Manganese N-Heterocyclic Carbene Pincers for the Electrocatalytic Reduction of Carbon Dioxide

Abstract

We report the synthesis, characterization, and catalytic CO2 reduction activity of two LMn­(CO)3Br complexes with carbene-pyridine-carbene pincer ligands, [MnCNCMe]Br 1 and [MnCNCBn]Br (Bn = benzyl) 2. X-ray crystallography reveals an octahedral coordination environment with an outer sphere Br anion for 1. Catalyst 2 performs the reduction of CO2 to CO at 100 mV more positive potential with similar current densities as 1. We hypothesize the bulkier benzyl arms on the pincer hinder formation of a dimer. They also alter the wingtip electronics, enabling operation at a lower overpotential. We use normal pulse voltammetry and diffusion ordered spectroscopy to quantify a 1e– reduction per manganese center at the catalytic onset. We now show turnover even in the absence of added protons..

Transition metal-based catalysts for the electrochemical CO2reduction: from atoms and molecules to nanostructured materials

“…N-Heterocyclic carbenes (NHC) also represent an important class of organic molecules effectively employed to improve the CO 2 RR catalytic performances of metal NPs. 448 Chelating multidentate NHC ligands have been successfully used for CO 2 electroreduction in homogeneous molecular catalysts [449][450][451][452] and polycrystalline metallic surfaces (vide infra). 453 The strong s-donating character of the NHC ligands is particularly attractive for CO 2 RR, leading to electron-rich metal surfaces with an enhanced reactivity towards CO 2 .…”

Chemical and Electrochemical Recycling of End-Use Poly(ethylene terephthalate) (PET) Plastics in Batch, Microwave and Electrochemical Reactors

“…Given our experience in the field of electrolytic hydrogen production [ 31 , 32 , 33 ] and reductive electrocatalysis [ 34 , 35 ], we investigated the electrochemical generation of the necessary basic conditions using current passage through a protic medium ( Scheme 1 ). We hypothesized that this methodology would have a distinct advantage over the batch and microwave methods occurring at room temperature in neutral salted media, with the necessary base generated in situ ( Scheme 1 ) at rates that one can control by dialing in the delivery of charge in coulombs/s.…”

Research Progress in Conversion of CO2 to Valuable Fuels

“…Many effective and selective homogeneous metal complex catalysts have been developed to promote CO 2 conversion. For example, a number of pincer complexes can reduce CO 2 into CO, CH 4 , or other compounds [ 79 , 80 , 81 , 82 ]. The ruthenium catalysts prepared by different methods are usually used in such systems [ 83 , 84 , 85 , 86 ] in which the turnover number (TON) of CO 2 to methanol reached 9900 at an optimal condition.…”