981 resultados para CU-2


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Copper(l) complexes of 1,2-bis(diphenylphosphino)ethane (dppe) with a stoichiometry Cu-2(dppe)(3)(X)(2) [X- = CN- (1), SCN- (2), NO3- (3)] are obtained from direct reactions of CuX and dppe. The complexes are structurally and spectroscopically (NMR and IR) characterized. The structure of the [Cu-2(dPPe)(3)](2+) dication is similar to the structural motif observed in many other complexes with a chelating dppe and a bridging dppe connecting two copper centers. In complexes 1 -3, the anions are confined to the cavity formed by the phosphines which force a monodentate coordination mode despite the predominant bidentate/bridging character of the anions. The coordination angles rather than the thermochemical radii dictate the steric requirement of anions. While the solution behavior of 3, with nitrate, is similar to complexes studied earlier, complexes with pseudohalides exhibit new solution behavior. (C) 2002 Elsevier Science Ltd. All rights reserved.

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We report here the synthesis and characterization of a few phenolate-based ligands bearing tert- amino substituent and their Zn(II) and Cu(II) metal complexes. Three mono/binuclear Zn(II) and Cu(II) complexes Zn(L1)(H2O)].CH3OH.H2O (1) (H (2) L1 = 6,6(')-(((2-dimethylamino)ethylazanediyl)bis(methylene))bis(2, 4-dimethylphenol), Zn-2(L2)(2)] (2) (H (2) L2 = 2,2(')-(((2-dimethylamino)ethyl)azanediyl)bis(methylene)bis(4- methylphenol) and Cu-2(L3)(2).CH2 Cl-2] (3) (H (2) L3 = (6,6(')-(((2-(diethylamino)ethyl)azanediyl)bis(methylene)) bis(methylene))bis(2,4-dimethylphenol) were synthesized by using three symmetrical tetradendate ligands containing N2O2 donor sites. These complexes are characterized by a variety of techniques including; elemental analysis, mass spectrometry, H-1, C-13 NMR spectroscopic and single crystal X-ray analysis. The new complexes have been tested for the phosphotriesterase (PTE) activity with the help of P-31 NMR spectroscopy. The P-31 NMR studies show that mononuclear complex Zn(L1)(H2O)].CH3OH.H2O (1) can hydrolyse the phosphotriester i.e., p-nitrophenyl diphenylphosphate (PNPDPP), more efficiently than the binuclear complexes Zn-2(L2)(2)] (2) and Cu-2(L3)(2).CH2Cl2] (3). The mononuclear Zn(II) complex (1) having one coordinated water molecule exhibits significant PTE activity which may be due to the generation of a Zn(II)-bound hydroxide ion during the hydrolysis reactions in CHES buffer at pH 9.0.

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Copper(II) and copper(I) complexes of a newly designed and crystallographically characterized Schiff base (HL) derived from rhodamine hydrazide and cinnamaldehyde were isolated in pure form formulated as Cu(L)(NO3)] (L-Cu) (1) and Cu(HL)(CH3CN)(H2O)]ClO4 (HL-Cu) (2), and characterized by physicochemical and spectroscopic tools. Interestingly, complex 1 but not 2 offers red fluorescence in solution state, and eventually HL behaves as a Cu(II) ions selective FRET based fluorosensor in HEPES buffer (1 mM, acetonitrile-water: 1/5, v/v) at 25 degrees C at biological pH with almost no interference of other competitive ions. The dependency of the FRET process on the +2 oxidation state of copper has been nicely supported by exhaustive experimental studies comprising electronic, fluorimetric, NMR titration, and theoretical calculations. The sensing ability of HL has been evaluated by the LOD value towards Cu(II) ions (83.7 nM) and short responsive time (5-10 s). Even the discrimination of copper(I) and copper(II) has also been done using only UV-Vis spectroscopic study. The efficacy of this bio-friendly probe has been determined by employing HL to detect the intercellular distribution of Cu(II) ions in HeLa cells by developing image under fluorescence microscope.

