Acta Chimica Sinica ›› 2022, Vol. 80 ›› Issue (1): 44-48.

Article

### 对称二环己基取代六元瓜环与3-吡啶甲酰肼的超分子自组装

1. a贵州省煤炭产品质量监督检验院 六盘水 553001
b贵州大学精细化工研究开发中心 贵阳 550025
• 投稿日期:2021-10-19 发布日期:2021-11-18
• 通讯作者: 金艳梅

### Supramolecular Self-assembly of Symmetric Dicyclohexanocucurbit[6]uril and Nicotinic Hydrazide

Yanmei Jina(), Ye Mengb, Yuan Lia, Jianhua Shia, Lei Denga

1. aGuizhou Coal Product Quality Supervision & Inspection Institute, Liupanshui 553001, China
bCenter for Research and Development of Fine Chemicals, Guizhou University, Guiyang 550025, China
• Received:2021-10-19 Published:2021-11-18
• Contact: Yanmei Jin

Cucurbit[n]uril (Q[n]) is a relatively new supramolecular macrocyclic compound, which has a unique structure comprised of a hydrophobic cavity with intermediate potential, two carbonyl portals with negative potential, and an outer surface with positive potential. Cyclohexyl-substituted Q[n]s have also attracted a lot of attention as the first member of the Q[n] family that can be dissolved in organic solvents and water. In this paper, the interaction modes between the symmetric dicyclohexanocucurbit[6]uril (CyH2Q[6]) as a host and nicotinic hydrazide (NH) as a guest were investigated by nuclear magnetic resonance spectroscopy (1H NMR), isothermal titration calorimetry (ITC), matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry, and single-crystal X-ray diffraction. The 1H NMR spectrum results showed that the proton peaks shift to the downfield, indicating that NH is located at the portal of CyH2Q[6]. ITC experiment results showed that the binding constant (Ka) of NH@CyH2Q[6] is (1.019±0.118)×103 L•mol-1, the host-guest binding ratio is 0.954±0.013, and the enthalpy value is ΔH=(–48.21±0.35) kJ•mol-1 and entropy value TΔS=(–31.04±0.52) kJ•mol-1. The MALDI-TOF mass spectrum also showed that the molecular ion peak m/z is 1242.4542 (theoretical value: 1242.1603), which is attributed to [CyH2Q[6]•HNH]+. These experimental results showed that CyH2Q[6] formed a stable 1∶1 exclusion complex with NH in an aqueous solution. In addition, the host CyH2Q[6], ZnCl2 and the guest NH were added to HCl aqueous solution, and the complex single-crystal structure was obtained by evaporation and standing. The single-crystal structure of the complex showed that there are ion-dipole interactions and hydrogen bonds between the carbonyl oxygen of CyH2Q[6] and NH, and there are ion-dipole interactions between the outer surface of CyH2Q[6] and [ZnCl4]2-. These weak interactions are the driving forces of the multi-dimensional and multi-level supramolecular framework formed by the complex.