Inspired by the light-dependent signal transduction in nature, we herein report a fully synthetic receptor AZO with the capacity of transmembrane signaling, working by photo-induced change of molecular conformation. O...Inspired by the light-dependent signal transduction in nature, we herein report a fully synthetic receptor AZO with the capacity of transmembrane signaling, working by photo-induced change of molecular conformation. Our receptor has an anchoring group, a rigid and photoresponsive transmembrane unit and a precatalyst tailgroup. After doping in lipid membranes, AZO is membrane anchored and the extended trans-isomer enables the tailgroup to bind with intravesicular Zn^(2+), thereby achieving enzyme activation and triggering downstream events(ester hydrolysis). However, the shortened cis-isomer pulls the tailgroup into lipids, thereby preventing the complexation and all transduction processes. Upon alternative irradiation of ultraviolet(UV) and visible light, the transduction process can be reversible switch between“ON” and “OFF”, achieving light signal transduction. This study provides a new strategy for future design of artificial signal transduction receptors.展开更多
Ion migration is a notorious problem in perovskite solar cells(PSCs)that severely mutilates device performance.Herein,a strategy to inhibit ion migration in situ is developed by using photoisomerization of azobenzene(...Ion migration is a notorious problem in perovskite solar cells(PSCs)that severely mutilates device performance.Herein,a strategy to inhibit ion migration in situ is developed by using photoisomerization of azobenzene(AZO)to immobilize cations in the lattice.During the nucleation process,the photoisomerized cis-AZO reacts with FA^(+),MA^(+)and Pb2+cations in the perovskite precursor by synergistic cation-πinteraction and Lewis base coordination,leading to heterogeneous nucleation to produce uniform perovskite film.Meanwhile,it accelerates conversion of intermediate yellowδ-phase to desired black aphase of FAPb I3for improved crystallinity with well-passivated grain surface.Consequently,defect density is effectively reduced for the perovskite film to demonstrate suppressed carrier recombination and enhanced carrier extraction.Subsequently,the solar cell efficiency is elevated from 21.29%to 23.58%with negligible J-V hysteresis.Long-term stability is also improved,with the bare device without any encapsulation retaining 84%of its initial efficiency after aging 744 hours in ambient.展开更多
The modulational instability of two incoherently coupled beams in azobenzene-containing polymer with photoisomerization nonlinearity is investigated analytically and numerically. Our results show that as a precursor t...The modulational instability of two incoherently coupled beams in azobenzene-containing polymer with photoisomerization nonlinearity is investigated analytically and numerically. Our results show that as a precursor to spatial optical soliton formation, modulational instability can be adjusted and controlled by the wavelength combinations of the signal and background beams. We also discuss the dependences of strength of modulational instability on intensities of two signal beams and background beam. These findings make it possible to predict the formation of incoherently coupled soliton pairs in azobenzene-containing polymer.展开更多
A polymer-bound photosensitizer was synthesized by the reaction of Merrifield resin with 9-anthracenemethanol in the presence of potassium hydride. The photoisomerization of trans-vitamin D3 to cis-vitamin D3 was car...A polymer-bound photosensitizer was synthesized by the reaction of Merrifield resin with 9-anthracenemethanol in the presence of potassium hydride. The photoisomerization of trans-vitamin D3 to cis-vitamin D3 was carried out with this polymer-bound photosensitizer in ethanol and toluene solutions. The experiment results demonstrate that this solid photosensitizer is efficient for the photoismerization and easy for separation from the reaction mixtures.展开更多
A realistic dynamics simulation study is reported for the trans-cis photoisomerization of azobenzene triggered by the n →π^＊ excitation and the results show that the formation ofcis isomer follows the rotational mo...A realistic dynamics simulation study is reported for the trans-cis photoisomerization of azobenzene triggered by the n →π^＊ excitation and the results show that the formation ofcis isomer follows the rotational motion around the N=N bond. The simulation find that the CNN bond angle bending vibrations also play a significant role in the vibronic coupling between the HOMO and LUMO, which essentially leads a nonadiabatic transition of the molecule to the electronic ground state.展开更多
