Shi Chao, Zhang Xi, Yu Chun-Hua, Yao Ye-Feng, Zhang Wen
Ordered Matter Science Research Center and Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, 211189, Nanjing, China.
Department of Physics & Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, East China Normal University, North Zhongshan Road 3663, 200062, Shanghai, China.
Nat Commun. 2018 Feb 2;9(1):481. doi: 10.1038/s41467-018-02931-8.
Deuteration of a hydrogen bond by replacing protium (H) with deuterium (D) can cause geometric changes in the hydrogen bond, known as the geometric H/D isotope effect (GIE). Understanding the GIEs on global structures and bulk properties is of great importance to study structure-property relationships of hydrogen-bonded systems. Here, we report a hydrogen-bonded host-guest crystal, imidazolium hydrogen terephthalate, that exemplifies striking GIEs on its hydrogen bonds, phases, and bulk dielectric transition property. Upon deuteration, the donor-acceptor distance in the O-H···O hydrogen bonds in the host structure is found to increase, which results in a change in the global hydrogen-bonded supramolecular structure and the emergence of a new phase (i.e., isotopic polymorphism). Consequently, the dynamics of the confined guest, which depend on the internal pressure exerted by the host framework, are substantially altered, showing a downward shift of the dielectric switching temperature.
通过用氘（D）取代氢（H）对氢键进行氘代会导致氢键发生几何变化，这被称为几何H/D同位素效应（GIE）。了解关于整体结构和体相性质的GIE对于研究氢键体系的结构-性质关系非常重要。在此，我们报道了一种氢键主客体晶体，对苯二甲酸咪唑鎓盐，它在其氢键、相和体相介电转变性质方面表现出显著的GIE。氘代后，发现主体结构中O-H···O氢键的供体-受体距离增加，这导致整体氢键超分子结构发生变化，并出现新的相（即同位素多晶型）。因此，取决于主体框架施加的内部压力的受限客体的动力学被显著改变，表现为介电开关温度的向下移动。
