Re(I) NHC Complexes for Electrocatalytic Conversion of CO2
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- 作者：Charles J. Stanton III ; Charles W. Machan ; Jonathon E. Vandezande ; Tong Jin ; George F. Majetich ; Henry F. Schaefer III ; Clifford P. Kubiak ; Gonghu Li ; Jay Agarwal
- 刊名：Inorganic Chemistry
- 出版年：2016
- 出版时间：March 21, 2016
- 年：2016
- 卷：55
- 期：6
- 页码：3136-3144
- 全文大小：596K
- ISSN：1520-510X
文摘
The modular construction of ligands around an N-heterocyclic carbene building block represents a flexible synthetic strategy for tuning the electronic properties of metal complexes. Herein, methylbenzimidazolium-pyridine and methylbenzimidazolium-pyrimidine proligands are constructed in high yield using recently established transition-metal-free techniques. Subsequent chelation to ReCl(CO)5 furnishes ReCl(N-methyl-N′-2-pyridylbenzimidazol-2-ylidine)(CO)3 and ReCl(N-methyl-N′-2-pyrimidylbenzimidazol-2-ylidine)(CO)3. These Re(I) NHC complexes are shown to be capable of mediating the two-electron conversion of CO2 following one-electron reduction; the Faradaic efficiency for CO formation is observed to be >60% with minor H2 and HCO2H production. Data from cyclic voltammetry is presented and compared to well-studied ReCl(2,2′-bipyridine)(CO)3 and MnBr(2,2′-bipyridine)(CO)3 systems. Results from density functional theory computations, infrared spectroelectrochemistry, and chemical reductions are also discussed.