Reactions of gallium(III) chloride with Li[E(SiMe3)3](E = Si or Ge): crystal structure of (R3Ge)ClGa(µ-OEt)2GaCl(GeR3)(R = SiMe3)
摘要:
Reactions of Li(ER(3))(thf)(x) (E = Si or Ge, R = SiMe(3), thf = tetrahydrofuran) with gallium(III) chloride were carried out in diethyl ether with 1:1 and 2:1 stoichiometries. The 1:1 reactions gave products that decomposed upon recrystallization from pentane or drying in vacuo. The NMR spectra were consistent with a mixture of Li[R(3)SiGaCl(3)](thf)(4) (major) and GaCl4(SiR(3)). thf (minor) in the case of E = Si and GaCl2(GeR3). thf for E = Ge. The 2: 1 E = Ge reactions gave a mixture of two products exhibiting needle and plate crystal morphologies. The NMR spectra and a partial structure determination identified the former as Li[R(3)GeGaCl(3)](thf)(4). A full structure determination of the latter showed it to be the diethoxy-bridged dimer, (R(3)Ge)ClGa(mu-OEt)(2)GaCl(GeR(3)). The latter product is thought to result from cleavage of the ether solvent by either Ga2Cl6 or the intermediate gallium complex. Possible pathways are discussed.