S1 Supplementary Information Normal and inverted redox potentials and structural changes tuned by medium effects in [M 2 Mo( 5 -C 5 Me 5 ) 2 (S 2 C 6 H 4 ) 2 (CO) 2 ] (M: Co, Rh) Satoshi Muratsugu, abc Keitaro Sodeyama, def Fusao Kitamura, g Satoru Tsukada, a Mizuki Tada, bc Shinji Tsuneyuki, d and Hiroshi Nishihara* a a. Department of Chemistry, School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan. b. Department of Materials Molecular Science, Institute for Molecular Science, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan. c. Department of Structural Molecular Science, The Graduate University for Advanced Studies, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan. d. Department of Physics, School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan. e. International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. f. CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 333-0012, Japan. g. Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4256, Nagatsuta, Midori-Ku, Yokohama 226-8502, Japan. Electronic Supplementary Material (ESI) for Chemical Science This journal is © The Royal Society of Chemistry 2011