Spectroscopic and electrochemical comparison of [FeFe]-hydrogenase active-site inspired compounds: Diiron monobenzenethiolate compounds containing electron-donating and withdrawing groups

The novel compounds [Fe-2(mu-SC6H4-p-NO2)(2)(CO)(6)] (1), [Fe-2(mu-SC6H4-p-Bu-t)(mu-SC6H4-p-NO2)(CO)(6)] (2), [Fe-2(mu-SC6H4-p-Bu-t)(2)(CO)(6)] (3), [Fe-2(mu-SC6H4-p-Bu-t)(mu-SC6H4-p-CF3)(CO)(6)] (4) and [Fe-2(mu-SC6H4-p-OCH3)(mu-SC6H4-p-CF3)(CO)(6)] (5) have been characterized by H-1 NMR, FTIR, elemental analysis, and cyclic voltammetry. X-ray crystallography of compounds 1 and 2 reveal an anti (ax,eq) S-aryl ligand orientation in the solid state. Carbonyl IR spectra and reduction potentials correlate strongly with Hammett constants of the electron donating/withdrawing groups. Evaluation for electrocatalytic formation of dihydrogen from acetic acid indicates a low overpotential of activity of 0.26 V for compound 5. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The structures and properties of five novel iron-based compounds were investigated, with X-ray crystallography revealing the solid-state structure of two of them, carbonyl IR spectra and reduction potentials correlating with Hammett constants of different groups, and compound 5 showing low overpotential activity in the electrocatalytic production of dihydrogen.