1. Department of Chemistry, Faculty of Science, Kobe University, Nada, Kobe, Hyogo 657, Japan
2. Department of Chemistry, Faculty of Engineerig, Mie University, Tsu, Mie 514, Japan
3. Institute for Chemical Research, Kyoto University, Uji, Kyoto 611, Japan
4. Institute for Materials Research, Tohoku University, Sendai, Miyagi 980, Japan