Dinitrogen reduction using ruthenium coordinated by nitrogen‐doped graphene and cobalt complex coordinated by anionic PNP pincer ligand as catalysts and Frustrated Lewis Pair as a co‐catalyst: Density Functional Theory studies

Abstract

Ammonia is an indispensable component for the development of human society due to its widespread applications and because it is an excellent source of energy. Chemists are looking for a viable catalyst for the activation of N2 molecule to subsequently synthesize ammonia. In this theoretical work, we have used [Co(N2)(RPNP)] (R = tBu, tBuPNP = 2,5‐bis(di‐tert‐butylphosphinomethyl)pyrrolide) complex and ruthenium coordinated by nitrogen‐doped graphene (NDG) as catalysts. To limit the competitive binding of N2 and H2 to the metal centre, we have utilized the concept of Frustrated Lewis Pair [AH]+[BH]− (FLP‐H2), which can act as a co‐catalyst. It can be utilized to functionalize the coordinated N2 into NH3 and hydrazine. According to the calculated thermodynamic and kinetic barriers, we have observed that the [Co(N2)(RPNP)] and ruthenium coordinated by NDG can be used as catalysts to activate N2. The alternative addition of H+ and H− to metal coordinated N2 molecule using the FLP‐H2 source is proposed in the catalytic cycle to generate NH3 and NH2NH2. The current investigation also reveals some thermodynamically feasible hexa‐ and penta‐coordinated metal‐hydride bond formation.