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 }·8 n -BuOH ( A ) was the product isolated and characterized by X-ray diffraction. Reaction of SPS with Me 3 SiCl resulted in the formation of the corresponding sym-cis -tetraphenyltetrakis(trimethylsiloxy)cyclotetrasiloxane, [PhSi(O)OSiMe 3 ] 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 Me 3 SiCl led to the formation of phenyl(trimethylsiloxy)di- n -butoxysilane, PhSi( n -BuO) 2 (OSiMe 3 ).