东南大学熊仁根团队报道了C–F···K相互作用组装的同手性多铁氰基桥连双金属配合物。相关研究成果于2022年6月7日发表在《德国应用化学》。

氰基桥联双金属配合物因其结构多样、性质多样而备受关注。然而，同手性氰基桥联双金属配合物很少见，赋予它们铁电性一直是一个巨大的挑战。

该文中，通过引入客体手性阳离子与主体[KFe（CN）6]2^-框架之间的C–F··K相互作用，研究人员设计了三维氰基桥联双金属多铁性[R-和S-3-氟吡咯烷基]2[KFe（CN）6]（R-和S-3-FPC）。镜像对称振动圆二色性（VCD）信号显示了它们的对映体特征。298 K时，R和S-3-FPC在同一手性极性空间群P21中结晶。压电响应力显微镜（PFM）、偏光显微镜和温度相关的二次谐波（SHG）测量证明了它们的多铁性，即铁电性和铁弹性共存，符合222F2的Aizu标记。重要的是，R-3-FPC显示出优异的铁电性，饱和极化率高达9.4μC/cm²，远高于其他氰基桥联铁电体。

该工作为设计手性氰基桥联双金属铁电体和多铁电体提供了一条可行的途径。

附：英文原文

Title: Homochiral Multiferroic Cyanido-Bridged Dimetallic Complexes Assembled by C–F···K Interactions

Author: Yu Mao, Xiao-Gang Chen, Zhu-Xiao Gu, Zhi-Xu Zhang, Xian-Jiang Song, Ning Gu, Ren-Gen Xiong

Issue&Volume: 2022-06-07

Abstract: Cyanido-bridged dimetallic complexes have attracted substantial attention due to the variety of structures with various interesting properties. However, the homochiral cyanido-bridged dimetallic complexes are rare, and endowing them with ferroelectricity has long been a great challenge. Here, through the introduction of C–F···K interactions between the guest chiral cations and the host [KFe(CN)  6  ]  2–  framework, we design three-dimensional cyanido-bridged dimetallic multiferroics, [  R  - and  S  -3-fluoropyrrolidinium]  2  [KFe(CN)  6  ] (  R  - and  S  -3-FPC). The mirror-symmetric vibrational circular dichroism (VCD) signal demonstrates their enantiomeric feature.  R  - and  S  -3-FPC crystallize in the same chiral-polar space group  P  2  1  at 298 K. Piezoresponse force microscopy (PFM), polarizing optical microscopy, and temperature-dependent second-harmonic generation (SHG) measurements demonstrate their multiferroic properties that is the coexistence of ferroelectricity and ferroelasticity, in line with the Aizu notation of 222F2. Importantly, the  R  -3-FPC shows excellent ferroelectricity with saturated polarization up to 9.4  μ  C/cm  2  , much higher than those of other cyanido-bridged ferroelectrics. This work provides a viable way to design chiral cyanido-bridged dimetallic ferroelectrics and multiferroics.

DOI: 10.1002/anie.202204135

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202204135