Porphyrins with Pendant ThiolGroups for Nitrogen Reduction (A04 – B03)

One of the most important transformations in both biology and synthetic chemistry is the multi-PCET reaction of dinitrogen to ammonia (NRR, nitrogen reduction reaction). The thermodynamics of each individual PCET step are governed by the bond dissociation free energies (BDFEs) of the relevant X–H bonds (X = N, O, S), making the rational design of proton and hydrogen-atom donors critical for catalyst development (A04). Project B03 investigates the role of thiols as proton relays in multi-PCET reactions of biological systems involving thiols and sulfides as proton and hydrogen-atom (H•) shuttles. Here, we aim to synthesize porphyrins bearing pendant thiol and thiophenol groups, and to prepare their molybdenum complexes for application in the NRR, with the goal of elucidating how these hydrogen-atom and proton-relay functionalities influence this multi-PCET transformation. This project uniquely combines the expertise in the synthesis of thiol-containing compounds from Project B03 with the expertise in porphyrin chemistry and nitrogen reduction catalysis from Project A04. Together, these groups will establish novel bifunctional compounds incorporating both porphyrin scaffolds and pendant thiol groups.