SbCl2(η2-1,4-dt)(μ2-1,4-dt)][AlCl4]: Ionic Liquid-based Synthesis of a Stibenium Cation (dt = dithiane)

Abstract

The reaction of antimony(III) chloride with 1,4-dithiane (1,4-dt) in the ionic liquid [BMIM]Cl ([BMIM]Cl: 1-butyl-4-methylimidazolium chloride) with an excess of the Lewis acid AlCl3 results in the formation of a ligand-stabilized stibenium cation [SbCl2]+. 1,4-Dithiane simultaneously serves as a chelating η2-ligand, exhibiting a boat-like conformation, as well as a bridging μ2-ligand, exhibiting a chair-like conformation, with Sb3+ as the coordinating cation. Due to the bridging 1,4-dithiane ligands, a chain-like structural building unit 1 ∞[SbCl2(η2-1,4-dt)1/1(μ2-1,4-dt)2/2]+ is formed.