1. Deprtment of Chemistry; Osaka University; 1-1, Machikaneyama Toyonaka 560-0043 Japan
2. Current address: Department of Chemistry; Da Nang University of Education; the University of Da Nang; Vietnam
3. Bruker BioSpin K.K.; 3-9, Moriya-cho Kanagawa-ku, Yokohama, Kanagawa