N-heterocyclic carbene stabilized copper- and silver-phenylchalcogenolate ring complexes

Abstract

The ligation of a N-heterocyclic carbene (NHC) to group 11 metal salts (Cu, Ag) was explored as an alternative to PR₃ ligands for the formation of copper- and silver-chalcogenolate cluster complexes. AgOAc and CuCl salts ligate with the NHC 1,3-di-isopropylbenzimidazole-2-ylidene (ⁱPr₂-bimy) forming [Ag(OAc)(ⁱPr₂-bimy)] 1, [Ag(OAc)(ⁱPr₂-bimy)₂] 2, [CuCl(ⁱPr₂-bimy)]₂3 and [CuCl(ⁱPr₂-bimy)₂] 4 depending on the ratio of ligand to metal used. These have been characterized via spectroscopic and crystallographic methods. Complexes 1 and 3 were reacted with S(Ph)SiMe₃ and Se(Ph)SiMe₃ to form the polynuclear metal–chalcogenolates [Ag₄(μ-EPh)₄(ⁱPr₂-bimy)₄] (5, E = S; 6, E = Se) and [Cu₃(μ-EPh)₃(ⁱPr₂-bimy)₃] (7, E = S; 8, E = Se) in good yields. The structures of 5–8, as determined by single crystal X-ray crystallography, are described.