Excited-state intramolecular proton-transfer(ESIPT)based fluorescence probes are particularly attractive due to their unique properties including environmental sensitivity,a large Stokes shift,and potential for ratiom...Excited-state intramolecular proton-transfer(ESIPT)based fluorescence probes are particularly attractive due to their unique properties including environmental sensitivity,a large Stokes shift,and potential for ratiometric sensing.In general,ESIPT-based fluorophore incorporates an intramolecular hydrogen bonding interaction between a hydrogen bond donor(-OH and NH_(2)are common)and a hydrogen bond acceptor(C=N and C=O).More,protection-deprotection of hydroxyl group as hydrogen bond donor could induce an off-on switch of ESIPT-based emission.Therefore,protection-deprotection of hydroxyl group has been the widely used strategy to design fluorescent probes,where the potential key issue is selecting a protective group that can specifically leave in the presence of the target analyte.In this review,we mainly summarize the specific protecting groups(sites)and deprotection mechanisms for biologically important species(including reactive sulfur species(RSS),reactive oxygen species(ROS),enzymes,etc.),and analyze the advantages and disadvantages of different protection mechanisms from some aspects including probe stability,selectivity,response rate and assay system,etc.Based on the aforementioned,we further point out the current challenges and the potential future direction for developing ESIPT-based probes.展开更多
Intracellular pH homeostasis is foundation of maintaining normal physiological functions.More and more evidences show that intracellular pH fluctuations were usually associated with many diseases(such as cancer,epilep...Intracellular pH homeostasis is foundation of maintaining normal physiological functions.More and more evidences show that intracellular pH fluctuations were usually associated with many diseases(such as cancer,epilepsy and neurodegenerative diseases).It is very important to develop in situ real-time determination of pH.In recent years,it has been verified that pH can regulate the isomerization process of spiropyran.Thus,we report a pH fluorescent probe BSL,which is a closed loop spiropyran structure by coupling benzothiazole derivatives with indole salts.We utilizes the process of spiropyran isomerization as the trigger of excited state intramolecular proton transfer(ESIPT)effect,and adjust the process of spiropyran isomerization through pH,and then the molecular transformation from enol to ketone(enol:525 nm,ketone:677 nm)through the ESIPT effect.This process achieved accurate measurement of pH.The probe BSL showed sensitive and reversible fluorescence response to pH in vitro.Ultimately,BSL was successfully applied to detect pH fluctuations in cell oxidative stress model.展开更多
Four crystals A–D based on a structurally simple ESIPT-active molecule 4MPP were obtained by subtly controlling the crystallization conditions. Notably, crystals A and C display single emission bands, which correspon...Four crystals A–D based on a structurally simple ESIPT-active molecule 4MPP were obtained by subtly controlling the crystallization conditions. Notably, crystals A and C display single emission bands, which correspond to the keto＊（K＊） and enol＊（E＊） emission, respectively. B and D exhibit dual emission with different proportion of E＊/K＊ emissions while D sucessfully achieves white emssion. The distinctively different emission properties of A–D is mainly because of the change in crystal structures. In addition, A displays amplified spontaneous emission, which indicates its potential as single crystal lasers.展开更多
