Ferroelectricity and polarity control in solid-state flip-flop supramolecular rotators
Ferroelectricity and polarity control in solid-state flip-flop supramolecular rotators
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DOI：
10.1038/nmat2377
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发表时间：
2009-04-01
期刊：
影响因子：
41.2
通讯作者：
Nakamura, Takayoshi
中科院分区：
文献类型：
--
作者：
Akutagawa, Tomoyuki;Koshinaka, Hiroyuki;Nakamura, Takayoshi
分子旋转在人工分子马达的开发中引起了广泛的关注，试图模仿生物分子马达的智能和有用的功能。分子链的随机运动--例如旋转单元的180度翻转运动--引起局部结构的旋转。在这里，我们表明，这样的运动是可控的，使用外部电场，并演示如何这样的分子旋转器可以被用作极化旋转单元中的铁电分子。特别地，间氟苯胺盐与二苯并[18]冠-6形成氢键组装，二苯并[18]冠-6作为[Ni（dmit）（2）]（-）阴离子的抗衡阳离子引入（dmit（2-）= 2-硫代-1，3-二硫杂环戊烯-4，5-二硫醇盐）。在外加电场作用下，间氟苯胺盐的超分子旋转体呈现偶极旋转，晶体在348 K发生铁电相变。这些发现将为铁电分子开辟新的策略，其中化学设计的偶极单元能够控制铁电转变温度的性质。
Molecular rotation has attracted much attention with respect to the development of artificial molecular motors, in an attempt to mimic the intelligent and useful functions of biological molecular motors. Random motion of molecular rotators-for example the 180 degrees flip-flop motion of a rotatory unit-causes a rotation of the local structure. Here, we show that such motion is controllable using an external electric field and demonstrate how such molecular rotators can be used as polarization rotation units in ferroelectric molecules. In particular, m-fluoroanilinium forms a hydrogen-bonding assembly with dibenzo[18]crown-6, which was introduced as the counter cation of [Ni(dmit)(2)](-) anions (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate). The supramolecular rotator of m-fluoroanilinium exhibited dipole rotation by the application of an electric field, and the crystal showed a ferroelectric transition at 348 K. These findings will open up new strategies for ferroelectric molecules where a chemically designed dipole unit enables control of the nature of the ferroelectric transition temperature.