与外壁作用相关的瓜环基超分子化学

Supramolecular Chemistry Related to Outer Surface Interaction of Cucurbi[n]urils

自从2014年提出瓜环外壁作用的概念以来,促进了“瓜环外壁作用”相关的瓜环化学发展。瓜环外壁作用源于静电势呈正性的外壁与各种静电势呈负性的物种、阴离子以及含芳环有机分子等的相互作用,因而涉及多学科多领域。如外壁作用可驱动瓜环基超分子框架的构筑,根据作用方式的不同,包括:1)自身诱导外壁作用;2)阴离子诱导外壁作用;3)芳环诱导外壁作用等多种构筑方式,而所构筑的瓜环基超分子框架可能涉及到(杂)多酸化学、杯芳烃或柱芳烃化学等,同样也具有框架多孔材料特有的多相催化、吸附和离子交换等特性。设计和构建具有结构新颖和性质特异的瓜环基超分子框架,不仅能进一步扩展框架化学的研究内容,还能开辟新的研究方向。作为最重要的驱动力——自身诱导外壁作用能促使瓜环产生光致聚集发光,这是所有瓜环固有属性。瓜环在固体状态和溶液状态下呈现光致发光特性,而另外2种外壁作用——阴离子诱导和芳环诱导外壁作用则能削弱或改变瓜环聚集状态光致发光特性。这些外壁作用导致的瓜环聚集状态光致发光特性的差异恰好可用于不同阴离子或有机分子的响应,具有重要的基础研究价值和广泛的潜在应用前景。再者,瓜环的自身诱导外壁作用致使瓜环分子具有相互聚集的特性,加之瓜环端口羰基氧的亲水固有属性,因此瓜环还具有形成水凝胶的倾向,可能被应用于生物学、医学、保健等诸多领域。若结合瓜环的光致聚集发光特性,瓜环可形成光致发光的水凝胶。

Since the concept of outer surface interaction of cucurbit[n]urils(OSIQ)was proposed in 2014,the development of supramolecular chemistry related to OSIQ has been promoted.The OSIQ originates from the interaction between the electrostatic potential positive outer surface of cucurbit[n]urils(Q[n]s)and various species with negative electrostatic potential,anions and organic molecules containing aromatic rings.Therefore,it may involve a wide range of subjects and may be extended and applied in many fields.For example,the OSIQs could drive the construction of Q[n]-based supramolecular frameworks,depending on the different modes of action,including(1)self-induced OSIQ,(2)anion-induced OSIQ and(3)aromatic-induced OSIQ,can drive the construction of Q[n]-based supramolecular frameworks,which may involve polyoxometalic acid chemistry,calixarene and pillar[n]arene chemistry,etc.,and also have multiphase catalysis,adsorption and ion exchanges characteristics of framework porous materials.The design and construction of Q[n]-based supramolecular frameworks with novel structures and specific properties will not only further expand the research content of framework chemistry,but also open up new research directions.As the most important driving force,the self-induced OSIQ can cause Q[n]s to produce clustering-triggered emission,which is the inherent property of all Q[n]s.The clustering-triggered emission of Q[n]s in solid state and solution state was observed,while the anion-induced aromatic-induced OSIQs weakened or changed the clustering-triggered emission of Q[n].The differences in the clustering-triggered emission characteristics of Q[n]s caused by these OSIQs can be applied to the response of different anions or organic molecules,which has important basic research values and a wide range of potential applications.Moreover,the self-induced OSIQ leads to the aggregation of melon ring molecules and the hydrophilic nature of portal carbonyl oxygen atoms of Q[n]s,so Q[n]s also tends to form hydrogels,which may be applied in many fields such as biology,medicine and health care.If combined with the clustering-triggered emission of Q[n]s,Q[n]s can form luminescent hydrogels.