Novel layered silica-organic nanostructured materials were prepared by hydrolysis and condensation of alkoxytrichlorosilanes (n-C n H 2n+1 OSiCl 3 , n ) 12, 14, 16, 18, and 20) as single precursors. The formation relies on the self-assembly of alkoxysilanetriols (n-C n H 2n+1 OSi-(OH) 3 ) generated by the preferential hydrolysis of Si-Cl groups in the precursors. The products exhibited the XRD patterns indicative of layered structures whose d spacings varied in the range of 3.95 to 6.13 nm depending on the alkyl chain lengths. The SEM images of the products showed well-defined platelike morphologies on micrometer length scales, reflecting the layered structures of the products. Further structural characterization by solidstate 29 Si and 13 C NMR and FTIR revealed that the layered structures consisted of bimolecular layers of long-chain alcohols and thin silica layers. Condensation of alkoxysilanetriols proceeded in the solid state to form silica networks, being accompanied by the cleavage of the alkoxy groups. The present results provide a new approach for the construction of silica-based nanostructured materials with well-regulated organic arrays and silica networks.

Dialkoxydichlorosilanes ((RO)2SiCl2, R = alkyl) react almost completely with interlayer silanol groups in a layered silicate octosilicate to create a new crystalline silicate structure consisting of new five-membered rings arranged regularly on both sides of the silicate layers. The introduction of dialkoxysilyl groups to the interlamellar region of layered silicates with regular reaction sites provides a new methodology for the design and construction of novel crystalline silicate frameworks by a soft chemical route.

Layered silicic acid-organic nanohybrid materials consisting of long-chain alkoxy groups attached to thin silica layers have been prepared via esterification of a layered silicic acid-alcohol nanostructured material derived from hexadecoxytrichlorosilane (C(16)H(33)OSiCl(3)). The esterification reaction was performed by heating the layered composite. The detailed characterization of the product heated at 80 degrees C revealed that the interlayer alcohol molecules partly ( approximately 50%) reacted with the interlayer surface silanol groups to form alkoxy groups. Unreacted alcohol molecules were removed by tetrahydrofuran (THF) treatment to form a novel alkoxylated layered silica material. This product retains its structure up to 120 degrees C and has a higher stability in organic solvents if compared with the layered silicic acid-alcohol nanocomposite before esterification, whose structure collapsed over 100 degrees C. Furthermore, various alcohols can be adsorbed into the esterified nanohybrid with the expansion of the interlayer spacing.