1. CNRS; LCC (Laboratoire de Chimie de Coordination); 205 Route de Narbonne B. P. 44099 31077 Toulouse Cedex 4 France
2. Université de Toulouse; UPS; INPT; 205 Route de Narbonne B. P. 44099 31077 Toulouse Cedex 4 France
3. Department of Biotechnology; Chemistry and Pharmacy; University of Siena; Via A. Moro 2 53100 Siena Italy
4. Department of Chemistry; University of Pavia; Via Taramelli 12 27100 Pavia Italy