| Cucurbit[n]urils(referred to as Q[n] or CB[n]) has two hydrophobic cavities and hydrophilic carbonyl portals. It can selectively bind different guest molecules to form host-guest complexes. As a new macrocyclic host molecule, Q[n] is not easy to change their shape for its structural rigidity and shows high chemical stability when it compared with the calixarene. The inclusion complexes of Q[n] and pesticide molecule can change the physical and chemical properties of pesticide molecules,such as photoelectric activity, solubility, and biological activity, and these changing properties can be used as a new method to detect trace pesticides.In this paper, nitrogen-containing heterocyclic pesticides are used as targeted pesticides and Q[n]-dye supramolecular fluorescent probes were established. We have designed a method which can be used for rapid and sensitive detection of pesticides.Meanwhile, the biological and antifungal activity of Q[n]-pesticide supramolecular assembly were carried out. In addition, a novel shell-like supramolecular assembly of4,4’-bipyridyl derivatives and twisted cucurbit[14]uril molecule was investigated. The research contents are as follows:Firstly, baesd on the interaction of Q[8] with acridine orange(AO) or pyroninY(PyY). Q[8]-AO(PyY) fluorescent probes at molar ratio 1: 1 were established, and host-guest interaction between fluorescent probes and pesticides(thiabendazole(TBZ),fuberidazole(FBZ) and carbendazim(CBZ)) were also explored. The results showed that pesticides TBZ, FBZ, CBZ can significantly enhance the fluorescence intensity of probe Q[8]-AO and Q[8]-PyY in acidic aqueous solution at room temperature. We found a linear correlation between fluorescent probes and concentration of pesticides from 0.40 to 5.0 μΜ. The detection limit is as low as 10-8 mol/L, and the recovery range is 96.5~97.9%. The method is used for the detection of thiabendazole,fuberidazole and carbendazim in aqueous samples. Cells staining studies showed that the probe can also achieve rapid detection of these three pesticides in cell.Secondly, the host-guest inclusion between thiabendazole(TBZ) and cucurbit[7]uril(Q[7]), symmetrical tetra-methylcucurbit[6]uril(TMeQ[6]) and meta-hexamethyl-substituted cucurbit[6]uril(HMeQ[6]) in aqueous solution were studied. The host Q[7] selectively binds the benzimidazole ring moiety of the guest molecule for Q[7]-TBZ system. The thiazole ring is encapsulated into the cavities of TMeQ[6] and HMeQ[6], but the benzimidazole rings located outside of the cavities.Q[n] and TBZ are both formed 1:1 host-guest inclusion. Thus the results demonstrate that complexation of TBZ with Q[n] could be used to improve the solubility and antifungal activity of TBZ and found that complexation of TBZ with Q[n] increased the inhibitory effect of TBZ on the growth of Fusarium graminearum in aqueous solution, but there is no obvious inhibitory effects in acidic or alkaline conditions.Thirdly, the supramolecular interaction of twisted cucurbit[14]uril(tQ[14]) with viologen derivative(PCn) were investigated, including the inclusion mode formed ratio, and related thermodynamic parameters of inclusion complexes. The resulting had a novel and special structure supramolecular assembly. We discovered that PCn guests form stable 1:1 inclusion complexes with the tQ[14] host, and 4’4- bipyridyl parts and alkyl chains of PCn are stay the cavity and shell-like shaped respectively.The formation of inclusion complexes are mainly enthalpy-driven for its higher enthalpy. |
PDF Full Text Request