Novel organic–inorganic hybrids based on T8 and T10 silsesquioxanes: synthesis, cage-rearrangement and properties

Abstract

In this paper, we present a simple approach for the synthesis of well-defined macromolecules based on precisely isolated amino- and amido-functionalized octa T₈ and deca T₁₀ silsesquioxanes (SQs). Here, we show that reorganization of the siloxane cage-like core (T₈ → T₁₀) can be easily performed, including isolation of intermediates, and cage rearrangement achieved by using Brønsted superacid, trifluoromethanesulfonic acid (CF₃SO₃H). Moreover, T₁₀-like SQs can be obtained in a one-step reaction by alkoxysilane condensation in trifluoromethanesulfonic acid conditions. The resulting decamers of amine-SQ and an amido-functionalized derivative containing long alkyl chains are reported for the first time in the literature. The non-fluorinated amido derivatives due to their lamellar-like nature and specific packing can serve as transparent hydrophobic coatings in various industrial applications. The obtained compounds were fully characterized using FT-IR, UV-vis, multinuclear NMR (¹H, ¹³C, ²⁹Si), DOSY NMR, TG-DTA, DSC, HR-MS, TEM, EDS and elemental analysis.