Hybrid networks constructed from tetrahedral silicon-centered precursors and cubic POSS-based building blocks via Heck reaction: porosity, gas sorption, and luminescence

Abstract

Cubic octavinylsilsesquioxane successively reacts with different tetrahedral silicon-centered precursors containing di-, tri-, or tetrabromophenyl groups to prepare hybrid porous polymers (HPPs) via Heck reaction. The resulting materials possess high porosities with Brunauer–Emmett–Teller specific surface areas of up to 875 m² g⁻¹. Their porosities can be tuned by altering the number of the connecting sites of silicon-centered units. For gas storage applications, HPP-5 exhibits the following properties: a high H₂ uptake of 7.76 mmol g⁻¹ (1.56 wt%) at 77 K and 1.01 bar; a moderate CO₂ uptake of 1.04 mmol g⁻¹ (4.58 wt%) at 298 K and 1.04 bar; and a low CH₄ uptake of 0.28 mmol g⁻¹ (0.45 wt%) at 298 K and 1 bar. These results suggest that these polymers can be applied as promising materials for H₂ and CO₂ storage as well as the selective adsorbents of CO₂ rather than CH₄. These polymers are also luminescent with the maximum emission at ca. 420 nm in the solid state; therefore, they could be potentially applied as blue light-emitting materials.