1. Department of Chemistry, Faculty of Science and Technology, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223, Japan, Department of Chemistry, Aichi University of Education, Igaya, Kariya 448, Japan, Department of Chemistry, Faculty of Science, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152, Japan, and Department of Chemistry, Faculty of Science, Okayama University, Tsushima, Okayama 700, Japan