Synthesis, Characterization and Electrochemical Studies of bis(Monothiolato) {FeFe} Complexes [Fe₂(μ‐SC₆H₄‐OMe‐m)₂(CO)₅L] (L = CO, PCy₃, PPh₃)

Abstract

Reaction of Fe 3 (CO) 12 with 3-methoxybenzenethiol in toluene afforded a new bis(monothiolato) hexacarbonyl diiron complex [Fe 2 (μ-SC 6 H 4 -OMe-m) 2 (CO) 6 ] 1. Substitution of CO in complex 1 with monodentate phosphine ligands (PCy 3 and PPh 3 ) further afforded two new complexes [Fe 2 (μ-SC 6 H 4 -OMe-m) 2 (CO) 5 (PCy 3 )] 2 and [Fe 2 (μ-SC 6 H 4 -OMe-m) 2 (CO) 5 (PPh 3 )] 3. All the three complexes were characterized by FTIR, NMR, UV-Vis, mass and elemental analysis. Further, complexes 1-3 were found to be electrocatalytically active for proton reduction in acetonitrile in the presence of both weak and strong acids as proton sources.

Enzymatic and Bioinspired Systems for Hydrogen Production

“…Unlike native [FeFe]-hydrogenases, their mimics undergo gradual degradation and loss of CO under light irradiation over a few hours, resulting in relatively low TON [22]. Substitution of one carbonyl with a phosphine ligand results in improved photostability, but also increases the electron density at the diiron site [264,265]. This effect, which is beneficial for electrocatalysis, is detrimental for the photoinduced process, because it disfavors the charge transfer from the photosensitizer.…”