1. Laboratoire de Chimie de Coordination du CNRS, UPR 8241, liée par conventions à l'Université Paul Sabatier et à l'Institut National Polytechnique de Toulouse, 205 route de Narbonne, 31077 Toulouse Cedex, France, Fax: +33‐5‐61553003
2. Present address: Department of Chemistry, University of California at Riverside, Riverside, CA 92521, USA
3. Present address: University of Bucharest, Faculty of Chemistry, Inorganic Chemistry Laboratory, Str. Dumbrava Rosie nr. 23, 020464 Bucharest, Romania
4. Institute of Chemistry, Academy of Sciences of Moldova, Academiei str. 3, 2028 Chisinau, Moldova