1. Department of Chemistry, University of Patras, Patras 26500 Greece; Foundation for Research and Technology Hellas, Institute of Chemical Engineering and High Temperature Processes (FORTH-ICEHT), P.O. Box 1414, Patras 26500, Greece; and INSTM, Unit of Trieste, Dipartimento di Scienze Farmaceutiche, Università di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy