Project Info
Understanding N–N bond formation in ammonia oxidation catalysts
Samantha Johnson
samanthajo.johnson@mines.edu
Project Goals and Description:
Ammonia has the potential to serve as a domestically produced, carbon free, transportable fuel. However, there are few homogeneous catalysts that can robustly oxidize ammonia to liberate protons and electrons. One of the more difficult steps in this reaction is the coupling of two nitrogen complexes to make an N-N bond. This N-N bond formation can occur early in the ammonia oxidation process, at a metal amidyl complex, or late in the mechanism, between two metal nitrido complexes. In particular, we do not understand the exact mechanism for N-N coupling when it occurs early in the process, thus we do not know how to design catalysts that favor early N-N coupling. In this project, you will use computational methods to calculate the mechanism for N-N coupling in several demonstrated ammonia oxidation catalysts and find descriptors that describe the chemical transformations occurring during the reaction. If successful, this project could lead to the design of new complexes for ammonia oxidation, helping to close the anthropomorphic nitrogen cycle.
More Information:
Grand Challenge: Manage the nitrogen cycle.
Dunn, P. L.; Cook, B. J.; Johnson, S. I.; Appel, A. M.; Bullock, R. M. Oxidation of Ammonia with Molecular Complexes. J. Am. Chem. Soc. 2020, 142 (42), 17845-17858
Johnson, S. I.; Heins, S. P.; Klug, C. M.; Wiedner, E. S.; Bullock, R. M.; Raugei, S. Design and reactivity of pentapyridyl metal complexes for ammonia oxidation. Chem. Commun. 2019, 55 (35), 5083-5086
Dunn, P. L.; Johnson, S. I.; Kaminsky, W.; Bullock, R. M. Diversion of Catalytic C–N Bond Formation to Catalytic Oxidation of NH3 through Modification of the Hydrogen Atom Abstractor. J. Am. Chem. Soc. 2020, 142 (7), 3361-3365
Liu, L.; Johnson, S. I.; Appel, A. M.; Bullock, R. M. Oxidation of Ammonia Catalyzed by a Molecular Iron Complex: Translating Chemical Catalysis to Mediated Electrocatalysis. Angew. Chem. Int. Ed. 2024, 63 (41), e202402635
Primary Contacts:
Samantha Johnson, samanthajo.johnson@mines.edu
Student Preparation
Qualifications
Read the suggested literature. Any computational skills are wonderful, but are not required.
TIME COMMITMENT (HRS/WK)
5
SKILLS/TECHNIQUES GAINED
You will learn how to run ab initio electronic structure calculations (density functional theory) to calculate a mechanism for an organometallic catalyst on a high performance computing cluster (Wendian). You will also learn about ligand field theory and ligand design. Since scientific communication is critical to knowledge dissemination, you will also learn how to write scientific reports and give scientific presentations in the context of group meetings.
MENTORING PLAN
I will meet with the student one-on-one on a weekly basis to provide training and feedback on the students work. We also will meet during our weekly group meeting. For informal interactions, I am available on Slack. In addition, the student will meet and interact with both undergraduate and graduate students within the group to learn from their peers.
Preferred Student Status
Junior
Senior