不对称苄基紫精与葫芦[8]脲包结行为的探究  

Inclusion Behaviors of Benzyl-Containing Asymmetric Viologen with Cucurbit[8]uril

作　　者：张锦锦 邹雷 王巧纯[1] ZHANG Jinjin;ZOU Lei;WANG Qiaochun(Key Laboratory for Advanced Materials,Institute of Fine Chemicals,School of Chemistry and Molecular Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学化学与分子工程学院,精细化工研究所,结构可控先进功能材料及其制备教育部重点实验室,上海200237

出　　处：《华东理工大学学报（自然科学版）》2022年第4期427-432,共6页Journal of East China University of Science and Technology

基　　金：国家自然科学基金(21572063)。

摘　　要：研究芳环取代紫精分子与葫芦[8]脲(CB[8])的包结模式,对进一步构建相关超分子聚合物,甚至是刺激响应型材料具有重要意义。选取不对称的1-乙基-1’-苄基-4,4’-联吡啶溴化盐(EBV),通过核磁共振氢谱(1H-NMR)、等温滴定量热法(ITC)和高分辨质谱(HRMS)等手段,详细考察了EBV与CB[8]在水中的包结行为。研究结果表明,EBV的苄基单元会进入CB[8]内腔中,在经历1∶1(EBV与CB[8]的物质的量之比)包结后,最终形成1个CB[8]分子包结2个苄基的1∶2超分子体系。其中1∶1包结过程的结合常数为(1.65±1.22)×10^(7)M^(−1)(1 M=1 mol/L,下同),整个过程的表观包结常数为(1.34±0.193)×10^(13)M^(−2),对应的ΔH和−TΔS分别为(−64.4±3.19)kJ/mol和−9.43 kJ/mol,表明该主客体组装行为是由焓和熵共同驱动的。Cucurbiturils(CB[n]s)is a hollow macrocyclic molecule formed by the condensation of glycoluril and formaldehyde under acidic conditions.The glycoluril units are linked together by methylene bridges,and the resulting cucurbiturils have hydrophobic cavity and polar carbonyl groups on both portals.Cucurbituril has strong inclusion ability for positively charged guest molecules such as protonated organic amines,pyridinium,and viologen.The study of the inclusion behaviors of aryl substituted viologen with cucurbit[8]uril urea(CB[8])is of great significance for the further construction of related supramolecular polymers as well as stimulus responsive materials.In this work,asymmetric 1-ethyl-1'-benzyl-4,4'-bipyridine bromide(EBV)was used to investigate its inclusion behaviors with CB[8]in aqueous solution by means of 1H-NMR spectroscopy,isothermal titration calorimetry(ITC)and high resolution electrospray ionization mass spectrometry(ESI-HRMS).The results showed that the benzyl unit of EBV firstly occupied the cavity of CB[8]to form a 1∶1 inclusion complex,and a 1∶2 supramolecular system where one CB[8]molecule encircled two benzyl groups ultimately forms.The binding constant of the first 1∶1 inclusion process was(1.65±1.22)×10^(7)M^(−1),and the correspondingΔH1 and−TΔS1 are(−26.2±1.26)kJ/mol and 14.6 kJ/mol,respectively.The apparent inclusion constant of the whole process was(1.34±0.193)×10^(13)M^(−2),and the correspondingΔH and−TΔS were(−64.4±3.19)kJ/mol and−9.43 kJ/mol,respectively,suggesting that the host-guest complexation was driven by both enthalpy and entropy.

关 键 词：超分子化学 葫芦脲 紫精 主客体作用 自组装 

分 类 号：O69[理学—化学]