Traditional fluorescence switching molecules achieving the state change between on and off states commonly based on UV irradiation. However, it is worth noting that UV irradiation is harmful to both the cancer cells a...Traditional fluorescence switching molecules achieving the state change between on and off states commonly based on UV irradiation. However, it is worth noting that UV irradiation is harmful to both the cancer cells and the normal cells. To achieve fluorescence switching under visible wavelength and avoid complicate molecular design, a fluorophore of 2,4,5,6-tetrakis(carbazol-9-yl)-1,3-dicyanobenzene(4Cz IPN) and a quencher of diarylethene(DAE) were physically incorporated within the biocompatible block copolymer poly(lactic-co-glycolic acid)-b-poly(ethylene glycol)(PLGA-b-PEG) to form 4Cz IPNDAE nanoparticles(NPs) through flash nanoprecipitation(FNP). By using the FNP method, the NPs were prepared within milliseconds in a confined impingement jets dilution(CIJ-D) mixer. Quenching and recovery of fluorescence could achieve in the presence of DAE under 475 nm and 560 nm irradiation.Appropriate structure and fluorescent properties of the nanoparticles can be tuned by external conditions for their efficient fluorescence resonance energy transfer(FRET) in a kinetic stabilization process. This NPs formation process was further optimized by varying the dilution ratio, Reynolds number(Re) and polymer concentration to modulate the mixing and particle nucleation and growth process. The size and fluorescence switching properties of the NPs were systematically investigated in solution and in cellular uptake experiments. This work is anticipated to provide a simple and highly effective engineering strategy for the modulation of fluorescence switching nanoparticles and beneficial to its engineering application.展开更多
Upon excitation of porphyrin or perylene subunit, the porphyrin-perylene dyad exhibitsreversible fluorescence emitting and quenching by formation and neutralization of the protonatedporphyrin subunit, thereby providin...Upon excitation of porphyrin or perylene subunit, the porphyrin-perylene dyad exhibitsreversible fluorescence emitting and quenching by formation and neutralization of the protonatedporphyrin subunit, thereby providing a prototype of molecular fluorescence switch working in anexpanded spectral range.展开更多
Dynamic molecular systems capable of controlled transformations are foundational for developing next-generation intelligent materials and sensors.However,achieving sequential,multistate switching with distinct optical...Dynamic molecular systems capable of controlled transformations are foundational for developing next-generation intelligent materials and sensors.However,achieving sequential,multistate switching with distinct optical outputs on a single molecular platform remains challenging.Here,we introduce a class of dynamic fluorescent systems built upon a single benzo-conjugated acceptor.This system undergoes programmed molecular reconfigura.tion and fluorescence switching through sequential chemical and pH driven triggers,leveraging intramolecular oxa/thiol-Michael addi-tion-elimination reactions via dynamic covalent bonding in agueous medias.Each distinct molecular state exhibits unique,trackable absorbance and fluorescence signatures,governed by precisely controlled pseudo-pK_(a)values.We demonstrate the utility of this system by achieving real-time,noninvasive optical tracking of topological transitions in soft materials,specifically monitoring hydrogel degradation and reformation(gel-sol-gel).Furthermore,by tuning the molecular scaffold,we developed derivatives for live-cell imaging,enabling dynamic visualization of intracellular pH fluctuations.This work presents a versatile platform for designing programmable,multistimuli-responsive molecular systems with potential in adaptive materials,chemical sensing,and advanced biomedical diagnostics.展开更多
This paper reported the synthesis of hexaar-ylbiimidazole-tetraphenylethene(HABI-TPE)conjugated photochromic fluorophore,which simultaneously exhib-ited photochromic property,condensed state enhanced emission and reve...This paper reported the synthesis of hexaar-ylbiimidazole-tetraphenylethene(HABI-TPE)conjugated photochromic fluorophore,which simultaneously exhib-ited photochromic property,condensed state enhanced emission and reversible fluorescence switching.Upon UV irradiation,a green species with a broad absorption band between 550 and 800 nm(the absorption maximum at 697 nm)was observed,which readily faded to colorless in the darkness.HABI-TPE launched strong fluorescence with the maximum emission wavelength at 520580 nm under the excitation with 450-500 nm visible light in condensed state,which is in contrast to nonfluorescence in solution.The maximum emission wavelength in condensed state was dependent of excitation wavelength.More interest-ingly,HABI-TPE exhibited reversible fluorescence switch-ing upon alternating irradiation with blue or near-UV light(wavelength less than 490 nm)and green light(more than 490 nm)in condensed state.Our evaluation demonstrated that HABI-TPE exhibited great photoswitchable fluores-cence,which is a promising photoswitchable fluorophore for localization-based super-resolution microscopy,evi-dencing by resolving nanostructures with sub-100nm resolution in polymethylmethacrylate films.展开更多
A new acid-base fluorescent switch containing both imidazo[4,5-f][1,10]-phenanthroline and triphenylamine groups has been synthesized.Its fluorescence emissions and absorptions can be reversibiy changed through proton...A new acid-base fluorescent switch containing both imidazo[4,5-f][1,10]-phenanthroline and triphenylamine groups has been synthesized.Its fluorescence emissions and absorptions can be reversibiy changed through protonation/deprotonation of imidazole and amine moiety by controlling the intramolecular charge transfer（ICT） process,leading to off-on-off fluorescent molecular switching.展开更多
