1. Department of Chemistry University of Fribourg Chemin du Musée 9 1700 Fribourg Switzerland
2. Department of Chemistry and Applied Biosciences Swiss Federal Institute of Technology ETH Zürich Vladimir-Prelog-Weg 2 8093 Zürich Switzerland
3. Department of Chemistry, Biochemistry, and Pharmaceutical Sciences University of Bern Freiestrasse 3 3012 Bern Switzerland