Synthesis, X-ray structures, and solution properties of vanadium(III) and -(IV) complexes with N-(2-hydroxyphenyl)-N-(2-pyridylmethyl)amine

New vanadium(III) and -(IV) complexes with N-(2-hydroxyphenyl)-N-(2- pyridylmethyl)amine (H₂hppma) have been prepared, and their structures have been determined by X-ray crystallography. As for the vanadium(III) complex, the vanadium(III) center has a center of symmetry and adopts an ordinary octahedral structure, in which the H₂hppma ligand coordinates as a monoanion (Hhppma) in a facial fashion. The vanadium(IV) complex with H₂hppma has been determined to be an unusual non-oxo or bare vanadium(IV) complex. In this complex, the H₂hppma ligand coordinates as a dianion (hppma) in a meridional fashion. Both complexes are fairly unstable in an aerobic solution and decompose to an oxovanadium(IV) complex.