中科院福建物构所的孙庆福研究小组近日通过可控自组装开发出一种三联双笼，并可通过响应多种外界刺激相互转换。这一研究成果发表在2021年1月20日出版的国际学术期刊《美国化学会志》上。

研究人员通过可控自组装合成了三个拓扑学上前所未有地互相联结的双笼，即一个以订书针方式互锁的Pd₁₂L₆笼（2）和两个螺旋异构的Pd₆L₃笼（3和4），它们是以同样的顺式封端的钯作为顶角的，并具有一个新的双齿配体（1）。

笼2具有三个机械偶联的空腔，而笼3和笼4则是基于同样金属/配体化学计量比的拓扑学异构的螺旋样双笼。笼2的单独形成或笼3和笼4的动态混合物可通过改变自组装时使用的溶剂来控制。笼3和笼4之间的结构切换可以被温度/溶剂的改变和诱导适应的客体分子包埋所触发。在这样的拓扑学复杂的超结构之间实现可控切换为在开关系统中获得一系列功能性打下了坚实的基础。

研究人员表示，离散配位超分子体系结构之间的刺激响应结构转变不仅是构建智能功能材料必不可少的，而且还提供了模仿生物学转化过程的多功能分子级平台。

附：英文原文

Title: Controlled Self-Assembly and Multistimuli-Responsive Interconversions of Three Conjoined Twin-Cages

Author: Li-Xuan Cai, Dan-Ni Yan, Pei-Ming Cheng, Jin-Jin Xuan, Shao-Chuan Li, Li-Peng Zhou, Chong-Bin Tian, Qing-Fu Sun

Issue&Volume: January 20, 2021

Abstract: Stimuli-responsive structural transformations between discrete coordination supramolecular architectures not only are essential to construct smart functional materials but also provide a versatile molecular-level platform to mimic the biological transformation process. We report here the controlled self-assembly of three topologically unprecedented conjoined twin-cages, i.e., one stapled interlocked Pd12L6 cage (2) and two helically isomeric Pd6L3 cages (3 and 4) made from the same cis-blocked palladium corners and a new bis-bidentate ligand (1). While cage 2 features three mechanically coupled cavities, cages 3 and 4 are topologically isomeric helicate-based twin-cages based on the same metal/ligand stoichiometry. Sole formation of cage 2 or a dynamic mixture of cages 3 and 4 can be controlled by changing the solvents employed during the self-assembly. Structural conversions between cages 3 and 4 can be triggered by changes in both temperature/solvent and induced-fit guest encapsulations. Well-controlled interconversion between such topologically complex superstructures may lay a solid foundation for achieving a variety of functions within a switchable system.

DOI: 10.1021/jacs.0c12064

Source: https://pubs.acs.org/doi/10.1021/jacs.0c12064