title: Enhancement in catalytic proton reduction by an internal base in a diiron pentacarbonyl complex: its synthesis, characterisation, inter-conversion and electrochemical investigation.
abstract: The reaction of a tripodal ligand (H2L) with a {S2N} donor-set with tri-iron dodecacarbonyl in toluene leads to the isolation of a diiron pentacarbonyl complex 1 as a model for the sub-site of the [FeFe]-hydrogenase. Protonation of this complex under CO (1 atm.) forms quantitatively the hexacarbonyl complex 2H+ with a pendant pyridinium group. Infrared spectroscopic investigations indicate that its pendant pyridinium group dissociates to give hexacarbonyl complex 2 which forms subsequently the pentacarbonyl complex 1. The electrochemistry of these complexes has been investigated. Complex 2H+ exhibits electrocatalysis on proton reduction at a potential more positive by over 200 mV compared to that for other neutral diiron hexacarbonyl complexes. This catalysis is enhanced under a CO atmosphere by freeing the bound base group which acts as a proton relay in the catalysis.
authors.affiliation: School of Chemistry, Nanchang University, Nanchang 330031, China.
authors.forename: Zhimei
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, China. xiaoming.liu@mail.zjxu.edu.cn xiaoming.liu@ncu.edu.cn.
authors.forename: Zhiyin
authors.initials: Z
authors.lastname: Xiao
authors.affiliation: School of Chemistry, Nanchang University, Nanchang 330031, China.
authors.forename: Fenfen
authors.initials: F
authors.lastname: Xu
authors.affiliation: College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, China. xiaoming.liu@mail.zjxu.edu.cn xiaoming.liu@ncu.edu.cn.
authors.forename: Xianghua
authors.initials: X
authors.lastname: Zeng
authors.affiliation: College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, China. xiaoming.liu@mail.zjxu.edu.cn xiaoming.liu@ncu.edu.cn.
authors.forename: Xiaoming
authors.identifier: http://orcid.org/0000-0003-0038-6292
authors.initials: X
authors.lastname: Liu