Electrochemical and Theoretical Investigations of the Oxidatively Induced Reactivity of the Complex [Fe₂(CO)₄(κ²‐dmpe)(μ‐adt^Bn)] Related to the Active Site of [FeFe] Hydrogenases

Abstract

Electrochemical oxidation of the complex [Fe (CO) (κ -dmpe)(μ-adt )] (adt =(SCH ) NCH C H , dmpe=Me PCH CH PMe ) (1) has been studied by cyclic voltammetry (CV) in acetonitrile and in dichloromethane in the presence of various substrates L (L=MeCN, trimethylphosphite, isocyanide). The oxidized species, [1-MeCN](PF ) , [1-(P(OMe) ) ](PF ) and [1-(RNC) ](PF ) (R=tert-butyl, xylyl), have been prepared and characterized by IR and NMR spectroscopies and, except [1-MeCN](PF ) , by X-ray diffraction analysis. The crystallographic structures of the new Fe Fe complexes reveal that the association of one additional ligand (P(OMe) or RNC) occurs and, according to the nature of the substrates, further substitutions of one or three carbonyl groups, by P(OMe) or RNC, respectively, arise. Density functional theory (DFT) calculations have been performed to elucidate and discriminate, in each case, the mechanisms leading to the corresponding oxidized species. Moreover, the different degree of ligand substitution in the diiron core has been theoretically rationalized.

The Photochemistry of Fe2(S2C3H6)(CO)6(µ-CO) and Its Oxidized Form, Two Simple [FeFe]-Hydrogenase CO-Inhibited Models. A DFT and TDDFT Investigation

“…On the contrary, 2 a + -CO formation is exothermic and spontaneous [38]. Similar considerations regarding the CO-binding process under oxidative conditions have also been reported for more electron-rich diiron models [39][40][41].…”

Synthesis, Characterization and Electrochemical Reductive Properties of Complexes [Fe2(CO)4(κ2‐PPh2NR2)(µ‐dithiolato)] Related to the H‐Cluster of [FeFe]‐H2ases

“…The preparation and the purification of the supporting electrolyte [NBu 4 ][PF 6 ] were as described previously. [ 25 ] The working electrode was a vitreous carbon disk of 0.3 cm in diameter, polished with alumina prior to use. A platinum wire was used as counter electrode.…”

Insights into the Two‐Electron Reductive Process of [FeFe]H2ase Biomimetics: Cyclic Voltammetry and DFT Investigation on Chelate Control of Redox Properties of [Fe2(CO)4(κ2‐Chelate)(μ‐Dithiolate)]

“…The preparation and the purification of the supporting electrolyte [NBu 4 ][PF 6 ]w ere as described previously. [27] The working electrode was av itreous carbon disk of 0.3 cm in diameter,p olished with alumina prior to use. Ap latinum wire was used as counter electrode.…”

“…All the electrochemical studies were carried out in a conventional three‐electrode cell under an inert atmosphere of either N 2 , Ar or CO. The preparation and the purification of the supporting electrolyte [NBu 4 ][PF 6 ] were as described previously [27] . The working electrode was a vitreous carbon disk of 0.3 cm in diameter, polished with alumina prior to use.…”