Hydroxy and ether functionalized dithiolanes: Models for the active site of the [FeFe] hydrogenase

In attempt to synthesize suitable [FeFe] hydrogenase model complexes, 2-methoxypropane-1,3-dithiole and 4-methyl-4-hydroxy-1,2-dithiolane were reacted with Fe3(CO)12 to give the respective complexes [Fe2(CO)6(H3COCH(CH2S)2)] and [Fe2(CO)6(HOC(CH3)(CH2S)2)]. The compounds were characterized by 1H and 13C NMR spectroscopy, mass spectrometry and elemental analysis. In addition, their electrochemical properties were investigated by cyclic voltammetry and compared with that of [Fe2(CO)6(HOC(CH2S)2)] known from literature.

Two [FeFe] hydrogenase model complexes 4 and 8, containing 2-oxy-1,3-dithiolato moiety was synthesized to investigate the role of hydrogen interactions with the [2Fe2S] cluster. The catalytic activity of the complexes was investigated by cyclic voltammetry to reveal dihydrogen formation from acetic acid.Figure optionsDownload as PowerPoint slideResearch highlights
► [2Fe2S] clusters catalyze the reduction of protons to dihydrogen.
► Adjacent bases can enhance protonation ability of the [FeFe] cluster.
► Alkylic alcohols show no impact on the catalytic cycle.