1. Fachbereich Biologie, Chemie und Pharmazie, Freie Universität Berlin, Fabeckstraße 34-36, 14159 Berlin, Germany
2. Department of Chemistry, Burke Laboratory, 41 College Street, Hanover, New Hampshire 03755, United States
3. Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330-8268, United States
4. Friedrich-Alexander-Universität Erlangen-Nürnberg, Regensburger Straße 16, 90478 Nuremberg, Germany