A convenient route to anionic and cyclic aluminosiloxanes: crystal structures of [PyH][Al{OSiPh2(OSiPh2)2O}2] and the first twelve-membered organic aluminosilicate Al2Si4O6 ring

Abstract

The reaction of Al₂Cl₆ with an excess of Ph₂Si(OH)₂ in THF in the presence of pyridine yielded new anionic and cyclic aluminosiloxanes: the structure of the anionic complex is composed of separated pyridinium cations and aluminosiloxane anions with a tetrahedral arrangement around the Al atom, which is similar to that in natural aluminosilicates; the core of the cyclic aluminosiloxane is a twelve-membered Al₂Si₄O₆ ring in a chair conformation, which contains a Cl group on each of the two Al atoms.