Bifunctional periodic mesoporous organosilicas with thiophene and isocyanurate bridging groups

Bifunctional periodic mesoporous organosilicas (BPMOs) with thiophene- and isocyanurate-bridging groups were prepared by one-pot co-condensation of 2,5-bis(triethoxysilyl)thiophene and tris[3-(trimethoxysilyl)propyl]isocyanurate precursors in the presence of a poly(ethylene oxide)-poly(DL-lactic acid-co-glycolic acid)-poly(ethylene oxide) (PEO-PLGA-PEO) triblock copolymer under acidic conditions. The resulting BPMOs exhibited 2D hexagonal ordering (p6mm), large mesopores of ∼7.7 nm, and high BET surface area (∼ 600-700 m²/g). ¹³C CP-MAS and ²⁹Si MAS NMR studies confirmed the presence of thiophene and isocyanurate bridging groups inside the framework of pore walls with the relative content reflecting the synthesis gel composition. Additional quantitative estimation was provided by N and S elemental analysis. Thermogravimetric analysis showed the thiophene-isocyanurate BPMOs are stable up to 250 °C in flowing air and up to 400 °C in flowing nitrogen.