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A new, phenoxo-bridged Cu-II dinuclear complex Cu-2(L)(2)(DMF)(2)] (1) has been obtained by employing the coumarin-assisted tridentate precursor, H2L, benzoic acid(7-hydroxy-4-methyl-2-oxo-2H-chromen-8-ylmethylene)-hydrazide]. Complex 1 has been systematically characterized by FTIR, UV-Vis, fluorescence and PR spectrometry. The single crystal X-ray diffraction analysis of 1 shows that the geometry around each copper ion is square pyramidal, comprising two enolato oxygen atoms belonging to different ligands (which assemble the dimer bridging the two metal centers), one imine-N and one phenolic-O atoms of the Schiff base and one oxygen atom from the DMF molecule. The temperature dependent magnetic interpretation agrees with the existence of weak ferromagnetic interactions between the bridging dinuclear Cu(II) ions. Both the ligand and complex 1 exhibit anti-mycobacterial activity and considerable efficacy towards M. tuberculosis H37Rv ATCC 27294 and M. tuberculosis H37Ra ATCC 25177 strains. The cytotoxicity study on human adenocarcinoma cell lines (MCF7) suggests that the ligand and complex 1 have potential anticancer properties. Molecular docking of H2L with the enoyl acyl carrier protein reductase of M. tuberculosis H37R(v) (PDB ID: 4U0K) is examined and the best docked pose of H2L shows one hydrogen bond with Thr196 (1.99 angstrom).

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Two new Cu(I) compounds, namely Cu-2(bds)(bpy)(2)]center dot 2H(2)O (1) and Cu-4(bds)(2)(azpy)(4)]center dot 6H(2)O (3) (where bds = benzene-1,3-disulfonate, bpy = 4,4'-bipyridine and azpy = 4,4'-azopyridine), and four Ag(I) compounds, namely Ag-2(bds)(bpy)(2)]center dot 2H(2)O (2), Ag-2(bds)(azpy)(2)]center dot 4H(2)O (4), Ag(bds)(1/2)(bpe)]center dot 3H(2)O (5), and Ag-4(bds)(2)(tmdp)(4)]center dot 9H(2)O (6) (where bpe = 1,2-di(4-pyridyl) ethylene and tmdp = 4,4'trimethylenedipyridine), have been synthesized, and their structures were determined and characterized by elemental analysis, IR, UV-vis and thermal studies. The structure of the compounds changed from 1D (1 and 2) to 2D (3-5) and interpenetrated 3D (6). In the case of 5, a solid-state 2 + 2] photochemical cycloaddition reaction has been performed. Compound 2 exhibits a reversible anion exchange for perchlorate and permanganate, whereas the other compounds (1, 3-6) exhibit an irreversible anion exchange behaviour for perchlorate. Catalytic studies on 2 indicate Lewis acidity.

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Cu,Cu.(RDF)(PA),.Cu2,,2331,221121012.Cu,,Cu,,.,.,,.

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<p>Adsorption of aqueous Pb(II) and Cu(II) on -quartz was studied as a function of time, system surface area, and chemical speciation. Experimental systems contained sodium as a major cation, hydroxide, carbonate, and chloride as major anions, and covered the pH range 4 to 8. In some cases citrate and EDTA were added as representative organic complexing agents. The adsorption equilibria were reached quickly, regardless of the system surface area. The positions of the adsorption equilibria were found to be strongly dependent on pH, ionic strength and concentration of citrate and EDTA. The addition of these non-adsorbing ligands resulted in a competition between chelation and adsorption. The experimental work also included the examination of the adsorption behavior of the doubly charged major cations Ca(II) and Mg(II) as a function of pH.</p> <p>The theoretical description of the experimental systems was obtained by means of chemical equilibrium-plus-adsorption computations using two adsorption models: one mainly electrostatic (the James-Healy Model), and the other mainly chemical (the Ion Exchange-Surface Complex Formation Model). Comparisons were made between these two models.</p> <p>The main difficulty in the theoretical predictions of the adsorption behavior of Cu(II) was the lack of the reliable data for the second hydrolysis constant(*_2) The choice of the constant was made on the basis of potentiometric titratlons of Cu^(2+)</p> <p>The experimental data obtained and the resulting theoretical observations were applied in models of the chemical behavior of trace metals in fresh oxic waters, with emphasis on Pb(II) and Cu(II).</p>

