Syntheses and Crystal Structures of Copper Complexes of the Imidazole Ligand

Two copper(II) complexes, [Cu(im)₆]Cl2·4H₂O (1), and [Cu(im)₆]Cl2·2H₂O (2) (im = imidazole), have been synthesised. In compound 1, [Cu(im)₆]²⁺cations and Cl^- counter anions alternately array in an ABAB fashion via N-H…Cl hydrogen bonding. There are two kinds of hydrogen bonds, inter- and intramolecular hydrogen bonding interactions, which form 2-D sheets. However, an interesting polymeric network is formed from the weak intermolecular interactions in compound 2.