Structural and spectroscopic characterization of two new Cu(II)-dipeptide complexes

Two new Cu(II) complexes of stoichiometry [Cu(L-dipept)], containing as ligands the dipeptides L-alanine-L-valine and L-alanine-L-phenylalanine were prepared. They were characterized by single crystal X-ray diffractometry, and infrared and electronic spectroscopy. Both crystallize in the orthorhombic space group P2(1)2(1)2(1) With Z = 4. The Cu(II) ion has essentially the same elongated pyramidal coordination, being equatorially cis coordinated by a N2O2 arrangement of ligand atoms and axially by a carbonyl oxygen atom. The compounds show rather similar polymeric structures that differ from each other basically in the dihedral angle between adjacent N2O2 planes. The infrared and electronic spectra are briefly discussed on the basis of the structural characteristics of the complexes. Superoxide dismutase-like activity was tested for both compounds.