1. Department of Chemistry, Faculty of Science; Okayama University of Science; 1-1 Ridaicho, Kita-ku Okayama 700-0005 Japan
2. X-ray Research Laboratory; Rigaku Corporation; 3-9-12 Matubaracho, Akishima Tokyo 196-8666 Japan
3. Department of Chemistry and Materials Science; Tokyo Institute of Technology; 2-12-1 Ookayama, Meguro-ku Tokyo 152-8551 Japan