With the decrease of pH value from 8.45 to -1.0, the UV-Vis absorption and fluorescent spectra of 1,2-bis（4-pyridyl） ethylene（BPE） took on the same changing trend at four different successive pH stages： 8.45--7.2...With the decrease of pH value from 8.45 to -1.0, the UV-Vis absorption and fluorescent spectra of 1,2-bis（4-pyridyl） ethylene（BPE） took on the same changing trend at four different successive pH stages： 8.45--7.20, 7.20--5.62, 5.62--2.60, and 2.60--1.0, namely, no change, decrease, increase, and decrease again. Among these, in a range of 7.20--5.62, the fluorescence wavelength blueshifted from 418 to 359 nm, but the UV-Vis absorption wavelength, in contrast, redshifted from 285 to 298 nm. The fluorescence intensity of BPE had a drop even to quench upon a decline in the pH value from 2.60 to -1.0 probably owing to its cation-re interaction to reduce the π electron cloud density of BPE. Two dissociation constants, pKa1（4.30±0.01） and PKa2（5.65±0.04）, were obtained based on fluorescence data. The changes of fluorescence spectra indicate that BPE has ＂oft-on-off＂ switch behavior. The fluorescent spectra of BPE were nearly independent on the presence of α- and β-cyclodextrins.展开更多
1-Imino nitroxide pyrene 1 has been characterized as a H^＋ fluorescent switch. The effects of various interfering species, solvents and the irradiation of ultraviolet light on the fluorescence intensity of 1 are also...1-Imino nitroxide pyrene 1 has been characterized as a H^＋ fluorescent switch. The effects of various interfering species, solvents and the irradiation of ultraviolet light on the fluorescence intensity of 1 are also investigated. 1 fluoresces weakly in the 85% ethanol media containing no more than 4.5x10-5 mol/L of H^＋ （HCI）, but can produce a burst increase of about 4 times in the fluorescence intensity when the concentration of H＋ is increased to or over 4.9×10^-5mol/L. The extremely sharp response of 1 to H＋ occurs only within such a narrow concentration range. Moreover, the decrease of H^＋ concentration through adding sodium hydroxide causes the fluorescence quenching, suggesting that 1 may serve as a fluorescent switch for monitoring the concentration change of H＋ around the point of 4.5×10^-5 mol/L.展开更多
Photosensitive fluorescent probes have become powerful tools in chemical biology and molecular biophysics,which are used to investigate cellular processes with high temporal and spatial resolution.Accordingly,photosen...Photosensitive fluorescent probes have become powerful tools in chemical biology and molecular biophysics,which are used to investigate cellular processes with high temporal and spatial resolution.Accordingly,photosensitive fluorescent probes,including photoactivatable,photoconvertible,and photoswitchable fluorophores,have been extensively developed during the past decade.The photoswitchable fluorophores have received much attention because they highlight cellular events clearly.This minireview summarizes recent advances of using reversibly photoswitchable fluorophores and their applications in innovative bioimaging.Photoswitchable fluorophores include photoswitchable fluorescent proteins,photoswitchable fluorescent organic molecules(dyes),and photoswitchable fluorescent nanoparticles.Several strategies have been developed to synthesize photoswitchable fluorophores,including engineering combination proteins,chemical synthesis,polymerization,and self-assembly.Here we concentrate on polymer nanoparticles with optically switchable emission properties:either fluorescence on/offor dualalternating-color fluorescence photoswitching.The essential mechanisms of fluorescence photoswitching enable different types of photoswitchable fluorophores to change emission intensity or wavelength(color)and thus validating the basis of the fluorescence on/offor dual-color photoswitching design.Generally the possible applications of any fluorophores are to label biological targets,followed by specific imaging.The newly developed photoswitchable fluorophores enable super-resolution fluorescence imaging because of their photosensitive emission.Finally,we summarize the important area regarding future research and development on photoswitchable fluorescent nanoparticles.展开更多
A photochromic molecular rotor based on stiff-stilbene(SSB-FMR)was handily prepared through coupled reaction,and further self-assembled with cucurbit[8]uril(CB[8])to form a 2:2 quaternary supramolecu-lar complex(SSB-F...A photochromic molecular rotor based on stiff-stilbene(SSB-FMR)was handily prepared through coupled reaction,and further self-assembled with cucurbit[8]uril(CB[8])to form a 2:2 quaternary supramolecu-lar complex(SSB-FMR/CB[8]).Significantly,the intervention of CB[8]on SSB-FMR achieved dual functions that assembly-induced emission enhancement and assembly-induced improvement of photoisomerized performance(especially reversibility)of stiff-stilbene molecular photoswitch.The supramolecular strategy further facilitated the assembly as a photoresponsive fluorescence switch with outstanding fatigue resis-tance,which was expediently applied in high-security-level QR code anti-counterfeiting and controllable lysosome targeted imaging.The study unprecedentedly provides a supramolecular method for highly effi-ciently improving photoisomerized performance especially reversibility of molecular photoswitches based on stiff-stilbene,and is of vital significance for the construction of intelligent materials with excellent ca-pability.展开更多
In this article,an acid-responsive luminescent material,1,4-di(quinoline-6-yl)buta-1,3-diyne(DQBD)is designed and synthesized.Upon different pH values,gradual changes of fluorescence colors for DQBD in both solution a...In this article,an acid-responsive luminescent material,1,4-di(quinoline-6-yl)buta-1,3-diyne(DQBD)is designed and synthesized.Upon different pH values,gradual changes of fluorescence colors for DQBD in both solution and solid phases are demonstrated due to the protonation effect.Moreover,such responsive characteristics can also be reversible,suggesting DQBD as a promising fluorescent material with great potential for reusable-and accurate-p H sensors in the future.展开更多
