Ogoshi Tomoki, Maruyama Keisuke, Sakatsume Yuma, Kakuta Takahiro, Yamagishi Tada-Aki, Ichikawa Takahiro, Mizuno Motohiro
JST, PRESTO , 4-1-8 Honcho , Kawaguchi , Saitama 332-0012 , Japan.
Department of Biotechnology, Faculty of Engineering , Tokyo University of Agriculture and Technology , Nakacho, Koganei, Tokyo 184-8588 , Japan.
J Am Chem Soc. 2019 Jan 16;141(2):785-789. doi: 10.1021/jacs.8b12253. Epub 2019 Jan 8.
State change is a key phenomenon in materials science. We report the first observation of vapor-responsive reversible structural liquid-to-solid and solid-to-structural liquid state changes. We observed that a macrocyclic compound, a pillar[6]arene derivative bearing 12 n-hexyl substituents, is a room temperature structural liquid with unique properties. Formation of a host-guest complex between the pillar[6]arene cavity and the n-hexyl substituent results in a structural liquid with nanoscale structural heterogeneities. The structural liquid solidifies when exposed to competitive cyclohexane guest vapor, whereupon cyclohexane replaces the n-hexyl substituents in the pillar[6]arene cavity and the n-hexyl substituents located outside of the cavity crystallize into distinct nanolayer assemblies. The solid reverts back to the structural liquid when the cyclohexane guest is removed through heating under reduced pressure because of rethreading of the n-hexyl substituents into the cavity. The structural liquid-to-solid and solid-to-structural liquid changes are reversible through the uptake and release of cyclohexane guest vapor.
状态变化是材料科学中的一个关键现象。我们首次观察到了对蒸汽响应的可逆结构液-固和固-结构液状态变化。我们观察到一种大环化合物，一种带有12个正己基取代基的柱[6]芳烃衍生物，是一种具有独特性质的室温结构液体。柱[6]芳烃空腔与正己基取代基之间形成主客体复合物会产生一种具有纳米级结构不均匀性的结构液体。当暴露于竞争性环己烷客体蒸汽时，该结构液体会固化，此时环己烷取代柱[6]芳烃空腔中的正己基取代基，而位于空腔外部的正己基取代基结晶形成不同的纳米层聚集体。当通过减压加热去除环己烷客体时，固体又会恢复为结构液体，这是因为正己基取代基重新穿入空腔。通过环己烷客体蒸汽的吸收和释放，结构液-固和固-结构液的变化是可逆的。
