Os complexos de vanádio(IV) e (V) com tartarato formados em solução e as suas possíveis interconversões foram estudados utilizando-se técnicas espectroscópicas e eletroquímicas. A investigação foi feita através de espectroscopia de NMR de V combinada com H, de NMR de C e espectroscopia de EPR. Como técnicas electroquímicas utilizaram-se a polagrografia e a voltametria cíclica. Verificou-se que ...

Vanadium(IV) and -(III) complexes of a tetradentate N(2)OS Schiff base ligand H(2)L [derived from methyl 2-((beta-aminoethyl)amino)cyclopent-1-ene-1-dithiocarboxylate and salicylaldehyde] are reported. In all the complexes, the ligand acts in a bidentate (N,O) fashion leaving a part containing the N,S donor set uncoordinated. The oxovanadium(IV) complex [VO(HL)(2)] (1) is obtained by the reacti...

The reaction of bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione (curcumin) and two novel ligands of bis[4-tetrabenzylglucose-3-methoxyphenyl]-1,6-heptadiene-3,5-dione (bis(tetrabenzylglucose)curcumin) (BTBGC) and bis[4-tetraacetylglucose-3-methoxyphenyl]-1,6-heptadiene-3,5-dione (bis(tetraacetylglucose)curcumin) (BTAGC) with vanadium in methanol, in a 2:1 molar ratio, which yield the co...

Early-transition-metal hydrogenation catalysts have received less attention than comparable late-transition-metal systems, particularly since the discovery of Wilkinson s catalyst. This emphasis on late-transition-metal systems has been largely driven by practical concerns including functional-group tolerance and ease of handling. Further examination of early-transition-metal systems is particu...

A series of oxoperoxovanadium(V) complexes (ligands: H3nta ) nitrilotriacetic acid, H3heida ) N-(2hydroxyethyl)iminodiacetic acid, H2ada ) N-(2-amidomethyl)iminodiacetic acid, Hbpg ) N,N-bis(2-pyridylmethyl)glycine, and tpa ) N,N,N-tris(2-pyridylmethyl)amine) were characterized as functional models for the vanadium haloperoxidase enzymes. The crystal structures of K[VO(O2)Hheida], K[VO(O2)ada],...