反溶剂结晶的三步机制,Crystal Growth & Design

当前位置： X-MOL 学术 › Cryst. Growth Des. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

反溶剂结晶的三步机制
Crystal Growth & Design ( IF 3.2 ) Pub Date : 2022-04-20 , DOI: 10.1021/acs.cgd.2c00014
Anish V. Dighe ₁ , Prem K. R. Podupu ₁ , Paria Coliaie ₁ , Meenesh R. Singh ₁

Affiliation

结晶材料的合成涉及两种最重要的方法：反溶剂和冷却结晶。尽管反溶剂法在各种有机和无机晶体的结晶中得到了广泛的应用，但反溶剂在激活这一过程中的控制机制尚不完全清楚。在热力学上，已知抗溶剂会增加化学势，从而增加溶液中溶质的过饱和度，从而导致晶体成核和生长。众所周知，溶质分子在自组装形成晶体之前，必须离开溶剂化壳。在这里，我们展示了一种以前未被认识的反溶剂驱动去溶剂化的三步机制，其中反溶剂由于与溶质的相互作用而首先进入溶剂化壳，然后它的重组，然后由于排斥力从溶剂化壳中排出反溶剂 - 溶剂对。为了证实这一机制，在不同浓度的乙醇（反溶剂）和过饱和度下，对水（溶剂）中的组氨酸（溶质）进行了分子模拟。模拟揭示了乙醇与水合组氨酸的竞争性结合，然后将其去湿以允许显着的溶质-溶质相互作用以促进晶体生长。然后使用这三步机制获得组氨酸去溶剂化的激活屏障，然后使用计算成本低的半经典方法预测晶体生长速率。从激活屏障获得的增长率合理地再现了实验增长率，

"点击查看英文标题和摘要"

Three-Step Mechanism of Antisolvent Crystallization

Synthesis of crystalline materials involves the two most important methods: antisolvent and cooling crystallization. Despite the extensive use of the antisolvent method in the crystallization of various organic and inorganic crystals, the governing mechanism of the antisolvent in activating this process is not fully understood. Thermodynamically, the antisolvent is known to increase the chemical potential, and thereby supersaturation, of solute in the solution leading to crystal nucleation and growth. It is well-known that, before the solute molecules can self-assemble to form crystals, they must leave their solvation shell. Here, we show a previously unrecognized three-step mechanism of antisolvent-driven desolvation, where the antisolvent first enters the solvation shell due to attractive interactions with solute, followed by its reorganization and then expulsion of an antisolvent–solvent pair from the solvation shell due to repulsive forces. To confirm this mechanism, molecular simulations of histidine (solute) in water (solvent) at various concentrations of ethanol (antisolvent) and supersaturation are performed. The simulations reveal competitive binding of ethanol to hydrated histidine followed by its dewetting to allow significant solute–solute interactions for crystal growth. This three-step mechanism is then used to obtain an activation barrier for desolvation of histidine followed by prediction of crystal growth rates using a computationally inexpensive semiclassical approach. Growth rates obtained from the activation barrier reproduce the experimental growth rates reasonably, thereby validating the governing three-step mechanism for antisolvent crystallization.

更新日期：2022-04-20

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南