Proton Shuttle Mediated by (SCH 2 ) 2 P═O Moiety in [FeFe]-Hydrogenase Mimics: Electrochemical and DFT Studies - Université de Bretagne Occidentale Access content directly
Journal Articles ACS Catalysis Year : 2021

Proton Shuttle Mediated by (SCH 2 ) 2 P═O Moiety in [FeFe]-Hydrogenase Mimics: Electrochemical and DFT Studies

Abstract

The synthesis, characterization, and protonation of [Fe2(CO)6{(μ-SCH2)2(Et)P═O}] (1) using the moderately strong acid CF3CO2H (pKaMeCN = 12.7) are reported. Digital simulations of the cyclic voltammetry of 1 in the presence of CF3CO2H and DFT calculations have allowed us to obtain a detailed mechanistic picture of the processes underlying the catalytic hydrogen evolution reaction (HER) that 1 can mediate. Moreover, DFT has shed light on the role of the P═O functionality in the whole catalytic cycle of proton reduction. The reductive behavior of 1 features a double electron transfer with potential inversion, which is associated with deep structural rearrangement of the catalyst. The double reduction appears also functional to the intramolecular proton transfer from the P═O group to the diiron core, a crucial process for the H+/H– heterocoupling yielding H2. The key intermediate for the H2 formation and release is predicted to be a 3H+/3e– species, in which P═O is perfectly poised to shuttle protons from solution to the Fe–H–Fe moiety. Therefore, the R-P═O bridgehead installed in a dithiolato linker of a diiron core proves a valid and versatile alternative to the natural nitrogen-based Fe2 strap.
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Dates and versions

hal-03251619 , version 1 (07-06-2021)

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Laith Almazahreh, Federica Arrigoni, Hassan Abul-Futouh, Mohammad El-Khateeb, Helmar Görls, et al.. Proton Shuttle Mediated by (SCH 2 ) 2 P═O Moiety in [FeFe]-Hydrogenase Mimics: Electrochemical and DFT Studies. ACS Catalysis, 2021, pp.7080-7098. ⟨10.1021/acscatal.0c05563⟩. ⟨hal-03251619⟩
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