南昌大学化学学院（厉害）

近日，南昌大学本科生在国际顶级期刊《Journal of the American Chemical Society》上以“Directional Intermolecular Interactions for Precise Molecular Design of a High-Tc Multiaxial Molecular Ferroelectric”（通过分子间作用导向实现高温多轴分子铁电体的精准设计）为题发表论文。

本文是在南昌大学国际有序物质科学研究院、高等研究院、化学学院的协同指导下，由南昌大学高等研究院本科生杨陈凯、陈旺楠、丁燕婷、王静、饶崟共同完成。论文报道的是通过分子基团的修饰，首次实现了高温多轴分子铁电体的精准设计。

高等研究院学生在学习、讨论

分子铁电为跨学科研究方向，涉及到的学科包括化学、材料、物理、电子等，是目前最热门的研究课题。自2018年9月，高等研究院午间举办学术沙龙开讲多轴分子铁电体的报告后，该学院本科生对分子铁电产生了浓厚的兴趣。在通过个人兴趣申报以及学院选拔后，形成了由杨陈凯同学为负责人的挑战杯团队，研究课题为多轴分子铁电体。

团队成员在实验室合影

该团队对科研有极大的热情，并投入了大量的时间，利用课余、周末甚至国庆假期，开展一系列研究工作，期间受到国际有序物质科学研究院老师的大力帮助。

通过分子基团修饰把非铁电分子[Q]ClO4变成铁电分子[3-氧代奎宁]ClO4

历经数月的研究，该团队以居里对称性原理和诺埃曼原理为指导，基于分子设计和晶体工程思想，通过对奎宁的3号位进行基团修饰，得到了高温分子铁电体[3-氧代奎宁]ClO4，成功地实现了对多轴铁电分子的精准设计，并利用电滞回线测量和二阶倍频测试（SHG）等对铁电性进行了充分表征，研究发现该分子铁电相变温度高达457K，并且具有6个等同的分子铁电轴。

[3-O-Q]ClO4分子的铁电相关测试

这项研究中准球型分子和氢键导向作用设计铁电分子的思想，给多轴分子铁电体的发现开启了新篇章，也将大力推动更多功能性分子铁电材料的持续开发。

Directional Intermolecular Interactions for Precise Molecular Design of a High-Tc Multiaxial Molecular Ferroelectric

Chen-Kai Yang, Wang-Nan Chen, Yan-Ting Ding, Jing Wang, Yin Rao, Wei-Qiang Liao, Yongfa Xie, Wennan Zou, and Ren-Gen Xiong

J. Am. Chem. Soc., Just Accepted Manuscript

DOI: 10.1021/jacs.8b13223

Publication Date (Web): January 7, 2019

Quasi-spherical molecules have recently been developed as promising building blocks for constructing high-performance molecular ferroelectrics. However, although the modification of spherical molecules into quasi-spherical ones can efficiently lower the crystal symmetry, it is still a challenge to precisely arouse a low-symmetric polar crystal structure. Here, by introducing directional hydrogen-bonding interactions in the molecular modification, we successfully reduced the cubic centrosymmetric Pm3 ̅m space group of [quinuclidinium]ClO4 at room temperature to the orthorhombic polar Pna21 space group of [3-oxo-quinuclidinium]ClO4. Different from the substituent groups of –OH, –CH3, and =CH2, the adding of =O group with H-acceptor to [quinuclidinium]+ forms directionally N–H···O=C hydrogen-bonded chains, which plays a critical role in the generation of polar structure in [3-oxo-quinuclidinium]ClO4. Systematic characterization indicates that [3-oxo-quinuclidinium]ClO4 is an excellent molecular ferroelectric with a high Curie temperature of 457 K, a large saturate polarization of 6.7 μC/cm2, and a multiaxial feature of 6 equivalent ferroelectric axes. This work demonstrates that the strategy of combining quasi-spherical molecule building blocks with directional intermolecular interactions provides an efficient route to precisely design new eminent molecular ferroelectrics.