Crystal structure of the (13-dimesityl-1H-imidazol-3-ium-2-yl)methano­latocopper(II) chloride dimer: insertion of formaldehyde into a copper–carbene bond

摘要

The crystal structure of bis­[μ-(1,3-dimesityl-1H-imidazol-3-ium-2-yl)methano­lato-κ² O:O]bis­[di­chlorido­copper(II)], [Cu2Cl4(C22H26N2O)2], is reported. The complex is assumed to have formed via the insertion of formaldehyde into the copper–carbon bond in an N-heterocyclic carbene complex of copper(I) chloride. The structure of the binuclear mol­ecule possesses a crystallographic­ally centrosymmetric Cu2O2 central core with the O atoms bridging between the Cu^II atoms and thus Z′ = 0.5. The copper centres are further ligated by two chloride ligands, resulting in the Cu^II atoms residing in a distorted square-planar environment. The Cu—O bond lengths are shorter than those previously reported in structures with the same central Cu2O2 motif. The complex displays C—H⋯Cl inter­actions involving the H atoms of the heterocycle backbone and the chloride ligands of a neighbouring mol­ecule.