Photochemically induced reductive elimination as a route to a zirconocene complex with a strongly activated N₂ ligand

The zirconocene dinitrogen complex [{(η⁵-C ₅Me₄H)₂Zr}₂(μ₂, η²,η²-N₂)] was synthesized by photochemical reductive elimination from the corresponding zirconium bis(aryl) or aryl hydride complexes, providing a high-yielding, alkali metal-free route to strongly activated early-metal N₂ complexes. Mechanistic studies support the intermediacy of zirconocene arene complexes that in the absence of sufficient dinitrogen promote C-H activation or undergo comproportion to formally Zr^III complexes. When N₂ is in excess arene displacement gives rise to strong dinitrogen activation. The zirconocene dinitrogen complex [{(η⁵-C₅Me₄H) ₂Zr}₂(μ₂,η², η²-N₂)] was synthesized by photochemical reductive elimination from the corresponding Zr bis(aryl) or aryl hydride complexes. Mechanistic studies support the intermediacy of zirconocene arene complexes that in the absence of sufficient N₂ promote C-H activation. When N ₂ is in excess arene displacement gives rise to strong dinitrogen activation.