Spectroscopy and redox behaviour of dicopper(II) and dinickel(II) complexes of Bis(cyclen) and Bis(cyclam) ligands

Abstract : The dinuclear CuII and NiII complexes of meta-xylyl and pyridyl biscyclen and biscyclam have been prepared and characterised in solution by means of UV/Visible spectra, electrochemical and EPR studies. X-ray structures of copper biscyclen complexes have been obtained. The comparison of all the data shows that the potentially coordinating N(py) py ridyl atom promotes the interaction between the two metal centers, whether it is spontaneously coordinated (biscyclen complexes) or not (biscyclam ones). © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.