The slightly water-soluble anticancer drug camptothecin (CPT) and its inclusion complexes with cucurbit[n = 7, 8]uril (Q[n] (n = 7, 8)) were investigated. The formation of 1:2 complexes with Q[n] (n = 7, 8) in aqueous solution was confirmed by fluorescence spectroscopy and the apparent stability constants were determined to be higher than 3.01 × 10 12 L 2 /mol 2 . The solid inclusion complexes of CPT and Q[n] (n = 7, 8) were also prepared by the co-evaporation method and characterized by Fourier transformation-infrared spectroscopy, differential scanning calorimetry and powder X-ray diffraction. Aqueous solubility and dissolution studies indicate that the complexes exhibited significantly increased dissolution rates compared with the pure drug and physical mixtures. The potential of Q[7] or Q[8] for stabilizing lactone modality of CPT was investigated by the High Performance Liquid Chromatography (HPLC) method. The results reveal more than 63% CPT lactone form (active form) in or Q[8] complexes compared to only 36% CPT lactone form in the absence of Q[7] or Q[8] after being incubated in the phosphate buffer solution (pH 7.4 at 37 °C) for 5 h. complexes, camptothecin, cucurbit[n]uril (n = 7, 8), dissolution properties, stability
In order to reduce the impact of CdS photogenerated electron-hole recombination on its photocatalytic performance, a narrow band gap semiconductor MoS2 and organic macromolecular cucurbit[ n]urils (Q[ n]) were used to modify CdS. Q[ n]/CdS-MoS2 ( n=6, 7, 8) composite photocatalysts were synthesized by hydrothermal method. Infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, ultraviolet-visible and photoluminescence spectrum were used to characterize the structure, morphology and optical properties of the products, and the catalytic degradation of the solutions of methylene blue, rhodamine B and crystal violet by Q[ n]/CdS-MoS2 composite catalyst was investigated. The results showed that the Q[ n] played a regulatory role on the growth and crystallization of CdS-MoS2 particles, Q[ n]/CdS-MoS2 ( n=6, 7, 8) formed flower clusters with petal-like leaves, the flower clusters of petal-like leaves increased the surface area and active sites of the catalyst, the Q[ n]/CdS-MoS2 barrier width decreased, the electron-hole pair separation efficiency was improved in the Q[6]/Cds-MoS2. Q[ n] makes the electron-hole pair to obtain better separation and migration. The Q[6]/CdS-MoS2 and Q[7]/CdS-MoS2 have good photocatalytic activity for methylene blue, and the catalytic process is based on hydroxyl radical principle.
CdS is widely used in photocatalytic research due to its unique photoelectrochemical properties. CdS recombination with narrow bandgap semiconductors and organic compounds plays an important role in photocatalyst exploration. In this study, a cucurbit[6]uril (Q[6]) composite and Ag 2 S-doped cadmium sulfide photocatalyst (Q[6]/CdS-Ag 2 S) were prepared by chemical precipitation method and their composite was characterized by different methods. The experiment is designed to use visible light as the light source and Rhodamine B as the simulated pollutant. Meanwhile, the effects of Q[6] on the photocatalytic performance of CdSAg 2 S were investigated. The results showed that the morphology of Q[6]/CdS-Ag 2 S composite after cucurbit[6]uril recombination was similar to cauliflower, while the particle size become smaller. Catalytic performance of the composite catalyst Q[6]/CdS-Ag 2 S was significantly higher than that of CdS-Ag 2 S, the photocatalytic reaction lasts 110 min, showing the catalytic degradation effciency of 92.4% using 15 mg composite catalyst on 100 mL, 6 mg/L Rhodamine B solution.
Complexation of 4-chloromethylpyridine hydrochloride (G) with cucurbit [8]uril (Q[8]) has been investigated using NMR spectroscopy, UV-visible spectroscopy, isothermal titration calorimetry (ITC), Quantum calculation, and X-ray crystallography. The data indicated that the guest 4-chloromethylpyridine hydrochloride is completely encapsulated by the cavity of the Q[8] host in both aqueous solution and the solid state, generating a highly stable inclusion complex, namely G 2 @Q[8]. Interestingly, iondipole interactions and hydrogen-bonding interactions play a central role in the formation of the inclusion complex G 2 @Q[8], which provides a reliable basis for the encapsulation of small organic guests by the hydrophobic microenvironment of the cavity.
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