Formation of [CoPt2Cl2(PPh3)4(μ 3-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(μ 3-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 distances 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.