Dinitrogen Activation and Functionalization by Heteronuclear Metal Cluster Anions FeV2C2– at Room Temperature

It is of great importance to study the mechanisms to activate dinitrogen (N2), the very inert molecule, under mild conditions. Gas-phase metal clusters are being actively generated to react with N2 to identify new reaction types and mechanisms. Herein, an unprecedented, mechanistically unique metal atom (Fe or V) ejection in the thermal reaction of FeV2C2- with N2 has been identified using mass spectrometry, photoelectron imaging spectroscopy, and quantum chemistry calculations. Strong evidence suggests that the complete cleavage of the N≡N triple bond and subsequent functionalization of two N atoms via C-N coupling were achieved in this reaction. The complementary cooperation between V atoms with strong electron-donating ability and an Fe atom with large electron-withdrawing ability as well as the geometric flexibility of the Fe-V-V ring drives the whole reaction. The important role of C ligands in N≡N cleavage was also revealed. This study emphasizes the importance of heteronuclear metal systems for N2 fixation.