Multi-step structural phase transitions with novel symmetry breaking and inverse symmetry breaking characteristics in a [Ag4I6]2 cluster hybrid crystal
Multi-step structural phase transitions with novel symmetry breaking and inverse symmetry breaking characteristics in a [Ag4I6]2 cluster hybrid crystal
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[Ag4I6]2 簇杂化晶体中具有新颖对称破缺和反对称破缺特性的多步结构相变
DOI：
10.1039/c9cc08394d
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Xiao-Ming Ren
中科院分区：
文献类型：
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作者：
Jin Zhang;Wan-Wan Yao;Lei Sang;Xue-Wei Pan;Xiao-Zu Wang;Wen-Long Liu;Lifeng Wang;Xiao-Ming Ren
本文制备了一种由（Pr-dabco）2Ag 4 I6簇合物（Pr-dabco+ = 1-丙基-1，4-二氮杂双环[2.2.2]辛烷-1-鎓）组成的多步相变杂化物，并通过显微分析、红外光谱、紫外-可见光谱、热重分析和差示扫描量热分析等技术对其进行了表征。相Ⅱ（P21/c空间群）和相Ⅲ（Pa空间群）之间的相变具有对称破缺（SB）性质，而相Ⅱ和相Ⅰ（Pbca空间群）之间的相变具有逆对称破缺（ISB）性质，在两个连续的相变中同时具有SB和ISB性质的物质是比较罕见的。最重要的是，每个相变都与介电异常有关，V相似乎是具有超高交流电导率（>10−2 S cm−1）的塑性晶体。我们的工作为在银杂化材料中寻找多相变材料开辟了新的途径。
In this study, a multi-step phase transition hybrid composed of (Pr-dabco)2Ag4I6 clusters (Pr-dabco+ = 1-propyl-1,4-diazabicyclo[2.2.2]octan-1-ium) has been prepared and characterized by microanalysis, IR and UV-vis spectroscopy, TG and DSC techniques, etc. This hybrid is thermally stable up to ∼486 K with five phases in the temperature region below 486 K. The phase transition shows symmetry breaking (SB) character between phases II (space group P21/c) and III (space group Pa), while inverse symmetry breaking (ISB) between phases II and I (space group Pbca), and it is rather exceptional for matter to exhibit simultaneously SB and ISB nature in two successive phase transitions. Most importantly, each phase transition is associated with a dielectric anomaly, and phase V appears to be a plastic crystal with extra high ac conductivity (>10−2 S cm−1). Our work opens up new avenues to find a multi-phase transition material in silver halide hybrids.