Attachment of the bulky bidentate ligand C(SiMe3)(2)SiMe2CH2CH2Me2Si(Me3Si)(2)C to K, Zn, Sn, and Yb. Crystal structures of LnMC(SiMe3)(2)SiMe2CH2CH2Me2Si(Me3Si)(2)CMLn (MLn = K(C6H6)(2), K(THF)(2), SnCl3, or SnMe2Cl) and CH2SiMe2C(SiMe3)(2)ZnC(SiMe3)(2)SiMe2CH2 (THF = tetrahydrofuran)

Reaction of the lithate [Li(THF)(4)][CH2SiMe2C(SiMe3)(2)LiC(SiMe3)(2)SiMe2C H2] with (KOBu)-Bu-t in THF has given the organopotassium reagent (THF)(2)K C(SiMe3)(2)SiMe2CH2CH2Me2Si(Me3Si)(2)CK(THF)(2), 8, and reaction of HC(SiMe 3)(2)SiMe2CH2CH2Me2Si(Me3Si)(2)CH with KMe in benzene has given the related ether-free species (C6H6)(2)KC(SiMe3)(2)SiMe2CH2CH2Me2Si-(Me3Si)(2)CK(C6H6 )(2), 7. The structures of 7 and 8 have been confirmed by X-ray studies whi ch indicate that both compounds show K ... Me contacts in the range 3.3-3.5 Angstrom. The ether-free reagent 7 reacted with YbI2 in benzene to give th e cyclic Yb(II) derivative CH2SiMe2(SiMe3)(2)YbC(SiMe3)(2)SiMe2CH2, which w as found to be somewhat more stable toward Et2O than the I previously studi ed Yb{C(SiMe3)(3)}(2). Reaction of the lithate [Li(TMEDA)(2)][CH2SiMe2C(SiM e3)(2)LiC(SiMe3)(2)SiMe2CH2] (2a) with ZnCl2 in THF gave a cyclic compound CH2SiMe2C(SiMe3)(2)ZnC(SiMe3)(2)SiMe2CH2, which is stable toward boiling aq ueous THF. An X-ray study shows that the angle at Zn is 170 degrees. In con trast, the reactions of 2a with SnCl4 or Me2SnCl2 gave linear species ClX2S nC(SiMe3)(2)SiMe2CH2CH2Me2Si(Me3Si)(2)CSnX2Cl, X = Cl or Me, the structures of which were confirmed by single-crystal X-ray diffraction studies.