Activation of Small Molecule and Organic Substrates by Tris(Phosphinoamide) Zr/Co Heterobimetallic Complexes

Book excerpt: There has been an accelerated increase in demand to develop catalysts for renewable energy chemistry, targeting small molecule activation reactions such as N2 fixation, CO2 reduction, and O2 reduction for either harnessing energy or improving the efficiency of energy consumption. Bimetallic complexes recently received strong interest as potential catalyst candidates owing to the unique advantages provided by their multinuclear cores. Particularly, multinuclear cores are designed to process multi-electron redox chemistry that is a prerequisite to small molecule activation, especially when using earth-abundant metal sources to construct catalysts that would allow the development of catalytic performance that is competitive to or even superior to that of expensive and toxic noble metal catalysts that are currently dominating the field. Studying fundamental questions related to bimetallic chemistry, such as metal-metal bonding interactions and metal-substrate interactions has been a focus to help understand metal-metal cooperativity and bimetallic reaction mechanisms. This dissertation is dedicated to the discussion of our recent structural and reactivity studies of C3-symmetric Zr/Co heterobimetallic complexes supported by a tris(phosphinoamide) ligand framework. The small molecule activation capabilities of tris(phosphinoamide) Zr/Co complexes will be discussed. Additionally, organic substrate activations conducted by Zr/Co complexes will be probed, in an effort to both understand their small molecule activation mechanisms, as well as to explore the application of bimetallic complexes in novel reactions to generate value-added products.