Andrew Cook

Andrew Cook
2018 Mellichamp Sustainability Fellow

Research

Atomically-precise nanoclusters (APNCs) are an emerging class of materials that feature properties found in both traditional metal complexes and bulk metals. APNCs have considerable practical appeal due to their potential use in nanoparticle-based devices or as robust catalysts, whose performance can be optimized only via synthetic control at the atomic level.

APNCs formed from earth-abundant, first row transition metals are unexplored, except for a handful of examples using copper. Therefore, development of APNCs of iron, cobalt, and nickel is of paramount importance and may lead to materials with heretofore unknown catalytic and magnetic properties. Iron APNCs are especially attractive as they may also be able to replace palladium as a catalyst for a variety of organic transformations. We therefore intend to synthesize iron APNCs and study their magnetic properties using SQUID magnetometry as well as their reactivity towards a variety of organic substrates.

Advisor:  Trevor Hayton

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2017 Mellichamp Sustainability Fellow Research:
Understanding the Importance of “Hydricity” in Enabling CO2 Reduction
Hydricity is defined as the free energy required to heterolytically cleave a metal-hydride bond, generating free hydride and a metal cation. This thermodynamic parameter is a critical predictor of metal-hydride-catalyzed CO2 to formic acid reduction. In particular, metal hydrides whose hydricity is less than 44 kcal/mol (the hydricity of formate in MeCN) are predicted to spontaneously react with CO2, while those with a hydricity greater than 44 kcal/mol will not. Thus, measuring the hydricity of a metal hydride is a key step in the design of CO2 reduction catalysts for use in developing fuels and carbon feedstocks. We have previously isolated examples of copper and silver hydride complexes, which have proven to be competent pre-catalysts for hydrosilylation reactions. To better understand the origins of group 11 hydride reactivity and to determine their efficacy as CO2 reduction catalysts, we endeavor to measure the hydricity of these complexes, as well develop a library of group 11 hydride complexes to explore the structure-function relationships of these materials.