Molekulare Verbindungen mit SiAl4-, SiAl3- und GeAl4-Einheiten: Synthese und Struktur von Si(AlCl2 · OEt2)4, Ge(AlCl2 · OEt2)4 und HSi(Cp*AlBr)3

Molecular Compounds containing SiAl₄, SiAl₃, and GeAl₄ Units: Sythesis and Structure of Si(AlCl₂ · OEt₂)₄, Ge(AlCl₂ · OEt₂)₄, and HSi(Cp*AlBr)₃ In the scope of our investigations of the reactivity and the potential for synthesis of solutions of Al^I halides we performed reactions between these solutions and SiCp or GeCp, respectively. From these reactions we could isolate an unusual cluster with a central Al₁₄Si unit, described elsewhere, and the compounds Si(AlCl₂ · OEt₂)₄, Ge(AlCl₂ · OEt₂)₄, and HSi(Cp*AlBr)₃, which will be presented and discussed here. In these species the Si respectively the Ge atoms are connected to 4 respectively 3 Al atoms. This bonding results in strong negative polarized Si/Ge centres. The change of the polarization with respect to “normal” Si–R or Ge–R linking leads to a drastic weakening of the Si–R respectively the Ge–R bonds.