Tricky but repeatable synthetic approach to branched, multifunctional silsesquioxane dendrimer derivatives

Abstract

The efficient one-pot procedure based on a sequence of hydrosilylation and reduction reactions was applied to obtain carbosilane dendrimers with different silsesquioxane (SQ) cores, i.e. from mono-T ₈ SQ, octa-T ₈ SQ to di- and tetrafunctional double-decker silsesquioxanes.

Abstract

Dendrimers are a wide group of chemical compounds that are still being studied extensively. New dendrimer cores are sought to improve their physicochemical properties. We present the syntheses of silsesquioxane dendrimers with different cores, from mono-T ₈, octa-T ₈ silsesquioxane to di- and tetrafunctional double-decker silsesquioxanes. These compounds were obtained by a sequence of hydrosilylation and reduction reactions in a one-pot protocol. As part of the research, the location of reactive Si–H and Si–Vi bonds on the selectivity of the hydrosilylation process was verified, as well as two reducing agents LiAlH ₄ and Red-Al®, on the reduction process. In addition, the reactivity of the obtained new hydrogen derivatives of these SQs was tested in the process of hydrosilylation with selected olefins and in a repetitive one-pot route to increase the generation of these dendritic systems.