Electronic Structure of Oxovanadium(IV) Complexes of (alpha)-Hydroxycarboxylic Acids

A series of VIVO bis chelated complexes of (alpha)-hydroxycarboxylic acids with a 2(COO-, O-) coordination set was analyzed by electronic absorption and EPR spectroscopy in aqueous solution. All the complexes exhibit a square-pyramidal geometry distorted toward trigonal bipyramid. The influence of the distortion of the geometry, as deduced from the steric hindrance produced by the substituents at the (alpha)-carbon atom of the ligands, on the spectroscopic parameters has been studied. The observed trends were related to the electronic structure of the metal ion in the distorted geometry.