Silicon-containing porous organic polymers: Preparation, tunable porosity and carbon dioxide sorption

Abstract

Silicon-containing porous organic polymers, POP-1∼POP-4, have been prepared by Sonogashira-Hagihara coupling reactions of tetrahedral silicon-centered monomers, i.e., tetrakis(4-bromophenyl)silane (p-Si) and tetrakis(3-bromophenyl)silane (m-Si), and pyridine-based precursors, i.e., 2,5-diethynylpyridine (p-DP) and 2,6-diethynylpyridine (m-DP). Compared with other porous polymers, the resulting materials exhibit high thermal stability and tunable porosity from nearly no porosity to moderate porosity with Brunauer-Emmett-Teller (BET) surface area of up to 410 m2 g−1 and pore volume of up to 0.34 cm3 g−1. It is found that their porosities largely depend on the structure geometry of silicon-centered and pyridine-based monomers, as well as the reactivity of pyridine-based monomers. Further comparison with other silicon-containing porous polymers reveals that co-polymerization, i.e., introducing the second monomer is an efficient way to tune the porosity of the final materials. For applications, POP-1 and POP-2 possess moderate carbon dioxide uptakes of up to 1.41 mmol g−1 at 273 K and 1.03 bar, and 0.87 mmol g−1 (3.83 wt%) at 298 K and 1.01 bar (POP-1), as well as a comparably high binding ability with CO2 with an adsorption enthalpy of 29.3 kJ mol−1, suggesting their potential applications as promising candidates for capturing and storing CO2.