Three-dimensional cubic (Im3m) periodic mesoporous organosilicas with benzene- and thiophene-bridging groups

Abstract

Three-dimensional cubic (Im3m) periodic mesoporous organosilicas with aromatic benzene- and thiophene-bridging groups were synthesized using 1,4-bis(triethoxysilyl)benzene and 2,5-bis(triethoxysilyl)thiophene as organosilica precursors in the presence of a F127 PEO–PPO–PEO triblock copolymer under acidic conditions. Highly ordered 3D cubic (Im3m) mesostructure was confirmed by synchrotron small angle X-ray scattering and transmission electron microscopy. Nitrogen adsorption analysis of the aforementioned samples (extracted and additionally calcined in nitrogen at 375–400 °C) revealed their high surface area (460–630 m² g⁻¹) and accessible ordered large pores (in the range of 6–9 nm). High thermal stability of these benzene- and thiophene-PMO samples (up to 500 and 400 °C, respectively) was confirmed by thermogravimetric analysis, while their framework chemistry was studied by solid-state ¹³C and ²⁹Si MAS NMR.