Insights into the Hydrolytic Polymerization of Trimethoxymethylsilane. Crystal Structure of (MeO)2MeSiONa

The commercially practiced conversion of trimethoxymethylsilane (MTM) to [OSi­(OMe)­Me)]n polymers and resins is assumed to proceed via the silanol (MeO)2MeSiOH. Access to this crucial silanol is gained via the synthesis of (MeO)2MeSiONa, the first methoxysilanoate to be crystallographically characterized. Mild protonation of this silanoate gives (MeO)2MeSiOH, which is shown to condense with (MeO)2MeSiOH but not with MTM. Condensation generates reactive disiloxanols but does not produce symmetric disiloxanes. Parallel results were obtained with (MeO)2PhSiOH.