Spiro(fluorene-9,9′-xanthene)-Based Porous Organic Polymers: Preparation, Porosity, and Exceptional Hydrogen Uptake at Low Pressure

Preparation and sorption properties of spiro(fluorene-9,9'-xanthene)-based porous organic polymers (SPOPs) are reported for the first time. Using a same linker monomer, the micropore size and specific surface area in SPOPs are tunable by variation of the structure of core building blocks. According to the obtained nitrogen physisorption isotherms, the Brunauer Emmett Teller specific surface area for these polymers varies between 750 and 1020 m(2) g(-1). Copolymer SPOP-3 containing spiro(fluorene-9,9'-xanthene) and spirobifluorene with 1:1 ratio, prepared through Suzuki coupling polymerization, possesses 2.22 wt % hydrogen adsorption capacity at 1.0 bar and 77 K, which not only is the exceptional uptake capacity for hydrogen at low pressure among the best reported results for organic polymers but also can be competitive with other kinds of porous materials such as activated carbons and metal-organic frameworks.