1. JCORP-JST, c/o NEC Corporation, 34 Miyukigaoka, Tsukuba 305-8501, Japan, Department of Chemistry, Faculty of Science, Chiba University, 1-33 Yayoi, Inage, Chiba 263, Japan, Center for Frontier Electronics and Photonics, Chiba University, 1-33 Yayoi, Inage, Chiba 263, Japan, Meijo University, 1-501 Shiogamaguchi, Tempaku, Nagoya 468-8502, Japan, NEC Corporation, 34 Miyukigaoka, Tsukuba 305-8501, Japan, and Departamento de Quimica Inorganica, Universidad de Alicante, Apartado 99, E-03080, Alicante, Spain