Synthesis, spectroscopic and voltammetric studies of a novel dioxovanadate(V) 8-hydroxyquinoline complex

Abstract

A novel solid oxovanadium(V) complex, monoaqua(8-hydroxyquinolinato)dioxovanadium(V), VO2(H2O)(Q) (Q=8-hydroxyquinolinate ion) was synthesized and characterized by FTIR and UV/Vis spectroscopy, voltammetric measurements and Hartree-Fock ab initio calculations on the models of the ligand Q and the respective phenol QH. Electrochemical measurements in solution clearly showed complex formation between NH4VO3 and 8-hydroxyquinoline, revealing an electrode reaction of the intermediate NH4[VO2(Q)OH] species on the mercury electrode in 0.1 M NH3/NH4Cl buffer (pH 9.85) as a reversible process at -0.700V (vs. Ag \ AgCl \ KClsat reference electrode). The square-wave voltammogram of an aqueous solution of the VO2(H2O)(Q) Complex obtained with thermal deamination of NH4[VO2(Q)OH] presented a new reversible peak at -0.720V.