Synthesis and structural characterization of tris(2-mercapto-1-methylbenzimidazolyl)hydroborato cadmium halide complexes, {[TmMeBenz]Cd(μ-Cl)}2 and [TmMeBenz]CdI: a rare example of cadmium in a trigonal bipyramidal sulfur-rich coordination environment

Abstract

The tris(2-mercapto-1-methylbenzimidazolyl)hydroborato cadmium complexes, {[Tm^MeBenz]Cd(μ-Cl)}₂ and [Tm^MeBenz]CdI, have been synthesized via the reactions of [Tm^MeBenz]K with CdCl₂ and CdI₂, respectively. While X-ray diffraction studies demonstrate that the iodide derivative, [Tm^MeBenz]CdI, is a monomer, the chloride derivative, {[Tm^MeBenz]Cd(μ-Cl)}₂, exists as a dimer, which is unprecedented for Group 12 [Tm^R]MX (X = Cl, Br, I) compounds. Furthermore, the cadmium centers of {[Tm^MeBenz]Cd(μ-Cl)}₂ are trigonal bipyramidal, which is an uncommon motif for cadmium complexes with a [S₃Cl₂] coordination sphere.