Poppe Silvio, Lehmann Anne, Scholte Alexander, Prehm Marko, Zeng Xiangbing, Ungar Goran, Tschierske Carsten
Institute of Chemistry, Organic Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes Strasse 2, D-06120 Halle/Saale, Germany.
Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK.
Nat Commun. 2015 Oct 21;6:8637. doi: 10.1038/ncomms9637.
Zeolites represent inorganic solid-state materials with porous structures of fascinating complexity. Recently, significant progress was made by reticular synthesis of related organic solid-state materials, such as metal-organic or covalent organic frameworks. Herein we go a step further and report the first example of a fluid honeycomb mimicking a zeolitic framework. In this unique self-assembled liquid crystalline structure, transverse-lying π-conjugated rod-like molecules form pentagonal channels, encircling larger octagonal channels, a structural motif also found in some zeolites. Additional bundles of coaxial molecules penetrate the centres of the larger channels, unreachable by chains attached to the honeycomb framework. This creates a unique fluid hybrid structure combining positive and negative anisotropies, providing the potential for tuning the directionality of anisotropic optical, electrical and magnetic properties. This work also demonstrates a new approach to complex soft-matter self-assembly, by using frustration between space filling and the entropic penalty of chain extension.
沸石是具有极其复杂多孔结构的无机固态材料。最近，通过网状合成相关的有机固态材料，如金属有机框架或共价有机框架，取得了重大进展。在此，我们更进一步，报道了首个模拟沸石框架的流体蜂窝结构的例子。在这种独特的自组装液晶结构中，横向排列的π共轭棒状分子形成五边形通道，环绕着更大的八边形通道，这也是一些沸石中发现的结构单元。额外的同轴分子束穿透较大通道的中心，而附着在蜂窝框架上的链无法到达这些中心。这创造了一种结合正、负各向异性的独特流体混合结构，为调节各向异性光学、电学和磁学性质的方向性提供了潜力。这项工作还展示了一种通过利用空间填充与链延伸的熵罚之间的受挫效应来实现复杂软物质自组装的新方法。
