New azamacrocyclic binuclear Cu(II) aminocarboxylate complexes: structural, magnetic, spectral and antiproliferative studies

Abstract New cationic complexes of Cu(II) with bridged aminocarboxylates: glycine and alanine, as well as octaazamacrocyclic ligand N,N',N'',N'''-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc), with general formula [Cu2(L)tpmc](ClO4)4∙Y, (1): L=glycine, Y=2H2O and (2): L=alanine, Y=CH3CN were synthesized. Characterization of the complexes was performed by elemental analysis (C, H, N, Cu), UV/Vis, FTIR spectroscopy and magnetic measurements. The single crystal X-ray analyses results show that reported compounds were obtained as hydrates with formulae [Cu2(gly)tpmc](ClO4)4•6.5H2O (M1) and [Cu2(ala)tpmc](ClO4)4•5H2O (M2). They crystallise in the orthorhombic system, P212121 space group. The metal centres are bridged by the carboxylate group of the glycine/alanine and bound via nitrogen atoms of tmpc. In the complex M1/M2, geometry around Cu(II) coordination sphere is square pyramidal (M1 : τ5=0.10/0.33 ; M2 : τ5=0.04/0.30). In the crystal structure of M1 and M2 the amino acids exist as a zwitterion. The temperature dependence of magnetic susceptibility indicated very weak ferromagnetic interaction between two Cu(II) ions. The antiproliferative effect of the complexes, the free ligands, and cis-platin, as referent cytostatic drug, were tested against human leukemia monocytic cell line (THP-1), leukemic T cell lymphoblast (JURKAT) and Human Caucasian Burkitt′s lymphoma (RAMOS). The IC50 values for the complexes were from 37.9±2.6 to 63.05±0.72 μM.