A catalyst-,acid-and base-free,environmental-friendly method for synthesis of 2/7-benzo[g]furo[2,3-e]indazoles,2H-benzo[g]-thieno[2,3-e]indazoles and 2H-benzo[g]pyrrolo[2,3-e]indazoles via UV light irradiation of 3-ph...A catalyst-,acid-and base-free,environmental-friendly method for synthesis of 2/7-benzo[g]furo[2,3-e]indazoles,2H-benzo[g]-thieno[2,3-e]indazoles and 2H-benzo[g]pyrrolo[2,3-e]indazoles via UV light irradiation of 3-phenyl-4-(2-heteroaryl)pyrazoles(aryl=furanyl,thiophenyl and N-methylpyrrolyl)in EtOH/H_(2)O at room temperature under argon atmosphere was described.展开更多
Tetraphenylethene(TPE),a star building block with promising aggregationinduced emission,has received much interest.Given that its intramolecular Woodward-Hoffmann cyclic intermediate instantaneously converts back to t...Tetraphenylethene(TPE),a star building block with promising aggregationinduced emission,has received much interest.Given that its intramolecular Woodward-Hoffmann cyclic intermediate instantaneously converts back to the original state within several picoseconds,the essentially photochromic characteristic of TPE is little investigated.Achieving a visible photocyclization of TPE is still an unsolved issue and considered as the bottleneck in the further advancement of applications.We report a strategy of attaching carbonate ester onto the TPE skeleton(TPE-4C)to enhance TPE photocyclization stability.As demonstrated,the incorporated cholesteryloxycarbonyloxy substituents in TPE-4C can increase the energy barrier for cycloreversion,thereby exhibiting extremely thermal stability of photocyclic intermediate upon UV irradiation,prolonging its lifetime from 63 picoseconds to 46 s by 7.2×10^(11)-fold.The photoinduced cyclization of TPE-4C could be monitored with naked eyes,and the photocyclization/cycloreversion is achieved by turning on/off UV light along with a relative fatigue resistance.Encapsulation of TPE-4C into the liquid crystal can induce a striking phase transformation(achiral↔chiral),which can be applicable to encode optical information.Employing carbonate ester into the TPE unit plays a vital role in enhancing the unprecedented TPE photocyclization stability,providing a toolbox to allow TPE-based photocyclization to be visually monitored.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
Phosphorus-containing functional materials have diverse applications in optoelectronics and bioscience owing to their unique properties.However,polycyclicπ-conjugated phosphonium salts have been rarely explored due t...Phosphorus-containing functional materials have diverse applications in optoelectronics and bioscience owing to their unique properties.However,polycyclicπ-conjugated phosphonium salts have been rarely explored due to their complex synthesis.In this work,a facile and efficient method for constructing polycyclicπ-conjugated phosphonium salts(TBPIMe derivatives)is proposed,based on the photocyclization of phosphindolium salts(TPPIMe derivatives).Systematic experimental and theoretical investigations reveal the changed photophysical and photochemical properties when TPPIMe derivatives are converted to TBPIMe derivatives.Notably,the novel polycyclicπ-conjugated phosphonium salt p-MOTBPIMe exhibits improved reactive oxygen species generation ability and much stronger specific affinity toward DNA than phosphindolium salts p-MOTPPIMe.Moreover,in vitro experiments demonstrate that p-MOTPPIMe can also be efficiently converted into p-MOTBPIMe under 405 nm laser irradiation in living cells,accompanied by the migration from cytoplasm to nucleus to enhance the photodynamic effect.Additionally,p-MOTBPIMe shows superior antibacterial activity against not only Gram-positive drug-resistant bacteria but also fungi,by leveraging both dark and light cytotoxicity.This work opens up a new chemical toolkit for novel polycyclicπ-conjugated phosphonium salts,which are promising for developing advanced theranostic agents with satisfactory accuracy and efficacy.展开更多
Transformation of the electronic spin states has received significant interest in recent years because of its applications in the magnetic information storage materials and optical response switches.However,it can be ...Transformation of the electronic spin states has received significant interest in recent years because of its applications in the magnetic information storage materials and optical response switches.However,it can be formidably challenging to use ultraviolet(UV)light as a contactless stimulus to alter the electronic spin states of the supramolecular cages.Inspired by the approach on the radical cation mechanism of the Scholl reaction and the photocyclization reactivity of tetraphenylethylene(TPE)derivatives,we report two photochromic cages(cage-TPE-1 and cage-TPE-2)that can be photochemically transformed from electron paramagnetic resonance(EPR)-silent to EPR-active form via UV irradiation due to the photo-induced electron transfer process at the TPE moiety.EPR provided a strong single-electron signal with a g value of 2.003 in cage-TPE-1 and cage-TPE-2 but no signal was detected for the pristine samples without the UVexposure.The transformation can be monitored by ultraviolet–visible–near-infrared(UV–vis–NIR)and photoluminescence(PL)spectroscopy.The photogenic radical cage intermediate was unstable in solution resulting in the degradation and intramolecular cyclization of the reactive species,while the radicals were found to be stable and persistent in the solid state due to the spin delocalization,the steric protection of confined cavities,and the oxygen isolation.Both theoretical calculations and spectral measurements suggest that the photogenic radical cage-TPE-2(•+)experiences photocyclization on the TPE core.Compared with the close-shell cage,the radical cage-TPE-1(•+)and cage-TPE-2(•+)exhibit better photothermal conversion performance due to the incubated infrared absorption from open-shell electron feature and reduced band gap.展开更多
The blue light using flavin(BLUF)domain is one of nature’s smallest photoswitching protein domains,yet a cross-species photoactivation mechanism is lacking.Its photoactivation involves an intricate bidirectional prot...The blue light using flavin(BLUF)domain is one of nature’s smallest photoswitching protein domains,yet a cross-species photoactivation mechanism is lacking.Its photoactivation involves an intricate bidirectional proton-coupled electron transfer(PCET)reaction;however,the key reverse PCET route remains largely elusive,with its elementary steps undissected.Here,we resolved the light-state photoreaction cycles of the BLUF domains in 3 species,i.e.,AppA from Rhodobacter sphaeroides,OaPAC from Oscillatoria acuminata,and SyPixD from Synechocystis sp.PCC6803,with a unified kinetic model.Using mutant design and femtosecond spectroscopy,we captured the spectroscopic snapshots of a key proton-relay intermediate in all species,revealing that the light-state photoreaction cycle consists of 4 elementary steps including a forward concerted electron-proton transfer(CEPT),a 2-step proton rocking,and a reverse CEPT.We emphasize that the last reverse CEPT step(1.5 to 3.7 ps)is shared by both the light-state and dark-state photocycles and is essential to the photoswitching functionality.展开更多
Photochromism of two bispyrryl-substituted ethenes, 2, 3-bis-(1-p-methoxyphenyl-5-phenyl-2-methyl-3-pyrryl)-2-butene (BPE1) and 2,3-bis(1-p-bromophenyl-4-phenyl-2-methyl-3-pyrryl)-2-butene (BPE2), was studied by laser...Photochromism of two bispyrryl-substituted ethenes, 2, 3-bis-(1-p-methoxyphenyl-5-phenyl-2-methyl-3-pyrryl)-2-butene (BPE1) and 2,3-bis(1-p-bromophenyl-4-phenyl-2-methyl-3-pyrryl)-2-butene (BPE2), was studied by laser flash photolysis technique. The results indicate that photocyclization of these compounds proceeds mainly via the excited triplet state, and the cis-trans isomerization proceeds mainly via the excited singlet state. After UV laser pulse irradiation, both photocylization and cis-trans isomerization of BPEl occur, but photocydization is the main reaction. On the other hand, laser photolysis of BPE2 leads mainly to photocydization. The effects of the substituents on the photochromic mechanism are also discussed.展开更多
Photochemical reaction is expected to become a promising type of green chemistry with merits of operational flexibility,excellent regioselectivity,high yield,and mild reaction condition.Recently,aggregation-induced em...Photochemical reaction is expected to become a promising type of green chemistry with merits of operational flexibility,excellent regioselectivity,high yield,and mild reaction condition.Recently,aggregation-induced emission(AIE)-based fluorescent molecules with photoresponsivity have been quickly developed and employed in the biomedical field.In this Review,photoresponsive AIE materials based on the inherent photochemical reactions are highlighted according to the photochemical pathways:photoisomerization,photocyclization,photodimerization,and multiple photoreactions.Following this,their biomedical applications are summarized and discussed,including photoactivatable bioimaging,diagnosis,and therapy.Finally,the challenges and future perspectives are presented.展开更多
