Tuning Proton Disorder in 3,5-Dinitrobenzoic Acid Dimers: the Effect of Local Environment
Tuning Proton Disorder in 3,5-Dinitrobenzoic Acid Dimers: the Effect of Local Environment
复制标题
调节 3,5-二硝基苯甲酸二聚体中的质子无序：局部环境的影响
DOI：
10.1021/cg300906j
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发表时间：
2013
影响因子：
3.8
通讯作者：
Chick C. Wilson
中科院分区：
文献类型：
--
作者：
Andrew O. F. Jones;N. Blagden;G. McIntyre;A. Parkin;C. Seaton;L. Thomas;Chick C. Wilson
羧酸二聚体是晶体工程和设计中经常观察到的分子间缔合体，其氢键上的质子无序。苯甲酸二聚体中的质子无序是一个动态的、温度依赖性的过程，其发生的报道仍然相对罕见。变温 X 射线和中子衍射的组合已被应用于证明局部结晶环境对 3,5-二硝基苯甲酸二聚体中质子无序程度和开始的影响。发现具有显着不对称局部分子间相互作用的二聚体具有更高的占据待观察的第二个氢原子位点的起始温度，表明两种构型之间更大的能量不对称性。使用高分辨率 X 射线衍射数据直接可视化这些二聚体中氢原子的电子密度来表征这种无序，结果表明与中子数据得出的结果非常一致。
The carboxylic acid dimer is a frequently observed intermolecular association used in crystal engineering and design, which can show proton disorder across its hydrogen bonds. Proton disorder in benzoic acid dimers is a dynamic, temperature-dependent process whose reported occurrence is still relatively rare. A combination of variable temperature X-ray and neutron diffraction has been applied to demonstrate the effect of local crystalline environment on both the degree and onset of proton disorder in 3,5-dinitrobenzoic acid dimers. Dimers which have significantly asymmetric local intermolecular interactions are found to have a higher onset temperature for occupation of a second hydrogen atom site to be observed, indicating a greater energy asymmetry between the two configurations. Direct visualization of the electron density of hydrogen atoms within these dimers using high resolution X-ray diffraction data to characterize this disorder is shown to provide remarkably good agreement with that derived from neutron data.