Molecular structure of a mono-peroxo vanadium(V) complex formed by D,L-lactic acid

The peroxo complex formed by vanadium(V) in the presence of D,L-lactic acid (H(2)lact) as heteroligand, K-2[{VO(O-2)(lact)}(2)] (1), is described. A s ingle-crystal X-ray diffraction study indicates that the ligand behaves as a bidentate chelator adopting the (O-, COO-) donor set. The complex has a d inuclear core based on the V2O2 cyclic arrangement arising from two vanadiu m(V) atoms sharing the hydroxyl oxygens of two ligands. The coordination sp here of each vanadium includes two hydroxyl oxygens, an oxygen atom from a carboxylate group, an oxo ligand and two peroxo oxygens. The geometry at th e metal ion is severely distorted and, in the ideal limit, it could be desc ribed as a trigonal bipyramid, in which one of the equatorial bonds corresp onds to the axis joining the vanadium atom and the centre of the peroxo gro up. A strikingly short interatomic O-O distance, 1.35 Angstrom, is measured for the peroxo group, suggesting both sigma- and pi-donor ability in the b onding to the metal ion. (C) 2000 Elsevier Science SA. All rights reserved.