1. Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, Kojirakawa, Yamagata 990-8560, Japan, X-Ray Research Laboratory, Rigaku Corporation, Matsubara 3-9-12, Akishima, Tokyo 196-8666, Japan, and Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, 669-1337, Japan