Dinitrogen reduction via photochemical activation of heteroleptic tris(cyclopentadienyl) rare-earth complexes

Dinitrogen can be reduced by photochemical activation of the Ln ³⁺ mixed-ligand tris(cyclopentadienyl) rare-earth complexes (η⁵-C₅Me₅)_3-x(C ₅Me₄H)_xLn (Ln = Y, Lu, Dy; x = 1, 2). [(C ₅Me₄R)₂Ln]₂(μ-η²: η²-N₂) products (R = H, Me) are formed in reactions in which N₂ is reduced to (Nî - N)^2- and (C ₅Me₄H)^- is oxidized to (C₅Me ₄H)₂. Density functional theory indicates that this unusual example of rare-earth photochemistry can be rationalized by absorptions involving the (η³-C₅Me₄H)^- ligands.