National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
Institute of Computational Molecular Science, Temple University , Philadelphia, Pennsylvania 19122, United States.
ACS Nano. 2016 Nov 22;10(11):10480-10488. doi: 10.1021/acsnano.6b06419. Epub 2016 Nov 10.
Memory effects, including shape, chirality, and liquid-crystallinity, have enabled macroscopic materials with novel functions. However, the generation of complex supramolecular nanosystems via memory effects has not yet been investigated. Here, we report a cyclotriveratrylene-crown (CTV) compound that self-assembles into supramolecular columns and spheres forming, respectively, hexagonal and cubic mesophases. Upon transition from one phase to the other, an epitaxial relationship holds, via an unprecedented supramolecular orientational memory effect. Specifically, the molecular orientation and columnar character of supramolecular packing is preserved in the cubic phase, providing an otherwise inaccessible structure comprising orthogonally oriented domains of supramolecular columns. The continuous columnar character of tetrahedrally distorted supramolecular spheres self-organized from the CTV derivative in the faces of the Pm3̅n lattice is the basis of this supramolecular orientational memory, which holds throughout cycling in temperature between the two phases. This concept is expected to be general for other combinations of periodic and quasiperiodic arrays generated from supramolecular spheres upon transition to supramolecular columns.
记忆效应，包括形状、手性和液晶性，使具有新颖功能的宏观材料成为可能。然而，通过记忆效应产生复杂的超分子纳米系统尚未得到研究。在这里，我们报告了一种环三聚藜芦醇-冠醚（CTV）化合物，它自组装成超分子柱和球体，分别形成六方和立方相。在从一个相转变为另一个相时，通过前所未有的超分子取向记忆效应保持了外延关系。具体而言，在立方相中保留了超分子堆积的分子取向和柱状特征，提供了原本无法获得的结构，其中包含正交取向的超分子柱域。从 Pm3̅n 晶格面的 CTV 衍生物自组织形成的四面体扭曲超分子球体的连续柱状特征是这种超分子取向记忆的基础，这种记忆在两个相之间的温度循环中保持不变。预计这一概念对于其他周期性和准周期性阵列的组合也适用，这些组合是通过超分子球体向超分子柱的转变产生的。
