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Autori: S. Nica, A. Pohlmann, W. Plass
Editorial: Eur. J. Inorg. Chem. , p.2032-2036, 2005.
The Schiff-base ligand derived from salicylaldehyde and γ-hydroxybutanoic acid hydrazide (H2Salhyhb) reacts with potassium metavanadate and hydrogen peroxide in a water/methanol solution with a pH value of around two to yield the corresponding vanadium(V)oxoperoxo complex [VO(O2)-HSalhyhb(H2O)] (1). Complex 1 crystallizes with one molecule of water as 1·H2O in the monoclinic space group P21/n. For the vanadium atom a pentagonal-bipyramidal coordination geometry is observed, with a side-on bonded peroxo ligand in the equatorial plane. The hydroxy side chain of the hydrazide ligand is involved in a hydrogen-bond network with the peroxo ligand at the vanadium atom. This network shows some similarities with the hydrogen-bonding scheme found for the peroxo form of vanadium haloperoxidases. The stoichiometric reaction of 1 with 1,3,5-trimethoxybenzene (TMB) in the presence of tetrabutylammonium bromide leads to the formation of 1-bromo-2,4,6-trimethoxybenzene (Br-
TMB), thus mimicking the oxidative halogenation function of the native enzyme. Complex 1 is also capable of oxidizing triphenylphosphane and methylphenylsulfane, yielding a cis-dioxovanadium(V) complex and the corresponding phosphane or sulfane oxide, respectively.
Cuvinte cheie: Hydrogen bonds, Oxidative bromination, Peroxo ligands, Salicylidenehydrazide ligand, Vanadium