Spectroscopic and electrochemical studies of hetero–bimetallic copper complexes with Schiff's base ligand

Using Schiff's base ligand, several Cu(II) based bimetallic complexes such as Cu–Cu, Cu–Co, Cu–Ni, Cu–Zn, Cu–Mn have been prepared in a stepwise procedure. The structures of these complexes and the ligand have been proposed on the basis of FAB mass, elemental analysis, UV–vis, IR, electron paramagnetic resonance (EPR) and CV studies. EPR parameters, obtained through complete simulation, suggest that the formation of bimetallic complexes forces the Cu(II) centre to increase the flexibility in comparison with the monometallic Cu(II) complex. However, the nature of the second metal ion in the bimetallic complex effects the distortion around the first metal ion. The reduction of the complexes from Cu(II) to Cu(I) involves a large geometrical change and is found to be irreversible. A large positive shift is seen in the cathodic process, which can be ascribed to increased distortion due to bimetallic coordination. These complexes have potential usage in DNA studies.