Based on density functional theory(DFT) and time-dependent density functional theory(TD-DFT), the effects of substituent on the excited-state intramolecular proton transfer(ESIPT) process and photophysical properties ...Based on density functional theory(DFT) and time-dependent density functional theory(TD-DFT), the effects of substituent on the excited-state intramolecular proton transfer(ESIPT) process and photophysical properties of 2-(2’-hydroxyphenyl)-4-chloromethylthiazole(HCT) are studied. The electron-donating group(CH_(3), OH) and electronwithdrawing group(CF_(3), CHO) are introduced to analyze the changes of intramolecular H-bond, the frontier molecular orbitals, the absorption/fluorescence spectra, and the energy barrier of ESIPT process. The calculation results indicate that electron-donating group strengthens the intramolecular H-bond in the S_(1) state, and leads to an easier ESIPT process. The electron-withdrawing group weakens the corresponding H-bond and makes ESIPT process a little harder. Different substituents also affect the photophysical properties of HCT. The electron-withdrawing group(CF_(3), CHO) has a little effect on electronic spectra. The electron-donating group(CH_(3), OH) red-shifts both the absorption and fluorescence emission peaks of HCT, respectively, which causes the Stokes shift to increase.展开更多
Using 4＇-methoxy-5-hydroxyisoflavone and 4＇,5-dihydroxy-7-methoxyisoflavone as leding compounds,6-methoxy-2 H-phenanthro[9,10-c]pyrazol-11-ol（1 a） and 9-methoxy-2 Hphenanthro [9,10-c]pyrazol-6,11-diol（1 b） were ...Using 4＇-methoxy-5-hydroxyisoflavone and 4＇,5-dihydroxy-7-methoxyisoflavone as leding compounds,6-methoxy-2 H-phenanthro[9,10-c]pyrazol-11-ol（1 a） and 9-methoxy-2 Hphenanthro [9,10-c]pyrazol-6,11-diol（1 b） were synthesized by two dehydration processes in the EtOH solution.They were characterized by IR,^1H NMR and ^13C NMR.The black prism crystal of 1 a was grown by the slow solvent evaporation technique from 40：1（v/v） CHCl3/MeOH,and it was determined by single-crystal X-ray diffraction.In the crystal structure,1 a was stabilized by intramolecular（O–H···N） and intermolecular（N–H···O,O–H···O,π···π,C–H···π） interactions.In addition,the fluorescence properties of 1 a and 1 b in the base and neutral media revealed that they possessed excited state intramolecular proton transfer phenomena（ESIPT）.展开更多
基金National Natural Science Foundation of China(Nos.22277104,22325703,22074084)the Natural Science Foundation of Shanxi Province(No.202203021212184)+3 种基金Research Project supported by Shanxi Scholarship Council of China(No.2022-002)the Basic Research Program of Shanxi Province(Free Exploration)(No.202203021221009)2022 Lvliang City science and technology plan project(Nos.2022SHFZ51,2022GXYF15)Scientific Instrument Center of Shanxi University(No.201512)。
文摘Excited-state intramolecular proton-transfer(ESIPT)based fluorescence probes are particularly attractive due to their unique properties including environmental sensitivity,a large Stokes shift,and potential for ratiometric sensing.In general,ESIPT-based fluorophore incorporates an intramolecular hydrogen bonding interaction between a hydrogen bond donor(-OH and NH_(2)are common)and a hydrogen bond acceptor(C=N and C=O).More,protection-deprotection of hydroxyl group as hydrogen bond donor could induce an off-on switch of ESIPT-based emission.Therefore,protection-deprotection of hydroxyl group has been the widely used strategy to design fluorescent probes,where the potential key issue is selecting a protective group that can specifically leave in the presence of the target analyte.In this review,we mainly summarize the specific protecting groups(sites)and deprotection mechanisms for biologically important species(including reactive sulfur species(RSS),reactive oxygen species(ROS),enzymes,etc.),and analyze the advantages and disadvantages of different protection mechanisms from some aspects including probe stability,selectivity,response rate and assay system,etc.Based on the aforementioned,we further point out the current challenges and the potential future direction for developing ESIPT-based probes.
