1. †Dulbecco Telethon Institute and ‡Department of Chemistry, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy
2. This is a Chemical Reviews Perennial Review. The root paper of this title was published in Chem. Rev., 2005, 105(9), 3297−3351, DOI: 10.1021/cr000095n; Published August 25, 2005. Updates to the text appear in red type.