The photoisomerization of trans-stilbene was studied in the water in oil (W/O) micro-emulsion formed by SDS (sodium dodecyl sulfate), n-C5H11OH (1-pentanol) and H2O. The experimental results show that after 2-minute U...The photoisomerization of trans-stilbene was studied in the water in oil (W/O) micro-emulsion formed by SDS (sodium dodecyl sulfate), n-C5H11OH (1-pentanol) and H2O. The experimental results show that after 2-minute UV-irradiation, the yield of cw-stilbene is higher in W/O microemulsion than in homogeneous solvent-n-C5H11OH.展开更多
In the present work, the photoisomerization of 2-methylfuran to 3-methylfuran is investigated with the complete active space SCF （CASSCF） molecular orbital method. Geometries of minima and transition states on the e...In the present work, the photoisomerization of 2-methylfuran to 3-methylfuran is investigated with the complete active space SCF （CASSCF） molecular orbital method. Geometries of minima and transition states on the excited and ground states are fully optimized at the CAS level with a 6-3 IG＊ basis set. A multireference MP2 algorithm that has been implemented in Gaussian is used to correct the energetics for dynamic correlation. The topology and reaction funnels of the singlet, triplet （S0, T1, T2） and potential energy surfaces have been characterized along the reaction coordinates corresponding to the mechanism. The reaction proceeds via two diradical intermediates, one intermediate product and four transition states. The two diradical S 1/T2 and T1/S0 energy surface crossing points are located along the reaction path and a T1/T2 conical intersection is also located. From this point the reaction soon returns to T1 surface. It is the most reasonable that the intersystem crossing from T1 to S0 takes place.展开更多
The trans-cis photoisomerization of pentamethine cyanine dye （Cy5） has been theoretically investigated by the analysis on an analogical molecule model. All possible isomers have been searched by rotating the differe...The trans-cis photoisomerization of pentamethine cyanine dye （Cy5） has been theoretically investigated by the analysis on an analogical molecule model. All possible isomers have been searched by rotating the different bridge C-C bonds of the model. The relative stability of the isomers for the ground and first excited states as well as the corresponding excitation mechanism has been envisaged by DFT and time-dependent DFT method. The results show different conjugation degree of the isomers resulting in different absorption energy upon the different C-C bridge bond rotation. From the analyses of electronic density distribution of the frontier orbitals, it is predicted that there is charge transfer besides the π-π^＊ excitation for the cyanine dye model, which makes the mechanism and photo-properties different form those of other conjugated molecules.展开更多
In this study, the photoisomerization of trans-stilbene was carded out in water in oil （W/O） microemulsions by using sodium dodecyl sulfate （SDS）, dodecyl trimethyl ammonium bromide （DTAB） and cetyl trimethyl am...In this study, the photoisomerization of trans-stilbene was carded out in water in oil （W/O） microemulsions by using sodium dodecyl sulfate （SDS）, dodecyl trimethyl ammonium bromide （DTAB） and cetyl trimethyl ammonium bromide （CTAB） as surfactant, respectively. The catalytic effect of microemulsion on this reaction is closely related to the structure of surfactant. When there is no photosensitizer 9,10-dicyanoanthracene （DCA）, the surfactant with shorter hydrophobic chain is preferred, while in the presence of DCA, the surfactant with anionic polar group is preferred.展开更多
Photoisomerization of a new polymer: monoesters of polymaleic acid containing naphthalene-azo-anthraquinone groups in side chains at the air-water interface of a Langmuir trough wan detected by recording the developme...Photoisomerization of a new polymer: monoesters of polymaleic acid containing naphthalene-azo-anthraquinone groups in side chains at the air-water interface of a Langmuir trough wan detected by recording the development of surface pressure with time. This process wan found to be a first-order reaction and complete within several minutes.展开更多
Study of interfacial processes between incorporated biomolecules and hydrogel matrix is of primary importance for the application of synthetic hydrogels as biomaterials, sensors, etc. Their hydrophilic nature, however...Study of interfacial processes between incorporated biomolecules and hydrogel matrix is of primary importance for the application of synthetic hydrogels as biomaterials, sensors, etc. Their hydrophilic nature, however, hampers fat-soluble biomolecule incorporation. We synthesized N-isopropylacrylamide (NIPAAm)- and Acrylamide (AA)-based hydrogels with hydrophilic-lipophilic balance that under specific conditions permit homogeneous incorporation of provitamins D3(7-dehydrocholesterol) and D2(ergosterol) dissolved in ethanol. Similarity of provitamins D photoisomerization in such hydrogel matrices with the photoreaction in ethanol shows great potential of the novel material for personal dosimetry of biologically active ‘antirachitic’ UV radiation.展开更多
Studies of direction of photoisomerization of retinal,retinonitrile,a- retinonitrile and a trienenitrile analog in different solvents with varying wave- lengths of excitation and reaction temperature led to the conclu...Studies of direction of photoisomerization of retinal,retinonitrile,a- retinonitrile and a trienenitrile analog in different solvents with varying wave- lengths of excitation and reaction temperature led to the conclusion that the well known solvent dependent photochemistry of retinoids is due to selective excitation of the hydrogen bonded species.展开更多
Microscale covert photonic barcodes demonstrate exceptional potential in anti-counterfeiting and information security applications due to their advanced security characteristics.However,the current methods suffer from...Microscale covert photonic barcodes demonstrate exceptional potential in anti-counterfeiting and information security applications due to their advanced security characteristics.However,the current methods suffer from spectral overlap and low concealment of security,restricting encoding capacity and requiring a high security level.These inherent drawbacks significantly restrict both the encoding capacity and the achievable security level.Here,we proposed a strategy to construct the high-security photonic barcodes via photomerization manipulation based on an excited-state intramolecular proton transfer(ESIPT)process in dye-doped whispering gallery mode(WGM)microcavities.The WGM microcavity is composed of highly polarized organic intramolecular charge-transfer(ICT)dye molecules,which have two cooperative gain states.Moreover,the light-manipulated covert photonic barcodes have further been obtained through an ESIPT energy-level process between the trans-excited state and cis-excited state.The WGM lasing spectrum constitutes the fingerprint of the corresponding microsphere,which can be modulated through tuning the dimensions of the microspheres.These results offer a promising route for exploring the light-manipulated security platform for advanced information anticounterfeiting.展开更多
Covalent organic framework(COF)is a desirable platform to tailor electronic properties for improving photocatalytic performances.However,the study on excited-state configurations that determine photogenerated carrier ...Covalent organic framework(COF)is a desirable platform to tailor electronic properties for improving photocatalytic performances.However,the study on excited-state configurations that determine photogenerated carrier dynamics has long been neglected.Herein,we concentrate on the molecular design ofβ-ketoenamine-linked COFs to drive their photoisomerization via the excited-state intra-molecular proton transfer(ESIPT),which can induce the partial keto-to-enol tautomerization and accordingly rearrange the photoinduced charge distribution.We demonstrate that the push-pull electronic effect of functional side groups attached on the framework linkers is directly correlated with the ESIPT process.The phenylene linkers modified with electron-withdrawing cyano-groups reinforce the ESIPT-induced tautomerization,leading to the in situ partial enolization for extendedπ-conjugation and rearranged electron-hole distribution.In contrast,the electron-rich linkers limit the photoisomerization of COF and suppress the photoinduced electron accumulation.Thus,the maximum hydrogen evolution rate is achieved by the cyano-modified COF,reaching as high as 162.72 mmol·g^(-1)·h^(-1) with an apparent quantum efficiency of 13.44%at 475 nm,which is almost 11.5-fold higher than those of analogous COFs with electron-rich linkers.Our work opens up an avenue to control over the excited-state structure transformation for enhanced photochemical applications.展开更多
The development of azobenzene photoisomerization materials marks a pivotal advancement in solar-thermal conversion technologies.Their properties and performance,explored through comprehensive characterization,are vita...The development of azobenzene photoisomerization materials marks a pivotal advancement in solar-thermal conversion technologies.Their properties and performance,explored through comprehensive characterization,are vital for further progress.Despite extensive research in this area,a detailed summary of characterization methods for azobenzene materials remains largely unexplored.This review addresses this gap by detailing structural and performance characterization techniques.It provides an in-depth overview of various experimental methods,highlighting their objectives,operational mechanics,and practical applications.This detailed review sheds light on the complex relationship between the materials'structure and their performance.Moreover,the review presents a critical analysis of these methods,assessing their strengths and limitations.By doing so,it highlights the revolutionary potential of azobenzene materials in the realm of solar energy conversion and underscores their significance in fostering sustainable energy solutions.展开更多
A diad compound 3 beta(bicyclo[2,2,1]hepta-2,5-diene-2-methylcarboxylate-3-carboxy)-androst-5-en-17-one (NBD-S-ONE) was synthesized and its photochemistry was examined. Irradiation of NBD-S-ONE in acetonitrile at lamb...A diad compound 3 beta(bicyclo[2,2,1]hepta-2,5-diene-2-methylcarboxylate-3-carboxy)-androst-5-en-17-one (NBD-S-ONE) was synthesized and its photochemistry was examined. Irradiation of NBD-S-ONE in acetonitrile at lambda > 300 nm selectively excited the keto chromophore. After intersystem crossing, the triplet energy of the keto group was transferred to the NBD group with 18.6% efficiency via a through-bond mechanism, resulting in the isomerization of the latter group to the quadricyclane group.展开更多
RGD peptides linked with a nonnatural amino acid, phenylazophenyl alaninine (azoAla), were synthesized and applied to cell adhesion inhibitors. The RGD peptides linked with azoAla at C terminal showed potent binding ...RGD peptides linked with a nonnatural amino acid, phenylazophenyl alaninine (azoAla), were synthesized and applied to cell adhesion inhibitors. The RGD peptides linked with azoAla at C terminal showed potent binding to the integrin on the surface of HeLa cells. Photoisomerization effect of the azobenzene side chain of synthesized peptides on the cell adhesion inhibition was further investigated. It was demonstrated that the cis form of azoAla linked RGD peptides revealed a little weak cell adhesion inhibition effect as compared with trans form of azoAla linked RGD peptide.展开更多
Herein we have employed high-level multi-reference CASSCF and MS-CASPT2 electronic structure methods to systematically study the photochemical mechanism of intramolecularly hydrogen-bonded 2-（2＇-hydroxyphenyl）-4-me...Herein we have employed high-level multi-reference CASSCF and MS-CASPT2 electronic structure methods to systematically study the photochemical mechanism of intramolecularly hydrogen-bonded 2-（2＇-hydroxyphenyl）-4-methyloxazole. At the CASSCF level, we have optimized minima, conical intersections, minimum-energy reaction paths relevant to the excited-state intramolecular proton transfer （ESIPT）, rotation, photoisomerization, and the excited-state deactivation pathways. The energies of all structures and paths are refined by the MS-CASPT2 method. On the basis of the present results, we found that the ESIPT process in a conformer with the OH... N hydrogen bond is essentially barrierless process; whereas, the ESIPT process is inhibited in the other conformer with the OH... O hydrogen bond. The central single-bond rotation of the S1 enol species is energetically unfavorable due to a large barrier. In addition, the excited-state deactivation of the S1 keto species, as a result of the ultrafast ESIPT, is very efficient because of the existence of two easily-approached keto S1/S0 conical intersections. In stark contrast to the S1 keto species, the decay of the S1 enol species is almostly blocked. The present theoretical study contributes valuable knowledge to the understanding of photochemistry of similar intramolecularly hydrogen-bonded molecular and biological systems.展开更多
The excited state characters of HY103 have been studied by means of time-resolved photon emission （time-correlated single photon counting） and time dependent density functional theory calculations. The experimental ...The excited state characters of HY103 have been studied by means of time-resolved photon emission （time-correlated single photon counting） and time dependent density functional theory calculations. The experimental and theoretical results demonstrate that HY103 dyes undergo an efficient one-bond-flip motion after photoexicitation at room temperature, which leads to a very short lifetime of the normM fluorescence state, and a weak fluorescence emission around 670 am. However, when HY103 are excited in amorphous glasses at 77 K, the normal fluorescence emission is prolonged to nanoseconds time scale about 2 ns, and the fluorescence emission is enhanced. Furthermore, a new emission state is produced, which is characterized as a volume-conserved twisted （VCT） state. This is the first observation of a VCT state. The experiment indicates that the VCT motion of excited state of π-conjugated molecules in restricted environment can form a stable emission state, and the excited state character of π-conjugated molecules in restricted environment is complex.展开更多
基金supported by the National Natural Science Foundation of China (No. 22171085)Shanghai Frontier Science Research Base of Optogenetic Techniques for Cell Metabolism (Shanghai Municipal Education Commission, No. 2021 Sci & Tech 03–28)。
文摘Inspired by the light-dependent signal transduction in nature, we herein report a fully synthetic receptor AZO with the capacity of transmembrane signaling, working by photo-induced change of molecular conformation. Our receptor has an anchoring group, a rigid and photoresponsive transmembrane unit and a precatalyst tailgroup. After doping in lipid membranes, AZO is membrane anchored and the extended trans-isomer enables the tailgroup to bind with intravesicular Zn^(2+), thereby achieving enzyme activation and triggering downstream events(ester hydrolysis). However, the shortened cis-isomer pulls the tailgroup into lipids, thereby preventing the complexation and all transduction processes. Upon alternative irradiation of ultraviolet(UV) and visible light, the transduction process can be reversible switch between“ON” and “OFF”, achieving light signal transduction. This study provides a new strategy for future design of artificial signal transduction receptors.
基金supported by the National Natural Science Foundation of China(21603140)the 111 Project(B21005)。
文摘Ion migration is a notorious problem in perovskite solar cells(PSCs)that severely mutilates device performance.Herein,a strategy to inhibit ion migration in situ is developed by using photoisomerization of azobenzene(AZO)to immobilize cations in the lattice.During the nucleation process,the photoisomerized cis-AZO reacts with FA^(+),MA^(+)and Pb2+cations in the perovskite precursor by synergistic cation-πinteraction and Lewis base coordination,leading to heterogeneous nucleation to produce uniform perovskite film.Meanwhile,it accelerates conversion of intermediate yellowδ-phase to desired black aphase of FAPb I3for improved crystallinity with well-passivated grain surface.Consequently,defect density is effectively reduced for the perovskite film to demonstrate suppressed carrier recombination and enhanced carrier extraction.Subsequently,the solar cell efficiency is elevated from 21.29%to 23.58%with negligible J-V hysteresis.Long-term stability is also improved,with the bare device without any encapsulation retaining 84%of its initial efficiency after aging 744 hours in ambient.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574167)
文摘The modulational instability of two incoherently coupled beams in azobenzene-containing polymer with photoisomerization nonlinearity is investigated analytically and numerically. Our results show that as a precursor to spatial optical soliton formation, modulational instability can be adjusted and controlled by the wavelength combinations of the signal and background beams. We also discuss the dependences of strength of modulational instability on intensities of two signal beams and background beam. These findings make it possible to predict the formation of incoherently coupled soliton pairs in azobenzene-containing polymer.
文摘A polymer-bound photosensitizer was synthesized by the reaction of Merrifield resin with 9-anthracenemethanol in the presence of potassium hydride. The photoisomerization of trans-vitamin D3 to cis-vitamin D3 was carried out with this polymer-bound photosensitizer in ethanol and toluene solutions. The experiment results demonstrate that this solid photosensitizer is efficient for the photoismerization and easy for separation from the reaction mixtures.
基金supported by the National Natural Science Foundation of China (No.20773168)Natural Science Foundation Project of CQ CSTC (No.2006BB2367 and 2006BB5368)Project of Science Technology Foundation of Chongqing Education Committee (No.KJ070506).