The inclusion of inorganic nanoparticles in biological environments has led to the creation of hybrid nanosystems that are employed in a variety of applications. One such system includes quantum dots (QDs) coupled wit...The inclusion of inorganic nanoparticles in biological environments has led to the creation of hybrid nanosystems that are employed in a variety of applications. One such system includes quantum dots (QDs) coupled with the photoactive protein, bacteriorhodopsin (BR), which has been explored in developing enhanced photovoltaic devices. In this work, we have discovered that the kinetics of the BR photocycle can be manipulated using CdSe/CdS (core/shell) QDs. The photocycle lifetime of protein samples with varying QD amounts were monitored using time-resolved absorption spectroscopy. Concentration-dependent elongations of the bR and M state lifetimes were observed in the kinetic traces, thus suggesting that excitonic coupling occurs between BR and QDs. We propose that the pairing of BR with QDs has the potential to be utilized in protein-based computing applications, specifically for real-time holographic processors, which depend on the temporal dynamics of the bR and M photointermediates.展开更多
Melittin differentially slowed down the fast (M412f) and the slow (M412s) decay components of the photocyde intermediate M of trimeric bacteriorhodopsin in purple membrane while it accelerated the M412s of Triton X-10...Melittin differentially slowed down the fast (M412f) and the slow (M412s) decay components of the photocyde intermediate M of trimeric bacteriorhodopsin in purple membrane while it accelerated the M412s of Triton X-100-solubilized bacteriorhodopsin monomers. Raising the bulk pH could enhance the effect of melittin on the M412s of bacteriorhodopsin in these two states. From pH 5.5 to 8.8, melittin slightly influenced the yield of intermediate M in purple membrane, whereas the yield of M412s decreased and subsequently reversed with the addition of melittin. Moreover, the monomeric bacteriorhodopsin bleached more readily in the presence of melittin and the higher pH made the bleaching effect of melittin more intensive as well. These results re-certify our former suggestions that there was electrostatic interaction between melittin and bacteriorhodopsin, and indicate that the biphasic M decay may not result from the well-known linear kinetic scheme (M→N →BR). At last the mechanisms underlying the interaction of melittin with purple membranes and bacteriorhodopsin monomers are analyzed.展开更多
基金We are grateful for financial support by the National Natural Science Foundation of China(No.21672132).
文摘A catalyst-,acid-and base-free,environmental-friendly method for synthesis of 2/7-benzo[g]furo[2,3-e]indazoles,2H-benzo[g]-thieno[2,3-e]indazoles and 2H-benzo[g]pyrrolo[2,3-e]indazoles via UV light irradiation of 3-phenyl-4-(2-heteroaryl)pyrazoles(aryl=furanyl,thiophenyl and N-methylpyrrolyl)in EtOH/H_(2)O at room temperature under argon atmosphere was described.
基金supported by NSFC/China(21788102,21636002,21622602,21875143,21908146,and 21908060)Shanghai Municipal Science and Technology Major Project(2018SHZDZX03)+3 种基金Innovation Program of Shanghai Municipal Education Commission,Scientific Committee of Shanghai(15XD1501400)Programme of Introducing Talents of Discipline to Universities(B16017)China Postdoctoral Science Foundation(2019M651417)Innovation Research Foundation of Shenzhen(JCYJ20180507182229597).
文摘Tetraphenylethene(TPE),a star building block with promising aggregationinduced emission,has received much interest.Given that its intramolecular Woodward-Hoffmann cyclic intermediate instantaneously converts back to the original state within several picoseconds,the essentially photochromic characteristic of TPE is little investigated.Achieving a visible photocyclization of TPE is still an unsolved issue and considered as the bottleneck in the further advancement of applications.We report a strategy of attaching carbonate ester onto the TPE skeleton(TPE-4C)to enhance TPE photocyclization stability.As demonstrated,the incorporated cholesteryloxycarbonyloxy substituents in TPE-4C can increase the energy barrier for cycloreversion,thereby exhibiting extremely thermal stability of photocyclic intermediate upon UV irradiation,prolonging its lifetime from 63 picoseconds to 46 s by 7.2×10^(11)-fold.The photoinduced cyclization of TPE-4C could be monitored with naked eyes,and the photocyclization/cycloreversion is achieved by turning on/off UV light along with a relative fatigue resistance.Encapsulation of TPE-4C into the liquid crystal can induce a striking phase transformation(achiral↔chiral),which can be applicable to encode optical information.Employing carbonate ester into the TPE unit plays a vital role in enhancing the unprecedented TPE photocyclization stability,providing a toolbox to allow TPE-based photocyclization to be visually monitored.
