1. Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Italy
2. Laboratoire de Chimie Inorganique Moléculaire et Catalyse, UMR 7177 CNRS, Université de Strasbourg, 1 rue Blaise Pascal, 67008 Strasbourg Cedex, France
3. Laboratory of Peptide & Protein Chemistry & Biology, Scientific and Technological Park, University of Florence, 50019 Sesto Fiorentino, Italy