Activation of Elemental Sulfur at a Two-Coordinate Platinum(0) Center.

Abstract

Platinum dichalcogenides have been known to exhibit two-dimensional layered structures. Herein, we describe the syntheses, isolation, and characterization of air-stable crystalline cyclic alkyl(amino) carbene (cAAC)-supported monomeric platinum disulfide three-membered ring complex [(cAAC)2 Pt(S2 )] (2). The highly reactive platinum(0) [(cAAC)2 Pt] complex (1) with two-coordinate platinum activates elemental sulfur to give 2. The brown crystals of bis-carbene platinum(II)monosulfate [(cAAC)2 Pt(SO4 )x (S2 )1-x ] (4) have been isolated when the reaction was performed in air. The dioxygen analogue of 2 was formed upon exposing the THF solution of 1 to aerial oxygen (O2 ). The binding of oxygen at the Pt(0) center was found to be reversible. Additionally, DFT study has been performed to elucidate the electronic structure and bonding scenario of 2, 3, and 4. Quantum chemical calculations showed donor-acceptor-type interaction for the Pt-S bonds in 2 and Pt-O bonds in 3 and 4.