Fluorescence photoswitch is becoming increasingly desirable for many applications,but its controllable fabrication still remains challenging yet.In this paper,a new strategy is proposed to fabricate fluorescence photo...Fluorescence photoswitch is becoming increasingly desirable for many applications,but its controllable fabrication still remains challenging yet.In this paper,a new strategy is proposed to fabricate fluorescence photoswitch by harnessing dual roles of albumin proteins as both photochrome carriers and biotemplates of fluorophore.As an example,we demonstrated the successful fabrication of a fluorescence photoswitch by incorporating both the photochromic diarylethene dye(CMTE)and red-emitting fluorescent gold nanoclusters(AuNCs)into the specific domains of bovine serum albumin(BSA)in a highly controllable manner.Detailed spectral and photophysical characterisation showed that CMTE well-retains the photochromic properties within the CMTE–BSA–AuNC construct,although its photoconversion rate is slightly retarded.Different from previously reported photoswitches,the fluorescence of the present system is mainly modulated via the inner filter effect(IFE)mechanism,which exhibits high switching efficiency with an on-off ratio up to 90%,reversible fluorescence response and good antifatigue performance.This work provides a new,generable albumin protein-assisted strategy of fabricating advanced fluorescence photoswitch,which can find wide applications in biological,optical and information fields.展开更多
In recent years, great progress has been made in research and development of small-molecule organic materials with various low-dimensional nanostructures. This paper presents a comprehensive review of recent research ...In recent years, great progress has been made in research and development of small-molecule organic materials with various low-dimensional nanostructures. This paper presents a comprehensive review of recent research progress in this field, including preparation, electronic and optoelectronic properties and applications. First, an introduction gives to the reprecipitation, soft templates methods, and progress in synthesis and morphological control of low-dimensional small-molecule organic nanomaterials. Their unique optical and electronic properties and research progress in these aspects are reviewed and discussed in detail. Applications based on low-dimensional small-molecule organic nanomaterials are briefly described. Finally, some perspectives to the future development of this field are addressed.展开更多
Dyes endowed with aggregation-induced emission(AIE)properties represent a very significant class of chromophores.Nonetheless,current AIE dyes have yet to possess a readily tunable fluorescence switching mechanism.Here...Dyes endowed with aggregation-induced emission(AIE)properties represent a very significant class of chromophores.Nonetheless,current AIE dyes have yet to possess a readily tunable fluorescence switching mechanism.Here,we delineate a structurally distinctive family of dyes,termed XD dyes,which exhibit AIE attributes.Notably,the novel XD dyes feature an intrinsic helical cyclization as a tunable fluorescence switch,conferring them with an advantage over conventional AIE fluorophores.Initially,the fluorescence of the XD dyes in water-tetrahydrofuran mixtures was investigated through spectral analysis as the volume of the aqueous component increased.Subsequently,particle size analysis,in conjunction with scanning electron microscopy(SEM),was employed to substantiate the aggregation propensity of the XD dyes.Of particular significance,XD-4 was observed for the first time to exhibit pronounced solid-state fluorescence,thereby corroborating the XD dyes'capacity for robust fluorescence emission in the aggregated state.Moreover,alterations in optical properties and aggregation behavior of the XD dyes were elucidated theoretically through quantum chemical computations and molecular dynamics simulations.Critically,the calculated reorganization energy of XD-4 was reduced in an aqueous medium was reduced compared to the gas phase,providing further confirmation of its AIE nature.The unique AIE characteristics of the XD dyes were validated through the integration of experimental data and theoretical insights,offering novel perspectives for the advancement of highperformance fluorescent dyes and probes.展开更多
Three novel dithienylethenes modified by bifluoroboron β-diketonate fragments have been successfully developed. Upon blue light irradiation, they reached photostationary state within 2-5 s, as well as 100% conversion...Three novel dithienylethenes modified by bifluoroboron β-diketonate fragments have been successfully developed. Upon blue light irradiation, they reached photostationary state within 2-5 s, as well as 100% conversion ratio and photocyclization quantum yield of > 0.70. Such fascinating photochromism were endowed by collaborative role of electron-withdrawing effect of BF_(2)bdk group to reduce HOMO-LUMO electronic gap for the open isomer, together with intramolecular hydrogen bonds and CH-π interactions favoring antiparallel conformation fixation. Moreover, they displayed specific discrimination and photoswitchable bacterial imaging for S. aureus.展开更多
In the version of article originally published in the volume 68,2025 of Sci China Chem(pages 3675-3688),the article was published in subscription format rather than open access format due to an oversight during the pr...In the version of article originally published in the volume 68,2025 of Sci China Chem(pages 3675-3688),the article was published in subscription format rather than open access format due to an oversight during the production stage.The corrected copyright and open access notes are provided below.The original article has been corrected.展开更多
