Triptycene-Based Polymers of Intrinsic Microporosity: Organic Materials That Can Be Tailored for Gas Adsorption
Triptycene-Based Polymers of Intrinsic Microporosity: Organic Materials That Can Be Tailored for Gas Adsorption
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DOI：
10.1021/ma100640m
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发表时间：
2010-06-22
期刊：
影响因子：
5.5
通讯作者：
McKeown, Neil B.
中科院分区：
文献类型：
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作者：
Ghanem, Bader S.;Hashem, Mohammed;McKeown, Neil B.
我们报道了由桥头位置带有烷基的三聚三烯单体衍生的具有内在微孔性的网络聚合物(网络PIM)的合成和性质。气体吸附可通过烷基链的长度和支化来控制，从而使材料的表观比表面积可在618-1760m(2)g(-1)范围内调节。较短的(例如甲基)或支化的(例如异丙基)烷链提供了最大的微孔率的材料，而较长的烷基链似乎阻碍了由刚性有机骨架产生的微孔率。与其他PIM相比，增强的微孔率来自于骨架的大分子形状，如三茂铁烯单元所决定的，这有助于减少刚性骨架延伸的平面支柱之间的分子间接触，从而降低固体内填充的效率。在中低压力下，甲基或异丙基取代的三苯基PIMs的吸氢量是纯有机材料中最高的(1bar/77K时为1.83%，18bar/77K时为3.4%)。这些材料令人印象深刻的吸氢能力与高密度的亚纳米微孔有关，正如Horvath-Kawazoe对低压氮气吸附数据的分析所证实的那样。
We report the synthesis and properties of network polymers of intrinsic microporosity (network PIMs) derived from triptycene monomers that possess alkyl groups attached to their bridgehead positions. Gas adsorption can be controlled by the length and branching of the alkyl chains so that the apparent BET surface area of the materials can be tuned within the range 618-1760 m(2) g(-1). Shorter (e.g., methyl) or branched (e.g., isopropyl) alkyl chains provide the materials of greatest microporosity, whereas longer alkyl chains appear to block the microporosity created by the rigid organic framework. The enhanced microporosity, in comparison to other PIMs, originates from the macromolecular shape of the framework, as dictated by the triptycene units, which helps to reduce intermolecular contact between the extended planar struts of the rigid framework and thus reduces the efficiency of packing within the solid. The hydrogen adsorption capacities of the triptycene-based PIMs with either methyl or isopropyl substituents arc among the highest for purely organic materials at low or moderate presures (1.83% by mass at 1 bar/77K, 3.4% by mass at 18 bar/77 K). The impressive hydrogen adsorption capacity of these materials is related to a high concentration of subnanometre micropores, as verified by Horvath-Kawazoe analysis of low-pressure nitrogen adsorption data.