High-activity base metal catalysts for strong carbon-heteroatom bond activation

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Discovery research in fundamental inorganic and coordination chemistry of the “earth abundant" transition metals - manganese, iron, cobalt, nickel, and copper - is proposed. This program is new to my Discovery Grant proposal, but it is not new to my research group. In 2008, major funding was obtained to create and develop “new-generation” hydrotreatment catalysts for petroleum upgrading. The objective of this industry-funded research is resolutely applied: introduce into industrial practice “process-ready” catalysts for hydrodesulfurization and hydrodenitrogenation of bitumen and other heavy oils, replacing the energy-intensive, unselective, and environmentally compromising catalysts in ubiquitous use today, worldwide. What we proposed we could do was unprecedented, with a central hypothesis unsupported by “prior art” and attributed to no identifiable school of current catalysis research. But the idea actually works. We would like to know how. And we need to know why. Our industrial funding does not extend to fundamental and exploratory investigations beyond those required to make and optimize our initial discoveries. This proposal is about turning discovery into scholarship. We propose the basic science necessary to understand structure, reveal mechanism, and provide a rational basis for iterative improvements in design. We also target a range of other important catalytic processes that currently require “energy-intensive” conditions (typically, high pressure and temperature) or precious metal catalysts, or both. This proposal is about exploring a new concept in designing high-activity catalysts of the earth-abundant transition metals. It is about fundamental research - design, synthesis, structure, bonding, electronic character, reactivity, and mechanism. Over the past fifty years, research in transition metal catalysis has been mostly about ligand design. First-row transition metals are physically small and favour high-spin (paramagnetic) electronic configurations. Ligand lability and structural stability is a serious issue for these elements; most of modern catalysis has adopted polydentate ligands, which stabilize the metal, but limit coordinative unsaturation, inhibiting reactivity and limiting substrate scope. The incorporation of “redox active” ligands also provide key advantages in this area, leading to steady, incremental, improvements in the field. With few exceptions, however, today’s first-row catalysts suffer from poor structural integrity, low activity, and limited substrate scope. In this work, a non-traditional approach to catalyst design is taken, nucleating multiple metals into functional, cooperative units using a single anionic ligand, one per metal. Many metals, one ligand - a “metallocentric” approach to first-row transition metal catalyst design.