1. Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Germany
2. Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
3. Department of Chemistry University of the Balearic Islands Cra. Valldemossa, Km. 7.5 07122 Palma de Mallorca Spain