1. On leave from the Department of Chemistry, Faculty of Science, Ehime University, Matsuyama, Ehime 790, Japan.
2. K. Kuroda,Chem. Lett., 93 (1979).
3. Y. Fukuda, M. Ishige, T. Ito, K. Kuroda, K. Sone, Y. Suzuki, S. Yano and S. Yoshikawa,Chem. Lett., 1699 (1981).
4. S. Aygen, Y. Kitamura, K. Kuroda, R. Kume, H. Kelm and R. van Eldik, submitted for publication.
5. Hoechst Analytical laboratory, Frankfurt, FRG.