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Titolo:
SYNTHESIS, MOLECULAR-STRUCTURE AND REACTIVITY OF A NEW DICOPPER(II) BENZIMIDAZOLE COMPLEX WITH NONIDENTICAL COPPER(II) SITES
Autore:
HOLZ RC; GOBENA FT;
Indirizzi:
UTAH STATE UNIV,DEPT CHEM & BIOCHEM LOGAN UT 84322
Titolo Testata:
Polyhedron
fascicolo: 13, volume: 15, anno: 1996,
pagine: 2179 - 2185
SICI:
0277-5387(1996)15:13<2179:SMAROA>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
LEUCINE AMINOPEPTIDASE; CRYSTAL-STRUCTURES; MAGNETIC-PROPERTIES; HEMOCYANIN MODELS; BOVINE LENS; IRON-OXO; UTEROFERRIN; RESOLUTION; PROTEINS; LIGANDS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
37
Recensione:
Indirizzi per estratti:
Citazione:
R.C. Holz e F.T. Gobena, "SYNTHESIS, MOLECULAR-STRUCTURE AND REACTIVITY OF A NEW DICOPPER(II) BENZIMIDAZOLE COMPLEX WITH NONIDENTICAL COPPER(II) SITES", Polyhedron, 15(13), 1996, pp. 2179-2185

Abstract

The dinucleating ligand ethylene glycol-bis(beta-aminoethyl ether) N,N,N'N'-tetrakis[2-(1-ethylbenzimidazoyl)] (EGTB-Et, 1) has been synthesized in good yield by the condensation of 1,2-diaminobenzene with ethylene glycol-bis(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid. This ligand was used to synthesize the dinuclear Cu-II diacetonitrile complex [Cu-2(ECTB-Et)(CH3CN)(2)](ClO4)(4) . 2CH(3)CN (2). The X-ray structure shows two distinct square pyramidal Cu-II centres with each Cu-II ion bound by two benzimidazole nitrogen atoms, one amine nitrogen atom, an ether oxygen atom and one acetinitrile nitrogen atom. The Cu--Cu separation is 5.809 Angstrom. Spectral titration of 2 with sodium acetate or sodium cyanide results in new complexes with terminal acetate or cyano groups. X-band EPR spectra of a powdered sample and an acetonitrile solution of 2 show isotropic signals with g = 2.10 and 2.14, respectively. The Delta M(s) = 2 transition at g similar to 4.5 expected for magnetically coupled Cu-II ions is not observed for either the powder or acetonitrile solution samples of 2. Based on the EPR spectra, the room-temperature magnetic moment (mu(eff) Cu = 2.16 BM) and the X-ray structure, no orbital overlap between the magnetic d(x2-y2) orbital of Cu(2) and the magnetic d(x2-y2) orbital of Cu(1) occurs requiring the two Cu-II centres to be uncoupled. Therefore, 2 is a dinuclear Cu-II complex with non-interacting Cu-II centres in non-identical sites.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 19:54:39