Catalytic Silylation of Dinitrogen with a Dicobalt Complex

A dicobalt complex catalyzes N₂ silylation with Me₃SiCl and KC₈ under 1 atm N₂ at ambient temperature. Tris(trimethylsilyl)amine is formed with an initial turnover rate of 1 N(TMS)₃/min, ultimately reaching a turnover number of ∼200. The dicobalt species features a metal-metal interaction, which we postulate is important to its function. Although N₂ functionalization occurs at a single cobalt site, the second cobalt center modifies the electronics at the active site. Density functional calculations reveal that the Co-Co interaction evolves during the catalytic cycle: weakening upon N₂ binding, breaking with silylation of the metal-bound N₂ and reforming with expulsion of [N₂(SiMe₃)₃]^-.