1. Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, U.K., Johnson Matthey Catalysts, PO Box 1, Belasis Avenue, Billingham, Cleveland, TS23 1LB, U.K., Bath Chemical Crystallography Unit, Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, U.K., and School of Informatics, University of Wales, Dean Street, Bangor, Gwynedd, LL57 1UT, U.K.