1. Department
of Organic Chemistry, University of Geneva, Quai Ernest Ansermet, 30, 1211 Geneva 4, Switzerland
2. Laboratory
of Crystallography, University of Geneva, Quai Ernest Ansermet, 24, 1211 Geneva 4, Switzerland
3. Ecole
Mational Supérieure de Chimie de Rennes, UMR 6226, Institut des sciences chimiques de Rennes - Equipe OMC, 11, allée
de Beaulieu, Rennes 7, France