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.