In natural and artificial systems,reversible reactions are commonly asymmetric with respect to the time scale and nature of the stimuli which drive the forward and backward processes.In applications for which switchin...In natural and artificial systems,reversible reactions are commonly asymmetric with respect to the time scale and nature of the stimuli which drive the forward and backward processes.In applications for which switching behavior is required,it is desirable that the reversible reaction goes as close to symmetric as possible;however,such systems are uncommon.Herein,we report an example of ultraviolet(UV)-visible light-regulated asymmetric reversible structural switching involving a diene-based coordination polymer,CP1 and its monocyclobutane product,CP1a.It is possible to cycle at least ten times through a forward [2+2] photocycloaddition reaction and the reverse,photocleavage reaction.A single cycle can be completed within a few minutes.The transformation is accompanied by fast and distinct fluorescence changes,arising from optimisation of the reaction conditions.Density functional theory calculations allow rationalisation of the asymmetric reversible transformation between CP1 and CP1a rather than between CP1 and its dicyclobutane product CP1b.This work provides a clear illustration of reversible structural switching which approaches symmetric behaviour with respect to reaction rate and stimuli.The insights gained from this work also assist in the design of fast,reversible switching materials.展开更多
Solid-state fluorescent switches with reversible luminescence characteristics have attracted considerable attention because of their broad applications in advanced photonics,such as anticounterfeiting inks,optical wri...Solid-state fluorescent switches with reversible luminescence characteristics have attracted considerable attention because of their broad applications in advanced photonics,such as anticounterfeiting inks,optical writing and erasing,and biological imaging.Herein,we have fabricated a solid-state reversible fluorescent switch under alternating UV(365 nm)and visible light treatments based on a fulgide(FUL)-functionalized tetraphenylethylene(TPE)derivative(TPE-FUL)containing a photochromic group FUL and aggregation-induced emission(AIE)luminogen TPE.TPE-FUL exhibited excellent reversible absorption and luminescence owing to the interconversion between open TPE-FUL(O-TPE-FUL)and closed TPE-FUL(C-TPE-FUL).Photophysical and theoretical investigations revealed that the luminescence of O-TPE-FUL is based on the local excited state of the TPE moiety,whereas the fluorescence quenching of C-TPE-FUL originates from the intramolecular charge transfer from the TPE to the FUL moiety.The excellent reversible photoswitching properties of TPE-FUL in the solid state allows for its potential use in advanced optical memory applications,such as anticounterfeiting,optical writing and erasing,and information encryption.展开更多
Polymers with tunable helicity and naked-eye structural change under external stimuli are valuable for fabricating smart materials. Herein, we report a novel thermoresponsive color and fluorescent polyphenylacetylene ...Polymers with tunable helicity and naked-eye structural change under external stimuli are valuable for fabricating smart materials. Herein, we report a novel thermoresponsive color and fluorescent polyphenylacetylene switch with a tunable critical temperature. It relies on the temperature and solvent sensitivity of intramolecular n→π* interactions between the vicinal carbonyl groups of ester substituents located at 3,5-positions, which are indispensable for forming the cis-cisoid helical conformation of polyene backbones. In a properly chosen solvent, a compressed cis-cisoid helix is stabilized by n→π* interactions at low temperatures and yields a colorless solution. Increasing temperature causes the conformational transition toward an extended cis-transoid helix due to the disruption of n→π* interactions and produces a yellow solution. Reducing the hydrogen bond donating ability or polarity of solvents increases the switching temperature. By introducing a fluorogenic pendant, this conformational transition can also be read out by fluorescence quenching. This work may open a new window for developing intelligent materials through precisely tuning conformational transitions.展开更多
基金financially supported by the National Key Research and Development Program of the International Scientific and Technological Innovation Cooperation Project among Governments (2021YFE0100400)Science and Technology Innovation Action Plan of Shanghai (22501100500)the international One Belt One Road Collaboration Project of Shanghai (18490740300)。
文摘Traditional fluorescence switching molecules achieving the state change between on and off states commonly based on UV irradiation. However, it is worth noting that UV irradiation is harmful to both the cancer cells and the normal cells. To achieve fluorescence switching under visible wavelength and avoid complicate molecular design, a fluorophore of 2,4,5,6-tetrakis(carbazol-9-yl)-1,3-dicyanobenzene(4Cz IPN) and a quencher of diarylethene(DAE) were physically incorporated within the biocompatible block copolymer poly(lactic-co-glycolic acid)-b-poly(ethylene glycol)(PLGA-b-PEG) to form 4Cz IPNDAE nanoparticles(NPs) through flash nanoprecipitation(FNP). By using the FNP method, the NPs were prepared within milliseconds in a confined impingement jets dilution(CIJ-D) mixer. Quenching and recovery of fluorescence could achieve in the presence of DAE under 475 nm and 560 nm irradiation.Appropriate structure and fluorescent properties of the nanoparticles can be tuned by external conditions for their efficient fluorescence resonance energy transfer(FRET) in a kinetic stabilization process. This NPs formation process was further optimized by varying the dilution ratio, Reynolds number(Re) and polymer concentration to modulate the mixing and particle nucleation and growth process. The size and fluorescence switching properties of the NPs were systematically investigated in solution and in cellular uptake experiments. This work is anticipated to provide a simple and highly effective engineering strategy for the modulation of fluorescence switching nanoparticles and beneficial to its engineering application.
