1. Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan, Department of Radiology, Komazawa Junior College, 1-23-1 Komazawa, Setagaya-ku, Tokyo 154-8525, Japan, and Integrated Inorganic Material Chemistry Laboratory, Department of Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan