Publication details

Porous aromatic organosilicates by non-hydrolytic sol-gel routes

Authors

PINKAS Jiří KEJÍK Martin MORAVEC Zdeněk BARNES Craig E.

Year of publication 2014
Type Conference abstract
MU Faculty or unit

Central European Institute of Technology

Citation
Description A series of porous hybrid organosilicate materials was prepared by non-hydrolytic sol-gel reactions of silicon(IV) acetate with rigid aromatic building blocks bearing phenolic hydroxyl functional groups with focus on readily available compounds that were previously utilized for synthesis of materials such as the porous aromatic frameworks (PAFs) and covalent organic frameworks (COFs). Upon elimination of acetic acid as a byproduct, an organosilicate gel is formed in polar ether solvents. Drying in vacuo offers powdered xerogels. The synthesis procedure was optimized in order to reach the maximum degree of condensation as monitored by gravimetry. All of the prepared materials were found to be amorphous, they do however possess large specific surface areas exceeding 800 m2 g-1 and generally exhibit high thermal stability (up to 400 °C under inert gas). The relationship between the size and symmetry of employed organic linker and the surface properties as well as the degree of condensation and thermal behavior were studied. Additionally the chemical properties and stability of these materials were studied in reactions with a variety of organic, inorganic and organometallic reagents (water, alcohols, phenol, chlorosilanes, AlR3, AlCl3, n-BuLi, ...). A method for post-synthetic replacement of the highly coordinating residual acetate functional groups was also found. Products were characterized by elemental analyses, solid-state 13C, 27Al, and 29Si NMR, IR spectroscopy, surface area analysis, thermal analysis TG/DSC, and XRD measurements.
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