Investigations into the Synthesis and Reactivity of Low-Coordinate Metal Isocyanide Compounds

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With funding from the Chemical Synthesis program of the Division of Chemistry, Professor Joshua S. Figueroa and his research team at the University of California, San Diego are developing new chemical transformations by focusing on the design, synthesis and study of novel metal compounds. It has been long recognized that the key to developing next-generation chemical processes is the discovery of new chemical compounds with high reactivity. For many processes of industrial, agro-chemical and fine-chemical importance, metal compounds lie at the forefront of productive, selective and energy efficient chemical transformations. In order to ensure an advancing synthetic chemistry enterprise, metal compounds capable of new reactivity are required. A key design feature of the compounds under investigation in this award are the molecular supporting groups, also known as ligands, that are used to stabilize the metal. These ligands allow for precise control of molecular geometry, while dictating selectivity in ensuing chemical transformations. In addition, the ligands allow for facile product analysis due to the presence of several convenient analytical markers. This research is emphasizing new transformations of nitrous oxide (N2O), which is a potent greenhouse gas and environmental pollutant, yet is a largely untapped for organic reactions. Also under investigation are more fundamental aspects of structure and bonding in metal complexes, with a specific focus on the synthesis and properties of compounds that contain multiple bonds between metals and elements such as carbon, nitrogen, and oxygen. The scientific work of this award is accompanied by outreach efforts to local San Diego area high school students. Professor Figueroa and his team are engaging young persons in Make & Measure enrichment activities. The goal of these efforts is to stimulate greater participation of young persons in STEM-related fields. Professor Figueroa is exploring the synthesis and reactivity of coordinatively and electronically unsaturated metal isocyanide complexes. The sterically encumbering m-terphenyl isocyanide ligand class is being used specifically to control the molecular geometries and electronic structures of transition metal centers, such that they are primed for selective reactions with specific small molecule substrates. In addition, molecular architectures are being targeted that can successfully support late transition-metal multiple bonding to carbon, nitrogen and oxygen. A significant emphasis is placed on the binding and activation of nitrous oxide (N2O) by cobalt-based m-terphenyl isocyanide complexes. A series of unique N2O-adducts of cobalt have been isolated, and the research is focused on delineating the reactivity available to these complexes, with specific attention being placed on the development of mild oxygen-atom transfer reactions to organic substrates. An additional focus is the synthesis and reactivity of late, 3d transition-metal carbyne complexes, with the goal of developing metathesis-based transformations. The synthetic and experimental research is accompanied by significant outreach efforts to San Diego area high school students. Professor Figueroa and his team have partnered with local high schools to engage young students in Make & Measure extracurricular enrichment activities. These activities focus on exposing students to advanced transition metal chemistry, but their overarching goal is to engage young persons in STEM-centered fields.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.