Dipolar order in an amphidynamic crystalline metal–organic framework through reorienting linkers
Dipolar order in an amphidynamic crystalline metal–organic framework through reorienting linkers
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DOI：
10.1038/s41557-020-00618-6
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发表时间：
2021-02
期刊：
影响因子：
21.8
通讯作者：
Y.-S. Su;E. Lamb;I. Liepuoniute;A. Chronister;A. L. Stanton;P. Guzman;S. Pérez-Estrada;T. Chang;K. Houk;M. Garcia‐Garibay;S. Brown
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文献类型：
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作者：
Y.-S. Su;E. Lamb;I. Liepuoniute;A. Chronister;A. L. Stanton;P. Guzman;S. Pérez-Estrada;T. Chang;K. Houk;M. Garcia‐Garibay;S. Brown
具有结晶性和支持动力学行为的两亲晶体非常适合于探索由动力学部分上的耦合引起的涌现现象。在这里，偶极转子已嵌入在结晶金属有机框架。该材料由Zn（ii）节点和两种类型的ditopic双环[2.2.2]辛烷为基础的接头，一个协调的锌簇通过两个1，4-氮杂部分，和一个二氟官能化的衍生物（偶极转子），协调通过连接的1，4-二羧酸基团，而不是。在冷却时，这些连接体由于相关的偶极-偶极相互作用而共同有序。变温，频率依赖性的介电测量揭示了一个transition temperatureTc= 100 K，当一个快速旋转，偶极无序，顺电相转变成一个有序的，反铁电的旋转链接的偶极矩在很大程度上相互抵消。在二维旋转晶格上的Monte Carlo模拟显示了基态的伊辛对称性和偶极-晶格和偶极-偶极相互作用的影响。
Amphidynamic crystals, which possess crystallinity and support dynamic behaviours, are very well suited to the exploration of emergent phenomena that result from the coupling on the dynamic moieties. Here, dipolar rotors have been embedded in a crystalline metal–organic framework. The material consists of Zn(ii) nodes and two types of ditopic bicyclo[2.2.2]octane-based linkers—one that coordinates to the Zn clusters through two 1,4-aza moieties, and a difluoro-functionalized derivative (the dipolar rotor) that coordinates through linked 1,4-dicarboxylate groups instead. Upon cooling, these linkers collectively order as a result of correlated dipole–dipole interactions. Variable-temperature, frequency-dependent dielectric measurements revealed a transition temperatureTc= 100 K, when a rapidly rotating, dipole-disordered, paraelectric phase transformed into an ordered, antiferroelectric one in which the dipole moments of the rotating linkers largely cancelled each other. Monte Carlo simulations on a two-dimensional rotary lattice showed a ground state with an Ising symmetry and the effects of dipole–lattice and dipole–dipole interactions.