Synthesis, characterisation and physicochemical properties of peroxo-vanadium(V) complexes with glycine as the hetero-ligand

Abstract

The first glycineperoxo complexes of vanadium- (V), NH 4[VO(O 2) 2GlyH]·H 2O ( 1), K[VO(O 2) 2- GlyH]·H 2O ( 2)and [V 2O 2(O 2) 3(GlyH) 2(H 2O) 2] ( 3) have been synthesised from the reaction of V 2O 5 with hydrogen peroxide and glycine (GlyH) at pH 3–4 ( 1 and 2) and pH 2 ( 3), respectively. The compounds have been characterised by elemental analysis, magnetic susceptibility and ESR, UVVis and IR spectroscopy. While glycine, occurring in its zwitterionic form, is coordinated to the V(V) centre in a monodentate fashion through its carboxylic oxygen, the peroxides in 1 and 2 occur as terminal bidentate ones. In compound 3 one of the peroxide ligands is present as a μ-peroxo group. Typically, an aqueous solution of 2 exhibits peroxoV(V) LMCT bands at 328 and in the 200–190 nm region, whereas complex 3 shows only one broad LMCT band at 310–330 nm.