基金the National Natural Science Foundation of China(No.22074084)One Hundred People Plan of Shanxi Province,Shanxi Province“1331 Project”Key Innovation Team Construction Plan Cultivation Team(No.2018-CT-1)+6 种基金Research Project Supported by Shanxi Scholarship Council of China(No.2022-002)Shanxi Province Foundation for Returness(No.2017-026)Shanxi Collaborative Innovation Center of High Value-added Utilization of Coalrelated Wastes(No.2015-10-B3)the Shanxi Province Foundation for Selected(2019),Innovative Talents of Higher Education Institutions of Shanxi,Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2019L0031)Key R&D Program of Shanxi Province(No.201903D421069),the Shanxi Province Science Foundation(No.201901D111015)Key R&D and Transformation Plan of Qinghai Province(No.2020-GX-101)Graduate Innovation Project of Shanxi Province and Scientific Instrument Center of Shanxi University(No.201512)。
文摘Intracellular pH homeostasis is foundation of maintaining normal physiological functions.More and more evidences show that intracellular pH fluctuations were usually associated with many diseases(such as cancer,epilepsy and neurodegenerative diseases).It is very important to develop in situ real-time determination of pH.In recent years,it has been verified that pH can regulate the isomerization process of spiropyran.Thus,we report a pH fluorescent probe BSL,which is a closed loop spiropyran structure by coupling benzothiazole derivatives with indole salts.We utilizes the process of spiropyran isomerization as the trigger of excited state intramolecular proton transfer(ESIPT)effect,and adjust the process of spiropyran isomerization through pH,and then the molecular transformation from enol to ketone(enol:525 nm,ketone:677 nm)through the ESIPT effect.This process achieved accurate measurement of pH.The probe BSL showed sensitive and reversible fluorescence response to pH in vitro.Ultimately,BSL was successfully applied to detect pH fluctuations in cell oxidative stress model.
基金supported by the National Natural Science Foundation of China (Nos. 51622304 and 51773077)
文摘Four crystals A–D based on a structurally simple ESIPT-active molecule 4MPP were obtained by subtly controlling the crystallization conditions. Notably, crystals A and C display single emission bands, which correspond to the keto＊（K＊） and enol＊（E＊） emission, respectively. B and D exhibit dual emission with different proportion of E＊/K＊ emissions while D sucessfully achieves white emssion. The distinctively different emission properties of A–D is mainly because of the change in crystal structures. In addition, A displays amplified spontaneous emission, which indicates its potential as single crystal lasers.
文摘Based on density functional theory(DFT) and time-dependent density functional theory(TD-DFT), the effects of substituent on the excited-state intramolecular proton transfer(ESIPT) process and photophysical properties of 2-(2’-hydroxyphenyl)-4-chloromethylthiazole(HCT) are studied. The electron-donating group(CH_(3), OH) and electronwithdrawing group(CF_(3), CHO) are introduced to analyze the changes of intramolecular H-bond, the frontier molecular orbitals, the absorption/fluorescence spectra, and the energy barrier of ESIPT process. The calculation results indicate that electron-donating group strengthens the intramolecular H-bond in the S_(1) state, and leads to an easier ESIPT process. The electron-withdrawing group weakens the corresponding H-bond and makes ESIPT process a little harder. Different substituents also affect the photophysical properties of HCT. The electron-withdrawing group(CF_(3), CHO) has a little effect on electronic spectra. The electron-donating group(CH_(3), OH) red-shifts both the absorption and fluorescence emission peaks of HCT, respectively, which causes the Stokes shift to increase.
基金supported by the National Natural Science Foundation of China(No.21672132)
文摘Using 4＇-methoxy-5-hydroxyisoflavone and 4＇,5-dihydroxy-7-methoxyisoflavone as leding compounds,6-methoxy-2 H-phenanthro[9,10-c]pyrazol-11-ol（1 a） and 9-methoxy-2 Hphenanthro [9,10-c]pyrazol-6,11-diol（1 b） were synthesized by two dehydration processes in the EtOH solution.They were characterized by IR,^1H NMR and ^13C NMR.The black prism crystal of 1 a was grown by the slow solvent evaporation technique from 40：1（v/v） CHCl3/MeOH,and it was determined by single-crystal X-ray diffraction.In the crystal structure,1 a was stabilized by intramolecular（O–H···N） and intermolecular（N–H···O,O–H···O,π···π,C–H···π） interactions.In addition,the fluorescence properties of 1 a and 1 b in the base and neutral media revealed that they possessed excited state intramolecular proton transfer phenomena（ESIPT）.
