RUI: N-N Bond Formation from NOx- on Pyridinediimine and Pyridinemonoimine Complexes

Western Washington University, Bellingham WA

Investigators

Abstract

With funding from the Chemical Catalysis Program of the Chemistry Division, Professors John Gilbertson and Tim Kowalczyk at Western Washington University will develop new kinds of complexes and catalysts to study the formation of N2O. Nitrous oxide (N2O) is one of the leading causes of ozone depletion and a potent greenhouse gas (~300 times worse than carbon dioxide). N2O formation is part of the Nitrogen Cycle, which governs the formation and degradation of organic nitrogen compounds on earth. A key step in N2O generation is the N-N bond formation step, and currently, chemists do not have a complete fundamental understanding of these steps. Synthetic complexes that can be designed to control N-N bond formation are vital to our knowledge and understanding of the Nitrogen Cycle. This project will combine computer calculations with laboratory experiments to aid in the prediction and verification of how the chemical reactions progress. The project will support the training of undergraduate students mentored by Professors Gilbertson and Kowalczyk to acquire the laboratory and communication skills necessary for successful careers in science. The project will also support the development of interactive discussion groups across multiple institutions, with particular emphasis on leveling the playing field for students from all backgrounds pursing chemistry. Professors John Gilbertson and Tim Kowalczyk at Western Washington University will develop coordination compounds to study the mechanism for N-N coupling to facilitate NOx- reduction and turnover. Complexes based on the modular, redox-active pyridinediimine (PDI) and pyridinemonoimine (PMI) scaffolds will be developed. The sterics, pKa, and reduction potentials will be investigated both experimentally and computationally for the production of complexes that are active for N-N bond formation from NOx-reduction. PDI and PMI ligands with H-bond donating anilines located in the secondary coordination sphere will be designed and any interactions with substrate will be characterized experimentally and computationally. The project will rely on computation as a guide to describe the electronic structure/mechanism of these complicated redox systems. The grant will support undergraduate researchers by providing interdisciplinary scientific and professional training. In addition to direct student involvement in the work, outreach activities proposed includes the continuation and expansion of the iCID program, providing a platform for students from diverse backgrounds to engage in scientific discussions across multiple institutional levels (R1, R2, PUIs). 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.