Dibutylammonium Hydrogen Oxalate: An Above-Room-Temperature Order鈥揇isorder Phase Transition Molecular Material

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• 作者：Tariq Khan ; Yuanyuan Tang ; Zhihua Sun ; Shuquan Zhang ; Muhammad Adnan Asghar ; Tianliang Chen ; Sangen Zhao ; Junhua Luo
• 刊名：Crystal Growth & Design
• 出版年：2015
• 出版时间：November 4, 2015
• 年：2015
• 卷：15
• 期：11
• 页码：5263-5268
• 全文大小：438K
• ISSN：1528-7505

文摘

An above-room-temperature new phase transition molecular material, dibutylammonium hydrogen oxalate (1), has been synthesized, which undergoes a reversible phase transition at 321.6 K. Differential scanning calorimetry (DSC) measurements confirm its reversible phase transition with a large heat hysteresis of 鈭?0 K. The dielectric constants of 1 exhibit an obvious step-like anomaly, showing the high and low dielectric constant states at high and room-temperature phases, respectively, which reveal that 1 might be considered a potential switchable dielectric material. Variable-temperature single crystal X-ray diffraction analyses disclose that the origin of this phase transition is greatly attributed to the coupling of the order鈥揹isorder change and reorientation of the dibutylammonium cation; that is, the frozen ordering of ethyl group in butyl moiety triggered by the decreasing temperature forces the reorientation of cation, thus resulting in the structural phase transition.