Organolanthanide and Organoyttrium Hydride Chemistry. 5. Improved Synthesis 2 Complexes and Their Reactivity with Alkenes, Alkynes, 1,2-Propadiene, Nitriles, and Pyridine, Including Structural Characterization of an Alkylideneamido Product

Article abstract of DOI:10.1021/ja00317a020

Hydrogenolysis of <(C5H5)2YCH3>2 in 10:1 toluene:THF or <(CH3C5H4)2YCH3>2 in 10:1 hexane:THF generates the corresponding complexes<(C5H4R)2YH(THF)>2 (1a, R = H; 1b, R = CH3) in high yield. 1a and 1b react with R'CN by 1,2-addition of Y-H to form <(C5H4R)2Y(N=CHR')>2 (2, R' = CH3; 3, R' = C(CH3)3). 3a crystallizes from THF under pentane diffusion in space group P<*> with unit cell dimensions a = 9.261 (5) Angstroem, b = 10.398 (6) Angstroem, c = 16.323 (8) Angstroem, α = 86.48 (4)^o, β = 88.95 (4)^o, γ = 70.29 (4)^o, and Z = 2 dimers for D_c = 1.36 g cm^-3.Least-squares refinement on the basis of 2532 observed reflections led to a final R value of 0.056.One of the two dimers in the unit cell has disorder in the tert-butyl group, but the other dimer is well-behaved.In the latter molecule, the two (C5H5)2Y units of the dimer are connected by asymmetrical N=CHR bridges with Y-N distances of 2.314 (9) and 2.382 (9) Angstroem and YN=C angles of 109.8 (9) and 149.4 (9)^o. 1a and 1b react (a) with H2C=CH2 and CH3CH=CH2 to form (C5H4R)2Y(CH2CH3)(THF) (4) and (C5H4R)2Y(CH2CH2CH3)(THF) (5), respectively, (b) with H2C=C=CH2 to form (C5H4R)2Y(η³-CH2CHCH2)(THF) (6), (c) with HC<*>CC(CH3)3 to form <(C5H4R)2YC<*>CC(CH3)3>2 (7), (d) with R''C<*>CR'' to form (C5H4R)2Y(THF) (8, R'' = C2H5; 9, R'' = C6H5), (e) with pyridine in nonpolar solvents to form <(C5H4R)2YH(NC5H5)>2 (10), and (f) with pyridine in polar solvents to form the 1,2-isomer of (C5H4R)2Y(NC5H6)(NC5H5) (11), which rearranges to the 1,4-isomer, 12.The new complexes were characterized by standard spectral and chemical methods. 1b and 8b are catalysts for activation of H2 in alkyne hydrogenation reactions.