Stettler Allison, Baker Gary A, Blanchard G J
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States.
Department of Chemistry, University of Missouri-Columbia, Columbia, Missouri 65211, United States.
J Phys Chem B. 2025 Jun 26;129(25):6300-6308. doi: 10.1021/acs.jpcb.5c02468. Epub 2025 Jun 16.
We have examined the composition-dependent rotational diffusion dynamics of the chromophores perylene (neutral), oxazine 725 (cationic) and disodium fluorescein (anionic) in a series of choline chloride/1,3-propanediol (ChCl/PD) deep eutectic solvents (DESs). We find that the rotational diffusion dynamics of all chromophores do not correlate with the bulk viscosities of any of these ChCl/PD DES compositions, consistent with dynamic heterogeneity in all cases. Comparison with other DES systems─choline chloride/ethylene glycol (ChCl/EG) and choline chloride/glycerol (ChCl/Gly)─enables evaluation of the influence of hydrogen bond donor (HBD) structure and hydroxyl group density. This comparison highlights the critical role of hydrogen-bonded networks in these DESs and underscores the pivotal function of ChCl in disrupting these networks at ca. 15 mol % ChCl across all three DES systems. Taken collectively, these data point to the constituent structural factors that mediate the properties of DESs on local and bulk scales.
我们研究了一系列氯化胆碱/1,3 - 丙二醇（ChCl/PD）低共熔溶剂（DESs）中，发色团苝（中性）、恶嗪725（阳离子）和荧光素二钠（阴离子）的组成依赖性旋转扩散动力学。我们发现，所有发色团的旋转扩散动力学与这些ChCl/PD DES组成中的任何一种的本体粘度均不相关，这与所有情况下的动态不均匀性一致。与其他DES体系——氯化胆碱/乙二醇（ChCl/EG）和氯化胆碱/甘油（ChCl/Gly）——进行比较，能够评估氢键供体（HBD）结构和羟基密度的影响。这种比较突出了氢键网络在这些DESs中的关键作用，并强调了ChCl在所有三种DES体系中约15 mol% ChCl时破坏这些网络的关键作用。总体而言，这些数据指出了在局部和整体尺度上介导DESs性质的组成结构因素。
