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Trinuclear copper–pyrazolate entities are present in various Cu-based enzymes and nanojar supramolecular arrangements. The reaction of copper(II) chloride with pyrazole (pzH) and sodium benzoate (benzNa) assisted by microwave radiation afforded a neutral centrosymmetric hexanuclear copper(II) complex, [Cu6(C7H5O2)4(OH)2(C3H3N2)6(C2H5OH)2]·2C2H5OH. Half a molecule is present in the asymmetric unit that comprises a [Cu3(μ3-OH)(pz)3]2+ core with the copper(II) atoms arranged in an irregular triangle. The three copper(II) atoms are bridged by an O atom of the central hydroxyl group and by three bridging pyrazolate ligands on each of the sides. The carboxylate groups show a chelating mode to one and a bridging syn,syn mode to the other two CuII atoms. The coordination environment of one CuII atom is square-planar while it is distorted square-pyramidal for the other two. Two ethanol molecules are present in the asymmetric unit, one binding to one of the CuII atoms, one as a solvent molecule. In the crystal, stabilization arises from intermolecular O—H...O hydrogen-bonding interactions.

A new binuclear copper(II) complex, namely [Cu2L(pz)(DMSO)], where L = 2,6-bis[(2-phenoxy)iminomethyl]-4-methylthiophenolate(3-) and pz = pyrazolate ligand, has been synthesized by a one-pot synthesis involving copper(II) acetate monohydrate, the S-protected ligand precursor 2-(N,Ndimethylthiocarbamato)-5-methylisophthalaldehyde di-2?-hydroxy anil, (I), and pyrazole, in which a metal-promoted S-deprotection reaction occurs during the formation of the complex. This was characterized by routine physicochemical studies, single crystal X-ray diffraction and electron paramagneticresonance (EPR) techniques. The structure analysis reveals that there are copper centres in two different environments, a slightly distorted square planar and a distorted square-pyramidal, arranged in binuclear units. The EPR study of these binuclear units performed at 9.4 GHz in the temperature range between 4 and 293 K shows an antiferromagnetic interaction between CuII ions, and allows evaluating g factors gx = 2.068(1), gy = 2.091(1) and gz = 2.165(1), with = 2.108(1), an exchange coupling parameter J0 = -26(1) cm−1 (defined as Hex = - J0 S1 S2), and a zero field splitting of the ground triplet state described by D = 86(2) × 10-4 cm-1 and E = -48(3) × 10-4 cm-1. These results are discussed and compared with the existing literature. Fil: Khadir, Narjes. Sharif University of Technology. Department of Chemistry; Irán Fil: Boghaei, Davar M.. Sharif University of Technology. Department of Chemistry; Irán Fil: Assoud, Abdeljalil. University of Waterloo. Department of Chemistry; Canadá Fil: Nascimento, Otaciro R.. Universidade de São Paulo. Instituto de Física de São Carlos. Departamento de Física e Ciência Interdisciplinar. Grupo de Biofísica Molecular Sergio Mascarenhas; Brasil Fil: Nicotina, Amanda. Universidade Federal do Rio de Janeiro. Instituto de Física; Brasil Fil: Ghivelder, Luis. Universidade Federal do Rio de Janeiro. Instituto de Física; Brasil Fil: Calvo, Rafael. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Física del Litoral; Argentina

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:49:10Z No. of bitstreams: 0 Made available in DSpace on 2013-08-22T18:49:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-01-01 Made available in DSpace on 2013-09-30T19:10:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:20:34Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T14:20:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) No presente trabalho é descrita a investigação do comportamento térmico de uma nova série de complexos ciclopaladados, obtidos a partir de reações do azido-complexo [Pd(dmba)(mi-N3)]2 (1) (dmba = N,N-dimetilbenzilamina) com os azo-ligantes aniônicos pirazolato (pz), imidazolato (imz) e 3,5-dimetil-pirazolato (3,5-dmpz). Os compostos binucleares [Pd(dmba)(mi-pz)]2 (2), [Pd(dmba)(mi-imz)]2 (3) e [Pd(dmba)(mi-3,5-dmpz)]2 (4) foram caracterizados por análise elementar, espectroscopia de absorção na região do infravermelho, espectroscopia de RMN de 13C{¹H} e ¹H e análise termogravimétrica. O produto final de decomposição térmica, paládio metálico, foi caracterizado pela difratometria de raios-X, método do pó. The present paper deals with the thermal behavior study of cyclopalladated complexes obtained from reactions of [Pd(dmba)N3]2 (1), dmba = N,N-dimethylbenzylamine, with azole-compunds, such as, the anionic ligands pyrazolate (pz), imidazolate(imz) and 3,5-dimethyl-pyrazolate (3,5-dmpz). The characterization of the binuclear complexes [Pd(dmba)(mu-pz)]2 (2), [Pd(dmba)(mu-imz)]2 (3) and [Pd(dmba)(mu-3,5-dmpz)]2 (4) was carried out by elemental analysis, IR and NMR spectroscopy. Their thermal behaviour has been investigated and the final product was identified by X-ray powder diffractometry which showed the formation of Pd(0) as final decomposition product. UNESP Instituto de Química Departamento de Química Geral e Inorgânica UCB Curso de Química UNESP Instituto de Química Departamento de Química Geral e Inorgânica