Dinitrogen Splitting without Barrier or Visible Light-Driven: Reactions of Vanadium Trimers and Dimers with...

The reaction of V atoms and small clusters with dinitrogen has been investigated by matrix isolation in solid Ne and by complementary quantum chemical calculations. The experiments disclose striking differences between the reactivity of V atoms, dimers, and trimers toward dinitrogen. Whereas V atoms react only by formation of complexes, both V₂ and V₃ react by cleavage of the N₂ triple bond to form nitride clusters. Whereas V₃ reacts immediately at the conditions of matrix deposition, the reaction of V₂ requires activation by irradiation with visible light. There is evidence for two isomers of V₂N₂, a planar one with a ⁵A_u electronic term and a long V─V distance, and a folded one with a ¹A₁ term and a short V─V distance. Furthermore, there are also complexes of V₂ and V₃ with N₂ that contain activated N₂ units.