HER catalysed by iron complexes without a Fe2S2 core: A review

The field of proton reduction by iron complexes without thiolate bridging ligand(s) in homogeneous systems is reviewed. Till date electrocatalytic proton reduction by iron complexes bioinspired from the hydrogenase enzymes has been studied with a significant progress in the field. The focus has mostly been on mimicking the [FeFe] hydrogenase enzyme active site. Very few iron complexes not directly resembling the enzyme active site have been reported as electrocatalysts for the proton reduction process. Herein, are discussed such type of complexes and a comparison study is being presented between the various reported complexes as proton reduction catalysts. (C) 2019 Elsevier B.V. All rights reserved.