1. Université Montpellier 2, Institut Charles Gerhardt, CNRS 5253, cc 1501, Place Eugène Bataillon 34095, Montpellier, France
2. Departament de Quimica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain
3. Chemistry Department, Yale University, 225 Prospect Street, P.O. Box 208107, New Haven, Connecticut 06520, United States.