Research Projects

Nitrogen fixation, also known as the nitrogen reduction reaction (N₂RR), is a crucial chemical transformation in both biological systems and industrial processes. In nature, biological nitrogen fixation is catalyzed by nitrogenase enzymes, whereas commercial production of NH₃ through the Haber-Bosch process requires extreme reaction conditions (i.e., 200-400 bar and 400-600°C). However, the conversion of dinitrogen to ammonia (or N₂H₄) is one of the most difficult and challenging tasks owing to the high bond dissociation energy (944 kJ/mol) of the N≡N triple bond. Catalytic nitrogen fixation based on main group metal complexes has received considerable attention for sustainable growth and development due to concerns regarding the economy, environment, and sustainable energy. Calcium (Ca), a promising alternative to lithium, produces ammonia by reacting calcium carbide (CaC₂) with N₂ at 1000°C to generate calcium cyanamide (CaCN₂), which was then hydrolyzed to yield NH₃. This project aims to develop calcium metal complexes and perform the catalytic nitrogen fixation under ambient conditions. In the first part, the focus of the project will be to synthesize a proper ligand that will accommodate the calcium ion. The designed ligand will be non-innocent, phosphine-free, NNN-tridentate with bulky substituent(s) which will enhance the stability of the metal complex. The idea is to generate a dearomatized calcium complex using a non-innocent ligand through which effective charge separation is possible. All the metal complexes will be characterized by spectroscopic methods and X-ray crystallography. In the next part, synthesized metal complexes will be optimized under different reaction conditions. Using these metal complexes, dinitrogen will be activated in the presence of reducing agents. For N₂RR, a suitable reagent combination will be evaluated. The net overpotential for the catalytic reaction is determined by the particular acid-reductant mixture, as well as other pertinent reaction parameters. The ease of protonation at Nβ is one aspect that determines the effectiveness of N₂-to-NH₃ reduction catalysis. In the last part, a comprehensive mechanistic investigation will be carried out. One of the main tasks in the current study area is the isolation of intermediates. To learn more about the suggested mechanistic route, a theoretical computation will be made. This project is highly valuable for the development of catalytic nitrogen fixation.