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Revestimentos produzidos a partir de ligas de Cu-Sn apresentam grande interesse em funo de suas propriedades, originando uma grande capacidade de aplicao industrial, especialmente em indstrias de componentes e materiais eletrnicos. Tais ligas tambm tm sido comercialmente utilizadas como revestimentos em metais diferentes, como o ao, para proteg-los contra a corroso e melhorar sua aparncia. Na presente dissertao, tcnicas de voltametria cclica, cronoamperometria e voltametria de varredura andica linear foram utilizadas para o estudo dos processos de deposio de Cu e/ou Sn a partir de dois conjuntos de solues contendo CuCl2.2H2O e SnCl2.2H2O nas razes de Cu:Sn = 1:10 e 10:1, alm de Na3C6H5O7 1,00 mol/L, em pH = 6,0. As curvas de voltametria cclica realizadas sobre o eletrodo de grafita foram utilizadas para o clculo das constantes de equilbrio dos complexos de ambos os metais com citrato de sdio, bem como na determinao dos potenciais catdicos aplicados nos ensaios de cronoamperometria. Aps a deposio da liga nos potenciais estipulados para cada uma das duas solues, os revestimentos de liga Cu-Sn foram ressolubilizados em soluo de NaNO3 0,5 mol/L, empregando varredura andica linear para a avaliao de suas composies qumicas. Os resultados iniciais mostraram que a variao da concentrao de Cu (II) e do potencial aplicado influenciaram no teor de cobre na liga. Contudo, percebeu-se que o teor de estanho no sofreu grandes variaes, independente das concentraes das solues e do potencial aplicado. Na soluo com maior concentrao de cobre foram alcanados teores dos metais na liga em maior proximidade com o da liga de bronze comercial. Com base nesses resultados, foram produzidos revestimentos de ligas sobre substrato de ao carbono, a partir de solues contendo CuCl2.2H2O e SnCl2.2H2O na razo de 10:1, empregando a tcnica de cronoamperometria potenciosttica. Quatro diferentes valores de potencial (-0,39V, -0,67V, -1,00V, -1,20V e -1,94V vs. Ag/AgClsat.) foram aplicados, obtendo-se camadas cujas coloraes variaram do rosa claro ao marrom escuro, sempre sem brilho. A eficincia de corrente catdica (Ef) decresceu conforme o potencial aplicado se tornou mais negativo. Nesta mesma direo, verificou-se um aumento do teor de estanho na liga depositada e menores tamanhos de gro. Porm, quando o potencial tornou-se mais negativo (-1,20V e -1,94V), observou-se a presena de cristalitos de diferentes tamanhos e de dendritos. Revestimentos com melhores resistncias corroso em soluo de NaCl 0,5 mol/L foram produzidos nos potenciais de -1,00V e -1,20V, cujas composies foram 99,40 % m/m Cu / 0,60 % m/m Sn e 97,70 % m/m Cu / 2,30 % m/m Sn, respectivamente. As anlises por DRX permitiram verificar que estes revestimentos eram constitudos, principalmente, da fase &#945;-CuSn

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Nd-Fe-BNd-Fe-B1983Sm-Co50MGOe3100.126%/KNd-Fe-B150Nd230Fe800Fe_2O_3, Nd_2O_3FeNdO_3NdBO_3BNd-Fe-B-SiNd-Fe-B150TcNd-Fe-B40Nd-Fe-BCuOY_2Cu_2O_5BaCuO_2RBa_2Cu_3O_(7-)RCuO77K110KCuOR-Ba-Cu-OCuOY_2Cu_2O_577300K_(eff) = 2.13BCu~(2+)1.73BY_2Cu_2O_5Cu~(3+)Tc90KY-Ba-Cu-OR-Ba-Cu-OR-Ba-Cu-O-AgIIRBa_2Cu_3O_(7-) (R = Y, Sm, Eu, Gd, Dy, Ho, Er, Tm)R'Ba_2Cu_3O_(7-) (R' = Y, Sm, Eu, Gd)Cu~(3+)Cu~(3+)Cu~(3+)Cu~(3+)RBa_2Cu_3O_(7-) (R = Gd, Dy, Er)Cu~(3+)Cu~(3+)

