Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, United States.
J Phys Chem B. 2021 Jul 8;125(26):7177-7186. doi: 10.1021/acs.jpcb.1c01692. Epub 2021 Jun 28.
The unique properties of deep eutectic solvents make them useful in a variety of applications. In this work we develop a first-principles force field for reline, which is composed of choline chloride and urea in the molar ratio 1:2. We start with the symmetry adapted perturbation theory (SAPT) protocol and then make adjustments to better reproduce the structure and dynamics of the liquid when compared to first-principles molecular dynamics (FPMD) simulations. The resulting force field is in good agreement with experiments in addition to being consistent with the FPMD simulations. The simulations show that primitive molecular clusters are preferentially formed with choline-chloride ionic pairs bound with a hydrogen bond in the hydroxyl group and that urea molecules coordinate the chloride mainly via the trans-H chelating hydrogen bonds. Incorporating polarizability qualitatively influences the radial distributions and lifetimes of hydrogen bonds and affects long-range structural order and dynamics. The polarizable force field predicts a diffusion constant about an order of magnitude larger than the nonpolarizable force field and is therefore computationally intensive. We hope this study paves the way for studying complex hydrogen-bonding liquids from a first-principles approach.
深共晶溶剂的独特性质使它们在各种应用中非常有用。在这项工作中，我们开发了一种用于 reline 的第一性原理力场，它由摩尔比为 1:2 的氯化胆碱和尿素组成。我们从对称适应微扰理论（SAPT）协议开始，然后进行调整，以更好地再现液体的结构和动力学，与第一性原理分子动力学（FPMD）模拟相比。除了与 FPMD 模拟一致外，所得力场与实验也非常吻合。模拟表明，原始分子簇优先形成，其中胆碱-氯化物离子对与羟基中的氢键结合，而尿素分子主要通过反式-H 螯合氢键配位氯离子。考虑极化率定性地影响氢键的径向分布和寿命，并影响远程结构有序性和动力学。极化力场预测扩散常数比非极化力场大约大一个数量级，因此计算量很大。我们希望这项研究为从第一性原理方法研究复杂氢键液体铺平道路。
