Chemistry of alkoxo-bonded oxovanadium(V) complexes incorporating azophenolcarboxylates and ethylene glycol

The reaction of (VO)-O-IV(L)(H2O) (where L = tridentate dinegative ONO dono r azo ligands) with ethane-1,2-diol (H(2)ed) in methanol solution produces the complex (VO)-O-V(L) (Hed) (in which H(2)ed coordinates in a monodeproto nated fashion) via aerial oxidation. The coordination sphere of the complex es is of the VO(ONO)(OO) type, where O atoms are of ore, phenolic, alcoholi c and carboxylic and N is of azo type. The completes are diamagnetic and ex hibit only one ligand-to-metal charge transfer (LMCT) transition near 490 n m in addition to other two intra-ligand transitions around 410 and 330 nm. The completes have low V(V)/V(IV) reduction potentials in the legion -0.40 V vs SCE leading to the stabilisation of pentavalent state.