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R_1Ba_2Cu_3O_(2-x) (R = LaNdSmEuGdDrHoErTmYb)Y_2Ba_2Cu_3O_(2-x) (x = 0.101.17)Y_1Ba_2Cu_3O_(7-x)S_x (x = 02)R_1Ba_2Cu_3O_(2-x)T > TcCuric-WeissY_1Ba_2Cu_3O_(2-x)Cu~(2+)Cu~(2+)R~(3+)CT > 700K)Curic-WeissCu~(2+)R_1Ba_2Cu_3O_(2-x)T < TcCuric-WeissR~(3+)SrR_1Ba_2Cu_3O_(2-x)BaSm~(3+)Curic-WeissSm_1Ba_2Cu_3O_(2-x)Sm~(3+)Van VlccKY_1Ba_2Cu_3O_(2-x)6.906.49(7-x) = 5.83123Curic-Weiss(7-x) = 6.90PauliPeffCu(2)dPeffCu(1)Cu~(2+)EPRY_1Ba_2Cu_3O_(2-x)EPRCu~(2+)(d~9, S = 1/2, I = 3/2)EPREPRCu(1)EPRCu(1)~(2+)Y_1Ba_2Cu_3O_(2-x)EPRY_2Cu_2O_5BaCuO_2Y_2BaCuO_5EPR1spin/cu(7-x) = 6.496.40Y_1Ba_2Cu_3O_2gY_1Ba_2Cu_3O_(2-x)Sxx = 0.11Tc = 92.6KY_1Ba_2Cu_3O_(7-x)2KTc0x = 0.040.060.111.20Curic-Weissx = 0.871.2230K240KCu1x = 0.11 (Tc = 92.6K)EPRCu~(2+)CuCu~(1+)-s-EPRCu(+1+2)

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1. Cl~- Cu SEM Cu 2. H_2SO_4 Cu 3. KCl C_6H_5NCS Cu 4. Bode Bode

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RT-PCRCdCuCdCuCdCu 1 CdCu 2 Cd Cu 3 MMRPCNA MMRPCNACdCu 4 MMRPCNA CdCuCdCu

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Three new metal-organic coordination polymers, [Cu(2,3-pydc)(bpp)]center dot 2.5H(2)O (1), [Zn(2,3-pydc)(bpp)]center dot 2.5H(2)O (2) and [Cd(2,3-pydc)(bpp)(H2O)]center dot 3H(2)O (3) (2,3-pydcH(2) = pyridine-2,3-dicarboxylic acid, bpp 1,3-bis(4-pyridyl)propane), have been synthesized at room temvperature. All complexes have metal ions serving as 4-connected nodes but represent two quite different structural motifs. Complexes 1 and 2 are isomorphous, both of which feature 2D -> 3D parallel interpenetration. Each two-dimensional (2D) layer with (4, 4) topology is interlocked by two nearest neighbours, one above and one below, thus leading to an unusual 3D motif. Complex 3 has a non-interpenetrating 3D CdSO4 framework with cavities occupied by uncoordinated water molecules.

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The title mixed-metal complex, {(NH4)(2)[Cu(C7H3NO4)(2)(H2O)(2)][CdCu(C7H3NO4)(2)(H2O)(6)]center dot 6H(2)O}(n), contains one octahedrally coordinated Cd-II center and two octahedrally coordinated Cu-II centers, each lying on an inversion center. The two Cu-II atoms are each coordinated by two O atoms and two N atoms from two 2,4-pydc (2,4-H(2)pydc = pyridine-2,4-dicarboxylic acid) ligands in the equatorial plane and two water molecules at the axial sites, thus producing two crystallographically independent [Cu(2,4-pydc)(2)(H2O)(2)](2-) metalloligands. One metalloligand exists as a discrete anion and the other connects the Cd(H2O)(4) units, forming a neutral chain.

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Two new Cull coordination polymers, namely [Cu-2(BDC)(2)(L)(4)(H2O)(2)]center dot 14H(2)O (1) and [Cu-1.5(BTC)(L)(1.5)(H2O)(0.5)]center dot 2H(2)O (2), where L = 1,1'-(1,4-butanediyl)bis(imidazole), BDC = 1,4-benzene dicarboxylate, and BTC = 1,3,5-benzenetricarboxylate, have been synthesized at room temperature. Complex 1 exhibits an unusual, square-planar, four-connected 2D (2)(6)4 net, which has been predicated by Wells. Interestingly, three types of water clusters, namely (H2O)(6), (H2O)(8), and (H2O)(10), are observed in the hydrogen-bonded layers constructed by the BDC ligands and water molecules. The BTC anion in compound 2 is coordinated to the Cu" cation as tetradentate ligand to form a (6(6))(2)(4(2)6(4)8(4))(2)(6(4)810) net containing three kinds of nonequivalent points, Thermogravimetric analyses (TGA) and IR spectra for 1 and 2 are also discussed in detail.