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 Pa3[combining macron]), 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.

中文翻译：

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[Ag4I6] 2-簇杂化晶体中具有新型对称破坏和反对称破坏特征的多步结构相变。

在这项研究中，由（Pr-dabco）2Ag4I6簇（Pr-dabco + = 1-丙基-1,4-二氮杂双环[2.2.2] octan-1-ium）组成的多步相变杂种已经制备并表征。通过显微分析，红外和紫外可见光谱，TG和DSC技术等，该混合物在高达486 K的温度下具有热稳定性，在486 K以下的温度区域内有五个相。相变显示相之间的对称破坏（SB）特性II（空间群P21 / c）和III（空间群Pa3 [结合宏]），而在相II和I（空间群Pbca）之间存在逆对称破坏（ISB），并且同时显示SB和两个连续相变中的ISB性质。最重要的是，每个相变都与电介质异常有关，相V似乎是具有超高交流电导率（> 10-2 S cm-1）的塑料晶体。我们的工作为在卤化银杂化物中寻找多相过渡材料开辟了新途径。