Synthesis of carboxylic acid-modified [FeFe]-hydrogenase model complexes amenable to surface immobilization Academic Article uri icon


  • Model complexes of [FeFe]-hydrogenase bearing carboxylic acid functionalities have been designed for applications toward immobilization of hydrogen production electrocatalysts on amino-functionalized carbon electrode surfaces. Using carboxylic acid-substituted thiols, complexes incorporating the -COOH moiety into the thiolate linkers have been synthesized: (-SCH 2CH 2COOH) 2[Fe(CO) 3] 2 (1) and the previously known (-(SCH 2) 2CHCOOH) [Fe(CO) 3] 2 (2). Carboxylic acid units have also been introduced via ligand substitution with a tricarboxyethyl phosphine to generate (-pdt)[Fe(CO) 3] [Fe(CO) 2-{P(C 2H 4COOH) 3}] (3). To mimic the linkage of complexes of these types to amino-functionalized monolayers, it has been demonstrated that 2 can be coupled with aniline in solution to generate (-(SCH 2) 2-CHCONHPh)[Fe(CO) 3] 2 (4), and the stability of this linkage has been addressed. The carboxylic acid-substituted complex 2 undergoes ligand substitution with PMe 3 to generate (-(SCH 2) 2CHCOOH)[Fe(CO) 2(PMe 3)] 2 (5). Complex 5 can then be protonated in either methanol or tetrahydrofuran solvent to generate (-(SCH 2) 2CHCOOMe) (-H)[Fe(CO) 2(PMe 3)] 2}PF 6 (6) and (-(SCH 2) 2CHCOOH)(-H)[Fe(CO) 2(PMe 3)] 2}PF 6 (7), respectively, demonstrating that a range of carboxy-functionalized complexes can be synthesized. Structural characterization and cyclic voltammetry of these complexes indicate that the carboxylic acid functionality has little effect on the structure and reactivity of the diiron dithiolate core. 2007 American Chemical Society.

published proceedings


author list (cited authors)

  • Thomas, C. M., Ruediger, O., Liu, T., Carson, C. E., Hall, M. B., & Darensbourg, M. Y.

citation count

  • 107

complete list of authors

  • Thomas, Christine M||Ruediger, Olaf||Liu, Tianbiao||Carson, Cody E||Hall, Michael B||Darensbourg, Marcetta Y

publication date

  • July 2007