New Insights into the Synthesis, Morphology, and Growth of Periodic Mesoporous Organosilicas

• Published in: Chemistry of materials 2000-12, Vol.12 (12), p.3857-3863
• Main Authors: Sayari, Abdelhamid, Hamoudi, Safia, Yang, Yong, Moudrakovski, Igor L, Ripmeester, John R
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Porous materials
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm000479u

Periodic mesoporous organosilicas with two-dimensional and three-dimensional hexagonal as well as cubic (Pm3n) symmetry were synthesized using bridged silsesquioxane species (RO)3Si−CH2−CH2−Si(RO)3 as precursors and cetyl- or octadecyltrimethylammonium chloride (C16TMACl or C18TMACl) as structure-directing species. These materials were characterized by N2 adsorption, SEM, TEM, and solid-state MAS NMR spectroscopy. 13C and 29Si NMR data showed unambiguously that all carbon atoms were covalently linked to Si. The cubic material obtained in the presence of C16TMACl and 1,2-bis(trimethoxysilyl)ethane (BTME) first formed into truncated rhombic dodecahedral particles that grew into spheres. The sample prepared in the presence of C18TMACl and BTME at 100 °C was entirely comprised of concentrically self-assembled 10-μm hexagonal rods. Using C16TMACl in the presence of 1,2-bis(triethoxysilyl)ethane (BTEE) at 95 °C afforded high-quality two-dimensional hexagonal organosilica comprised of unusually long (30−40 μm) faceted empty tubules.