A Novel N-heterocyclic Carbene Containing [Fe–Fe] Hydrogenase Model Complex as Bio-Mimetic Catalyst For Proton Reduction and Benzene Hydroxylation

Abstract

This study reports the synthesis of a new di-iron complex, μ-(SCH(CH₂CH₃)CH₂S)Fe₂(CO)₅IPr (2, where IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), and its comprehensive characterization using mass spectrometry, elemental analysis, solution IR, and NMR spectroscopy. The CO/L substitution reaction was used to introduce the sterically hindered nitrogen-containing heterocyclic carbene ligand (IPr) and coordinate it to the iron center under mild conditions. The di-iron complex was studied for its potential in proton electrocatalysis and benzene hydroxylation. Complex 2 underwent two irreversible reductions around − 2.204 V and effectively facilitated proton reduction into hydrogen using HOAc as the proton source. Complex 2 catalyzed the hydroxylation of benzene, resulting in a phenol yield of 12.9% and nearly 96% selectivity.

Graphical Abstract

A new diiron complex µ-(SCH(CH₂CH₃)CH₂S)Fe₂(CO)₅IPr was synthesized and characterized by solution IR spectra, mass spectrum,NMR spectra and elemental analysis. This complex were used as catalyst for proton reduction and benzene hydroxylation.