Tris(trichlorosilyl)tetrelide Anions and a Comparative Study of Their Donor Qualities

Trichlorosilylated tetrelides [(Cl₃ Si)₃ E]^- have been prepared by adding 1 equiv of a soluble Cl^- salt to (Cl₃ Si)₄ Si (E=Si) or 4 Si₂ Cl₆ /GeCl₄ (E=Ge). To assess their donor qualities, the anions [(Cl₃ Si)₃ E]^- (E=C, Si, Ge) have been treated with BCl₃ , AlCl₃ , and GaCl₃ . Both BCl₃ and GaCl₃ give 1:1 adducts with the anionic centers. AlCl₃ leads to Cl^- abstraction from [(Cl₃ Si)₃ E]^- with formation of (Cl₃ Si)₄ E (E=Si or Ge). (Cl₃ Si)₄ Ge is cleanly converted to the perhydrogenated (H₃ Si)₄ Ge by use of Li[AlH₄ ]. Another case of Cl^- abstraction was observed for [(Cl₃ Si)₃ Ge⋅GaCl₃ ]^- , which reacts with GaCl₃ to afford the neutral dimer [(Cl₃ Si)₃ Ge-GaCl₂ ]₂ .