1. Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
2. Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10 Prague, Czech Republic
3. Institute of Chemistry, Technische Universität Berlin, Hardenbergstraße 40, 10623 Berlin, Germany