NMR studies on [VS 4–Cu n] ( n=3, 4, 5, 6) clusters

Abstract

The complexes containing [VS 4–Cu n ] ( n=3, 4, 5, 6) clusters were characterized by NMR spectra. The relationship between the 51V NMR chemical shift and the number of copper atoms in a cluster was established. 51V NMR chemical shifts were used to identify possible products of the reactions of Cu(PPh 3)Cl and [VS 4–Cu 3] with various mole ratios in CDCl 3 in order to study their reaction mechanism in solution. The results demonstrate that the reaction of tetranuclear [VS 4–Cu 3] and Cu(PPh 3)Cl in CDCl 3 successively yields penta-, hexa- and hepta-nuclear V–Cu–S heterometallic clusters when the mole ratio of [VS 4–Cu 3] to Cu(PPh 3)Cl is decreased, and the process can be reversed when [VS 4–Cu 3] is added to [VS 4–Cu 6] gradually. Theoretical calculations were also carried out to explain the experimental results.