Oxovanadium(IV) complexes with aromatic aldehydes

The synthesis, structure and spectroscopic properties of complexes with the formula [(VO)-O-IV( dsal)(2)(H2O)], where Hdsal = salicylaldehyde, o-vanil lin and 3-ethoxysalicylaldehyde, are presented. The crystal and molecular s tructures of [(VO)-O-IV(o-van)(2)(H2O)] (1) (o-Hvan = o-vanillin = 3-methox ysalicylaldehyde) is studied by single-crystal X-ray diffraction. Each mole cule exhibits an octahedral geometry with the two o-van ligands coordinated cis to the (VO2+)-O-IV group. 1 is the first example of a structurally cha racterized vanadium complex involving O-aldehyde as the donor atom and this enables a comparison between the bonding characteristics and the contribut ions of O-aldehyde, O-amide, O-carboxylate and O-ketone (in acetylacetone) to the parallel hyperfine coupling constant in VOL2 complexes. (C) 2000 Els evier Science Inc. All rights reserved.