1. Department of Chemical Science and Technology, University of Udine, Via del Cotonificio 108, 33100 Udine, Italy, Department of Biomedical Science and Technology, University of Udine, School of Medicine, Piazzale Kolbe 4, 33100 Udine, Italy, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands