Borane-linked diphosphine complexes towards dual activation of substrates relevant to energy catalysis

In order to minimize the activation barriers assocd. with the activation of inert small mols. such as carbon dioxide and water, biol. enzymes frequently employ multiple simultaneous modes of substrate interaction, including coordination to multiple metal sites and/or strategically placed hydrogen bonding functionalities. In particular, carbon dioxide is a prime candidate for activation by both Lewis acids and bases, as both natural enzymes and recent work in frustrated Lewis pair chem. have demonstrated. Herein we disclose a series of compds. designed to deploy an analogous strategy towards carbon monoxide fixation in which a redox-active transition metal serves as the Lewis base, and a pendant borane as the Lewis acid.