1. Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, D-93040 Regensburg, Germany
2. Department of Chemistry, University of California, Berkeley, California 94720, United States
3. Institute of Biophysics and Physical Biochemistry, Faculty of Biology and Preclinical Medicine, University of Regensburg, D-93040 Regensburg, Germany
4. Institute of Theoretical and Physical Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, D-93040 Regensburg, Germany