The influence of a disorder in cation substructure on proton conductivity of imidazolium malonate (Im‐MAL) is studied. Imidazolium in salts with dicarboxylic acids have been found to have a well ordered hydrogen‐bond network and only in Im‐MAL [Pogorzelec‐Glaser et al. (2006). Mater. Sci.‐Pol. (2006), 24, 245–252] were two types of cation observed: ordered Im‐I and disordered Im‐II. Im‐I is involved in hydrogen bonds with malonic acid molecules, whereas Im‐II is disordered between two symmetrically equivalent positions with occupancy of 0.5. NMR studies by Mizuno et al. [Hyperfine Interact. (2015), 230, 95–100] showed an 180° flip of ordered Im‐I and calculated contribution of Im‐I flipping to proton conductivity of Im‐MAL. Ławniczak et al. [Solid State Ionics (2017), 306, 25] reported that temperature variation of the proton conductivity by impedance spectroscopy yielded the conductivity value higher than that calculated by Mizuno for Im‐I. Moreover these detailed structure studies at 240 K and 280 K excluded any phase transition. Repeated X‐ray studies from 14 K to 360 K show a continuous increase in anisotropic displacement factors. The half‐occupied hydrogen bonds linking the Im‐II nitrogen atoms with hydroxyl oxygen atoms may be considered as electric dipoles and the interbond proton transfer as dipolar switching. It assumed here a coherent switching at low temperatures and a decrease of the coupling at higher temperatures with the disappearance at cross‐over temperature at 318 K. The possible proton pathway in the crystal structure is determined and the contribution of the proton dynamics of Im‐II to phonon‐assisted proton diffusion in the ordered substructure is estimated.

中文翻译：

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咪唑亚结构紊乱对丙二酸咪唑鎓盐中质子动力学的影响

研究了阳离子亚结构紊乱对丙二酸咪唑鎓（Im-MAL）质子电导率的影响。已发现二羧酸盐中的咪唑鎓具有良好有序的氢键网络，仅在Im-MAL中有效[Pogorzelec-Glaser等。（2006）。母校 科幻 （2006年），24，245-252]有两种类型阳离子的观察：有序IM-我和无序IM-II。Im‐I与丙二酸分子发生氢键结合，而Im‐II在两个对称当量位置之间杂乱无章，占有率为0.5。Mizuno等人的NMR研究。[超精细互动。（2015），230，95-100]显示了有序Im-I的180°翻转，计算出的Im-I翻转对Im-MAL的质子传导率的贡献。Ławniczak等。[固态离子学（2017），306[25]报道，通过阻抗谱分析质子电导率的温度变化产生的电导率值比美津浓为Im-I计算的值高。此外，这些在240 K和280 K的详细结构研究排除了任何相变。从14 K到360 K的重复X射线研究表明，各向异性位移因子不断增加。连接Im-II氮原子和羟基氧原子的半占氢键可被视为电偶极子，键间质子转移可被视为偶极子开关。这里假设低温下的相干开关和高温下的耦合减小，而在318 K的交叉温度下消失。