Building block approach to organic/silica hybrid materials

The reaction of the cubic octameric silicate anion, Si₈O₂₀^8–, with dimethyldichlorosilane in 2,2-dimethoxypropane yielded solid products. FT-IR and solid-state ²⁹Si NMR spectra of the products indicate that the silicate anion becomes cross-linked via the dimethylsilyl group without degradation of the cubic core, resulting in the formation of organic/silica hybrids consisting of the Si₈O₂₀^8–structure as a building block. The hybrids are thermally stable up to ca. 380°C in air. The specific surface area of the hybrids is 31 m² g^–1, while the value increases to 339 m² g^–1 after calcination at 350°C in air. The process of increasing the surface area of the hybrids by the heat-treatment was investigated using solid-state ¹³C NMR spectroscopy.