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Copper Complexes (copper + complex)
Selected AbstractsStability of disubstituted copper complexes in the gas phase analyzed by electrospray ionization mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2010Ines Starke A series of nitrogen ligand (L)/copper complexes of the type [CuIL]+, [CuIIL(X)]+ and [CuIL2]+ (X,=,Cl,, BF, acac,, CH3COO, and SO3CF) was studied in the gas phase by electrospray ionization mass spectrometry. The following ligands (L) were employed: 1,12-diazaperylene (dap), 1,1,-bisisoquinoline (bis), 2,2,-bipyridine (bpy), 1,10-phenanthroline (phen), 2,11-disubstituted 1,12-diazaperylenes (dap), 3,3,-disubstituted 1,1,- bisisoquinoline (bis), 5,8-dimethoxy-substituted diazaperylene (meodap), 6,6,- dimethoxy-substituted bisisoquinoline (meobis) and 2,9-dimethyl-1,10-phenanthroline (dmphen). Collision-induced decomposition measurements were applied to evaluate the relative stabilities of the different copper complexes. The influence of the spatial arrangement of the ligands, of the type of substituents and of the counter ion of the copper salts employed for the complexation was examined. Correlations were found between the binding constants of the [ML2]+ complexes in solution and the relative stabilities of the analogous complexes in the gas phase. Furthermore, complexation with the ligands 2,11-dialkylated 1,12-diazaperylenes [alkyl,=,ethyl (dedap) and isopropyl (dipdap)] was studied in the solvents CH3OH and CH3CN. Copyright © 2010 John Wiley & Sons, Ltd. [source] Ligand-Accelerated Asymmetric [1,2]-Stevens Rearrangment of Sulfur Ylides via Decomposition of Diazomalonates Catalyzed by Chiral Bisoxazoline/Copper ComplexADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009Jian-Ping Qu Abstract The first example of catalytic asymmetric [1,2]-Stevens rearrangement reaction of 1,3-oxathiolanes with diazomalonates has been developed and up to 90% ee is achieved by the bisoxazoline 4e/copper(II) triflate [Cu(OTf)2] complex. [source] ChemInform Abstract: Ligand-Accelerated Asymmetric [1,2]-Stevens Rearrangement of Sulfur Ylides via Decomposition of Diazomalonates Catalyzed by Chiral Bisoxazoline/Copper Complex.CHEMINFORM, Issue 25 2009Jian-Ping Qu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Tuning the Magnetic Properties of a Dinuclear Copper Complex: From Ferromagnetic to Antiferromagnetic CouplingEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2004Simon P. Foxon Abstract A novel structural motif in oxalate bridged copper(II) complexes has been prepared namely a metallamacrocyclic compound of the dinucleating ligand 1,3-bis[bis(2-pyridylmethyl)amino]benzene (= 1,3-tpbd). It could be demonstrated that the magnetic properties of copper(II) complexes of the 1,3-tpbd ligand can be adjusted from weakly ferromagnetic (J = +9.3 cm,1) to strongly antiferromagnetic [J = ,366(9) cm,1] by variation of the additional ligands (e.g. perchlorate, azide, oxalate etc.). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] ChemInform Abstract: Reusable Polymer-Supported Terpyridine Copper Complex for [3 + 2] Huisgen Cycloaddition in Water.CHEMINFORM, Issue 33 2010Toshimasa Suzuka No abstract is available for this article. [source] ChemInform Abstract: Asymmetric 1,4-Conjugate Addition of Diethylzinc to Cyclic Enones Catalyzed by a Self-Assembled Copper Complex.CHEMINFORM, Issue 15 2010Shaohua Gou Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: In situ Generation of Novel Acyclic Diaminocarbene,Copper Complex.CHEMINFORM, Issue 37 2009Dimitri Hirsch-Weil Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Synthesis and Crystal Structure of a Novel A-Zeolite-Like Copper Complex: [Cu12(SO4)12(3H2O)] ×H2O.CHEMINFORM, Issue 