1. Dipartimento di Chimica “G. Ciamician”, Università di Bologna, via Selmi 2, 40126 Bologna, Italy, Centro Interdipartimentale di Ricerca in Scienze Ambientali (CIRSA), Università di Bologna, Via S. Alberto 163, 48100 Ravenna, Italy, Department of Inorganic Chemistry, Budapest University of Technology and Economics, H-1521 Budapest Szt Gellért tér 4, Hungary, and Chemistry Department, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, Sussex, U.K.