The effect of bridgehead steric bulk on the ground state and intramolecular exchange processes of (mu-SCH2CR2CH2S)[Fe(CO)(3)][Fe(CO)(2)L] complexes Academic Article uri icon


  • The flexibility of the coordination sphere in the diiron organometallic is likely an important design component in nature's electrocatalyst for proton reduction or H2 oxidation, i.e, the active site of [FeFe]hydrogenase. A series of complexes, (-SCH2CRRCH2S)[Fe(CO)3][Fe(CO)2L] with steric bulk incorporated into the -S-to-S linker was synthesized and the compounds were analyzed by infrared spectroscopy and cyclic voltammetry [(R/R = Me/Me, Et/Et, Bu/Et), (L = CO, PPh3, IMes (1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene), and IMe (1,3-dimethylimidazole-2-ylidene))]. While added steric bulk at the bridgehead carbon of the -SCH2CR2CH2S produced little change in the ground state structures (X-ray diffraction) and electronic character for the (-SRS)[Fe(CO)3]2 complexes, monosubstitution of a CO with L produced distortions consistent with steric interference of the -SRS with nearby ligands as compared to the similar (-pdt)[Fe(CO)3][Fe(CO)2L] (pdt = S(CH2)3S). Variable temperature NMR studies have shown that the activation barrier for CO site exchange on the sterically bulky complexes decreases in a manner predicted by theory [J.W. Tye, M.B. Hall, M.Y. Darensbourg, Inorg. Chem. 45 (2006) 1552]. 2008 Acadmie des sciences.

published proceedings


author list (cited authors)

  • Singleton, M. L., Jenkins, R. M., Klernashevich, C. L., & Darensbourg, M. Y.

citation count

  • 63

complete list of authors

  • Singleton, Michael L||Jenkins, Roxanne M||Klernashevich, Cory L||Darensbourg, Marcetta Y

publication date

  • January 2008