1. Department of Chemistry and Chemical Engineering University of Paisley, Paisley PA1 2BE, UK Department of Chemistry, University of Glasgow Glasgow G12 8QQ, UK ICMAT-CNR, AdR di Roma, CP 10, I-00016 Monterotondo Stazione, Italy European Synchrotron Radiation Facility, BP 220 F-38043 Grenoble Cedex, France Faculté de Pharmacie, Université de Grenoble F-38706 La Tronche, France