文摘A realistic dynamics simulation study is reported for the trans-cis photoisomerization of azobenzene triggered by the n →π^＊ excitation and the results show that the formation ofcis isomer follows the rotational motion around the N=N bond. The simulation find that the CNN bond angle bending vibrations also play a significant role in the vibronic coupling between the HOMO and LUMO, which essentially leads a nonadiabatic transition of the molecule to the electronic ground state.
文摘The photoisomerization of trans-stilbene was studied in the water in oil (W/O) micro-emulsion formed by SDS (sodium dodecyl sulfate), n-C5H11OH (1-pentanol) and H2O. The experimental results show that after 2-minute UV-irradiation, the yield of cw-stilbene is higher in W/O microemulsion than in homogeneous solvent-n-C5H11OH.
基金This project was supported by the Yunnan Provincial Science and Technology Department (2003A0003M)
文摘In the present work, the photoisomerization of 2-methylfuran to 3-methylfuran is investigated with the complete active space SCF （CASSCF） molecular orbital method. Geometries of minima and transition states on the excited and ground states are fully optimized at the CAS level with a 6-3 IG＊ basis set. A multireference MP2 algorithm that has been implemented in Gaussian is used to correct the energetics for dynamic correlation. The topology and reaction funnels of the singlet, triplet （S0, T1, T2） and potential energy surfaces have been characterized along the reaction coordinates corresponding to the mechanism. The reaction proceeds via two diradical intermediates, one intermediate product and four transition states. The two diradical S 1/T2 and T1/S0 energy surface crossing points are located along the reaction path and a T1/T2 conical intersection is also located. From this point the reaction soon returns to T1 surface. It is the most reasonable that the intersystem crossing from T1 to S0 takes place.
基金supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (2008-890)The Key Project of Educational Committee of Anhui Province (KJ2010A143)+1 种基金Special Project (xzx200812)Doctor’s Project Grant of Anhui Normal University
文摘The trans-cis photoisomerization of pentamethine cyanine dye （Cy5） has been theoretically investigated by the analysis on an analogical molecule model. All possible isomers have been searched by rotating the different bridge C-C bonds of the model. The relative stability of the isomers for the ground and first excited states as well as the corresponding excitation mechanism has been envisaged by DFT and time-dependent DFT method. The results show different conjugation degree of the isomers resulting in different absorption energy upon the different C-C bridge bond rotation. From the analyses of electronic density distribution of the frontier orbitals, it is predicted that there is charge transfer besides the π-π^＊ excitation for the cyanine dye model, which makes the mechanism and photo-properties different form those of other conjugated molecules.
文摘In this study, the photoisomerization of trans-stilbene was carded out in water in oil （W/O） microemulsions by using sodium dodecyl sulfate （SDS）, dodecyl trimethyl ammonium bromide （DTAB） and cetyl trimethyl ammonium bromide （CTAB） as surfactant, respectively. The catalytic effect of microemulsion on this reaction is closely related to the structure of surfactant. When there is no photosensitizer 9,10-dicyanoanthracene （DCA）, the surfactant with shorter hydrophobic chain is preferred, while in the presence of DCA, the surfactant with anionic polar group is preferred.
文摘Photoisomerization of a new polymer: monoesters of polymaleic acid containing naphthalene-azo-anthraquinone groups in side chains at the air-water interface of a Langmuir trough wan detected by recording the development of surface pressure with time. This process wan found to be a first-order reaction and complete within several minutes.
文摘Study of interfacial processes between incorporated biomolecules and hydrogel matrix is of primary importance for the application of synthetic hydrogels as biomaterials, sensors, etc. Their hydrophilic nature, however, hampers fat-soluble biomolecule incorporation. We synthesized N-isopropylacrylamide (NIPAAm)- and Acrylamide (AA)-based hydrogels with hydrophilic-lipophilic balance that under specific conditions permit homogeneous incorporation of provitamins D3(7-dehydrocholesterol) and D2(ergosterol) dissolved in ethanol. Similarity of provitamins D photoisomerization in such hydrogel matrices with the photoreaction in ethanol shows great potential of the novel material for personal dosimetry of biologically active ‘antirachitic’ UV radiation.
