Synthesis, structural characterization and DNA interaction of new copper-terpyridine complexes

As a part of our studies of copper(II) complexes with possible antitumor activity, the synthesis and structural characterization of two new copper terpyridine (terpy) complexes: [Cu(terpy)(SO4)(H2O)]·2H2O and [Cu2(terpy)2(SO4)2]·4H2O are presented. The crystal structures show that the copper ion in both complexes is in a square pyramidal environment, coordinated equatorially to the terpy N atoms and completing the coordination with O atoms from the sulfate or water molecules. The second compound is a sulfate bridged dinuclear complex. In aqueous solution the coordination scheme is modified. Taking the crystal structure as a starting point the geometries of the complexes were optimized and vibrational spectroscopy calculations were performed allowing an assignation of the experimental IR spectra. Finally, the interaction of the complexes with DNA was studied, by UV titration and docking studies of the complexes. The results suggest that the interaction occur by minor groove interaction and partial insertion of the terpy into the DNA bases and that terpy interaction with DNA is strongly influenced by the Cu-coordination process.

Two new Cu-terpy complexes were characterized by X-ray diffraction. By means of theoretical calculations the IR spectra is interpreted in detail. Docking studies of the complexes with DNA suggest a minor groove interaction and partial insertion of the terpy into the DNA, which is strongly influenced by the coordination process.Figure optionsDownload as PowerPoint slide