Preparation of [VO(sal-L-Trp)(H2O)] (sal-L-Trp = N-salicylidene-L-tryptophanate) and characterisation of an unusual product obtained from its solutions in water-pyridine

A vanadium(rv) complex [VO(sal-L-Trp)(H2O)] 1 (sal-L-Trp = N-salicylidene-L -tryptophanate) has been isolated from solutions containing oxovanadium(Iv) , L-tryptophan and salicylaldehyde. From solutions also containing quinolin -8-ol (Hhquin) a similar oxovanadium(Iv) complex VO(sal-L-Trp). Hhquin . 2H (2)O 2 was isolated. From solutions of 1 in water-pyridine, orange-brown cr ystals of [Hpy(+)](4)[C14H13N2+](2)[V10O286-] 3 were isolated and character ised by X-ray diffraction. The mechanism proposed for this reaction involve s the attack of a pyridine molecule at the beta-carbon atom of the tryptoph an residue in 1.