Chemistry Letters, Vol.47, No.7, 864-867, 2018
Selective and High-yielding Preparation of Ammonium-functionalized Cage-like Octasilsesquioxanes Using Superacid Catalyst in Dimethyl Sulfoxide
Ammonium-functionalized polyhedral oligomeric silses-quioxanes (N-POSSs) with only cage-like octamers were selectively prepared in high yields (N-ca. 90%) within relatively short reaction time (N-7-12 h), when the hydrolytic condensations of 3-aminopropyltrimethoxysilane (N-APTMS), 3-(N-2-aminoethylamino) propyltrimethoxysilane (N-AEAPTMS), and an APTMS-AEAPTMS mixture, respectively, were performed using super-acid trifluoromethanesulfonic acid as a catalyst in dimethyl sulfoxide at ca. 50-60 degrees C. The reaction was carried out in an open system to concentrate the reaction solution, followed by precipitating and washing using acetone-chloroform mixed solvent.