| Cucurbit[n]uril?referred to as Q[n]or CB[n]?are a set of macrocyclic compounds bridged by methylene through glycosamide unit.Q[n]have rigid structures and can selectively accommodate guest molecules with matching size and shape,which show the unique molecular recognition function and form the unique host-guest chemistry.As typical guest molecules,pesticides have been playing an important role as agricultural production materials in daily production and life,such as seed treatment,prevention and control of insect diseases in seedling period,fruit storage,antiseptic and antiseptic in transportation and so on.However,most organic pesticides are poorly soluble in water,unstable in air,volatile,or easily oxidized and decomposed under light conditions.Using the encapsulation property of Q[n],the Q[n]-pesticide inclusion compounds can be formed.It can change the physical and chemical properties of pesticide molecules without changing the chemical structure of the molecules,improve the stability and utilization rate of pesticides.In addition,using Q[n]as fluorescence sensitizers or fluorescent probes can establish a new way to analyze and detect trace pesticides.Therefore,it is of great theoretical significance and practical value to introduce Q[n]into pesticide field.In this paper,several kinds of pesticide molecules with appropriate structure and size were selected as research objects,and Q[n]with different cavity size and different solubility were selected to research assembly characterization,basic properties and action mechanism.The spectral properties,water solubility,stability,biological activity and detection performance of the selected Q[n]-pesticides supramolecular system were studied in detail.These work provide ideas and methods for improving the properties of pesticide molecules in Q[n]-pesticides supramolecular system.Specific research methods and contents are as follows:Firstly,the interaction between ABOB and two different Q[n]?Q[7]and Q[8]?was investigated using hydrogen nuclear magnetic resonance spectroscopy?1H NMR?,mass spectrometry?MS?,UV visible absorption spectrophotometry?UV?,thermostatic titration calorimetry?ITC?and XRD.The results show that ABOB can form host-guest inclusion complexes with Q[7,8]in a ratio of 1:1 under neutral water,with the order of magnitude of binding constant being 104.However,in aqueous hydrochloric acid solution,the ABOB@Q[8]inclusion complex crystal with a measurement ratio of 1:2 can be obtained.Secondly,the supramolecular interactions between three different Q[n]?HMeQ[6],Q[7]and tQ[14]?and the fungicide hymexazol?HMI?were studied by 1H NMR,MS,ITC and bacteriostatic assay.The results show that HMI can form the host and guest inclusion complexes with a ratio of 1:1 with three different Q[n],respectively.And that the inclusion compound of Q[n]and HMI could improve the antifungal activity of HMI against BC in aqueous solution.Thirdly,the supramolecular interaction of pyroquilon?Pyn?with Q[7]and Q[8]was studied by 1H NMR,MS,UV,ITC,release experiment and light stability experiment.It can be known that under the condition of neutral water,Pyn and Q[7,8]can form the host-guest inclusion complexes with a ratio of 1:1.Inclusion complex Q[7]@pyn has a certain sustained release effect on roqualone,while Q[8]inhibits the release of Pyn.Moreover,Q[7]has little effect on the photodegradation of Pyn and Q[8]can effectively block ultraviolet radiation to protect Pyn from photolysis.Fourthly,using the known ThT@tQ[14]?1:1?as a fluorescent probe to determine the non-fluorescent triazole fungicides in aqueous solution,including flusilazole,azaconazole,triadimefon,tebuconazole,tricyclazole,flutriafol,penconazole and triadimenol isomer A.The experimental results showed that the ThT@t Q[14]fluorescent probe had high selectivity and sensitivity to flusilazole,with the detection limit of 1.27×10-8 mol/L,and was not disturbed by common metal ions and anions in the water system(except Ca2+).The response mechanism of ThT@tQ[14]fluorescent probe to flusilazole was deduced by using 1H NMR and ITC.Lastly,the results of 1H NMR,UV,ITC and release experiment showed that dinotefuran?DIN?could form the host-guest inclusion complexes with a ratio of 1:1with HMeQ[6]and Q[7],respectively.The results of the release experiments on DIN showed that the inclusion of Q[n]had a certain sustained release effect on DIN.Similarly,in the condition of neutral water,acetamiprid?AMP?and thiamethoxam?TMX?can form a host-guest inclusion complex with a ratio of 1:1 with Q[7],respectively.Unfortunately,the inclusion of Q[7]had no effect on the release of AMP and TMX in the water. |
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