxifen-based compounds and their ferrocenyl (ferrocifens and ruthenocenyl (ruthenocifens derivatives, as well as their cytotoxicity against HepG2 human hepatoma cells. Surprisingly with these series, results indicate that the biological activity of ruthenocifens is better than that of ferrocifens and other tamoxifen-like compounds. The synthesis of a new metal-based compound is also described. It was shown, for the first time, that ruthenocifens are good antiplasmodial prototypes. Further studies will be conducted aiming at a better understanding of their mechanism of action and at obtaining new compounds with better therapeutic profile.

High Molar Extinction Coefficient Ru(II-Mixed Ligand Polypyridyl Complexes for Dye Sensitized Solar Cell Application

Directory of Open Access Journals (Sweden)

Malapaka Chandrasekharam

2011-01-01

Full Text Available Two new ruthenium(II mixed ligand terpyridine complexes, “Ru(Htcterpy(NCS(L1 (N(C4H94, mLBD1” and Ru(Htcterpy(NCS(L2(N(C4H94, mLBD2 were synthesized and fully characterized by UV-Vis, emission, cyclic voltammogram, and other spectroscopic means, and the structures of the compounds are confirmed by 1H-NMR, ESI-MASS, and FT-IR spectroscopes. The influence of the substitution of L1 and L2 on solar-to-electrical energy conversion efficiency (η of dye-sensitized solar cells (DSSCs was evaluated relative to reference black dye. The dyes showed molar extinction coefficients of 17600 M−1 cm−1 for mLBD1 and 21300 M−1 cm−1 for mLBD2 both at λ maximum of 512 nm, while black dye has shown 8660 M−1 cm−1 at λ maximum of 615 nm. The monochromatic incident photon-to-collected electron conversion efficiencies of 60.71% and 75.89% were obtained for mLBD1 and mLBD2 dyes, respectively. The energy conversion efficiencies of mLBD1 and mLBD2 dyes are 3.15% (SC=11.86 mA/cm2, OC=613 mV, ff=0.4337 and 3.36% (SC=12.71 mA/cm2, OC=655 mV, ff=0.4042, respectively, measured at the AM1.5G conditions, the reference black dye-sensitized solar cell, fabricated and evaluated under identical conditions exhibited η-value of 2.69% (SC=10.95 mA/cm2, OC=655 mV, ff=0.3750.

Determination of the extractive capacity of para-tert butyl calix[8]arene octa-phosphinoylated towards uranyl ions from an aqueous-acidic-salty medium

International Nuclear Information System (INIS)

Serrano V, E. C.

2011-01-01

The extraction properties of octa-phosphinoylated para-tert butyl calix[8]arene (prepared in the laboratory) in chloroform towards uranyl ions from an aqueous-acidic-salty medium (HNO 3 -3.5 NaNO 3 ) containing uranyl nitrate salt, was investigated. Two spectroscopic techniques UV/Vis and Luminescence were used for this study. The latter permitted analyze the fluorescence from the uranyl ions influenced by the surrounding medium. Both permitted to learn about the power of this calixarene as extractant towards the mentioned ions. Its extraction ability or capability using this calixarene at 5.91 x 10 -4 M towards the uranyl ions was 400% as determined by UV/Vis while fluorescence revealed 100% of uranyl ion extraction. A closed analysis of the results obtained by using these techniques revealed that the stoichiometry of the main extracted species was 1calixarene:2 uranyl ions. The loading capacity of the calixarene ligand towards the uranyl ions was also investigated using both techniques. UV/Vis resulted to be inadequate for quantifying exactly the loading capacity of the calixarene whereas luminescence was excellent indeed, using a 5.91 x 10 -4 M calixarene concentration, its loading capacity was 0.157 M of free uranyl ions from 0.161 M of uranyl ions present in the aqueous-acidic-salty medium. The extracts from the ability and capacity studies were concentrated to dryness, purified and the dried extracts were analyzed by infrared and neutron activation analysis. By these techniques it was demonstrated that during the extraction of the uranyl ions by the calixarene ligand they form thermodynamically and kinetically stable complexes, since in the solid state, the 1:2, calixarene; uranyl ions stoichiometry was kept with the minimum formula: (UO 2 ) 2 B 8 bL 8 (NO 3 ) 4 (H 2 O) 4 CHCl 3 (CH 3 OH) 3 the methanol molecules come from its purification. It is proposed that B 8 bL 8 calixarene in chloroform medium is a good extractant for the treatment of nuclear wastes or

Synthesis of a ruthenium(II) bipyridyl complex coordinated by a functionalized Schiff base ligand: characterization, spectroscopic and isothermal titration calorimetry measurements of M2+ binding and sensing (M2+=Ca2+, Mg2+).

