1. Department of Applied Chemistry, Osaka University and PRESTO, JST, 2-1 Yamada-oka, Suita 565-0871, Japan, Entropy Control Project, ICORP, JST, 4-6-3 Kamishinden, Toyonaka 560-0085, Japan, and Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, B.C. V8W 3V6, Canada