Oxovanadium(IV) complexes with aromatic aldehydes

The synthesis, structure and spectroscopic properties of complexes with the formula [V(IV)O(dsal)2(H2O)], where Hdsal = salicylaldehyde, o-vanillin and 3-ethoxysalicylaldehyde, are presented. The crystal and molecular structures of [V(IV)O(o-van)2(H2O)] (1) (o-Hvan = o-vanillin = 3-methoxysalicylaldehyde) is studied by single-crystal X-ray diffraction. Each molecule exhibits an octahedral geometry with the two o-van ligands coordinated cis to the V(IV)O2+ group. 1 is the first example of a structurally characterized vanadium complex involving O(aldehyde) as the donor atom and this enables a comparison between the bonding characteristics and the contributions of O(aldehyde), O(amide), O(carboxylate) and O(ketone) (in acetylacetone) to the parallel hyperfine coupling constant in VOL2 complexes.