Synthesis and characterization of three new Cu(II)-dipeptide complexes

Three new copper(II) complexes of stoichiometry [Cu(L-dipeptide)].nH(2)O, containing as ligands the dipeptides L-alanine-L-isoleucine, L-alanine-L-threonine and L-alanine-L-tyrosine were prepared. They were characterized by single crystal X-ray diffractometry, and electronic and infrared spectroscopy. In all cases, the Cu(II) cation has essentially the same elongated square pyramidal coordination, being equatorially cis coordinated by a N(2)O(2) arrangement of ligand atoms and axially by a carbonyl oxygen atom. The compounds show rather similar polymeric structures which resemble those recently reported for the [Cu(ala-val)] and [Cu(ala-phe)] complexes. The electronic and infrared spectra are briefly discussed on the basis of the structural peculiarities of the complexes. Superoxide dismutase (SOD)-like activity was also tested for the compounds.