期刊
DALTON TRANSACTIONS
卷 51, 期 25, 页码 9748-9769出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/d2dt00419d
关键词
-
资金
- Commonwealth Scholarship Commission
- Royal Society of Chemistry
- King's College London
- Robert A. Welch Foundation [B-1093-MGR]
- Spectroelectrochemistry Reading, a spinout company of the University
In this study, FeFe biomimics containing redox-active ferrocenyl diphosphine were prepared and their ability to reduce protons and oxidize H-2 was investigated. The complexes exhibited different chemical behavior in oxidation reactions in different solvents, providing valuable insights for studying their catalytic performances.
[FeFe]-Ase biomimics containing a redox-active ferrocenyl diphosphine have been prepared and their ability to reduce protons and oxidise H-2 studied, including 1,1 '-bis(diphenylphosphino)ferrocene (dppf) complexes Fe-2(CO)(4)(mu-dppf)(mu-S(CH2)(n)S) (n = 2, edt; n = 3, pdt) and Fe-2(CO)(4)(mu-dppf)(mu-SAr)(2) (Ar = Ph, p-tolyl, p-C6H4NH2), together with the more electron-rich 1,1 '-bis(dicyclohexylphosphino)ferrocene (dcpf) complex Fe-2(CO)(4)(mu-dcpf)(mu-pdt). Crystallographic characterisation of four of these show similar overall structures, the diphosphine spanning an elongated Fe-Fe bond (ca. 2.6 angstrom), lying trans to one sulfur and cis to the second. In solution the diphosphine is flexible, as shown by VT NMR studies, suggesting that Fe2MIDLINE HORIZONTAL ELLIPSISFe distances of ca. 4.5-4.7 angstrom in the solid state vary in solution. Cyclic voltammetry, IR spectroelectrochemistry and DFT calculations have been used to develop a detailed picture of electronic and structural changes occurring upon oxidation. In MeCN, Fe-2(CO)(4)(mu-dppf)(mu-pdt) shows two chemically reversible one-electron oxidations occurring sequentially at Fe-2 and Fc sites respectively. For other dppf complexes, reversibility of the first oxidation is poor, consistent with an irreversible structural change upon removal of an electron from the Fe-2 centre. In CH2Cl2, Fe-2(CO)(4)(mu-dcpf)(mu-pdt) shows a quasi-reversible first oxidation together with subsequent oxidations suggesting that the generated cation has some stability but slowly rearranges. Both pdt complexes readily protonate upon addition of HBF4 center dot Et2O to afford bridging-hydride cations, [Fe-2(CO)(4)(mu-H)(mu-dcpf)(mu-pdt)](+), species which catalytically reduce protons to generate H-2. In the presence of pyridine, [Fe-2(CO)(4)(mu-dppf)(mu-pdt)](2+) catalytically oxidises H-2 but none of the other complexes do this, probably resulting from the irreversible nature of their first oxidation. Mechanistic details of both proton reduction and H-2 oxidation have been studied by DFT allowing speculative reaction schemes to be developed.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据