1. Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K.
2. Department of Physics, B5, University of Liège, B-4000, Sart-Tilman, Belgium
3. Department of Chemistry, Missouri University of Science and Technology, University of Missouri, Rolla, Missouri 65409-0010
4. Department of Inorganic Chemistry, Faculty of Science, Palacký University, tr. 17. Listopadu 12, 77146 Olomouc, Czech Republic