Science.gov (United States)

Dixit, Namrata; Mishra, Lallan; Mustafi, Sourajit M; Chary, Kandala V R; Houjou, Hirohiko

2009-07-01

Bis-[methylsalicylidine-4'benzoic acid]-ethylene (LH2) complexed with cis-Ru(bpy)2Cl(2).2H2O provides a complex of composition [Ru(bpy)2L].2NH4PF6 (1), which has been characterized spectroscopically. Its binding behaviour towards Mg2+ and Ca2+ ions is monitored using 1H NMR titration, isothermal titration calorimetry (ITC) and luminescence microscopy. The luminescent ruthenium complex binds Ca2+ in a more selective manner as compared to Mg2+.

Liquid-liquid extraction of U(VI), Np(V) et Th(IV) ions by two calix[4]arene carboxyls, and effect of Na+ and K+ alkaline ions

International Nuclear Information System (INIS)

Montavon, Gilles

1996-01-01

As the process mainly used for the reprocessing of nuclear wastes was the Purex process, this research thesis first presents this process and outlines that it allows the residual fissile matter to be recovered and reused for the fabrication of new fuel elements, but is neither efficient nor safe enough to separate fission and activation products. Thus, this thesis reports the study of extraction and selectivity properties of two compounds derived from the p-tert-butyl-calix[4]arene with respect to actinide ions such as Th(IV), U(VI) and Np(VI). The liquid-liquid extraction technique has been used with chloroform and 1,2-dichloroethane as solvents. After some generalities on actinides, calixarenes and the liquid-liquid extraction technique, and a presentation of the experimental method, the author reports and discusses the extractive properties of the studied calixarenes with respect to Na + and K + ions. Structural studies by proton NMR have been performed. He reports and discusses the liquid-liquid extraction on actinide ions when they are alone or in presence on Na + and K + alkaline ions [fr

Phenylalanine-a biogenic ligand with flexible η6- and η6:κ1-coordination at ruthenium(ii) centres

KAUST Repository

Reiner, Thomas; Jantke, Dominik; Miao, Xiaohe; Marziale, Alexander N.; Kiefer, Florian J.; Eppinger, Jö rg

2013-01-01

The reaction of (S)-2,5-dihydrophenylalanine 1 with ruthenium(iii) chloride yields the μ-chloro-bridged dimeric η6-phenylalanine ethyl ester complex 3, which can be converted into the monomeric analogue, η6:κ1-phenylalanine ethyl ester complex 12, under basic conditions. Studies were carried out to determine the stability and reactivity of complexes bearing η6- and η6: κ1-chelating phenylalanine ligands under various conditions. Reaction of 3 with ethylenediamine derivatives N-p-tosylethylenediamine or 1,4-di-N-p-tosylethylenediamine results in the formation of monomeric η6:κ1-phenylalanine ethyl ester complexes 14 and 15, which could be saponified yielding complexes 16 and 17 without changing the inner coordination sphere of the metal centre. The structure of η6:κ1-phenylalanine complex 17 and an N-κ1-phenylalanine complex 13 resulting from the reaction of 3 with an excess of pyridine were confirmed by X-ray crystallography. © 2013 The Royal Society of Chemistry.

The income distribution and contribution of palm sugar producer in increasing the household welfare of palm sugar maker in Kolaka Southeast Sulawesi Indonesia

Science.gov (United States)

Rianse, I. S.; Rianse, U.; Abdullah, W. G.; Hartono, S.; Suryantini, A.; Jamhari; Muhidin

2018-02-01

The objective of the research were to analyze socio-economic characteristics and motivation of farmers in aren sugar processing business in Kolaka District, Southeast Sulawesi, Indonesia. The analysis used in this research was quantitative descriptive analysis. The results showed that average state of socio-economic characteristics of aren sugar farmer that were in the category of productive age, which was 46.12 years old, has fulfill basic education category (9 years education), low category of dependents as many as three people, the Average experience of aren sugar processing business during 18 years, and the Average aren trees were tapped as much as seven trees, every day, (b) farmer’s motivation in aren sugar processing business in low category, with the indicator is the motive of imitation, economic, security, affiliations, awards, and self-actualization

Study of the simultaneous complexation of a cation and of an anion using functionalized calixarenes; Etude de la complexation simultanee d'un cation et d'un anion par des calixarenes fonctionnalises

Energy Technology Data Exchange (ETDEWEB)

Moli, Ch [CEA Cadarache, Dept. d' Etudes des Dechets, DED, 13 - Saint Paul lez Durance (France); [Universite Louis Pasteur, 67 - Strasbourg (France)

