Electronic structure of oxovanadium IV complexes of alpha-hydroxycarboxylic acids.

A series of V(IV)O 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.