| Organic fluorescent sensors have the advantages of high sensitivity,high specificity,and good reproducibility.They are effective methods and reliable technologies for the detection of toxic and hazardous substances in the future.In particular,new sensing technologies that can be portable,visualized and easy to operate can be established.With the continuous development of science and technology,the application of new detection technologies in the fields of industrial and agricultural production,food and drug safety,environmental testing,and medical diagnosis is becoming more and more important.Therefore,using the advantages of organic fluorescence sensors in analysis and detection to construct a diversified organic small molecule fluorescence sensor is still one of the research hotspots in the field of materials.At present,some achievements have been made in the research of organic fluorescent sensors,but there are still problems such as poor selectivity,low sensitivity,poor water solubility,and poor biocompatibility.This thesis focuses on the analysis and detection of biological neurotoxins hydrazine and phosgene,as well as the analysis and detection of copper ions and reactive oxygen species-hypochlorous acid related to biological metabolism to design and synthersize four types of D-?-A structures.The performance of the four reactive organic fluorescence sensors has been characterized and analyzed through theoretical calculations and experimental tests.Some sensors have been applied to cell fluorescence imaging.The following research results have been achieved:(1)Synthesis and performance study of fluorescence-off Cu2+sensor based on anthracene derivatives.This sensor LXLS-1 is a new type of fluorescence sensor with D-?-A configuration of anthracene ring structure.Although the fluorescence quantum yield of the previous anthracene derivative sensors is high,the selectivity is poor and the emission wavelength is short(usually below 450nm)),so designed and synthesized a Schiff base conjugate structure composed of anthracycline fluorophore and salicylaldehyde recognition group,which makes the emission spectrum of sensor LXLS-1 red-shifted to 484nm,and exhibits fluorescence of copper ion.The“on-off”type of specific recognition has a linear range:1×10-5mol/L?1×10-4mol/L,and the lowest detection limit is 0.105?mol/L.(2)Synthesis and performance study of a fluorescent shut-off phosgene sensor based on carbazole derivatives.This sensor uses carbazole as a fluorophore,a benzene ring as a connecting arm,and o-diphenylamine as a recognition group to form a sensor KZ-1 that can recognize phosgene.The sensor recognition group o-diphenylamine can undergo a nucleophilic substitution reaction with phosgene to form a lactam five-membered ring KZ-1-PHOS,which makes the sensor change from the original D-?-D structure to the D-?-A structure,with fluorescence Quenching occurs.After quantitative calculations,it is found that after the sensor recognizes phosgene,the previous charge transfer excitation(CT)is converted to charge local excitation(LE),and the n??*transition leads to fluorescence quenching.The sensor KZ-1 has high selectivity to phosgene,and can be used in nerve gas simulants(diethyl chlorophosphate(DCP),five acylation/phosphorylation reagents:oxalyl chloride((COCl)2),acetyl chloride).(CH3COCl),thionyl chloride(SOCl2),phosphorous oxychloride(POCl3),p-toluenesulfonyl chloride(p-Ts Cl)and two acids:trifluoroacetic acid(TFA)and hydrochloric acid(HCl).The phosgene is specifically identified with a detection limit of 0.9 ppm.The sensor KZ-1 is prepared as a thin-layer plate simple detection device to simulate a factory phosgene leak to successfully detect phosgene.(3)Synthesis and performance research of ratio-type hydrazine fluorescence sensor based on benzimidazole derivatives.The sensor MZ-DA is based on the previousstudyonthefluorescenceperformanceof5-(4-(dimethylamino)phenyl)-1H-pyrrole-2-carboxylic acid,and summarizes the shortcomings in the design of copper ion and phosgene sensors.Based on the theoretical calculation of the fluorescence spectroscopy properties of the multiple sensors designed,it was finally screened and compared to use benzimidazole as the electron donor,phthalimide as the electron acceptor,and thiophene as the bridge between the two.The use of phthalimide groups can carry out Ing-Manske reaction with N2H4,thereby cutting off the electron-withdrawing part of phenyl phthalimide to form a new electronic push-pull system principle.The sensor MZ1-DA was designed and successfully synthesized.With the help of drug design ideas,without changing the electronic relationship between the electron donor and acceptor in the sensor,the structure of MZ1-DA is modified by introducing sodium methylene carboxylate group into the N-3 of MZ1-DA,and a new structure is obtained.The sensor MZ-DA,water solubility and biocompatibility have been greatly improved,and its Log P(Oct/buff)=1.68,Log D7.4=-1.97 through testing.The sensor can detect hydrazine in a proportional mode in the DMSO/water(1:99)system.The linear range of detection is 0.28?120?M,and the detection limit is 0.038?M.It is suitable for low-abundance application detection;and can be identified by naked eyes.In addition,it has been successfully used to detect river water samples,hydrazine in vapor form,and fluorescence imaging of hydrazine in A549 cells.(4)Synthesis and performance research of ratio-based hypochlorous acid fluorescence sensor based on carbazole derivatives.Based on the research of the phosgene sensor,the carbazole ring is structurally modified and modified by introducing longer conjugated fragments at the 3 and 6 positions of the carbazole,and calculating the multiple sensors designed by density functional theory.The fluorescence spectroscopy properties of the pyridine quaternary ammonium salt was screened as the cell targeting group,and the fluoroboric acid was used as the new recognition group to innovatively design and synthesis the new organic fluorescence sensor KZ-BFK of a hypochlorous acid with high sensitivity and high selectivity.The quantitative calculation shows after the sensor KZ-BFK recognizes hypochlorous acid,the phenolic hydroxyl group formed after the fluoroboric acid recognition group is oxidized by hypochlorous acid,which reduces the energy gap between the HOMO and LUMO orbitals of the entire sensor molecule,and the emission wavelength A large red shift(115nm)has occurred,with obvious intramolecular charge transfer effect.The sensor KZ-BFK can work in a polar environment of almost pure water,with a linear range of 0?70?mol/L and a detection limit of 0.012?mol/L.It is suitable for low-abundance application detection and can be identified by the naked eye.In addition,the sensor KZ-BFK has a long emission wavelength of 585nm,which can be used for fluorescence imaging detection of hypochlorous acid in organisms without being interfered by the fluorescence background of organisms.Because it contains hydrophilic and biocompatibility bifunctional groups,taking into account water solubility and biocompatibility,compared with hydrazine sensors and most hypochlorous acid sensors,it has higher hydrophilicity and biocompatibility;And through MTT experiments and flow cytometry experiments,KZ-BFK can enter adenocarcinoma human alveolar basal epithelial cells and normal human hepatocytes in a very short time(30min),and has been successfully used to detect secondary A549cells Fluorescence imaging of chloric acid. |
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