Ferrocene-linked porous organic polymers for carbon dioxide and hydrogen sorption

Two novel ferrocene-containing porous organic polymers, FPOP-1 and FPOP-2, have been prepared by Sonogashira-Hagihara coupling reactions of 1,1′-diethynylferrocene with tri(4-bromophenyl)phenylsilane or tetrakis(4-bromophenyl)silane. The resultant polymers show high thermal stability and high porosity with Brunauer-Emmer-Teller (BET) surface area of up to 954 m2 g−1 (FPOP-2) and total pore volume of up to 0.74 cm3 g−1 (FPOP-2). The porosity comparison with other ferrocene-containing porous polymers indicates that the introduction of tetrahedral silicon-centered units is beneficial to enhancing the porosity. The gas sorption investigations reveal that these polymers possess comparable CO2 capacities of 1.44 mmol g−1 (6.3%) at 273 K and 1.0 bar, and 0.91 mmol g−1 (4.0 wt%) at 298 K and 1.0 bar (FPOP-2), and comparable H2 uptakes of 7 mmol g−1 (1.4 wt%) (FPOP-2). The values are higher than other non-ferrocene-containing porous polymers with higher porosity, thereby indicating that the incorporation of ferrocene units can improve the gas sorption property. Furthermore, these results demonstrate that these materials can be promisingly utilized as solid absorbents for storing CO2 and H2.