Synthesis, structure and solution chemistry of mixed-ligand oxovanadium(IV) and oxovanadium(V) complexes incorporating tridentate ONO donor hydrazone ligands

The reaction of VIVO(acac)2 with the acetylhydrazones of salicylaldehyde or 2-hydroxy acetophenone (H2L) in presence of bipyridine or phenanthroline (B) produces tetravalent VIVO(L)(B) complexes but pentavalent VVO(L)(hq) complexes are obtained if B ligand is replaced by 8-hydroxyquinoline (Hhq).