Sidearm Effects. Synthesis, Structural Characterization, and Reactivity of Rare Earth Complexes Incorporating a Linked Carboranyl-Indenyl Ligand with a Tethered Oxygen Atom^§

New ether-functionalized carboranyl-indenyl hybrid ligands were prepared. They can prevent lanthanocene chlorides from ligand redistribution reactions and offer samarium(II) complexes unusual reactivities. Treatment of Me2SiCl(C9H6CH2CH2OMe) with 1 equiv of Li2C2B10H10 in toluene/Et2O afforded the monolithium salt [Me2Si(C9H5CH2CH2OMe)(C2B10H11)]Li(OEt2) (2). Interaction of 2 with 1 equiv of n-BuLi in Et2O produced the dilithium salt [Me2Si(C9H5CH2CH2OMe)(C2B10H10)]Li2(OEt2)2 (3). Reaction of 3 with 1 equiv of LnCl3 at room temperature gave the complex salts of general formula [{[η5:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]Ln(THF)(μ-Cl)3Ln[η5:η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]}2{Li(THF)}][Li(THF)4] (Ln = Y (4), Yb (5)). Upon heating, 5 was converted into [η5:η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]Yb(THF)(μ-Cl)2Yb[η5:η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)] (6) by eliminating LiCl. Treatment of 4 or 5 with 2 equiv of group 1 metal amides gave organo-rare-earth amide complexes [η5:η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]Y(NHC6H3-2,5-tBu2)(μ-Cl)Li(THF)3 (8) or [η5:η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]Yb(NHC6H3-2,6-iPr2)(μ-Cl)Li(THF)3 (9). An equimolar reaction of SmI2 with 3 in THF generated, after addition of LiCl, [{[η5:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]2Sm}{Li(THF)}]n (10) and [{η5:η1:η6-Me2Si(C9H5CH2CH2OMe)(C2B10H10)Sm}2(μ-Cl)][Li(THF)4] (11). In sharp contrast, a less reactive YbI2 reacted with 3 in THF, producing only salt metathesis product [η5:η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]Yb(DME)(THF) (12). 12 reacted with 1 equiv of 3 to give the ionic complex {[(μ-η5:η2):η1:σ-Me2Si(C9H5CH2CH2OMe)(C2B10H10)]2Yb}{Li(THF)2}2 (13). All complexes were characterized by various spectroscopic techniques and elemental analyses. The structures of 5, 6, and 8−13 were further confirmed by single-crystal X-ray analyses.