Octa(3-chloroammoniumpropyl) octasilsesquioxane

Abstract

The octahydrochloride salt of octa(3-aminopropyl)octasilsesquioxane can be isolated in 30% yields by controlled hydrolytic condensation of 3-aminopropyltriethoxysilane in strongly acidic methanol. The analytically pure product can be filtered from the reaction solution. The product was characterized by standard analytical and spectroscopic tools. Efforts were made to explore the potential utility of the product for preparing amide and imide compounds that serve as models of polyimides with the goal of making novel materials, especially those that offer high strength and that are flame-resistant. Efforts to make the octa-acetamide were unsuccessful as the hexadeca-acetamide was formed in preference. These results provided the motivation to explore the synthesis of the succinic-anhydride-derived octa-imide. This reaction was found to proceed quite readily. The latter compound is stable in nitrogen to ≈500 °C and more importantly, it appears to behave as a liquid-crystalline material in the temperature range 90–190 °C. This behavior is unusual, given that no aromatic or mesogenic groups are present on the cube. Copyright © 1999 John Wiley & Sons, Ltd.