MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
Nat Commun. 2013;4:2534. doi: 10.1038/ncomms3534.
Host-guest composites may exhibit abnormal and/or controllable physical properties that are unavailable for traditional solids. However, it is still very difficult to control or visualize the occupancy and motion of the guest. Here we report a flexible ultramicroporous coordination polymer showing exceptional guest-responsive thermal-expansion properties. The vacant crystal exhibits constant and huge thermal expansion over a wide temperature range not only in vacuum but also in air, as its ultramicroporous channel excludes air adsorption even at 77 K. More interestingly, as demonstrated by single-crystal X-ray crystallography, molecular dynamic simulations and solid-state nuclear magnetic resonance, it selectively responds to the molecular rearrangement of N,N-dimethylformamide, leading to conformation reversion of the flexible ligand, which transfers these actions to deform the whole crystal lattice. These results illustrate that combination of ultramicroporous channel and flexible pore surface could be an effective strategy for the utilization of external physical and chemical stimuli.
主体-客体复合材料可能表现出异常和/或可控制的物理性质，这些性质在传统固体中是不存在的。然而，要控制或可视化客体的占据和运动仍然非常困难。在这里，我们报告了一种具有优异客体响应热膨胀性能的柔性超微孔配位聚合物。在真空和空气中，空晶体在很宽的温度范围内表现出恒定且巨大的热膨胀，这是因为其超微孔通道甚至在 77 K 时也排除了空气吸附。更有趣的是，正如单晶 X 射线晶体学、分子动力学模拟和固态核磁共振所证明的那样，它选择性地响应 N，N-二甲基甲酰胺的分子重排，导致柔性配体的构象反转，从而将这些作用传递到整个晶格的变形。这些结果表明，超微孔通道和柔性孔表面的结合可能是利用外部物理和化学刺激的有效策略。
