1. Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
2. Department of Organic Chemistry, Faculty of Science, Charles University in Prague, 128 40 Prague 2, Czech Republic
3. Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, USA
4. Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, 128 40 Prague 2, Czech Republic