Multifunctional Triggering by Solid-Phase Molecular Motion: Relaxor Ferroelectricity, Modulation of Magnetic Exchange Interactions, and Enhancement of Negative Thermal Expansion
Multifunctional Triggering by Solid-Phase Molecular Motion: Relaxor Ferroelectricity, Modulation of Magnetic Exchange Interactions, and Enhancement of Negative Thermal Expansion
复制标题
固相分子运动的多功能触发：弛豫铁电性、磁交换相互作用的调制以及负热膨胀的增强
DOI：
10.1021/acs.chemmater.2c03552
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发表时间：
2023
影响因子：
8.6
通讯作者：
Takayoshi
中科院分区：
文献类型：
--
作者：
Li;Simin; Takahashi;Kiyonori; Huang;Rui-Kang; Xue;Chen; Kokado;Kenta; Hoshino;Norihisa; Akutagawa;Tomoyuki; Nishihara;Sadafumi; Nakamura;Takayoshi
尽管近年来人工分子机器的发展引起了相当大的关注，但多功能固态分子机器的建设仍然面临着一些挑战。在这里，我们报告了一种超分子方法，作为建立多功能触发系统的有效策略。在由自旋OFS=1/2的[Ni(Dmit)2]−和由4-氨基吡啶+和苯并[18]冠-6组成的超分子结构组成的晶体中，具有动态自由度的超分子阳离子影响着晶体的磁性和介电性能，并导致负热膨胀。晶体中的超分子阳离子形成一维柱。相邻的两个柱通过苯并[18]冠-6的苯亚基之间的π···π相互作用形成超分子梯形结构，并排列在一个二维层内。在一个结晶学独立的苯并[18]冠-6中观察到苯环的两个位置之间的无序。无序的苯并[18]冠-6在晶体内形成极性域，导致弛豫铁电性。随着温度的升高，超分子梯形分子拉长，苯并[18]冠-6的平移运动使分子梯形分子相互靠近。结果表明，[Ni(Dmit)2]−晶体在垂直于梯形结构的方向上收缩，表现为单轴NTE，破坏了[Ni(Dmit)2]TiO4晶体之间的磁交换作用。
Although the development of artificial molecular machines has garnered considerable attention in recent years, the construction of multifunctional solid-state molecular machines still faces several challenges. Herein, we report a supramolecular approach as an efficient strategy for building multifunctional trigger systems. In crystals composed of [Ni(dmit)2]−with a spin ofS= 1/2 and supramolecular structures consisting of 4-aminopyridinium+and benzo[18]crown-6, supramolecular cations with dynamic degrees of freedom affect the magnetic and dielectric properties and induce negative thermal expansion (NTE). The supramolecular cations in the crystals form one-dimensional columns. Two adjacent columns form a supramolecular ladder structure via π···π interactions between the phenylene groups of benzo[18]crown-6 and are arranged within a two-dimensional layer. A disorder between the two sites of the phenylene ring was observed in one of the crystallographically independent benzo[18]crown-6. Disordered benzo[18]crown-6 formed polar domains within the crystal, resulting in relaxor ferroelectricity. With increasing temperature, the supramolecular ladders elongated and the translational motion of benzo[18]crown-6 caused the molecular ladder to move closer to each other. Consequently, the crystals shrunk in the direction perpendicular to the ladder, exhibiting uniaxial NTE, and the magnetic exchange interaction between the [Ni(dmit)2]−crystals was disrupted.