Synthesis and structure of sodium phenylsiloxanolate

Two different synthetic routes for the formation of sodium phenylsiloxanolate (SPS) have been developed: (i) the cleavage of oligo(phenylsilsesquioxane), OPSSO, by NaOH in n-butyl alcohol and (ii) the reaction of phenyltri-n-butoxysilane, PhSi(n-BuO)(3), and NaOH in n-butyl alcohol in the presence of water. From both reactions, (i) and (ii), crystalline sym-cis-{(Na+)(4)-[PhSi(O)O-](4)}. 8n-BuOH (A) was the product isolated and characterized by X-ray diffraction. Reaction of SPS with Me3SiCl resulted in the formation of the corresponding sym-cis-tetraphenyltetrakis(trimethylsiloxy)cyclotetrasiloxane, [PhSi(O)OSiMe3](4). Under anhydrous conditions, PhSi(n-BuO)(3) and NaOH(-)reacted to give sodium phenyldi-n-butoxysilanolate, PhSi(ONa)(n-BuO)(2). Subsequent treatment with Me3SiCl led to the formation of phenyl(trimethylsiloxy)di-n-butoxysilane, PhSi(n-BuO)(2)(OSiMe3).