Organometallic compounds of the lanthanides. 64. Synthesis and X-ray crystal structures of dimethylgermyl bis(tetramethylcyclopentadienyl) halide and alkyl derivatives of the lanthanides

Article abstract of DOI:10.1021/om00054a017

Metathesis of Me₂GeCl₂ or Me₂SnCl₂ with 2 equiv of LiC₅Me₄H affords Me₂Ge(C₅Me₄H)₂ (1) and Me₂Sn(C₅Me₄H)₂ (2), respectively. The subsequent deprotonation of 1 with MeLi yields only the desired dilithium salt Me₂Ge(C₅Me₄Li)₂ (3) whereas 2 forms Me₄Sn and two LiC₅Me₄H. The trichlorides of neodymium, samarium, holmium, and lutetium react with the dilithium salt 3 with the formation of Me₂Ge(C₅Me₄)₂LnCl ₂Li(THF)₂ (Ln = Nd (4), Sm (5), Ho (6), Lu (7)). The reaction of 4 and 6 with LiCH(SiMe₃)₂ produces Me₂Ge(C₅Me₄)₂LnCH(SiMe ₃)₂ (Ln = Nd (8), Ho (9)). The new compounds have been characterized by elemental analysis, mass and NMR spectra, as well as X-ray structural analysis of 5, 7, and 9. The halides 5 and 7 crystallize in the monoclinic space group P2₁/c (No. 14) with a = 9.7284 (9), b = 19.397 (1), c = 16.610 (2) ?, β = 98.963 (9)°; Z = 4 or a = 9.578 (3), b = 19.218 (4), c = 16.525 (4) ?, β = 99.73 (2)°; Z = 4, respectively. Least-squares refinement led to a final R value of 0.020 (F_o > 4σ(F_o)) for 5554 independent reflections for 5 or of 0.028 (F_o > 3σ(F_o)) for 5822 independent reflections for 7. Compound 9 crystallizes in the monoclinic space group P2₁/m (No. 11) with a = 9.2621 (8), b = 14.216 (2), c = 11.839 (2) ?, β = 107.79 (1)°, Z = 2, and R = 0.023 (F_o > 4σ(F_o)) for 2954 reflections. The structure of 9 shows a short Ho-C (methyl) contact of 2.774 (4) ?.