大连理工大学孟银杉团队报道了维铁（II）配合物中吡唑啉环的自旋交叉调谐旋转获得协同的磁性和介电跃迁。相关研究成果发表在2022年6月26日出版的国际学术期刊《德国应用化学》。
显示磁性和介电跃迁协同作用的材料是未来分子器件的候选材料。面临的挑战是如何通过对外部刺激的反应实现自旋和介电跃迁之间的协同作用。
该文中，研究人员设计了一种二维自旋交叉（SCO）配合物[Fe II (dpa)][(pzTp)FeIII(CN)3]2(1) （dpa=1,2-双（4-吡啶基）乙炔，pzTp=四（吡唑基）硼酸盐）。Fe II离子的局部结构变化通过刚性桥联配体（dpa）传播到整个晶体，导致弹性相互作用，从而实现[（pzTp）FeIII（CN）3]单元中极性顶端吡唑环的突然SCO和旋转运动。介电测量证实，自旋跃迁后发生了实质性的介电变化（Δε'=2.3）。
该项工作为耦合极性元件的自旋跃迁和旋转提供了一种合理的策略，这对于磁和介电的协同切换至关重要。
附：英文原文
Title: Spin-Crossover Tuned Rotation of Pyrazolyl Rings in a 2D Iron(II) Complex towards Synergetic Magnetic and Dielectric Transitions
Author: Wen Wen, Qiang Liu, Shi-Hui Zhang, Nian-Tao Yao, Hiroki Oshio, Yin-Shan Meng, Tao Liu
Issue&Volume: 2022-06-26
Abstract: Materials showing synergy of magnetic and dielectric transitions are promising candidates for future molecular devices. The challenge is how to realize synergy between spin and dielectric transitions with responses to external stimuli. Herein, we design a 2D spin crossover (SCO) complex, [Fe II (dpa)][(pzTp)Fe III (CN) 3 ] 2 ( 1 ) (dpa = 1,2-bis(4-pyridyl)ethyne and pzTp = tetrakis(pyrazolyl)borate). The local structural changes about the Fe II ion were propagated to the whole crystal through the rigid bridging ligands (dpa), leading to elastic interactions to realize the abrupt SCO and rotational movements of polar apical pyrazolyl rings in the [(pzTp)Fe III (CN) 3 ] units. Dielectric measurements confirmed a substantial dielectric change ( Δε' = 2.3) upon the spin transition. This work provides a rational strategy to couple the spin transition and rotation of polar components, which is crucial for the synergetic switch of magnetism and dielectricity.
DOI: 10.1002/anie.202208886
Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202208886
