Successful incorporation of triptycene into benzimidazole-linked polymers leads to the highest CO(2) uptake (5.12 mmol g(-1), 273 K and 1 bar) by porous organic polymers and results in high CO(2)/N(2) (63) and CO(2)/CH(4) (8.4) selectivities.
The first microcrystalline borazine-linked polymer, BLP-2(H), has been synthesized. BLP-2(H) crystallizes into 2D sheets that stack in an eclipsed AA fashion, has high thermal stability (∼420 °C) and high porosity (SA(BET) = 1178 m(2) g(-1)) and it can store up to 2.4 wt% of hydrogen at 77 K and 15 bar with isosteric heat of adsorption of 6.8 kJ mol(-1).
The synthesis of highly porous borazine-linked polymers (BLPs) and their gas uptakes are reported. BLPs exhibit high surface areas up to 2866 m 2 g À1 and can store significant amounts of H 2 (1.93 wt%) and CO 2 (12.8 wt%) at 77 K and 273 K, respectively at 1.0 bar with respective isosteric heats of adsorption of 6.0 and 25.2 kJ mol À1 .Recently there has been great interest in the design and synthesis of highly porous organic architectures due to their multifaceted potential use in applications that include storage, separation, conductivity, and catalysis. 1 The chemical composition, physical and textural properties are dictated during synthesis that allow for materials with enhanced properties relevant to their respective applications. With the exception of microcrystalline covalent-organic frameworks (COFs), 2,3 these polymeric materials are amorphous yet can possess considerable porosity and well-defined cavities which render them highly attractive especially in adsorptive gas storage. 4 Such desirable traits are imparted into organic materials through the use of rigid building blocks that direct the growth of polymer networks without the aid of templating agents. [1][2][3] In addition to customized porosity, polymerization processes can lead to pore wall functionalization that significantly enhance gas uptake and selectivity as we have demonstrated recently for benzimidazole-linked polymers. 5 Alternative methods for improved gas uptake (i.e. hydrogen) by porous architectures can also be accessed by the use of polarizable building units that increase hydrogen-framework interactions. 6 Along this line, we sought after the inclusion of borazine (B 3 N 3 ) as a functionalized and polarizable building block into porous organic polymers. 7 Borazine is isostructural to the boroxine units found in COFs prepared by boronic acid self-condensation reactions 2 and has been mainly used for the fabrication of BN-based ceramics or in organic optoelectronics. [8][9][10] However, up to date, the use of borazine for the preparation of porous polymers for gas storage remains fairly undeveloped.We report herein on the synthesis and characterization of a new class of highly porous borazine-linked polymers and investigate their performance in gas (H 2 , CO 2 , CH 4 ) storage application under low pressure and cryogenic conditions. The synthesis of BLP-1(H) and Scheme 1 Synthesis of BLP-1(H) and BLP-12(H) from in situ thermal decomposition of arylamine-borane adducts.
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