1. Institut Charles Gerhardt Montpellier UMR 5253 CNRS/UM2/ENSCM/UM1 8 rue de l'Ecole Normale 34296 Montpellier Cedex 5 France
2. Institute of General and Inorganic Chemistry Bulgarian Academy of Sciences Acad. G. Bonchev Str., bl. 11 1113 Sofia Bulgaria