1. Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P. O. Box 9502, 2300 RA Leiden, The Netherlands, Fax: +31‐71‐5274451
2. National Institute for Chemical and Petrochemical Research, Splaiul Independentei 202, 060021 Bucharest, Romania
3. Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, P. O. Box 55, (A. I. Virtasen aukio 1), 00014 Helsinki, Finland