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, Canada H2A 2 K6