Formation of [CoPt2Cl2(PPh3)4(µ3-S)2] from facile heterometallation of [Pt2(PPh3)4(µ-S)2] and its facile deheterometallation via carbonylative desulfurization to give Pt–Pt bonded [Pt2(CO)2(PPh3)2(µ-S)]

Abstract

Metallation of [Pt₂(PPh₃)₄(µ-S)₂]1 with CoCl₂ gave [CoPt₂Cl₂(PPh₃)₄(µ₃-S)₂]2 at room temperature. Treatment of 2 with CO in an autoclave resulted in a binuclear compound [Pt₂(CO)₂(PPh₃)₂(µ-S)]3, via a reductive desulfurization mechanism with the removal of the heterometal fragment and formation of a Pt–Pt bond. Complexes 2 and 3 have been characterized by single-crystal X-ray crystallography. The structure of 2 shows a trigonal-bipyramidal arrangement of a {CoPt₂S₂} core with non-bonding Pt–Pt and Co–Pt distance at 3.197(4) and 3.066(1)Å respectively. Complex 3 contains a {Pt₂S} trinagular core with two PPh₃ ligands trans and two CO cis to the Pt–Pt bond [2.600(1)Å]. Some theoretical aspects of the strength of the Pt–Pt bond in relation to the ligands on the {Pt₂S} core are discussed.