Copper(II) complexes with 2,2′-biimidazole. Preparation and crystal structure determination of a complex of stoichiometry Cu1.5Cl3(H2bim)2 (H2bim=2,2′-biimidazole)

By reacting 2,2′-biimidazole and copper(II) chloride in aqueous HCl we obtained the complex CuCl2(H2bim) as the main product and a compound with stoichiometry Cu1.5Cl3(H2bim)2 as a byproduct. The structure of the latter compound has been determined by X-ray analysis: monoclinic, a= 794.0(3), b=3146.8(6), c=722.9(4) pm, β= 114.2(1)°, space group P21/c. The compound actually contains two species, namely [Cu(H2bim)2]Cl2 and [CuCl2(H2bim)] in a 1:2 molar ratio.