Oxovanadium(IV) complexes containing bidentate Schiff-base ligands: synthesis and structural and spectroscopic data

Abstract

The synthesis and properties of some oxovanadium(IV) complexes, [VOL₂], containing N-substituted salicylal-dimines (L) are reported. An unusually low VO stretching frequency (<900 cm^–1) has been observed when R = C₆H₄Cl-4 and C₆H₄NO₂-4. This reduction in frequency has previously been attributed to polymerisation of the VO unit, however the present crystal-structure analysis shows that bis[N-(4-chlorophenyl)salicylideneiminato]oxovanadium(IV) is monomeric in the solid state. The co-ordination polyhedron, which in the crystal has C₂ symmetry, is based on a distorted trigonal bipyramid. The three oxygen and vanadium atoms are in the equatorial plane and the two nitrogen donors occupy axial positions. The vanadium–oxygen bond length (1.615 Å) is among the largest found in oxovanadium complexes.