An elastic metal-organic crystal with a densely catenated backbone
An elastic metal-organic crystal with a densely catenated backbone
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DOI：
10.1038/s41586-021-03880-x
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发表时间：
2021-10-14
期刊：
影响因子：
64.8
通讯作者：
Sato, Hiroshi
中科院分区：
文献类型：
--
作者：
Meng, Wenjing;Kondo, Shun;Sato, Hiroshi
自20世纪70年代首次报道聚链烷和聚轮烷以来，对于由互锁主链组成的材料，可以预期什么特定的机械性能一直是材料科学中的一个长期问题（1-3）。在这里，我们报告了一个三维多孔金属有机晶体，这是例外，因为它的经线和纬线连接只有通过连锁。这种多孔晶体由四方晶格组成，并且在客体分子释放、吸收和交换时，以及即使在低温范围内也在温度变化时动态地改变其几何形状。我们将晶体（4）沿其a/B轴沿着缩进，并获得在N，N-二甲基甲酰胺中为1.77 +/- 0.16 GPa和在四氢呋喃中为1.63 +/- 0.13 GPa的杨氏模量，这是迄今为止报道的多孔金属有机晶体（5）中最低的。令我们惊讶的是，流体静力学压缩表明，这种弹性多孔晶体是最易变形的沿着其c轴，其中发生5%的收缩时，压缩到0.88 GPa没有结构恶化。在0.46 GPa下获得的晶体结构表明，链状大环收缩时会发生位移。我们预计我们的机械联锁分子为基础的设计是一个起点，多孔材料的发展与异国情调的机械性能。例如，可挤压的多孔晶体即将出现，它可能会解决实现客体吸收和释放的高能力的根本困难。据报道，一种橡胶状的金属有机晶体具有机械互锁的索烃骨架，这可以使客体分子易于吸收和释放。
What particular mechanical properties can be expected for materials composed of interlocked backbones has been a long-standing issue in materials science since the first reports on polycatenane and polyrotaxane in the 1970s(1-3). Here we report a three-dimensional porous metal-organic crystal, which is exceptional in that its warps and wefts are connected only by catenation. This porous crystal is composed of a tetragonal lattice and dynamically changes its geometry upon guest molecule release, uptake and exchange, and also upon temperature variation even in a low temperature range. We indented(4) the crystal along its a/b axes and obtained the Young's moduli of 1.77 +/- 0.16 GPa in N,N-dimethylformamide and 1.63 +/- 0.13 GPa in tetrahydrofuran, which are the lowest among those reported so far for porous metal-organic crystals(5). To our surprise, hydrostatic compression showed that this elastic porous crystal was the most deformable along its c axis, where 5% contraction occurred without structural deterioration upon compression up to 0.88 GPa. The crystal structure obtained at 0.46 GPa showed that the catenated macrocycles move translationally upon contraction. We anticipate our mechanically interlocked molecule-based design to be a starting point for the development of porous materials with exotic mechanical properties. For example, squeezable porous crystals that may address an essential difficulty in realizing both high abilities of guest uptake and release are on the horizon.A rubber-like, metal-organic crystal is reported with a mechanically interlocked catenane backbone, which could allow for easy guest molecule uptake and release.