Exploration of Rhenium and Manganese Complexes as Potential Catalysts for Carbon Dioxide Hydrogenation

Abstract

Carbon dioxide is currently one of the leading greenhouse gases affecting global climate today due to its increased anthropogenic emissions. The ability to convert waste CO2 into a renewable energy source would not only help cut down on greenhouse gases, but also allow a new alternative to feedstock hydrocarbons. Manganese and rhenium transition metal complexes with N-heterocyclic carbene and pyridine containing bidentate ligands have been utilized as effective ligands in CO2 hydrogenation and dehydrogenation. Incorporation of proton-responsive features at the ligands assist in substrate activation during catalysis. A library of such compounds has been explored for their ability as hydrogenation/dehydrogenation catalysts through photocatalysis. This project aims to validate the synthetic pathways for obtaining pure metal complexes and further characterize the N-heterocyclic carbene - pyridine bidentate ligated rhenium and manganese complexes, [L2M(CO)3Br] where L2 is a bidentate ligand. Advanced air-sensitive and Schlenk line techniques are used in the synthesis and spectroscopic analysis via 1H-NMR, 13C-NMR, FT-IR, and UV/vis, and structure determination via X-ray diffraction (XRD) are utilized throughout.