1. Section of Inorganic and Analytical Chemistry, Department of Chemistry, University of Ioannina 45110 Ioannina, Greece, Fax: (internat) + 30‐26510‐44831
2. Department of Chemistry, A. Mickiewicz University, ul. Grunwaldzka 6, 60‐780 Poznan, Poland
3. Department of Chemistry, McGill University, 801 Sherbrooke, Montreal, Quebec H2A 2K6, Canada