Transition metal catalysts for the hydrogenation of carbon dioxide to value added materials

Abstract

Over the last several years the field of CO2 hydrogenation has become robust and is still growing. There is great deal of interest into the sector as new ligands, catalysts, and systems are published regularly which help us further understand the intricacies of the reaction and how we might improve it for future use. This work first analyzes the current catalysts employable for hydrogenation of carbon dioxide to formates, formamides, and methanol. We produced a iPrPNPhP ligand derived from the commonly used ligands iPrPNMeP and iPrPNHP. We used these ligands to isolate and characterize a series of ruthenium hydride complexes and demonstrated their very different catalytic ability for formic acid dehydrogenation and hydrogenation of carbon dioxide to formate. We furthered our labs previous work on the increased reactivity of non metal ligand cooperative mechanism for the Lewis acid assisted hydrogenation of carbon dioxide to formate with our work on a series of manganese pincer complexes. The reactivity of the manganese systems matched those previously seen on iron, and mechanistic studies were performed to further elucidate the effect non-metal ligand cooperative mechanisms have on catalyst activity. Lastly we report the current synthetic progress towards a phospholane bear pincer ligand. Success was had in isolating the ligand system and several metal complexes though work is still underway to further elucidate its effect on catalysis.