Dinitrogen Reduction via Photochemical Activation of Heteroleptic Tris(cyclopentadienyl) Rare-Earth Complexes

Dinitrogen can be reduced by photochemical activation of the Ln3+ mixed-ligand tris­(cyclopentadienyl) rare-earth complexes (η5-C5Me5)3–x(C5Me4H)xLn (Ln = Y, Lu, Dy; x = 1, 2). [(C5Me4R)2Ln]2(μ-η2:η2-N2) products (R = H, Me) are formed in reactions in which N2 is reduced to (NN)2– and (C5Me4H)− is oxidized to (C5Me4H)2. Density functional theory indicates that this unusual example of rare-earth photochemistry can be rationalized by absorptions involving the (η3-C5Me4H)− ligands.