1. Laboratoire de Physico‐Chimie Bioinorganique, UMR 7509 du CNRS, ECPM, Université Louis Pasteur, 25 rue Becquerel, 67200 Strasbourg, France, Fax: (internat.) +33‐3‐90242639
2. Swiss Federal Institute of Technology Lausanne, Institute of Molecular and Biological Chemistry, BCH 1402, 1015 Lausanne, Switzerland