基金This research was supported by the National Natural Science Foundation of China(Grant No.50073018)the authors are also thankful to the support from the Key Laboratory of Supramolecular Structure and Materials in Jilin University.
文摘Upon excitation of porphyrin or perylene subunit, the porphyrin-perylene dyad exhibitsreversible fluorescence emitting and quenching by formation and neutralization of the protonatedporphyrin subunit, thereby providing a prototype of molecular fluorescence switch working in anexpanded spectral range.
基金the National Natural Science Foundation of China(No.21907080,22278330)and Youth Innovative Team(No.xtr052022012)from Xi’an Jiaotong Universitysupported by the State Key Laboratory of Fine Chemicals,Dalian University of Technology(KF2301).
文摘Dynamic molecular systems capable of controlled transformations are foundational for developing next-generation intelligent materials and sensors.However,achieving sequential,multistate switching with distinct optical outputs on a single molecular platform remains challenging.Here,we introduce a class of dynamic fluorescent systems built upon a single benzo-conjugated acceptor.This system undergoes programmed molecular reconfigura.tion and fluorescence switching through sequential chemical and pH driven triggers,leveraging intramolecular oxa/thiol-Michael addi-tion-elimination reactions via dynamic covalent bonding in agueous medias.Each distinct molecular state exhibits unique,trackable absorbance and fluorescence signatures,governed by precisely controlled pseudo-pK_(a)values.We demonstrate the utility of this system by achieving real-time,noninvasive optical tracking of topological transitions in soft materials,specifically monitoring hydrogel degradation and reformation(gel-sol-gel).Furthermore,by tuning the molecular scaffold,we developed derivatives for live-cell imaging,enabling dynamic visualization of intracellular pH fluctuations.This work presents a versatile platform for designing programmable,multistimuli-responsive molecular systems with potential in adaptive materials,chemical sensing,and advanced biomedical diagnostics.
文摘This paper reported the synthesis of hexaar-ylbiimidazole-tetraphenylethene(HABI-TPE)conjugated photochromic fluorophore,which simultaneously exhib-ited photochromic property,condensed state enhanced emission and reversible fluorescence switching.Upon UV irradiation,a green species with a broad absorption band between 550 and 800 nm(the absorption maximum at 697 nm)was observed,which readily faded to colorless in the darkness.HABI-TPE launched strong fluorescence with the maximum emission wavelength at 520580 nm under the excitation with 450-500 nm visible light in condensed state,which is in contrast to nonfluorescence in solution.The maximum emission wavelength in condensed state was dependent of excitation wavelength.More interest-ingly,HABI-TPE exhibited reversible fluorescence switch-ing upon alternating irradiation with blue or near-UV light(wavelength less than 490 nm)and green light(more than 490 nm)in condensed state.Our evaluation demonstrated that HABI-TPE exhibited great photoswitchable fluores-cence,which is a promising photoswitchable fluorophore for localization-based super-resolution microscopy,evi-dencing by resolving nanostructures with sub-100nm resolution in polymethylmethacrylate films.
基金the financial support of the State National Natural Science Foundation of China (No.50325311)National 863 Project Foundation of China(No.2007AA10Z334)
文摘A new acid-base fluorescent switch containing both imidazo[4,5-f][1,10]-phenanthroline and triphenylamine groups has been synthesized.Its fluorescence emissions and absorptions can be reversibiy changed through protonation/deprotonation of imidazole and amine moiety by controlling the intramolecular charge transfer（ICT） process,leading to off-on-off fluorescent molecular switching.
