title: Re(I) NHC Complexes for Electrocatalytic Conversion of CO2.
abstract: 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.
authors.affiliation: Department of Chemistry, University of Georgia , Athens, Georgia 30602, United States.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Stanton
authors.affiliation: Department of Chemistry and Biochemistry, University of California , San Diego, California 92093, United States.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Machan
authors.affiliation: Center for Computational Quantum Chemistry, University of Georgia , Athens, Georgia 30602, United States.
authors.forename: Jonathon E
authors.initials: JE
authors.lastname: Vandezande
authors.affiliation: Department of Chemistry, University of New Hampshire , Durham, New Hampshire 03824, United States.
authors.forename: Tong
authors.initials: T
authors.lastname: Jin
authors.affiliation: Department of Chemistry, University of Georgia , Athens, Georgia 30602, United States.
authors.forename: George F
authors.initials: GF
authors.lastname: Majetich
authors.affiliation: Center for Computational Quantum Chemistry, University of Georgia , Athens, Georgia 30602, United States.
authors.forename: Henry F
authors.initials: HF
authors.lastname: Schaefer
authors.affiliation: Department of Chemistry and Biochemistry, University of California , San Diego, California 92093, United States.
authors.forename: Clifford P
authors.initials: CP
authors.lastname: Kubiak
authors.affiliation: Department of Chemistry, University of New Hampshire , Durham, New Hampshire 03824, United States.
authors.forename: Gonghu
authors.initials: G
authors.lastname: Li
authors.affiliation: Center for Computational Quantum Chemistry, University of Georgia , Athens, Georgia 30602, United States.
authors.forename: Jay
authors.initials: J
authors.lastname: Agarwal