Chemistry of platinum sulphido-complexes. Part 3. Crystal and molecular structure of tetrasulphido[1,2-bis(diphenylphosphino)ethane]platinum(II) and a study of its bonding and reactions

Abstract

The structure of [PtS₄(Ph₂PCH₂CH₂PPh₂)] has been determined by single-crystal X-ray techniques using diffractometer data. The compound crystallises in the monoclinic space group P2₁/a, with four molecules in a cell of dimensions a= 9.736(3), b= 30.964(7), c= 9.806(5)Å, and β= 117.81(4)° Least-squares refinement of the structure led to a final R value of 0.043 using 3 292 observed intensities. The complex is approximately square planar and the tetrasulphido-ligand behaves as a dianionic chelating ligand. The resultant PtS₄ ring adopts an approximately C₂ conformation. The central S–S bond is 0.046 Å shorter than the outer S–S bonds [average 2.058(15)Å]. A molecular orbital analysis of the bonding in this and related complexes has been used to interpret this geometric feature.