4 2008Xing-Jing Zhang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Polymer-Supported Copper Complex for C,N and C,O Cross-Coupling Reactions with Aryl Boronic Acids.CHEMINFORM, Issue 50 2004Gary C. H. Chiang Abstract For Abstract see ChemInform Abstract in Full Text. [source] Solvent-Free Oxidation of Alcohols by t-Butyl Hydroperoxide Catalyzed by Water-Soluble Copper Complex.CHEMINFORM, Issue 13 2004Gabriel Ferguson Abstract For Abstract see ChemInform Abstract in Full Text. [source] Synthesis, DNA-Inhibiting and Antitumor Activity of Thiosemicarbazones of 2-Formyl-2,5-dimethoxy-2,3-dihydro-4H-pyran, Its Ethyl Analogue and Copper Complex.CHEMINFORM, Issue 3 2003N. A. Keiko No abstract is available for this article. [source] Synthesis and Crystal Structure of the Copper Complex of 7,16-Bis(2-hydroxy-5-methylbenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecaneCHINESE JOURNAL OF CHEMISTRY, Issue 1 2004Shu-Lan Ma Abstract A lariat crown ether ligand 7.16-bis (2-hydroxy-5-methylbenzyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (Ll) has been prepared via one-pot Mannich reaction. Its copper(II) complex Cu-Ll was synthesized and characterized by elemental analysis, IR and UV-visible spectroscopy. The crystal structure of the complex has been determined by X-ray diffraction analysis. The result shows that the copper(II) ion is six-coordinated by two nitrogen and four oxygen atoms, two from the crown ether and the other two from the deprotonated phenolate anions, forming an elongated octahedral complex. Electrochemical study indicates that the complex undergoes reversible reduction in DMF solution. [source] Synthesis, Structure and Characterization of Two-dimensional Network Copper Complex [Cu3(nta)2(azpy)2(H2O)2]·6H2OCHINESE JOURNAL OF CHEMISTRY, Issue 2 2002Bao-Long Li Abstract The copper(II) complex[Cu3(nta)2(azpy)2(H2O)2]·6H2O (nta = nitrilotriacetate, azpy = 4,4,-azobispyridine) has been synthesized and characterized. The X-ray analysis reveals that there are two kinds of copper(II) coordination environments. Cu(1) has a distorted square plane symmetry and Cu(2) has a distorted octahedral symmetry. Cu(1) is linked to Cu(2) through nta and bound to Cu(1C) by azpy, and Cu(2) is linked to Cu(2A) through azpy, which extends to two-dimensional network with large rhombus 1.2 nm × 1.7 nm. [source] Copper Complexes with Neutral N4 Tripodal Ligands: Influence of the Number of Nitrogen Donors on Their Structures, Properties, and Reactivity,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 26 2009Kiyoshi Fujisawa Abstract Copper coordination complexes of the neutral tetradentate nitrogen-containing ligands tris(3,5-dimethylpyrazol-1-ylmethyl)amine (L0N4) and tris(3,5-diisopropylpyrazol-1-ylmethyl)amine (L1N4), namely the copper(II) chlorido complexes [CuII(L0N4)Cl2] (1) and [CuII(L1N4)Cl2] (2), the copper(II) nitrato complexes [CuII(L0N4)(NO3)](NO3) (3) and [CuII(L1N4)(NO3)](NO3) (4), and the copper(II) sulfato complexes [CuII(L0N4)(SO4)] (5) and [CuII(L1N4)(SO4)] (6), and the copper(I) complexes [CuI(L0N4)](PF6) (7) and [CuI(L0N4)(PPh3)](ClO4) (8), have been systematically synthesized in order to investigate the influence of the number of nitrogen donors on their structures, properties, and reactivity. All copper(II) complexes were fully characterized by X-ray crystallography and by IR/far-IR, UV/Vis absorption, and ESR spectroscopy. Although the structure of 7 was not determined by X-ray crystallography, this complex and the structurally characterized copper(I) triphenylphosphane complex 8 were fully characterized by IR/far-IR and NMR spectroscopy. A comparison of the copper(II) complexes with two tris(pyrazol-1-ylmethyl)amine ligands with different bulkiness of the pyrazolyl rings has allowed us to evaluate the second coordination sphere effects of the ligands. Moreover, the structures and physicochemical properties of these complexes are compared with those of related complexes containing the neutral tridentate tris(pyrazolyl)methane ligand and the neutral bidentate bis(pyrazolyl)methane ligand. Finally, the relative stability of the copper(I) complexes is discussed. The influence of the number of nitrogen donors in copper complexes is observed from these systematic results.