基金Supported by the National Natural Science Foundation of China(No.20675009)
文摘With the decrease of pH value from 8.45 to -1.0, the UV-Vis absorption and fluorescent spectra of 1,2-bis（4-pyridyl） ethylene（BPE） took on the same changing trend at four different successive pH stages： 8.45--7.20, 7.20--5.62, 5.62--2.60, and 2.60--1.0, namely, no change, decrease, increase, and decrease again. Among these, in a range of 7.20--5.62, the fluorescence wavelength blueshifted from 418 to 359 nm, but the UV-Vis absorption wavelength, in contrast, redshifted from 285 to 298 nm. The fluorescence intensity of BPE had a drop even to quench upon a decline in the pH value from 2.60 to -1.0 probably owing to its cation-re interaction to reduce the π electron cloud density of BPE. Two dissociation constants, pKa1（4.30±0.01） and PKa2（5.65±0.04）, were obtained based on fluorescence data. The changes of fluorescence spectra indicate that BPE has ＂oft-on-off＂ switch behavior. The fluorescent spectra of BPE were nearly independent on the presence of α- and β-cyclodextrins.
基金Financial support from the NNSF of China(Nos.20375044 and 20435030)the Chinese Academy of Sciences(KJCX2-SW-H06)is acknowledged.
文摘1-Imino nitroxide pyrene 1 has been characterized as a H^＋ fluorescent switch. The effects of various interfering species, solvents and the irradiation of ultraviolet light on the fluorescence intensity of 1 are also investigated. 1 fluoresces weakly in the 85% ethanol media containing no more than 4.5x10-5 mol/L of H^＋ （HCI）, but can produce a burst increase of about 4 times in the fluorescence intensity when the concentration of H＋ is increased to or over 4.9×10^-5mol/L. The extremely sharp response of 1 to H＋ occurs only within such a narrow concentration range. Moreover, the decrease of H^＋ concentration through adding sodium hydroxide causes the fluorescence quenching, suggesting that 1 may serve as a fluorescent switch for monitoring the concentration change of H＋ around the point of 4.5×10^-5 mol/L.
基金This work was supported in part by the Fundamental Research Funds for the Central Universities(HUST2010MS101),the NSFC(20874025)the Program for New Century Excellent Talents(NCET-07-00273)+1 种基金National Key Basic Research Program of China(2007CB310500)the National Science Foundation(NSF)Chemistry Division(CHE-0805547).
文摘Photosensitive fluorescent probes have become powerful tools in chemical biology and molecular biophysics,which are used to investigate cellular processes with high temporal and spatial resolution.Accordingly,photosensitive fluorescent probes,including photoactivatable,photoconvertible,and photoswitchable fluorophores,have been extensively developed during the past decade.The photoswitchable fluorophores have received much attention because they highlight cellular events clearly.This minireview summarizes recent advances of using reversibly photoswitchable fluorophores and their applications in innovative bioimaging.Photoswitchable fluorophores include photoswitchable fluorescent proteins,photoswitchable fluorescent organic molecules(dyes),and photoswitchable fluorescent nanoparticles.Several strategies have been developed to synthesize photoswitchable fluorophores,including engineering combination proteins,chemical synthesis,polymerization,and self-assembly.Here we concentrate on polymer nanoparticles with optically switchable emission properties:either fluorescence on/offor dualalternating-color fluorescence photoswitching.The essential mechanisms of fluorescence photoswitching enable different types of photoswitchable fluorophores to change emission intensity or wavelength(color)and thus validating the basis of the fluorescence on/offor dual-color photoswitching design.Generally the possible applications of any fluorophores are to label biological targets,followed by specific imaging.The newly developed photoswitchable fluorophores enable super-resolution fluorescence imaging because of their photosensitive emission.Finally,we summarize the important area regarding future research and development on photoswitchable fluorescent nanoparticles.
基金National Natural Science Foundation of China (No.21801063)Top-Notch Talents Program of Henan Agricultural University (No.30501049)+1 种基金Natural Science Foundation of Henan Province (No.232300420132)the Merit Funding for the Oversea Staff of Henan Province for financial support
文摘A photochromic molecular rotor based on stiff-stilbene(SSB-FMR)was handily prepared through coupled reaction,and further self-assembled with cucurbit[8]uril(CB[8])to form a 2:2 quaternary supramolecu-lar complex(SSB-FMR/CB[8]).Significantly,the intervention of CB[8]on SSB-FMR achieved dual functions that assembly-induced emission enhancement and assembly-induced improvement of photoisomerized performance(especially reversibility)of stiff-stilbene molecular photoswitch.The supramolecular strategy further facilitated the assembly as a photoresponsive fluorescence switch with outstanding fatigue resis-tance,which was expediently applied in high-security-level QR code anti-counterfeiting and controllable lysosome targeted imaging.The study unprecedentedly provides a supramolecular method for highly effi-ciently improving photoisomerized performance especially reversibility of molecular photoswitches based on stiff-stilbene,and is of vital significance for the construction of intelligent materials with excellent ca-pability.
