Unique Group Transfer and Coupling Reactivity Promoted by Middle and Late Transition Metals in Bulky Alkoxide Ligand Environments

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Carbodiimides are a type of molecule that are frequently used in chemical and pharmaceutical industries. Likewise ketenimines are molecular starting points for the production of complicated medicinal chemicals and azoarenes are commonly used dyes in the textile and food industries. While all of these are valuable industrial reagents, a serious disadvantage of all of them is that they are obtained from wasteful processes that involve toxic reagents such as mercury and isocyanate. In order to reduced these problems, the development of new routes to these compounds is an important goal. Dr. Stanislas Groysman, Chemistry Department, Wayne State University and Dr. Richard Lord, Chemistry Department, Grand Valley State University, are supported by the Chemical Synthesis Program of the Chemistry Division to develop new, efficient methods to prepare azoarenes, carbodiimides, and ketenimines. The research develops new cost-effective reagents that exploit metals like iron and cobalt to efficiently produce these molecules. The laboratory experiments are carried out in Dr. Groysman's laboratories and the results are interpreted using computational chemistry conducted by Dr. Lord and his students. Wayne State is a graduate research university, while Grand Valley State is a primarily undergraduate institution. The collaboration provides the opportunity for students from both institutions to be part of both graduate and undergraduate research experiences. The reactivity of metal-bound carbene and nitrene depends on the electronic structure of the metal complex, which is underwritten by the metal type and its ancillary ligand environment. Most existing middle and late nitrene/carbene complexes utilize strong-field ancillary ligands which stabilize formally high-valent metal centers. This project seeks to develop middle and late transition metal complexes featuring weak-field bulky bis(alkoxide) ligation. The electronic properties and the steric bulk of the alkoxide ligands allow the formation of reactive low-coordinate species. The chemistry is explored across the first-row transition metals from Cr to Ni. The effect of the alkoxide ligand field on the electronic structure is explored by computational chemistry. The synthetic work is carried out in the Groysman lab at Wayne State University and the computational work in the Lord lab at Grand Valley State University. This collaboration between a research university and a primarily undergraduate institution provides a valuable experience for students at both institutions.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.