{"title":"Design of Rigidified μ-(9-Fluorenethiolate) {FeFe} Hydrogen Evolving Catalysts","authors":"Tashika Agarwal, Meenakshi Joshi, Ritu, Matthias Stein, Sandeep Kaur-Ghumaan","doi":"10.1021/acs.organomet.4c00036","DOIUrl":null,"url":null,"abstract":"The hexacarbonyl diiron complex [Fe<sub>2</sub>(μ-9-fluorenethiol)<sub>2</sub>(CO)<sub>6</sub>] (<b>1</b>) has been synthesized and characterized by various spectroscopic techniques as well as quantum chemical calculations. The molecular structure for complex <b>1</b> was determined by single-crystal X-ray diffraction and was supported by density functional theory (DFT) calculations. Complex <b>1</b> crystallized in the tetragonal <i>P</i>4̅2<sub>1</sub><i>m</i> crystal system with both fluorene moieties <i>anti</i> to each other. According to a QM conformational search, this corresponds to the lowest energy conformer. The complex displayed electrocatalytic activity for proton reduction in the presence of organic acids (acetic acid and trifluoroacetic acid), which was investigated by cyclic voltammetric (CV) and controlled-potential coulometric (CPC) experiments and calculations. Bulk electrolysis of complex <b>1</b> in the presence of an acid resulted in significant hydrogen evolution. DFT calculations demonstrated that complex <b>1</b> undergoes a one-electron metal-based reduction with a calculated redox potential in excellent agreement with experiment (at a low potential of −1.32 V), while a two-electron reduction occurs at a more negative potential of −1.70 V. Due to the rigidity of the μ-bridging 9-fluorenethiolates and structural integrity of <b>1</b> during reduction events, a two-electron-reduction mechanism followed by protonation of a terminal iron hydride species appears feasible.","PeriodicalId":56,"journal":{"name":"Organometallics","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organometallics","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.organomet.4c00036","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
The hexacarbonyl diiron complex [Fe2(μ-9-fluorenethiol)2(CO)6] (1) has been synthesized and characterized by various spectroscopic techniques as well as quantum chemical calculations. The molecular structure for complex 1 was determined by single-crystal X-ray diffraction and was supported by density functional theory (DFT) calculations. Complex 1 crystallized in the tetragonal P4̅21m crystal system with both fluorene moieties anti to each other. According to a QM conformational search, this corresponds to the lowest energy conformer. The complex displayed electrocatalytic activity for proton reduction in the presence of organic acids (acetic acid and trifluoroacetic acid), which was investigated by cyclic voltammetric (CV) and controlled-potential coulometric (CPC) experiments and calculations. Bulk electrolysis of complex 1 in the presence of an acid resulted in significant hydrogen evolution. DFT calculations demonstrated that complex 1 undergoes a one-electron metal-based reduction with a calculated redox potential in excellent agreement with experiment (at a low potential of −1.32 V), while a two-electron reduction occurs at a more negative potential of −1.70 V. Due to the rigidity of the μ-bridging 9-fluorenethiolates and structural integrity of 1 during reduction events, a two-electron-reduction mechanism followed by protonation of a terminal iron hydride species appears feasible.
期刊介绍:
Organometallics is the flagship journal of organometallic chemistry and records progress in one of the most active fields of science, bridging organic and inorganic chemistry. The journal publishes Articles, Communications, Reviews, and Tutorials (instructional overviews) that depict research on the synthesis, structure, bonding, chemical reactivity, and reaction mechanisms for a variety of applications, including catalyst design and catalytic processes; main-group, transition-metal, and lanthanide and actinide metal chemistry; synthetic aspects of polymer science and materials science; and bioorganometallic chemistry.