Department of Chemistry, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia.
Department of Chemistry, Faculty of Science, University of Khartoum, Khartoum 11114, Sudan.
Molecules. 2023 Jan 23;28(3):1136. doi: 10.3390/molecules28031136.
The inclusion complexes of cucurbit[n]uril, CB[n] (n = 6-8), with poly aromatic hydrocarbon (PAH) Benzo(a)Pyrene (BaP), and fluoranthene (FLT) were investigated carefully in aqueous media. Fluorescence and H NMR spectroscopy were used to characterize and investigate the inclusion complexes that were prepared in the aqueous media. The most predominant complexes of both guests with hosts were the 1:1 guest: host complexes. Stability constants of 2322 ± 547 M, 7281 ± 689 M, 3566 ± 473 M were obtained for the complexes of BaP with CB[6], CB[7], and CB[8], respectively. On the other hand, stability constants of 5900.270 ± 326 M, 726.87 ± 78 M, 3327.059 ± 153 M were obtained for the complexes of FLT with CB[6], CB[7], and CB[8], respectively. Molecular dynamic (MD) simulations were used to study the mode and mechanism of the inclusion process and to monitor the stability of these complexes in aqueous media at an atomistic level. Analysis of MD trajectories has shown that both BaP and FLT form stable inclusion complexes with CB[7] and CB[8] in aqueous media throughout the simulation time, subsequently corroborating the experimental results. Nevertheless, the small size of CB[6] prohibited the encapsulation of the two PAHs inside the cavity, but stable exclusion complex was observed between them. The main driving forces for the stability of these complexes are the hydrophobic forces, van der Waals interactions, electrostatic effect, the π····π and C-H···π interaction. These results suggest that BaP and FLT can form stable complexes with CB[n] (n = 6-8) in solution.
在水相介质中，仔细研究了葫芦脲（CB[n]）（n = 6-8）与多环芳烃（PAH）苯并（a）芘（BaP）和荧蒽（FLT）的包合复合物。荧光和 H NMR 光谱用于对在水相介质中制备的包合复合物进行表征和研究。两种客体与主体形成的最主要的配合物都是 1:1 的客体：主体配合物。对于 BaP 与 CB[6]、CB[7]和 CB[8]的配合物，分别获得了 2322 ± 547 M、7281 ± 689 M 和 3566 ± 473 M 的稳定常数。另一方面，对于 FLT 与 CB[6]、CB[7]和 CB[8]的配合物，分别获得了 5900.270 ± 326 M、726.87 ± 78 M 和 3327.059 ± 153 M 的稳定常数。分子动力学（MD）模拟用于研究包合过程的模式和机制，并在原子水平上监测这些配合物在水相中的稳定性。MD 轨迹分析表明，在整个模拟时间内，BaP 和 FLT 在水相介质中均与 CB[7]和 CB[8]形成稳定的包合配合物，随后与实验结果相符。然而，CB[6]的小尺寸阻止了两种 PAHs 被包入空腔内，但观察到它们之间形成了稳定的排除复合物。这些配合物稳定性的主要驱动力是疏水作用力、范德华相互作用、静电效应、π····π 和 C-H···π 相互作用。这些结果表明，BaP 和 FLT 可以在溶液中与 CB[n]（n = 6-8）形成稳定的配合物。
