1. Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 8, 12843 Praha 2, Czech Republic, Fax: +420‐221‐951‐326, http://orgchem.cz/kotora
2. Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 12843 Praha 2, Czech Republic, Fax: +420‐221‐951‐253, http://web.natur.cuni.cz/~stepnic/
3. Institute of Organic Chemistry and Biochemistry, AS CR, v.v.i., Flemingovo nám. 2, 16610 Praha 6, Czech Republic