1. Laboratory of Bioinorganic Coordination Chemistry, Department of Chemistry, School of Sciences, University of Crete, P.O. Box 1470, 71409 Heraklion Crete, Greece, Laboratoire de biomathématiques, Faculté de pharmacie Université Paris V, 4 avenue de l'observatoire, 75006 Paris, France, LURE, Bat 209D, Université Paris XI, 91405 Orsay, France, and NCRS, Demokritos, Agia Paraskevi, 15310 Athens, Greece