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Copper Complexes with (2,7-Di- tert -butylfluoren-9-ylidene)methanedithiolate: Oxidatively Promoted Dithioate Condensation,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2006José Vicente Abstract The reaction of [Cu(NCMe)4]PF6 with piperidinium 2,7-di- tert -butyl-9H -fluorene-9-carbodithioate (pipH)[S2C(tBu-Hfy)] (1; tBu-Hfy = 2,7-di- tert -butylfluoren-9-yl), affords [Cun{S2C(tBu-Hfy)}n] (2), which reacts with various P ligands to give [Cu{S2C(tBu-Hfy)}L2] [L = PPh3 (3a), PCy3 (3b), PiPr3 (3d); L2 = 1,1,-bis(diphenylphosphanyl)ferrocene (dppf, 3c), bis(diphenylphosphanyl)methane (dppm, 3e)]. Compounds 3a,c react with atmospheric oxygen and moisture in the presence of NEt3 to give the dinuclear complexes [Cu2{[SC=(tBu-fy)]2S}L2] [tBu-fy = 2,7-di- tert -butylfluoren-9-ylidene; L = PPh3 (4a), PCy3 (4b); L2 = dppf (4c)], which contain a new dithiolato ligand formally resulting from the condensation of two dithioato ligands with loss of a sulfide ion and two protons. Neutral CuI dithiolate complexes of the type [Cu4{S2C=(tBu-fy)}2L4] [S2C=(tBu-fy) = [2,7-di- tert -butylfluoren-9-ylidene)methanedithiolate; L = PPh3 (5a), P(C6H4OMe- p)3 (5b), PiPr3 (5d) or L2 = dppf (5c)] were obtained by treating 1 with [Cu(NCMe)4]PF6, the corresponding phosphane, and piperidine in a 1:2:2:1 molar ratio. The reaction of 1 with Cu(ClO4)2·6H2O and (Pr4N)OH in a 2:1:2 molar ratio gives the CuII complex (Pr4N)2[Cu{S2C=(tBu-fy)}2] [(Pr4N)26], which readily oxidizes to the CuIII complex Pr4N[Cu{S2C=(tBu-fy)}2] (Pr4N7) in the presence of atmospheric oxygen and moisture. The salt PPN7 [PPN+ =(Ph3P)2N+] was obtained from 1, CuCl2·2H2O, PPNCl, and piperidine in a 2:1:1:2 molar ratio under aerobic conditions. The crystal structures of 3a, 3c·CH2Cl2, 4a·4Me2CO, and 4c·CH2Cl2 have been determined by X-ray diffraction studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] ChemInform Abstract: Syntheses of Acetonitrile-Ligated Copper Complexes with Perfluoroalkoxy Aluminate as Counter Anion and Their Catalytic Application for Olefin Aziridination.CHEMINFORM, Issue 3 2009Yang Li Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Highly Enantioselective Insertion of Carbenoids into N,H Bonds Catalyzed by Copper Complexes of Chiral Spiro Bisoxazolines.CHEMINFORM, Issue 37 2007Bin Liu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Chiral Copper Complexes of Phosphino Sulfenyl Ferrocenes as Efficient Catalysts for Enantioselective Formal Aza Diels,Alder Reactions of N-Sulfonyl Imines.CHEMINFORM, Issue 22 2004Olga Garcia Mancheno Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Enantioselective Catalytic Cyclopropanation of Styrenes by Copper Complexes with Chiral Pinene-[5,6]-bipyridine Ligands.CHEMINFORM, Issue 14 2001Didier Loetscher Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Modulation of the Aerobic Oxidative Polymerization in Phenylazomethine Dendrimers Assembling Copper ComplexesCHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2010Dr. Takane Imaoka Abstract The aerobic oxidative polymerization of phenol derivatives can provide poly(phenylene oxide)s, which are known as engineering plastics. This oxidation can be carried out