October, 1993] 700 cm'l. This research was partially supported by a Grant- in-Aid from the Okayama Foundation for Science and Technology. We are grateful to Professor Masanori Utaka of the Faculty of Engineering of Okayama Uni- versity for the helpful discussions throughout this work. We are also grateful to Mr. Eiichiro Amano of the Fac— ulty of Engineering for elemental analysis and the SC— NMR Laboratory of Okayama University for the NMR ...