Multi-walled carbon nanotubes (MWNTs) were hydrogenated by using lithium in ethylenediamine under Benkeser's conditions, which is convenient due to the avoidance of liquid ammonia used in the classical Birch reaction. The hydrogenated MWNTs were characterized by Raman, infrared spectroscopy, transmission electron microscopy and thermogravimetric analysis. The hydrogenation degree was also studied.

The interactions of N-piperidineethyl-functionalized indene compounds 1-R-3-C 5 H 10 NCH 2 CH 2 C 9 H 6 (R ) H-(1), Me 3 Si-( 2)) with lanthanide(III) amides [(Me 3 Si) 2 N] 3 Ln(µ-Cl)Li(THF) 3 (Ln ) Yb, Eu, Sm, Nd) were studied. The results indicated that the ligands and reductive potentials of Ln 3+ /Ln 2+ have an influence on the reaction patterns and the coordination mode of the indenyl ligands with the central metals. Reactions of [(Me 3 Si) 2 N] 3 Ln(µ-Cl)Li(THF) 3 (Ln ) Yb, Eu) with 2 equiv of corresponding indene compounds 1-R-3-C 5 H 10 NCH 2 CH 2 C 9 H 6 (R ) H-(1), Me 3 Si-(2)) produced organolanthanide(II) complexes [η 5 :η 1 -C 5 H 10 NCH 2 CH 2 C 9 H 6 ] 2 Ln II (Ln ) Yb (3), Eu (5)) and novel organolanthanide(II) complexes with general formula [η 4 :η 4), Eu ( 6)), and a new highly conjugated bis(N-piperidineethyl)dibenzofulvalene, (C 5 H 10 NCH 2 CH 2 C 9 H 5 ) 2 ( 9), was unexpectedly isolated as a byproduct in the preparation of 6, indicating the ligands' effects on the coordination and reactivity patterns. Theoretical calculations on ytterbium(II) complexes having indenyl ligands indicated that the indenyl hapticity depends on the strain, steric, and electronic effects. Treatment of lanthanide(III) amides [(Me 3 Si) 2 N] 3 Ln(µ-Cl)Li(THF) 3 (Ln ) Sm, Nd) with 2 equiv of C 5 H 10 NCH 2 CH 2 C 9 H 7 (1) afforded indenyl lanthanide(III) complexes with general formula [η 3 -C 5 H 10 NCH 2 CH 2 C 9 H 6 ] 2 Ln III [η 3 :η 1 -C 5 H 10 NCH 2 CH 2 C 9 H 6 ] (Ln ) Sm (7), Nd (8)). The shortest distances involving the nonbridging atoms of the C 5 portions of the indenyl groups indicated an allyl-like nature of the ligand-to-metal coordination. The interaction of [(Me 3 Si) 2 N] 3 Sm III (µ-Cl)Li-(THF) 3 with 2 equiv of 1-Me 3 Si-3-C 5 H 10 NCH 2 CH 2 C 9 H 6 (2) produced an unexpected bis(N-piperidineethyl)dibenzofulvalene (C 5 H 10 NCH 2 CH 2 C 9 H 5 ) 2 (9) and other unidentified solids, suggesting the ligands' influence on the reactivity patterns. All the compounds were fully characterized by spectroscopic methods and elemental analyses. The structures of compounds 4, 7, 8, and 9 were additionally determined by X-ray diffraction study. The catalytic activity of the organolanthanide complexes 3-8 on MMA polymerization was examined. It was found that the π-bonded tris(N-piperidineethylindenyl)lanthanide(III) complexes 7 and 8 exhibit unexpected good catalytic activity on MMA polymerization, and complex 7 also showed an unexpected high catalytic activity on ε-caprolactone polymerization. It was found that the catalytic activity of the complexes depended on the polymerization conditions. The solvents, temperatures, substituted groups, and lanthanide ionic radii effects on the catalytic activity of the complexes were examined.

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The reaction of 2 equiv of C 9H6-1-SiMe3-3-CH2CH2NC5H10 (2) with the ytterbium(III) amide [(Me3Si)2N]3Yb-(μ-Cl)Li(THF)3 produced a novel ytterbium(II) complex with an indenyl ligand bonded to the metal via the benzo ring with η4 hapticity, [η4:η2:η1-(C5H10NCH2CH2C9H5SiMe3)Li(μ-Cl)]Yb-(η5:η1-C5H10NCH2CH2C9H5SiMe3) (1), as verified by a solid-state structure determination and theoretical calculations.