Reduction of Dinitrogen with an Yttrium Metallocene Hydride Precursor, [(C₅Me₅)₂YH]₂

Treatment of [(C5Me5)2YH]2, 1, with KC8 under N2 in methylcyclohexane generates the unsolvated reduced dinitrogen complex, [(C5Me5)2Y]2(μ-η2:η2-N2), 2, and extends the range of yttrium and lanthanide LnZ2Z′/M (Z = monoanion; M = alkali metal) dinitrogen reduction reactions to (Z′)− = (H)−. The hydride complex, 1, is unique in this reactivity compared to other alkane-soluble yttrium metallocenes, [(C5Me5)2YX]x {X = [N(SiMe3)2]−, (Me)−, (C3H5)−, and (C5Me5)−} which did not generate 2 when treated with KC8. [(C5Me5)2LnH]x/KC8/N2 reactions with Ln = La and Lu did not give isolable dinitrogen complexes. Complex 2 and the unsolvated lutetium analogue, [(C5Me5)2Lu]2(μ-η2:η2-N2), 3, were obtained using benzene as a solvent and [(C5Me5)2Ln][(μ-Ph)2BPh2] as precursors with excess KC8. Complex 2 functions as a reducing agent with PhSSPh to form [(C5Me5)2Y(μ-SPh)]2, 4, in high yield.