1. Department of Inorganic Chemistry, Institute of Chemistry, P.J. Šafárik University in Košice, Košice, Slovakia;
2. Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic;
3. Department of Inorganic Chemistry, Faculty of Science, Charles University, Prague, Czech Republic;
4. NMR Laboratory, Institute of Chemistry, P.J. Šafárik University in Košice, Košice, Slovakia