1. Department
of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland
2. Institute
of Organic Chemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
3. Institute
of Applied and Physical Chemistry, University of Bremen, Leobener Strasse
UFT, 28359 Bremen, Germany
4. Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland