Gatiatulin Askar K, Osel'skaya Viktoria Yu, Ziganshin Marat A, Gorbatchuk Valery V
A. M. Butlerov Institute of Chemistry, Kazan Federal University 18 Kremlyovskaya Str. Kazan 420008 Russia
RSC Adv. 2019 Nov 20;9(65):37778-37787. doi: 10.1039/c9ra08710a. eCollection 2019 Nov 19.
Hydration history was found to control the inclusion capacity of α-cyclodextrin (aCD) for volatile organic guests, so that its level may be switched from zero to the stoichiometric value and back by the variation of aCD hydration/dehydration order and direction. Such variation of the inclusion capacity is caused by the balance of two water roles: the activation of guest inclusion and guest/water competition. These observed concurrent roles and the cooperativity of guest inclusion and hydration make possible the smart tuning of the guest inclusion by the subtle change of preparation procedure. Depending on the hydration history, aCD was shown to form hydrates with the same water contents but different packing types and different kinetics of dehydration, which correlates with their different inclusion capacities for organic guests. This correlation reveals how the "high-energy" and "low-energy" water works in the guest inclusion by aCD, which may be relevant for other cyclodextrins and hydrophilic receptors of biomimetic and biological natures. The results can help to rationalize the technologies of producing various inclusion compounds of cyclodextrins.
研究发现，水合历史可控制α-环糊精（αCD）对挥发性有机客体的包合能力，因此通过改变αCD的水合/脱水顺序和方向，其包合水平可在零至化学计量值之间切换并再切换回来。包合能力的这种变化是由水的两种作用的平衡引起的：客体包合的活化作用和客体/水的竞争作用。这些观察到的同时存在的作用以及客体包合与水合的协同作用，使得通过制备程序的细微变化对客体包合进行智能调控成为可能。根据水合历史，αCD可形成具有相同含水量但堆积类型不同且脱水动力学不同的水合物，这与其对有机客体的不同包合能力相关。这种相关性揭示了“高能”水和“低能”水在αCD客体包合过程中的作用方式，这可能与其他环糊精以及具有仿生和生物性质的亲水性受体有关。这些结果有助于使生产各种环糊精包合化合物的技术合理化。
