Alkyl sulphide and selenide complexes of the platinum group metals

Abstract

trans-Square-planar complexes of the type MX₂L₂(M = Pd, Pt; X = Cl, Br; L = R₂S, Et₂Se; R = Buⁿ, Buⁱ, Bu⁸, Prⁿ) have been prepared and studied using low-frequency i.r., n.m.r., and electronic spectroscopic techniques. Metal–halogen, metal–sulphide and metal–selenide stretching frequencies have been assigned in the i.r., and ligand to metal charge-transfer transitions in the u.v. region are observed. The influence of the cis-halogen on the α carbon protons of the sulphide and selenide ligands is well demonstrated from the ¹H n.m.r. spectra of the complexes. Octahedral complexes fac-MX₃L₃(M = Ru, Os, Rh, Ir; X = Cl, Br, l; L = Et₂S, Prⁿ₂S, Et₂Se) have also been prepared and investigated in a similar manner. The i.r. spectra indicates that compared to phosphines the sulphide and selenide ligands are less effective π-acceptors.