[1] University Hassan II of Casablanca, Faculty of sciences Ben M'sik, Department of Chemistry, Laboratory of Physical Chemistry of Materials, Casablanca, Morocco
[2] Universityof Pisa, Department of Chemistry and Industrial Chemistry, Pisa, Italy
[3] Italian National Council for Research - Institute for the Chemistry of OrganoMetallic Compounds, Florence, Italy
[4] University of Florence, Department of ChemistryU. Schiff, Florence, Italy
[5] University of Bologna, Department of Chemistry G. Ciamician, Bologna, Italy