with atmospheric oxygen molecules as the oxidizing reagent in the presence of copper complexes as the catalyst; however, stoichiometric or excess amounts of bases are also generally required. By using a phenylazomethine dendrimer complexed with several equivalent amounts of copper chloride, the additive (base)-free polymerization of 2,6-difluorophenol was successful with a very small amount of the catalyst (0.7,mol,% of copper for the monomer) because the dendrimer was composed of many Schiff base units, affording a base and catalyst (copper complex) condensed reaction field. The resulting polymer was nearly linear and the molecular weight was very high. When the equimolar amount of the copper complex in one dendrimer molecule was increased, the polymer obtained under this reaction condition was rather branched, resulting in a higher glass transition temperature. [source] Synthesis of C1 -Symmetric BINOLs Employing N-Heterocyclic Carbene,Copper ComplexesCHEMISTRY - A EUROPEAN JOURNAL, Issue 38 2009Alain Grandbois Fucntionalizing BINOL: Bis-NHCCu complexes can be used for the oxidative coupling of 2-naphthols. Product yields are highest when using electron-deficient 2-naphthols. Mixed couplings between electron-rich and electron-poor 2-naphthols can be conducted to give good yields of the mixed products. [source] Antitumour activity of synthetic curcuminoid analogues (1,7-diaryl-1,6-heptadiene-3,5-diones) and their copper complexesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2006V. D. John Abstract Four new curcuminoid analogues, 1,7-bis(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione, 1a; 1,7-di(2-furyl)-1,6-heptadiene-3,5-dione, 1b; 1,7-di(2-naphthyl)-1,6-heptadiene-3,5-dione, 1c; 1,7-bis(2-chlorophenyl)-1,6-heptadiene-3,5-dione, 1d; and their copper(II) complexes of ML2 stoichiometry were synthesized and characterized by UV, IR, 1H NMR, ESR and mass spectral data. The compounds were investigated for their possible cytotoxic and antitumour activities. It was found that copper chelates are remarkably active compared with free curcuminoid analogues. All the compounds were found to be cytotoxic towards Ehrlich ascites carcinoma cells and cultured L929 (lung fibroblast cells). In the case of culture studies, concentrations needed for 50% cell death were around 5 µg/ml for copper complexes and 10 µg/ml for curcuminoid analogues. Copper complex of 1a with hydroxyl group in the phenyl ring was found to be most active towards L929cells (1 µg/ml produced 43.3 ± 1.3% cell death). Compound 1b, which possesses a furyl ring system, was found to show least activity towards increase in life span of tumour-bearing mice (increase in life span 39.31%). Copper chelates of all curcuminoid analogues showed a significant reduction (p < 0.001) of solid tumour volume in mice. Copyright © 2005 John Wiley & Sons, Ltd. [source] Controlled Assembly of [Nb6,xWxO19](8,x), (x = 0,4) Lindqvist Ions with (Amine)copper ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2008Travis M. Anderson Abstract The mixed addenda isopolyanion, [N(CH3)4]2Na2[cis -Nb2W4O19]·18H2O, reacts with Cu(NO3)2 in water and in the presence of NH2CH2CH2NH2 (en) or NH4OH at 60 °C to yield a phase that is decorated {[Cu(en)2(H2O)]2[Nb2W4O19]·2H2O (1)} or charge-balanced {[Cu(NH3)4(H2O)]2[Nb2W4O19]·8H2O (2)}, respectively, by (amine)copper complexes. The prolonged heating at 95 °C of [N(CH3)4]6[Nb10O28]·6H2O, [N(CH3)4]2Na2[cis -Nb2W4O19]·18H2O, or Na4K2[cis -Nb4W2O19]·12H2O and Cu(NO3)2 in a mixed water/amine [en or NH2CH2CH2CH2NH2 (dap)] solution results in the formation of two-dimensional materials with alternate layers of (amine)copper complexes linking Lindqvist [Nb6,xWxO19](8,x), (x = 0,4) clusters. These phasesinclude: [Cu(dap)2]3[Nb4W2O19]·7H2O (3), [Cu(dap)2]3[H2Nb6O19]·6H2O (4), [Cu(dap)2]3[Nb3W3O19]·Cl·6H2O (5), and [Cu(en)2]3[Nb4W2O19]·6H2O (6). Complexes 4 and 5 result from the decomposition of [Nb10O28]6, and [cis -Nb2W4O19]4, to [H2Nb6O19]6, and [fac -Nb3W3O19]5,, respectively, in alkaline solution. Complex 5 contains an extra-framework site that is occupied by Cl,, but this site is occupied by a water molecule in 3 and is vacant in structures 4 and 6. The results of this study suggest that charge density, cluster charge and symmetry, and cluster-cation pairing are all important parameters in the incorporation of d-electron metals onto the surfaces of [Nb6,xWxO19](8,x), (x = 0,4) clusters or into the frameworks of Lindqvist-based complex materials.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Crystal growth and magnetic properties of the copper coordination polymer [Cu(µ -C2O4)(4-aminopyridine)2(H2O)]nCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2007A. V. Prokofiev Abstract In this paper, we consider various ways of crystal growth of the polymer [Cu(µ -C2O4)(4-aminopyridine)2(H2O)]n. Single crystals of the size of 1.5×1.5×0.2 mm3 have been grown by a slow diffusion technique from solutions of the monoammine copper complex and of the mixture of potassium oxalate and aminopyridine with the stoichiometric ratio. Magnetic susceptibility and ESR measurements have been performed on single crystals large enough for investigating anisotropic properties. The susceptibility can be well described within the model of a Heisenberg antiferromagnetic spin chain. The magnetic measurements reveal a small concentration of paramagnetic moments reflecting the high quality of the single crystals. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Hexaazamacrocycle Containing Pyridine and Its Dicopper Complex as Receptors for Dicarboxylate AnionsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2005Feng Li Abstract The host,guest binding interactions of the hexaazamacrocycle [26]py2N4, in its tetraprotonated form H4[26]py2N44+ as well as in its dicopper(II) complex [Cu2([26]py2N4)(H2O)4]4+, with dicarboxylate anions of different stereoelectronicrequirements, such as oxalate (ox2,), malonate (mal2,), succinate (suc2,), fumarate (fu2,) and maleate (ma2,), were evaluated. The association constants were determined using potentiometric methods in aqueous solution, at 298.0 K and 0.10 mol·dm,3 KCl. These values for the tetraprotonated ditopic receptor with the dicarboxylate anions revealed that the main species in solution corresponds to the formation of {H4[26]py2N4(A)}2+ (pH , 4,9), A being the substrate anion. The values determined are not especially high, but the receptor exhibits selectivity for the malonate anion. The study of the cascade complexes revealed several species in solution, involving mononuclear and dinuclear complexes, mainly protonated and hydrolysed species, as well as the expected complexes [Cu2([26]py2N4)(A)(H2O)x]2+ or [Cu2([26]py2N4)(A)2(H2O)y]. Ox2, and mal2, form cascade complexes with only one anion, which will necessarily bridge the two copper atoms because of the symmetrical arrangement of the dinuclear complex. The two other studied anions, suc2, and ma2,, form species involving two substrate anions, although species with only one suc2, anion were also found. UV/Vis and EPR spectroscopy have shown that the dicopper complex can operate as a sensor to detect and quantitatively determine oxalate spectrophotometrically because of the red shift of the maximum of the visible band observed by addition of ox2, to an aqueous solution of the dinuclear copper complex. However the selectivity of [Cu2([26]py2N4)(H2O)4]4+ as a receptor for ox2, in the studied series is not sufficiently