1. Institute for Organic Chemistry Department of Chemistry and Pharmacy University of Regensburg Universitätsstrasse 31 93040 Regensburg Germany
2. Stratingh Institute for Chemistry Faculty of Science and Engineering University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
3. Institute for Biophysics and Physical Biochemistry Regensburg Center for Biochemistry University of Regensburg Universitätsstrasse 31 93040 Regensburg Germany