CO reduction with Re(i)-NHC compounds: driving selective catalysis with a silicon nanowire photoelectrode.

The CO-reduction activity of two Re(i)-NHC complexes is investigated employing a silicon nanowire photoelectrode to drive catalysis. Photovoltages greater than 440 mV are observed along with excellent selectivity towards CO over H formation. The observed selectivity towards CO production correlates with strong adsorption of the catalysts on the photoelectrode surface.

Mn-NHC Electrocatalysts: Increasing π Acidity Lowers the Reduction Potential and Increases the Turnover Frequency for CO Reduction.

A new manganese(I) N-heterocyclic carbene electrocatalyst containing a benzimidazole-pyrimidine-based ligand is reported for the two-electron conversion of CO. The increased π acidity of pyrimidine shifts the two-electron reduction to -1.77 V vs Fc/Fc, 70 mV more positive than that for MnBr(2,2'-bipyridine)(CO); increased catalytic current enhancement is also observed (5.

Re(I) NHC Complexes for Electrocatalytic Conversion of CO2.

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.

Electrocatalytic Reduction of Carbon Dioxide by Mn(CN)(2,2'-bipyridine)(CO)3: CN Coordination Alters Mechanism.

MnBr(2,2'-bipyridine)(CO)3 is an efficient and selective electrocatalyst for the conversion of CO2 to CO. Herein, substitution of the axial bromide for a pseudohalogen (CN) is investigated, yielding Mn(CN)(2,2'-bipyridine)(CO)3. This replacement shifts the first and second reductions to more negative potentials (-1.

NHC-containing manganese(I) electrocatalysts for the two-electron reduction of CO2.

The synthesis and characterization of the first catalytic manganese N-heterocyclic carbene complexes are reported: MnBr(N-methyl-N'-2-pyridylbenzimidazol-2-ylidine)(CO)3 and MnBr(N-methyl-N'-2-pyridylimidazol-2-ylidine)(CO)3. Both new species mediate the reduction of CO2 to CO following two-electron reduction of the Mn(I) center, as observed with preparative scale electrolysis and verified with (13)CO2. The two-electron reduction of these species occurs at a single potential, rather than in two sequential steps separated by hundreds of millivolts, as is the case for previously reported MnBr(2,2'-bipyridine)(CO)3.