1. L. V. Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of the Ukraine, Prospekt Nauki 31, Kiev, 03028 (Ukraine), Fax: (+380) 4452 56216
2. N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky Prosp. 31, 119991 Moscow, GSP‐1 (Russian Federation), Fax: (+7) 4959 521 279
3. Equipe Organométalliques et Matériaux Moléculaires, Sciences Chimiques de Rennes, UMR UR1‐CNRS 6226, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes cedex (France), Fax: (+33) 2232 36840