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）.
基金supported by the National Natural Science Foundation of China(U23A20594 and 22375066)the Guangdong Basic and Applied Basic Research Foundation(2023B1515040003)the Fundamental Research Funds for the Central Universities(2024ZYGXZR004).
文摘Phosphorus-containing functional materials have diverse applications in optoelectronics and bioscience owing to their unique properties.However,polycyclicπ-conjugated phosphonium salts have been rarely explored due to their complex synthesis.In this work,a facile and efficient method for constructing polycyclicπ-conjugated phosphonium salts(TBPIMe derivatives)is proposed,based on the photocyclization of phosphindolium salts(TPPIMe derivatives).Systematic experimental and theoretical investigations reveal the changed photophysical and photochemical properties when TPPIMe derivatives are converted to TBPIMe derivatives.Notably,the novel polycyclicπ-conjugated phosphonium salt p-MOTBPIMe exhibits improved reactive oxygen species generation ability and much stronger specific affinity toward DNA than phosphindolium salts p-MOTPPIMe.Moreover,in vitro experiments demonstrate that p-MOTPPIMe can also be efficiently converted into p-MOTBPIMe under 405 nm laser irradiation in living cells,accompanied by the migration from cytoplasm to nucleus to enhance the photodynamic effect.Additionally,p-MOTBPIMe shows superior antibacterial activity against not only Gram-positive drug-resistant bacteria but also fungi,by leveraging both dark and light cytotoxicity.This work opens up a new chemical toolkit for novel polycyclicπ-conjugated phosphonium salts,which are promising for developing advanced theranostic agents with satisfactory accuracy and efficacy.
基金Foundation of China(21871133)the Natural Science Foundation of Jiangsu Province(BK20211146)the Science,Technology,and Innovation Commission of Shenzhen Municipality(JCYJ20180307153251975)for financial support。
文摘Transformation of the electronic spin states has received significant interest in recent years because of its applications in the magnetic information storage materials and optical response switches.However,it can be formidably challenging to use ultraviolet(UV)light as a contactless stimulus to alter the electronic spin states of the supramolecular cages.Inspired by the approach on the radical cation mechanism of the Scholl reaction and the photocyclization reactivity of tetraphenylethylene(TPE)derivatives,we report two photochromic cages(cage-TPE-1 and cage-TPE-2)that can be photochemically transformed from electron paramagnetic resonance(EPR)-silent to EPR-active form via UV irradiation due to the photo-induced electron transfer process at the TPE moiety.EPR provided a strong single-electron signal with a g value of 2.003 in cage-TPE-1 and cage-TPE-2 but no signal was detected for the pristine samples without the UVexposure.The transformation can be monitored by ultraviolet–visible–near-infrared(UV–vis–NIR)and photoluminescence(PL)spectroscopy.The photogenic radical cage intermediate was unstable in solution resulting in the degradation and intramolecular cyclization of the reactive species,while the radicals were found to be stable and persistent in the solid state due to the spin delocalization,the steric protection of confined cavities,and the oxygen isolation.Both theoretical calculations and spectral measurements suggest that the photogenic radical cage-TPE-2(•+)experiences photocyclization on the TPE core.Compared with the close-shell cage,the radical cage-TPE-1(•+)and cage-TPE-2(•+)exhibit better photothermal conversion performance due to the incubated infrared absorption from open-shell electron feature and reduced band gap.
基金supported by the National Key Research and Development Program of China(grant 2020YFA0509700)National Natural Science Foundation of China(grant 31971233).
