Tetramethylcyclopentadienyl vs cyclopentadienyl substituents. Synthesis and structural characterization of organolanthanide compounds derived from the versatile ligand Me2Si(C5Me4H) (C2B10H11)

Reaction of Me2Si(C5Me4H)Cl with 1 equiv of Li2C2B10H10 in toluene/Et2O gav e the monoanionic salt [Me2Si(C5Me4)(C2B10H11)] Li(OEt2)(0.5) (1), which co uld be conveniently converted into the dianionic salt [{[mu-eta (5)):sigma -Me2Si(C5Me4)(C2B10H10)]Li(THF)}(2)Li][Li(THF)(4)]. THF (2) by treatment wi th 1 equiv of n-BuLi. 1 reacted with 1 equiv of LnCl(3) in THF to give [eta (5)-Me2Si(C5Me4)(C2B10H11)] LnCl(3)Li(THF)(3) (Ln = Nd (3), Sm (4)). 3 cou ld further react with 1 equiv of 1 to afford [eta (5)-Me2Si(C5Me4)(C2B10H11 )](2)Nd(mu -Cl)(2)Li(OEt2)(THF) (6), which could also be prepared from the reaction of NdCl3 with 2 equiv of 1. Partial hydrolysis of 4 resulted in th e isolation of the novel cluster [{[eta (5)-Me2Si(C5Me4)(C2B10H11)]Sm}(2)(m u (2)-Cl)(3)(mu (3)-Cl)(4) Li(THF)(2)Sm(mu (4)-O)](2) (5). Treatment of 1 w ith 4 equiv of NaNH2 in THF, followed by reaction. with 1 equiv of YbCl3, p roduced (eta (5)-C5Me4H)(2)Yb(mu -Cl)(2)Li(THF)(2) (7). An equimolar reacti on between 2 and NdCl3 yielded the anionic compound [{eta (5): sigma -Me2Si (C5Me4)(C2B10H10)}(2)Nd][Li(DME)(3)] (11). Interaction of LnC4 with 0.5 equ iv of 2 resulted in the isolation of the lanthanocene chloride compounds [{ eta (5): sigma -Me2Si(C5Me4)(C2B10H10)}LnCl(mu -Cl)](2) [Li(S)(n)](2)(S = T HF, n = 4, Ln = Sm(8), Y (9); S = DME, n = 3, Ln E Yb (10)). Reaction of 9 with 2 equiv of NaN(SiMe3)(2) gave the unsolvated compound [eta (5): sigma :Me2Si(C5Me4)(C2B10H10)]YN(SiMe3)(2) (12). Treatment of LnI(2) with 0.5 equ iv of 2 afforded the ionic organolanthanide(II) compounds [{eta (5): sigma -Me2Si(C5Me4)(C2B10H10))LnI(2)][Li(DME)(3)](2) (Ln = Sm (13), Yb (14)). All of these new compounds were characterized by various spectroscopic data an d element analyses. The solid-state structures of compounds 2, 5-7, 10, and 14 were further confirmed by single-crystal X-ray analyses.