1. Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, Alexza Molecular Delivery Corporation, 1001 East Meadow Circle, Palo Alto, California 94303, Department of Chemistry, University of Missouri, Rolla, Missouri 65409-0010, and Centre de Recherche Paul Pascal, CNRS UPR 8641, Av. Dr. A. Schweitzer, 33600 Pessac, France