high to detect ox2, spectrophotometrically in the presence of the other anions. Molecular dynamics simulations indicated that the H4[26]py2N44+ receptor provides a large and flexible cavity to accommodate the studied anions. Molecular recognition is based in electrostatic interactions rather than in multiple hydrogen-bonding interactions acting cooperatively. By contrast, the [Cu2([26]py2N4)]4+ receptor has a well-shaped cavity with adequate size to uptake these anions as bridging ligands with formation of four Cu,O bonds. The ox2, anion is encapsulated within the cascade complex while the remaining anions are located above the N6 macrocyclic plane, suggesting a selective coordination behaviour of this receptor. In spite of our molecular simulation being carried out in gas phase, the modelling results are consistent with the solution studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] A New Trinuclear Linear Copper(II) Complex: Unusual Crystal Structure with Semi-Coordinated Thiophene Moieties and Weak Antiferromagnetic Coupling Through the Bridging Imidazolate RingsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2004Yufei F. Song Abstract A trinuclear copper(II) complex, [Cu3(imthio)2(NO3)4(MeOH)2] [where Himthio is 1,1-bis(imidazol-2-yl)-3-(thiophen-2-yl)-2-azapropane], has been synthesized by the reaction of Himthio with Cu(NO3)2·3H2O in MeOH. The structure of the copper complex is centrosymmetric and contains a linear trinuclear array of copper atoms. The central copper(II) ion, Cu1, which lies on an inversion centre, is equatorially coordinated by four nitrogen atoms from two anionic imthio ligands and axially by two semicoordinated thiophene sulfur atoms to give an octahedral environment (Cu1,S1 3.136 Å). The Himthio ligand bridges Cu1 and the terminal copper(II) ions through imidazole nitrogen atoms. The coordination around the external ions is completed by the oxygen atoms from two nitrate groups and by a methanol molecule in a distorted square-pyramidal geometry. The two terminal copper(II) complexes can be considered to be chelating ligands for the central CuII ion. The EPR spectrum of the complex in MeOH at 77 K shows two mononuclear species, as is fully confirmed by EPR simulation. Magnetic susceptibility of the complex shows weak antiferromagnetic behaviour (J = ,71.37 cm,1) caused by the overlapping of the magnetic orbitals of the copper atoms and the bridging imidazolate rings. (© Wiley-VCH Verlag GmbH & Co.. KGaA, 69451 Weinheim, Germany, 2004) [source] Metal-complex formation and DNA interaction of 5, 10,15,20-tetrakis(1-methyl-4-pyridiyl)-porphine: Study of the mechanistic aspectsINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 2 2010Sabriye Aydinoglu The macrocyclic porphyrin 5,10,15,20-tetrakis(1-methyl-4-pyridiyl)-porphine is studied in its ability to coordinate Cu(II) even at very low pH values and to interact, as a copper complex, with calf-thymus (CT-DNA). The kinetics and equilibria for metal-ligand complexes formation are spectrophotometrically studied, particularly focussing on the mechanistic information provided by the kinetic approach. The rate constants of complex formation is much lower than that of water exchange at Cu(II); this behavior is ascribed to an equilibrium between two porphyrin populations, only one of them being reactive. Concerning the interaction of the copper,porphyrin complex (D) with CT-DNA, it has been found that the complex binds to G,C base pairs by intercalation while forms external complex with the A,T base pairs. The kinetic results agree with a reaction mechanism that takes into account the slow shuffling from an AT-bound form (DAT) to a GC-bound form (DGC) of the copper complex (D), finally leading to a more stable DGC* intercalated form. Kinetic and equilibrium parameters for the copper complex binding to the nucleic acid are obtained, and the binding mechanism is discussed. A mechanism is proposed where D reacts simultaneously with (G,C) and (A,T) base pairs. The resulting bound forms interconvert according to a "shuffling" process, which involves formation of an intermediate (DGC) form. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 79,89, 2010 [source] Studies on Energetic Compounds Part,27: Kinetics and Mechanism of Thermolysis of Bis(Ethylenediamine)Metal Nitrates and Their Role in the Burning Rate of Solid PropellantsPROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 5 2003Gurdip Singh Abstract Four bis(ethylenediamine)metal(II) nitrate (BEMN) complexes, i.e. [M(EDA)2](NO3)2, where M=Cu, Co, Ni and Zn, have been prepared and characterized. Thermolysis of these complexes induced by heat and drop-weight impact has been investigated by TG-DTG, DTA, explosion delay (DE), explosion temperature (TE) and impact sensitivity measurement. The kinetics of early thermolysis reaction prior to fast decomposition have been evaluated. Contracting area (CA, n=2) and contracting cube (CC, n=3) equations were found to give the best fits in isothermal TG data among all tested nine mechanism-based kinetic models. The values of activation energy (Ea), TE, DE and activation energy for explosion (E*) have been found to be quite lower for the copper complex as compared to cobalt, nickel and zinc complexes. A mechanism of thermolysis has also been proposed. All these complexes were found to be insensitive towards impact of 2,kg weight up to the height of 110,cm. These complexes were used as energetic burning rate modifiers in the combustion of hydroxy-terminated polybutadiene (HTPB)-ammonium perchlorate (AP) composite solid propellants. A two-fold increase in burning rate was observed with copper and cobalt complexes at low concentration (2% by wt.). The in situ freshly formed metal oxides with large number of active sites in their crystallites seem to be better additives for combustion of propellants. [source] Bis[bis(methoxycarbimido)aminato]copper(II) 1-methylpyrrolidin-2-one disolvateACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Ann M. Chippindale The title compound, [Cu(C4H8N3O2)2]·2C5H9NO, consists of a neutral copper complex, in which the CuII centre coordinates to two bis(methoxycarbimido)aminate ligands, solvated by two molecules of 1-methylpyrrolidin-2-one. The complex is planar and centrosymmetric, with the CuII centre occupying a crystallographic inversion centre and adopting approximately square-planar geometry. N,H...O hydrogen-bonding interactions exist between the amine NH groups of the ligands and the O atoms of the 1-methylpyrrolidin-2-one molecules. The associated units pack to form sheets. [source] Asymmetric 1,4-conjugation addition of diethylzinc to cyclic enones catalyzed by a self-assembled copper complexAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 12 2009Shaohua Gou Abstract A new self-assembled catalyst system based on copper complex was developed for the 1,4-conjugation addition of diethyl zinc to cyclic enones. The self-assembled catalyst was readily prepared from (R)-[1,1,]binaphthalenyl-2,2,-diamine (1a), (L)-tryptophan (3f) and copper(I) chloride (CuCl). Several enones were found to be suitable substrates in the presence of the self-assembled copper catalyst [10 mol% (R)-1a, 10 mol% (L)-3f and 10 mol% CuCl] under optimized conditions. The desired products were afforded with high isolated yields (up to 98%) and moderate to good enantioselectivities (up to 80% ee) in mild conditions (at 0 °C). Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||