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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..

Two 1,5-diaza-3,7-diphosphacyclooctane (P2N2) ligands with alkyl-substituted phosphines have been synthesized via a versatile method that allows for improved control of the phosphine substituent. T...

Organometallic complexes of Re(I) with ligands having opposite redox properties have been synthesized and structurally characterized. X-ray crystal structures of the complexes show typical fac-ReI(CO)3 coordination to the redox active ligands. Complete electrochemical and spectroelectrochemical studies on the ligands and the metal complexes were performed. The IR-spectroelectrochemical responses were monitored using the fac-Re(CO)3 unit as a probe. The 15–20 cm−1 hypsochromic or bathochromic shift of the νCO bands upon reduction or oxidation is attributed to ligand-centered processes.