Synthesis of periodic mesoporous organosilicas with chemically active bridging groups and high loadings of thiol groups

Abstract

Chemically active isocyanurate-bridged periodic mesoporous organosilica materials with high loadings of pendant thiol groups have been synthesized via co-condensation under acidic conditions, using the triblock copolymer EO₂₀PO₇₀EO₂₀ (P123) as template and a mixture of mercaptopropyl-containing silane and isocyanurate-containing silsesquioxane to form the framework. The obtained SH–ICS–PMOs were characterized by XRD, transmission electron microscopy (TEM), solid state ¹³C and ²⁹Si MAS NMR spectroscopy, and N₂ physical sorption. The data show that well-ordered SH–ICS–PMOs were obtained with 40% of the framework Si atoms bearing the thiol pendant groups. Interestingly, the introduction of the thiol groups improved the mesostructural ordering and favored the cross-linking of the pore walls. The determination of Hg²⁺ uptake from aqueous solution as a test case showed that both the bridging ICS groups and the pendant thiol groups in the SH–ICS–PMOs are active in adsorbing Hg²⁺. Our study demonstrated that well-ordered periodic mesoporous organosilicas are capable of supporting both chemically active bridging groups and active pendant groups with high loadings.