Investigations on the PNP‐chelated diiron dithiolato complexes Fe2(μ‐edt)(CO)4{κ2‐(Ph2P)2NC6H4R} related to the [FeFe]‐hydrogenase active site

Abstract

AbstractThe chemistry of the diiron dithiolato hexacarbonyl complex Fe2(μ‐edt)(CO)6 (edt, 1,2‐ethanedithiolate) has received special attention, largely because that its structure is similar with the active site of [FeFe]‐hydrogenase. In order to enrich the chemistry of complex Fe2(μ‐edt)(CO)6 and synthesize new hydrogen evolution catalysts, a new route to the diiron dithiolato hexacarbonyl complex Fe2(μ‐edt)(CO)6 was described. Reaction of Fe3(CO)12 and Me3SiSCH2CH2SSiMe3 in the presence of Et3N at 80 °C afforded Fe2(μ‐edt)(CO)6 in 90 % yield. Furthermore, reaction of Fe2(μ‐edt)(CO)6 and aminodiphosphine ligands (Ph2P)2NC6H4R (R=−3‐CCH, 4‐CCH) produced the new PNP‐chelated diiron dithiolato complexes Fe2(μ‐edt)(CO)4{κ2‐(Ph2P)2NC6H4R} (1 and 2). All the complexes were characterized by elemental analysis, IR, NMR spectroscopy, and particularly for 1 and 2 by X‐ray single diffraction analysis. In addition, the electrochemical results indicated that 1 and 2 could be considered as electrocatalysts for hydrogen evolution reaction.