基金the Ministry of Science and Technology of China(Nos.2017YFA0204503,2016YFB0401100)the National Natural Science Foundation of China(Nos.21875259,51725304,51633006,61890943,91833306,51822308,21975263)the Strategic Priority Research Program(No.XDB12030300)of the Chinese Academy of Sciences and Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXXM-202012)。
文摘In this article,an acid-responsive luminescent material,1,4-di(quinoline-6-yl)buta-1,3-diyne(DQBD)is designed and synthesized.Upon different pH values,gradual changes of fluorescence colors for DQBD in both solution and solid phases are demonstrated due to the protonation effect.Moreover,such responsive characteristics can also be reversible,suggesting DQBD as a promising fluorescent material with great potential for reusable-and accurate-p H sensors in the future.
基金Natural Science Foundation of Chongqing,Grant/Award Number:cstc2021jcyj-msxmX0980Fundamental Research Fund for the Central University,Grant/Award Number:3102019jcc005+1 种基金Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,Grant/Award Number:CX2021053Research Fund of the State Key Laboratory of Solidification Processing,Grant/Award Number:2020-QZ-01。
文摘Fluorescence photoswitch is becoming increasingly desirable for many applications,but its controllable fabrication still remains challenging yet.In this paper,a new strategy is proposed to fabricate fluorescence photoswitch by harnessing dual roles of albumin proteins as both photochrome carriers and biotemplates of fluorophore.As an example,we demonstrated the successful fabrication of a fluorescence photoswitch by incorporating both the photochromic diarylethene dye(CMTE)and red-emitting fluorescent gold nanoclusters(AuNCs)into the specific domains of bovine serum albumin(BSA)in a highly controllable manner.Detailed spectral and photophysical characterisation showed that CMTE well-retains the photochromic properties within the CMTE–BSA–AuNC construct,although its photoconversion rate is slightly retarded.Different from previously reported photoswitches,the fluorescence of the present system is mainly modulated via the inner filter effect(IFE)mechanism,which exhibits high switching efficiency with an on-off ratio up to 90%,reversible fluorescence response and good antifatigue performance.This work provides a new,generable albumin protein-assisted strategy of fabricating advanced fluorescence photoswitch,which can find wide applications in biological,optical and information fields.
基金supported by the National Natural Science Foundation of China (NSFC) under Grant No.60736005 and 60425101-1the Foundation for Innovative Research Groups of the NSFC under Grant No.60721001+3 种基金Provincial Project under grant No.9140A02060609DZ0208 and No.20090185110020Program for New Century Excellent Talents in University under Grant No.NCET-06-0812 and No. 08-0088SRF for ROCS,SEM under Grant No.GGRYJJ08-05Young Excellent Project of Sichuan Province under Grant No.09ZQ026-074
文摘In recent years, great progress has been made in research and development of small-molecule organic materials with various low-dimensional nanostructures. This paper presents a comprehensive review of recent research progress in this field, including preparation, electronic and optoelectronic properties and applications. First, an introduction gives to the reprecipitation, soft templates methods, and progress in synthesis and morphological control of low-dimensional small-molecule organic nanomaterials. Their unique optical and electronic properties and research progress in these aspects are reviewed and discussed in detail. Applications based on low-dimensional small-molecule organic nanomaterials are briefly described. Finally, some perspectives to the future development of this field are addressed.
基金supported by the National Natural Science Foundation of China(22277014,22077048)the Guangxi Natural Science Foundation(AD21220061,2021GXNSFDA075003)+2 种基金the Startup Fund of Guangxi University(A3040051003)the financial support from the National Research Foundation of Republic of Korea(CRI Project No.2018R1A3B1052702,J.S.K)the University of Bath and the Open Research Fund of the School of Chemistry and Chemical Engineering,Henan Normal University(2020ZD01)for support。
文摘Dyes endowed with aggregation-induced emission(AIE)properties represent a very significant class of chromophores.Nonetheless,current AIE dyes have yet to possess a readily tunable fluorescence switching mechanism.Here,we delineate a structurally distinctive family of dyes,termed XD dyes,which exhibit AIE attributes.Notably,the novel XD dyes feature an intrinsic helical cyclization as a tunable fluorescence switch,conferring them with an advantage over conventional AIE fluorophores.Initially,the fluorescence of the XD dyes in water-tetrahydrofuran mixtures was investigated through spectral analysis as the volume of the aqueous component increased.Subsequently,particle size analysis,in conjunction with scanning electron microscopy(SEM),was employed to substantiate the aggregation propensity of the XD dyes.Of particular significance,XD-4 was observed for the first time to exhibit pronounced solid-state fluorescence,thereby corroborating the XD dyes'capacity for robust fluorescence emission in the aggregated state.Moreover,alterations in optical properties and aggregation behavior of the XD dyes were elucidated theoretically through quantum chemical computations and molecular dynamics simulations.Critically,the calculated reorganization energy of XD-4 was reduced in an aqueous medium was reduced compared to the gas phase,providing further confirmation of its AIE nature.The unique AIE characteristics of the XD dyes were validated through the integration of experimental data and theoretical insights,offering novel perspectives for the advancement of highperformance fluorescent dyes and probes.
