1. Department of Chemistry, University of Paderborn, Warburger Str. 100, 33098 Paderborn, Germany
2. Institute of Organic Chemistry, Clausthal University of Technology, Leibnizstr. Str. 6, 38678 Clausthal-Zellerfeld, Germany
3. Department of Physics, University of Paderborn, Warburger Str. 100, 33098 Paderborn, Germany