1. Department of Chemistry University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
2. Department of Chemistry University of Zurich Winterthurerstrasse 190 8057 Zurich Switzerland
3. Prievidza Chemical Society M. Hodžu 10/16 971 01 Prievidza Slovak Republic
4. Current address: Department of Chemistry, Biochemistry and Pharmaceutical Sciences University of Bern Freiestrasse 3 3012 Bern Switzerland