DFT studies of protonation and anion binding of Chatt type dinitrogen complex: Who is first?

[Display omitted] •DFT studies have been carried out to understand the reactivity pattern of Chatt dinitrogen complex.•Diethyl ether solution of HBF4 has been employed as a proton and anion source.•Protonation followed by anion binding is energetically feasible path way.•Anion binding followed by protonation is not energetically feasible. In order to understand the reactivity pattern displayed by Chatt type dinitrogen complex, DFT calculations have been carried out. Although Chatt type catalytic cycle is well established and answered most of the relevant questions by several research groups, we have done DFT calculations to answer certain unanswered questions. In this regard, we have calculated the energy barriers for the protonation of coordinated dinitrogen followed by anion binding, anion binding followed by protonation and simultaneous reaction of protonation of dinitrogen and anion binding. Our calculated energy barriers clearly reveal that the protonation of dinitrogen followed by anion binding and simultaneous reaction of protonation of dinitrogen and anion binding would be more feasible when compared to anion binding followed by protonation of dinitrogen.