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

Treatment of [(C5Me5)(2)YH](2), 1, with KC8 under N-2 in methylcyclohexane generates the unsolvated reduced dinitrogen complex, [(C5Me5)(2)Y](2)(mu-eta(2):eta(2)-N-2), 2, and extends the range of yttrium and lanthanide LnZ(2)Z'/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)(2)YX](x) {X = [N(SiMe3)(2)](-), (Me)(-), (C3H5)(-), and (C5Me5)(-)} which did not generate 2 when treated with KC8. [(C5Me5)(2)LnH](x)/KC8/N-2 reactions with Ln = La and Lu did not give isolable dinitrogen complexes. Complex 2 and the unsolvated lutetium analogue, [(C5Me5)(2)Lu](2)(mu-eta(2):eta(2)-N-2), 3, were obtained using benzene as a solvent and [(C5Me5)(2)Ln][(mu-Ph)(2)BPh2] as precursors with excess KC8. Complex 2 functions as a reducing agent with PhSSPh to form [(C5Me5)(2)Y(mu-SPh)](2), 4, in high yield.