Soszka N, Hachuła B, Tarnacka M, Grelska J, Jurkiewicz K, Geppert-Rybczyńska M, Wrzalik R, Grzybowska K, Pawlus S, Paluch M, Kamiński K
Institute of Chemistry, Faculty of Science and Technology, University of Silesia in Katowice, Szkolna 9, 40-006 Katowice, Poland; Institute of Physics, Faculty of Science and Technology, University of Silesia in Katowice, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland.
Institute of Chemistry, Faculty of Science and Technology, University of Silesia in Katowice, Szkolna 9, 40-006 Katowice, Poland.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Aug 5;276:121235. doi: 10.1016/j.saa.2022.121235. Epub 2022 Apr 6.
In this paper, the steric hindrance effect related to the presence of either a cyclic or aromatic ring on the self-association process in the series of monohydroxy alcohols (MAs), from cyclohexanemethanol to 4-cyclohexyl-1-butanol and from benzyl alcohol to 4-phenyl-1-butanol, was studied using X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) spectroscopy, Broadband Dielectric Spectroscopy (BDS) and the Pendant Drop (PD) methods. Based on FTIR results, it was shown that phenyl alcohol (PhA) and cyclohexyl alcohol (CA) derivatives reveal substantial differences in the association degree, the activation energy of dissociation, and the homogeneity of supramolecular nanoassociates suggesting that the phenyl ring exerts a stronger steric impact on the self-assembling of molecules than cyclohexyl one. Additionally, XRD data revealed that phenyl moiety introduces more heterogeneity in the organization of molecules compared to the cyclic one. The changes in the self-association process of alcohols were also reflected in differences in the molecular dynamics of the H-bonded aggregates, as well as in the Kirkwood factor, defining the long-range correlation between dipoles, which were slightly higher for CAs with respect to those determined for PhAs. Unexpectedly it was also found that the surface layers of PhAs were more organized than those formed by CAs. Thus, these findings provided insight into the impact of aromaticity on the self-assembly process, H-bonding pattern, supramolecular structure, and intermolecular dynamics of the studied alcohols.
在本文中，利用X射线衍射（XRD）、差示扫描量热法（DSC）、傅里叶变换红外（FTIR）光谱、宽带介电谱（BDS）和悬滴法（PD），研究了在从环己甲醇到4-环己基-1-丁醇以及从苯甲醇到4-苯基-1-丁醇的单羟基醇（MAs）系列中，与环状或芳香环的存在相关的空间位阻效应在自缔合过程中的作用。基于FTIR结果表明，苯甲醇（PhA）和环己醇（CA）衍生物在缔合程度、解离活化能和超分子纳米缔合体的均匀性方面表现出显著差异，这表明苯环比环己基对分子自组装的空间影响更强。此外，XRD数据显示，与环状部分相比，苯基部分在分子组织中引入了更多的不均匀性。醇类自缔合过程的变化也反映在氢键聚集体分子动力学的差异以及定义偶极子之间长程相关性的柯克伍德因子的差异上，CA的这些因子相对于PhA的略高。出乎意料的是，还发现PhA的表面层比CA形成的表面层更有序。因此，这些发现为芳香性对所研究醇类的自组装过程、氢键模式、超分子结构和分子间动力学的影响提供了深入了解。
