STRUCTURES AND PROPERTIES OF COPPER(II) COMPLEXES WITH IMINODIACETATO AND IMIDAZOLE OR RELATED LIGANDS. I. CRYSTAL STRUCTURE OF AQUA(IMIDAZOLE) (IMINODIACETATO)COPPER(II) MONOHYDRATE AND (IMIDAZOLE)(N-CARBOXYMETHYL-D,L-THREONINATO)COPPER(II)

Abstract

Abstract The crystal structures of two mixed-ligand copper(II) complexes having iminodiacetate(2-) (IDA) or N-carboxymethyl-D,L-threoninato(2-) ion (CMT) as terdentate ligands and imidazole (ImH) as an N-heterocyclic ligand are reported. Both compounds crystallize in the orthorhombic system, space group Pbca with Z = 8. Aqua(imidazole)(iminodiacetato)copper(II) monohydrate (I,R = 0.065, R w = 0.075) consists of H2O molecules and [Cu(IDA)(ImH)(H2O)] complex units in a hydrogen bonding network. The structure of imidazole(N-carboxymethyl)-D,L-threoninatocopper(II) (IV, R = 0.066, Rω 0.078) is built up of hydrogen bonded polynuclear chains. In both compounds the Cu(II) ion exhibits a flattened and distorted square-based pyramidal coordination, with a terdentate aminoacidate ion, IDA or CMT, and one ImH ligand at the base and H2O (in I) or the oxygen atom of the OH side chain from one adjacent CMT ion (in IV) as the fifth apical ligand. The nearly coplanar conformation of the two five-membered chelate rings in I and IV is discussed in connection with the known structure of corresponding aquacomplexes (with H2O instead of ImH) and the ability of terdentate aminoacids to give ternary Cu(II) complexes having two N-heterocyclic donors (2 ImH or one 2,2′-bipy) per Cu(II) atom.