基金financial support from the Natural Science Foundation of Henan Province(No.222300420501)the Science and Technology Project of Henan Province(No.212102210549)+1 种基金the Key Scientific Research Project of Higher Education of Henan Province(No.22A430007)National College Students Innovation and Entrepreneurship Training Program(No.202110482010)。
文摘Three novel dithienylethenes modified by bifluoroboron β-diketonate fragments have been successfully developed. Upon blue light irradiation, they reached photostationary state within 2-5 s, as well as 100% conversion ratio and photocyclization quantum yield of > 0.70. Such fascinating photochromism were endowed by collaborative role of electron-withdrawing effect of BF_(2)bdk group to reduce HOMO-LUMO electronic gap for the open isomer, together with intramolecular hydrogen bonds and CH-π interactions favoring antiparallel conformation fixation. Moreover, they displayed specific discrimination and photoswitchable bacterial imaging for S. aureus.
文摘In the version of article originally published in the volume 68,2025 of Sci China Chem(pages 3675-3688),the article was published in subscription format rather than open access format due to an oversight during the production stage.The corrected copyright and open access notes are provided below.The original article has been corrected.
基金supported by the National Natural Science Foundation of China (22271203)the State Key Laboratory of Organometallic Chemistry of Shanghai Institute of Organic Chemistry(KF2021005)+2 种基金the Collaborative Innovation Center of Suzhou Nano Science and Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Project of Scientific and Technologic Infrastructure of Suzhou (SZS201905)。
文摘In natural and artificial systems,reversible reactions are commonly asymmetric with respect to the time scale and nature of the stimuli which drive the forward and backward processes.In applications for which switching behavior is required,it is desirable that the reversible reaction goes as close to symmetric as possible;however,such systems are uncommon.Herein,we report an example of ultraviolet(UV)-visible light-regulated asymmetric reversible structural switching involving a diene-based coordination polymer,CP1 and its monocyclobutane product,CP1a.It is possible to cycle at least ten times through a forward [2+2] photocycloaddition reaction and the reverse,photocleavage reaction.A single cycle can be completed within a few minutes.The transformation is accompanied by fast and distinct fluorescence changes,arising from optimisation of the reaction conditions.Density functional theory calculations allow rationalisation of the asymmetric reversible transformation between CP1 and CP1a rather than between CP1 and its dicyclobutane product CP1b.This work provides a clear illustration of reversible structural switching which approaches symmetric behaviour with respect to reaction rate and stimuli.The insights gained from this work also assist in the design of fast,reversible switching materials.
基金supported by the National Natural Science Foundation of China(nos.21835001,51773080,21674041,and 52073116)Program for Changbaishan Scholars of Jilin Province,and the“Talents Cultivation Program”of Jilin University.
文摘Solid-state fluorescent switches with reversible luminescence characteristics have attracted considerable attention because of their broad applications in advanced photonics,such as anticounterfeiting inks,optical writing and erasing,and biological imaging.Herein,we have fabricated a solid-state reversible fluorescent switch under alternating UV(365 nm)and visible light treatments based on a fulgide(FUL)-functionalized tetraphenylethylene(TPE)derivative(TPE-FUL)containing a photochromic group FUL and aggregation-induced emission(AIE)luminogen TPE.TPE-FUL exhibited excellent reversible absorption and luminescence owing to the interconversion between open TPE-FUL(O-TPE-FUL)and closed TPE-FUL(C-TPE-FUL).Photophysical and theoretical investigations revealed that the luminescence of O-TPE-FUL is based on the local excited state of the TPE moiety,whereas the fluorescence quenching of C-TPE-FUL originates from the intramolecular charge transfer from the TPE to the FUL moiety.The excellent reversible photoswitching properties of TPE-FUL in the solid state allows for its potential use in advanced optical memory applications,such as anticounterfeiting,optical writing and erasing,and information encryption.
基金supported by the National Natural Science Foundation of China(51833001,51921002,52103001)the China Postdoctoral Science Foundation(2021T140007,2020M680191).
文摘Polymers with tunable helicity and naked-eye structural change under external stimuli are valuable for fabricating smart materials. Herein, we report a novel thermoresponsive color and fluorescent polyphenylacetylene switch with a tunable critical temperature. It relies on the temperature and solvent sensitivity of intramolecular n→π* interactions between the vicinal carbonyl groups of ester substituents located at 3,5-positions, which are indispensable for forming the cis-cisoid helical conformation of polyene backbones. In a properly chosen solvent, a compressed cis-cisoid helix is stabilized by n→π* interactions at low temperatures and yields a colorless solution. Increasing temperature causes the conformational transition toward an extended cis-transoid helix due to the disruption of n→π* interactions and produces a yellow solution. Reducing the hydrogen bond donating ability or polarity of solvents increases the switching temperature. By introducing a fluorogenic pendant, this conformational transition can also be read out by fluorescence quenching. This work may open a new window for developing intelligent materials through precisely tuning conformational transitions.
