Jain Prashant, Dalal Naresh S, Toby Brian H, Kroto Harold W, Cheetham Anthony K
Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA.
J Am Chem Soc. 2008 Aug 13;130(32):10450-1. doi: 10.1021/ja801952e. Epub 2008 Jul 18.
[(CH3)2NH2]Zn(HCOO)3, 1, adopts a structure that is analogous to that of a traditional perovskite, ABX3, with A = [(CH3)2NH2], B = Zn, and X = HCOO. The hydrogen atoms of the dimethyl ammonium cation, which hydrogen bond to oxygen atoms of the formate framework, are disordered at room temperature. X-ray powder diffraction, dielectric constant, and specific heat data show that 1 undergoes an order-disorder phase transition on cooling below 156 K. We present evidence that this is a classical paraelectric to antiferroelectric phase transition that is driven by ordering of the hydrogen atoms. This sort of electrical ordering associated with order-disorder phase transition is unprecedented in hybrid frameworks and opens up an exciting new direction in rational synthetic strategies to create extended hybrid networks for applications in ferroic-related fields.
[(CH₃)₂NH₂]Zn(HCOO)₃（1）具有一种类似于传统钙钛矿ABX₃的结构，其中A = [(CH₃)₂NH₂]，B = Zn，X = HCOO。在室温下，与甲酸盐骨架的氧原子形成氢键的二甲基铵阳离子的氢原子是无序的。X射线粉末衍射、介电常数和比热数据表明，1在冷却至156 K以下时会发生有序-无序相变。我们提供的证据表明，这是一种由氢原子有序化驱动的经典顺电到反铁电相变。这种与有序-无序相变相关的电有序现象在混合框架中是前所未有的，并为合理的合成策略开辟了一个令人兴奋的新方向，以创建用于铁电相关领域应用的扩展混合网络。
