1. Department of Chemistry, Dalhouse University, Halifax, NS B3H 4J3, Canada
2. Chemistry Department, University of New Brunswick, E3B 6E2 Fredericton, N.B., Canada, Fax: (internat.) +1‐506‐453‐48‐21
3. N. S. Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences 117907 Moscow GSP‐1, Leninsky Prospect 31, Russia