CAREER: Small Molecule Activations Enabled by Coordination-Driven Self-Assembly

Nature provides many examples of catalysts (molecules that speed reactions up) that contain multiple metal atoms in their active sites. These catalysts are very effective at changing small molecules into more desirable products and play a role in many critical processes, such as photosynthesis and respiration. Understanding how multiple metal atoms can work together requires control over the size and shape of a given catalyst. In this project, Dr. Cook is using self-assembly methods to design highly tunable catalysts in which size and shape can be systematically changed to see how they affect small molecules. His group can change the distance between metal centers, the type of metals present, and the nature of the supporting organic building blocks. The study of these systems provides a deeper understanding of small molecule activations. Ultimately, they may serve as guides for the design of catalysts that enable renewable energy and greener routes to chemical feedstocks. In parallel with this research program, Dr. Cook is using 3D-printing technology as a tool to illustrate self-assembly and other fundamental chemistry concepts with interactive, dynamic models for the classroom. These efforts include a partnership with the Buffalo Public School System to provide research opportunities and professional development for teachers in the design and use of classroom materials. With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Cook of the University at Buffalo is using self-assembly as a synthetic methodology to construct architectures in which metal-containing porphyrins, diglyoximes, and related polypyrrole macrocycles serve as catalytically active sites. These self-assembly reactions use metal-ligand bond formation as a driving force to organize cofacial geometries. This synthetic approach provides modularity and control over metal-metal separation, substrate access, structural rigidity, and molecular modifications to tune electronic structure. The role of these parameters on the electrochemical reduction of molecular oxygen, protons and carbon dioxide is being established using activity studies, electrochemical methods, and structural analyses. The resulting information about the structure-activity relationships and mechanistic insight governing selectivity, turnover frequency, and catalyst stability is providing a deeper understanding of small molecule activations. Dr. Cook is actively designing classroom materials for STEM education centered on interactive, dynamic models to illustrate self-assembly and general chemistry concepts for use by high school teachers and undergraduate lecturers. These activities involve the Buffalo Public School System through research opportunities and teacher professional development. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.