2002-03-01

The chemical reprocessing of irradiated nuclear fuels leads to the production of high-level radioactive liquid wastes which contain long-lived toxic radioelements. In the framework of the long-term management of these wastes, important research work is carried out for the separation of these radioelements for their further transmutation or immobilization inside specific matrices. These radioelements are present in acid solutions of fission products in the form of cations (cesium), anions (technetium, selenium) and molecules (iodine). Crown calixarenes have been successfully used for the extraction of cesium thanks to their exceptional selectivities. This work is mainly based on the use of the chelating properties of calixarenes for the extraction of anionic radioelements. Calixarenes functionalized by amino-carbon chains have been selected. The synthesis of amine calix[4]arenes and calix[6]arenes is described and their extractive and ionophoretic properties with respect to radioelements are shown using aqueous selective separation techniques like the liquid-liquid extraction and the supported liquid membrane transport. Technetium and selenium are extracted by amine calixarenes from a 10{sup -2} M aqueous solution of nitric acid. At this acidity, no selenium transport is observed, while technetium transport is efficient: the solution is quasi-totally decontaminated in 6 hours. Molecular iodine is efficiently extracted with a simple organic diluent, the 1,2-nitro-phenyl-hexyl-ether, from a strongly concentrated aqueous solution of nitric acid (HNO{sub 3} = 3 M). The transport of iodine becomes faster and more efficient when its concentration in the solution is higher. (J.S.)

Preparation of Organic-Inorganic Hybrid Materials Based on MCM-41 and Its Applications

Directory of Open Access Journals (Sweden)

Sana M. Alahmadi

2013-01-01

Full Text Available This work reports the covalent attachment of three different calix[4]arenes (calix[4]arene (C4, p-sulfonatocalix[4]arene (C4S, and p-tert-butyl-calix[4]arene (PC4 to MCM-41, using a three-step modification process. 3-Chloropropyltrimethoxysilane (ClPTS was first attached to the mesoporous silica surface and subsequently converted to amides via the reaction with toluene diisocyanate (TDI. Finally, calix[4]arene derivatives attached to the isocyanate ending remained available on toluene di-iso-cyanate. Changes in the surface properties of the mesoporous silica caused by the chemical modification were monitored using the Fourier transform infrared spectroscopy (FTIR, thermal analysis (TGA, and elemental analysis. The FTIR spectra and TGA analysis verify that the calix[4]arene derivatives are covalently attached to the mesoporous silica. The preservation of the MCM-41 channel system was checked by the X-ray diffraction and nitrogen adsorption analysis. These materials were then used to evaluate the sorption properties of some organotins compounds (Tributyltin (TBT, Triphenyltin (TPT, and Dibutyltin (DBT.

Self-assembled Thiolated Calix[n]arene (n=4, 6, 8) Films on Gold Electrodes and Application for Electrochemical Determination Dopamine

International Nuclear Information System (INIS)

Zheng, Gang; Chen, Ming; Liu, Xinyue; Zhou, Jun; Xie, Ju; Diao, Guowang

2014-01-01

Highlights: • TCnA/GE was prepared by using a simple self-assembled strategy. • Multilayer self-assembled films of TCnA molecules were fabricated on GE. • TCnA/GE exhibited high supramolecular recognition and enrichment capability. • TC8A/GE showed excellent electrochemical performance for DA. - Abstract: In this study, gold electrodes (GE) modified with three kinds of thiolated calix[4,6,8]arenes (TCnA: TC4A, TC6A, TC8A) were successfully prepared using a simple self-assembly strategy. Three self-assembled films were characterized by cyclic voltammetry measurement, electrochemical impedance spectroscopy, static contact angle measurement and atomic force microscopy. The results confirmed that TCnA molecules effectively absorbed onto the surface of gold electrodes to fabricate the multilayer self-assembled films. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurement showed that the TCnA/GE exhibited high supramolecular recognition and enrichment capability and consequently displayed good electrochemical response toward dopamine (DA). Especially, TC8A/GE exhibited an excellent electrochemical performance for DA with high current densities of 1.5 mA mmol −1 L cm −2 , broad linear range (1 × 10 −6 to 1 × 10 −3 mol L −1 ) and low detection limit (5 × 10 −7 mol L −1 ). The mechanism of supramolecular recognition and enrichment capability of TCnA/GE was discussed

Ion selective electrode for cesium based on 5-(4'-nitrophenylazo)25,27-bis(2-propyloxy)26,28-dihydroxycalix[4]arene.

