Synthesis And Properties Study Of Fluorescent Dyes Based On Coumarin,Spiropyran And BODIPY

Fluorescent chemosensors can be used as an effective tool for detection metal ions,anions and pH,due to their high selectivity,high sensitivity and low cost.In this paper,coumarin,spiropyran and BODIPY were used as fluorescence groups,and several new fluorescence chemosensors were obtained by structural modification of the parent and introduction of different recognition groups,and the properties of these derivatives were further explored.The main research contents are as follows:?1?In this study,we have successfully synthesized two novel pyrazoline-coumarin based fluorescent chemosensors PC-1 and PC-2 for recognition of Cu²⁺.The structures of chemosensors PC-1 and PC-2 were characterized by ¹H NMR,¹³C NMR and ESI-HR-MS.Sensors PC-1 and PC-2 showed obvious“on-off”fluorescence quenching response toward Cu²⁺,and the quenching efficiency reached a maximum of 95%and 98%,respectively.The detection limits of sensors PC-1 and PC-2 were 3.3?M and 0.9?M to Cu²⁺.In addition,sensors PC-1 and PC-2 showed a 1:1 binding stoichiometry to Cu²⁺in CH₃CN/HEPES buffer medium?9:1 v/v,pH=7.2?.The stable pH range of sensors PC-1 and PC-2 to Cu²⁺was from3 to 8.?2?A tren-based fluorescent probe CTS was synthesized and characterized by ¹H NMR,¹³C NMR and ESI-HR-MS.This tren-based chemosensor CTS showed an“on-off-on”fluorescence response toward Cu²⁺and H₂PO₄^-with a 1:1 binding stoichiometry in CH₃CN/HEPES buffer medium?9:1 v/v?by UV/vis and fluorescence spectroscopies.The detection limits of sensor CTS to Cu²⁺was determined to be 0.37?M,while that of CTS-Cu²⁺complex to H₂PO₄^-was 1.6?M,respectively.The sequential recognition behavior can be repeated four times with little fluorescence efficiency loss using Cu²⁺and H₂PO₄^-.The stable pH range for Cu²⁺and H₂PO₄^-determination was from 4 to 7.5.?3?In this study,we have successfully synthesized a new coumarin based fluorescent chemosensor CTQ,in which tren and quinolone are introduced as receptors for sequential recognition of Cu²⁺and PPi.The structure of chemosensor CTQ was characterized by ¹H NMR,¹³C NMR and ESI-HR-MS.Sensor CTQ showed an obvious“on-off”fluorescence quenching response toward Cu²⁺,and the quenching efficiency reached a maximum of 99.6%with the addition of 20 equiv.of Cu²⁺.The CTQ-Cu²⁺complex showed an“off-on”fluorescence enhancement response toward PPi over many competitive anions,especially HPO₄^2-and H₂PO₄^-.The detection limit of sensor CTQ was 1.9×10^-6 M to Cu²⁺and5.96×10^-8 M to PPi.In addition,sensor CTQ showed a 1:1 binding stoichiometry to Cu²⁺and sensor CTQ-Cu²⁺showed a 2:1 binding stoichiometry to PPi in CH₃CN/HEPES buffer medium?9:1 v/v,pH=7.4?.The stable pH range of sensor CTQ to Cu²⁺and CTQ-Cu²⁺to PPi was from 4 to 8.?4?In this study,a highly sensitive and selective fluorescent chemosensor CQ,was synthesized and characterized by ¹H NMR,¹³C NMR and ESI-MS.Sensor CQ showed an“on-off”fluorescence response to Pb²⁺with a 1:1 binding stoichiometry in CH₃CN/HEPES buffer medium?9:1 v/v?.The detection limit of sensor CQ to Pb²⁺was determined to be 0.5?M,and the stable pH range for Pb²⁺detection was from 4 to 8.?5?In this study,a spiropyrane-based fluorescence chemosensor BSP connected by pyridine ring was characterized by ¹H NMR and ESI-MS.Sensor BSP had good backlight chromogenic property and positive solvent effect,and showed obvious fluorescence quenching response and naked eye recognition effect to Fe³⁺,while the sensor BSP-Fe³⁺showed obvious fluorescence enhanced response to PPi.Sensor BSP showed a 2:1 binding stoichiometry to Fe³⁺and PPi,with detection limits of 2.3?M and 0.6?M,respectively.The effective pH range of sensor BSP was 1¹2,the optimal pH range was 5⁸,and the unsuitable pH range was>12.?6?In this study,a BODIPY-based fluorescence chemosensor BBP was sythesized by introducing BODIPY as the fluorescence group and quinoline as the recognition group.The sensor can be well used for H⁺recognition,showing high specificity to H⁺and naked eye recognition effect in a wide range of cations.When the cyclic response reaches 5 times,the fluorescence intensity has no obvious attenuation,indicating that the recognition of H⁺by the sensor has a high stability,and the color change only occurs within 3s,indicating that the recognition has a high sensitivity.In the range of pH 2-4,the fluorescence intensity showed a linear relationship with pH.Taking log[(I_max-I_x)/(I_x-I_min)]as the abscissa and pH as the ordinate,the pKa value was obtained as 2.94.