[Fe(C5Ar5)(CO)2Br] complexes as hydrogenase mimics for the catalytic hydrogen evolution reaction

• Published in: Applied catalysis. B, Environmental Environmental, 2018-04, Vol.223, p.234-241
• Main Authors: Hemming, E.B., Chan, B., Turner, P., Corcilius, L., Price, J.R., Gardiner, M.G., Masters, A.F., Maschmeyer, T.
• Format: Article
• Language: English
• Subjects: Catalysis; Chemical synthesis; Cobalt; Crystallography; Electrochemistry; Hydrogen evolution catalysts; Hydrogen evolution reactions; Hydrogenase; Hydrogenase mimics; Hydrogenases; Iron; Iron-based catalysts; Studies; Trichloroacetic acid; X-ray crystallography
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2017.04.053

[Display omitted] •[Cp**Fe(CO)2Br] and [Fe(C5(p-C6H4Br)5)(CO)2Br] were studied as HER catalysts.•Crystal structures for [Fe(C5(p-C6H4Br)5)(CO)2Br] and two analogues were determined.•[Fe(C5(p-C6H4Br)5)(CO)2Br] was found to be the most efficient catalyst.•Both complexes were more efficient than previously reported analogues. A new iron-based hydrogenase mimic, [Fe(C5(p-C6H4Br)5)(CO)2Br], was synthesised and characterised using X-ray crystallography. Two analogous catalytic precursors, [Fe(C5Ar5)(CO)2Br] (Ar=C6H5; p-C6H4Br), were also analysed electrochemically in order to investigate how bulkier and more electron withdrawing C5Ar5 ligands affect the catalytic generation of hydrogen from trichloroacetic acid. Compared to previously reported iron-based cyclopentadienyl analogues, these complexes were found to have smaller overpotentials and larger turnover numbers. The [Fe(C5(p-C6H4Br)5)(CO)2Br] complex was found to be the most efficient of the two catalytic precursors with a turnover number of 25, an overpotential of around 310mV and a faster rate of reaction compared to [Fe(C5Ph5)(CO)2Br].