X-RAY-DIFFRACTION STRUCTURE OF A TERNARY COPPER(II) PEPTIDE COMPLEX (BENZIMIDAZOLE) (GLYCYLGLYCINATO) COPPER(II) TRIHYDRATE

A new ternary complex [Cu(gg)(bzim)]. 3H(2)O (1) (gg = glycylglycine(2 -), bzim = benzimidazole) has been crystallized from aqueous solution. The coordination geometry about the copper is approximately square pl anar with the tridentate glyclyglycine dianion and the N(1) of the ben zimidazole ligand occupying the corners of the square. The plane of th e bzim ligand is twisted 19.0(1)degrees from the square plane. IR and electronic spectral data of the compound are discussed and related to the binding mode derived from the crystal structure determination. The three water molecules are involved in a hydrogen bonding network.