Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University , Tianjin 300071, P.R. China.
Acc Chem Res. 2014 Jul 15;47(7):1925-34. doi: 10.1021/ar500009g. Epub 2014 Mar 25.
Developments in macrocyclic chemistry have led to supramolecular chemistry, a field that has attracted increasing attention among researchers in various disciplines. Notably, the discoveries of new types of macrocyclic hosts have served as important milestones in the field. Researchers have explored the supramolecular chemistry of several classical macrocyclic hosts, including crown ethers, cyclodextrins, calixarenes, and cucurbiturils. Calixarenes represent a third generation of supramolecular hosts after cyclodextrins and crown ethers. Easily modified, these macrocycles show great potential as simple scaffolds to build podand-like receptors. However, the inclusion properties of the cavities of unmodified calixarenes are not as good as those of other common macrocycles. Calixarenes require extensive chemical modifications to achieve efficient endo-complexation. p-Sulfonatocalix[n]arenes (SCnAs, n = 4-8) are a family of water-soluble calixarene derivatives that in aqueous media bind to guest molecules in their cavities. Their cavities are three-dimensional and π-electron-rich with multiple sulfonate groups, which endow them with fascinating affinities and selectivities, especially toward organic cations. They also can serve as scaffolds for functional, responsive host-guest systems. Moreover, SCnAs are biocompatible, which makes them potentially useful for diverse life sciences and pharmaceutical applications. In this Account, we summarize recent work on the recognition and assembly properties unique to SCnAs and their potential biological applications, by our group and by other laboratories. Initially examining simple host-guest systems, we describe the development of a series of functional host-guest pairs based on the molecular recognition between SCnAs and guest molecules. Such pairs can be used for fluorescent sensing systems, enzymatic activity assays, and pesticide detoxification. Although most macrocyclic hosts prevent self-aggregation of guest molecules, SCnAs can induce self-aggregation. Researchers have exploited calixarene-induced aggregation to construct supramolecular binary vesicles. These vesicles respond to internal and external stimuli, including temperature changes, redox reactions, additives, and enzymatic reactions. Such structures could be used as drug delivery vehicles. Although several biological applications of SCnAs have been reported, this field is still in its infancy. Continued exploration of the supramolecular chemistry of SCnAs will not only improve the existing biological functions but also open new avenues for the use of SCnAs in the fields of biology, biotechnology, and pharmaceutical research. In addition, we expect that other interdisciplinary research efforts will accelerate developments in the supramolecular chemistry of SCnAs.
大环化学的发展催生了超分子化学，这一领域吸引了各学科研究人员越来越多的关注。值得注意的是，新型大环主体的发现是该领域的重要里程碑。研究人员探索了几种经典大环主体的超分子化学，包括冠醚、环糊精、杯芳烃和瓜环。杯芳烃是继环糊精和冠醚之后的第三代超分子主体。这些大环可以很容易地进行修饰，作为构建类似荚醚受体的简单支架具有很大的潜力。然而，未修饰杯芳烃空腔的包容性能不如其他常见的大环。杯芳烃需要进行广泛的化学修饰才能实现有效的内配合。对磺酸钠杯[n]芳烃（SCnAs，n=4-8）是一类水溶性杯芳烃衍生物，在水介质中，它们的空腔可以与客体分子结合。它们的空腔是三维的，富π电子，并带有多个磺酸基，这赋予它们迷人的亲和力和选择性，特别是对有机阳离子。它们还可以作为功能响应的主体-客体体系的支架。此外，SCnAs具有生物相容性，这使得它们在各种生命科学和药物应用中具有潜在的用途。在本综述中，我们总结了我们小组和其他实验室最近在 SCnAs 的独特识别和组装特性及其潜在生物学应用方面的工作。最初研究简单的主客体体系，我们描述了一系列基于 SCnAs 与客体分子之间分子识别的功能主客体对的发展。这样的对可以用于荧光传感体系、酶活性测定和农药解毒。虽然大多数大环主体可以阻止客体分子的自聚集，但 SCnAs 可以诱导自聚集。研究人员利用杯芳烃诱导的聚集来构建超分子二元囊泡。这些囊泡对外界和内部刺激有响应，包括温度变化、氧化还原反应、添加剂和酶反应。这些结构可以用作药物输送载体。尽管已经有报道称 SCnAs 具有几种生物学应用，但该领域仍处于起步阶段。对 SCnAs 超分子化学的进一步探索不仅将提高现有的生物学功能，而且为 SCnAs 在生物学、生物技术和药物研究领域的应用开辟新的途径。此外，我们预计其他跨学科研究工作将加速 SCnAs 超分子化学的发展。
