Institute of Optical Materials and Technologies "Acad. J. Malinowski", Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Faculty of Chemistry and Pharmacy, Sofia University "St. Kliment Ohridski", 1164 Sofia, Bulgaria.
Molecules. 2023 Feb 5;28(4):1540. doi: 10.3390/molecules28041540.
With the emergence of host-guest systems, a novel branch of complexation chemistry has found wide application in industries such as food, pharmacy, medicine, environmental protection and cosmetics. Along with the extensively studied cyclodextrins and calixarenes, the innovative cucurbiturils (CB) have enjoyed increased popularity among the scientific community as they possess even better qualities as cavitands as compared to the former molecules. Moreover, their complexation abilities could further be enhanced with the assistance of metal cations, which can interestingly exert a dual effect on the complexation process: either by competitively binding to the host entity or cooperatively associating with the CB@guest structures. In our previous work, two metal species (Mg and Ga) have been found to bind to CB molecules in the strongest fashion upon the formation of host-guest complexes. The current study focuses on their role in the complex formation with three dye molecules: thiazole orange, neutral red, and thioflavin T. Various key factors influencing the process have been recognized, such as pH and the dielectric constant of the medium, the cavity size of the host, M charge, and the presence/absence of hydration shell around the metal cation. A well-calibrated DFT methodology, solidly based and validated and presented in the literature experimental data, is applied. The obtained results shed new light on several aspects of the cucurbituril complexation chemistry.
随着主客体体系的出现，超分子化学这一分支在食品、制药、医学、环保和化妆品等行业得到了广泛的应用。与广泛研究的环糊精和杯芳烃相比，葫芦脲作为一种新型主体分子，因其具有更好的空腔性质，在科学界越来越受欢迎。此外，金属阳离子的辅助可以进一步增强其络合能力，这些金属阳离子对络合过程具有双重影响：可以通过与主体实体竞争结合，或者与 CB@客体结构协同结合。在我们之前的工作中，发现两种金属物种（Mg 和 Ga）在形成主客体络合物时以最强的方式结合到 CB 分子上。本研究重点研究它们在与三种染料分子（噻唑橙、中性红和硫堇 T）形成配合物中的作用。已经认识到影响该过程的各种关键因素，例如 pH 值和介质的介电常数、主体空腔大小、M 电荷以及金属阳离子周围是否存在水化壳。应用了一种经过良好校准的 DFT 方法，该方法基于并验证了文献中的实验数据。所得结果为葫芦脲络合化学的几个方面提供了新的见解。