Science.gov (United States)

Ramanjaneyulu, P S; Singh, Parminder; Sayi, Y S; Chawla, H M; Ramakumar, K L

2010-03-15

A polyvinylchloride (PVC) based liquid membrane ion selective electrode (ISE) for cesium was fabricated with 5-(4'-nitrophenylazo)25,27-bis(2-propyloxy)26,28-dihydroxycalix[4]arene as ionophore. Different membrane constituents were investigated to realise optimum performance of the ISE developed. Of the four plasticizers and two ion additives studied, the best response was observed with membrane having 2-nitro phenyl octyl ether (oNPOE) as plasticizer and potassium tetrakis (perchloro phenyl) borate (KTpClPB) as ion additive. Linear response over concentration range of 10(-5)-10(-1)M CsCl was obtained. The Nernstian slope of the response was 56 mV per decade for Cs with a response time less than 20s. Matched potential method has been applied to find out the selectivity for Cs over several ions like Rb(+), K(+), Na(+), NH(4)(+), Sr(2+), Ba(2+), Ca(2+), Mg(2+), Cu(2+), Pb(2+), Zn(2+), Ni(2+) and Ce(3+). The response of ISE for Cs(+) was fairly constant over the pH range of 3-11. The lifetime of the electrode is 9 months which is the longest life for any membrane-based Cs-ISE so far developed. The concentration of cesium in two simulated high level active waste streams was determined and results agreed well with those obtained independently employing atomic absorption spectrometry. (c) 2009 Elsevier B.V. All rights reserved.

para-Sulfonatocalix[4]arene and polyamidoamine dendrimer nanocomplexes as delivery vehicles for a novel platinum anticancer agent.

Science.gov (United States)

Pang, Chi Ting; Ammit, Alaina J; Ong, Yu Qing Elysia; Wheate, Nial J

2017-11-01

Novel para-sulfonatocalix[4]arene (sCX[4]) and polyamidoamine (PAMAM) dendrimer nanocomplexes were evaluated as delivery vehicles for the platinum anticancer agent [(1,10-phenanthroline)(1S,2S-diaminocyclohexane)platinum(II)] chloride (PHENSS). Different ratios of sCX[4] to PHENSS were tested for their compatibility, with a ratio of 6:1 sCX[4]:PHENSS having the best solubility. The loading of sCX[4], and sCX[4]-bound PHENSS, onto three different generations of PAMAM dendrimers (G3.0-5.0) was examined using UV-visible spectrophotometry. The quantity of sCX[4] bound was found to increase exponentially with dendrimer size: G3, 15 sCX[4] molecules per dendrimer; G4, 37; and G5, 78. Similarly, the loading of sCX[4]-bound PHENSS also increased with increasing dendrimer size: G3, 7 PHENSS molecules per dendrimer; G4, 14; and G5, 28.5. The loading of sCX[4]-bound PHENSS molecules is significantly lower when compared with that of sCX[4], which indicates that less than half of the binding sites were occupied (45, 44, and 44%, respectively). By 1 H NMR and UV-vis analysis, the nanocomplex was found to be stable in NaCl solutions at concentrations up to 150mM. While PHENSS is more active in vitro than cisplatin against the human breast cancer cell line, MCF-7, delivery of PHENSS using the sCX[4]-dendrimer nanocomplexes, regardless of dendrimer generation, had little effect on PHENSS cytotoxicity. The results of this study may have application in the delivery of a variety of small molecule metal-based drugs for which chemical conjugation to a nanoparticle is undesired or not feasible. Copyright © 2017 Elsevier Inc. All rights reserved.

Simultaneous Enrichment of Polycyclic Aromatic Hydrocarbons and Cu(2+) in Water Using Tetraazacalix[2]arene[2]triazine as a Solid-Phase Extraction Selector.

Science.gov (United States)

Zhao, Wenjie; Yang, Liu; He, Lijun; Zhang, Shusheng

2016-08-10

On the basis of the definite retention mechanism proven by the stationary phase for high-performance liquid chromatography, tetraazacalix[2]arene[2]triazine featuring multiple recognition sites was assessed as a solid-phase extraction (SPE) selector. The applicability of its silica support was used for the extraction of trace amounts of polycyclic aromatic hydrocarbons (PAHs) and Cu(2+) in aqueous samples, followed by high-performance liquid chromatography fluorometric and graphite furnace atomic absorption spectrometric determination. On the basis of the π-π interaction with PAHs and the chelating interaction with Cu(2+), the simultaneous extraction of PAHs and Cu(2+) and stepwise elution through tuning the eluent were successfully achieved, respectively. The SPE conditions affecting the extraction efficiency were optimized, including type and concentration of organic modifier, sample solution pH, flow rate, and volume. As a result of the special adsorption and desorption mechanism, high extraction efficiency was achieved with relative recoveries of 94.3-102.4% and relative standard deviations of less than 10.5%. The limits of detection were obtained with 0.4-3.1 ng L(-1) for PAHs and 15 ng L(-1) for Cu(2+), respectively. The method was applied to the analyses of PAHs and Cu(2+) in Xiliu Lake water samples collected in Zhengzhou, China.