文摘The blue light using flavin(BLUF)domain is one of nature’s smallest photoswitching protein domains,yet a cross-species photoactivation mechanism is lacking.Its photoactivation involves an intricate bidirectional proton-coupled electron transfer(PCET)reaction;however,the key reverse PCET route remains largely elusive,with its elementary steps undissected.Here,we resolved the light-state photoreaction cycles of the BLUF domains in 3 species,i.e.,AppA from Rhodobacter sphaeroides,OaPAC from Oscillatoria acuminata,and SyPixD from Synechocystis sp.PCC6803,with a unified kinetic model.Using mutant design and femtosecond spectroscopy,we captured the spectroscopic snapshots of a key proton-relay intermediate in all species,revealing that the light-state photoreaction cycle consists of 4 elementary steps including a forward concerted electron-proton transfer(CEPT),a 2-step proton rocking,and a reverse CEPT.We emphasize that the last reverse CEPT step(1.5 to 3.7 ps)is shared by both the light-state and dark-state photocycles and is essential to the photoswitching functionality.
基金Project supported by the Chinese Academy of Sciencesthe National Natural Science Foundation of China
文摘Photochromism of two bispyrryl-substituted ethenes, 2, 3-bis-(1-p-methoxyphenyl-5-phenyl-2-methyl-3-pyrryl)-2-butene (BPE1) and 2,3-bis(1-p-bromophenyl-4-phenyl-2-methyl-3-pyrryl)-2-butene (BPE2), was studied by laser flash photolysis technique. The results indicate that photocyclization of these compounds proceeds mainly via the excited triplet state, and the cis-trans isomerization proceeds mainly via the excited singlet state. After UV laser pulse irradiation, both photocylization and cis-trans isomerization of BPEl occur, but photocydization is the main reaction. On the other hand, laser photolysis of BPE2 leads mainly to photocydization. The effects of the substituents on the photochromic mechanism are also discussed.
基金supported by the National Natural Science Foundation of China(21788102)the GuangDong Basic and Applied Basic Research Foundation(2023B1515040003,2022 A 1515010315 and 2019B030301003)the Fundamental Research Funds for the Central Universities(2022ZYGXZR107).
文摘Photochemical reaction is expected to become a promising type of green chemistry with merits of operational flexibility,excellent regioselectivity,high yield,and mild reaction condition.Recently,aggregation-induced emission(AIE)-based fluorescent molecules with photoresponsivity have been quickly developed and employed in the biomedical field.In this Review,photoresponsive AIE materials based on the inherent photochemical reactions are highlighted according to the photochemical pathways:photoisomerization,photocyclization,photodimerization,and multiple photoreactions.Following this,their biomedical applications are summarized and discussed,including photoactivatable bioimaging,diagnosis,and therapy.Finally,the challenges and future perspectives are presented.
基金the National Institutes of Health (GM-34548)the National Science Foundation (No. CAREER-1554800).
文摘The inclusion of inorganic nanoparticles in biological environments has led to the creation of hybrid nanosystems that are employed in a variety of applications. One such system includes quantum dots (QDs) coupled with the photoactive protein, bacteriorhodopsin (BR), which has been explored in developing enhanced photovoltaic devices. In this work, we have discovered that the kinetics of the BR photocycle can be manipulated using CdSe/CdS (core/shell) QDs. The photocycle lifetime of protein samples with varying QD amounts were monitored using time-resolved absorption spectroscopy. Concentration-dependent elongations of the bR and M state lifetimes were observed in the kinetic traces, thus suggesting that excitonic coupling occurs between BR and QDs. We propose that the pairing of BR with QDs has the potential to be utilized in protein-based computing applications, specifically for real-time holographic processors, which depend on the temporal dynamics of the bR and M photointermediates.
基金Project supported by the National Natural Science Foundation of China and Grant for Key Project from the Chinese Academy of Sciences.
文摘Melittin differentially slowed down the fast (M412f) and the slow (M412s) decay components of the photocyde intermediate M of trimeric bacteriorhodopsin in purple membrane while it accelerated the M412s of Triton X-100-solubilized bacteriorhodopsin monomers. Raising the bulk pH could enhance the effect of melittin on the M412s of bacteriorhodopsin in these two states. From pH 5.5 to 8.8, melittin slightly influenced the yield of intermediate M in purple membrane, whereas the yield of M412s decreased and subsequently reversed with the addition of melittin. Moreover, the monomeric bacteriorhodopsin bleached more readily in the presence of melittin and the higher pH made the bleaching effect of melittin more intensive as well. These results re-certify our former suggestions that there was electrostatic interaction between melittin and bacteriorhodopsin, and indicate that the biphasic M decay may not result from the well-known linear kinetic scheme (M→N →BR). At last the mechanisms underlying the interaction of melittin with purple membranes and bacteriorhodopsin monomers are analyzed.