文摘Studies of direction of photoisomerization of retinal,retinonitrile,a- retinonitrile and a trienenitrile analog in different solvents with varying wave- lengths of excitation and reaction temperature led to the conclusion that the well known solvent dependent photochemistry of retinoids is due to selective excitation of the hydrogen bonded species.
基金supported by the National Key R&D Program of China(Nos.2023YFB2806702 and 2023YFB2905603)the Zhejiang Provincial Natural Science Foundation of China(No.LQN25A040001)the Research Initiation Project of China Jiliang University(No.241197)。
文摘Microscale covert photonic barcodes demonstrate exceptional potential in anti-counterfeiting and information security applications due to their advanced security characteristics.However,the current methods suffer from spectral overlap and low concealment of security,restricting encoding capacity and requiring a high security level.These inherent drawbacks significantly restrict both the encoding capacity and the achievable security level.Here,we proposed a strategy to construct the high-security photonic barcodes via photomerization manipulation based on an excited-state intramolecular proton transfer(ESIPT)process in dye-doped whispering gallery mode(WGM)microcavities.The WGM microcavity is composed of highly polarized organic intramolecular charge-transfer(ICT)dye molecules,which have two cooperative gain states.Moreover,the light-manipulated covert photonic barcodes have further been obtained through an ESIPT energy-level process between the trans-excited state and cis-excited state.The WGM lasing spectrum constitutes the fingerprint of the corresponding microsphere,which can be modulated through tuning the dimensions of the microspheres.These results offer a promising route for exploring the light-manipulated security platform for advanced information anticounterfeiting.
基金financially supported by the NSFC(Nos.52173197 and 52373202).
文摘Covalent organic framework(COF)is a desirable platform to tailor electronic properties for improving photocatalytic performances.However,the study on excited-state configurations that determine photogenerated carrier dynamics has long been neglected.Herein,we concentrate on the molecular design ofβ-ketoenamine-linked COFs to drive their photoisomerization via the excited-state intra-molecular proton transfer(ESIPT),which can induce the partial keto-to-enol tautomerization and accordingly rearrange the photoinduced charge distribution.We demonstrate that the push-pull electronic effect of functional side groups attached on the framework linkers is directly correlated with the ESIPT process.The phenylene linkers modified with electron-withdrawing cyano-groups reinforce the ESIPT-induced tautomerization,leading to the in situ partial enolization for extendedπ-conjugation and rearranged electron-hole distribution.In contrast,the electron-rich linkers limit the photoisomerization of COF and suppress the photoinduced electron accumulation.Thus,the maximum hydrogen evolution rate is achieved by the cyano-modified COF,reaching as high as 162.72 mmol·g^(-1)·h^(-1) with an apparent quantum efficiency of 13.44%at 475 nm,which is almost 11.5-fold higher than those of analogous COFs with electron-rich linkers.Our work opens up an avenue to control over the excited-state structure transformation for enhanced photochemical applications.
基金supported by the National Natural Science Foundation of China(No.51966015).
文摘The development of azobenzene photoisomerization materials marks a pivotal advancement in solar-thermal conversion technologies.Their properties and performance,explored through comprehensive characterization,are vital for further progress.Despite extensive research in this area,a detailed summary of characterization methods for azobenzene materials remains largely unexplored.This review addresses this gap by detailing structural and performance characterization techniques.It provides an in-depth overview of various experimental methods,highlighting their objectives,operational mechanics,and practical applications.This detailed review sheds light on the complex relationship between the materials'structure and their performance.Moreover,the review presents a critical analysis of these methods,assessing their strengths and limitations.By doing so,it highlights the revolutionary potential of azobenzene materials in the realm of solar energy conversion and underscores their significance in fostering sustainable energy solutions.
基金Project supported by the National Natural Science Foundation of China.
文摘A diad compound 3 beta(bicyclo[2,2,1]hepta-2,5-diene-2-methylcarboxylate-3-carboxy)-androst-5-en-17-one (NBD-S-ONE) was synthesized and its photochemistry was examined. Irradiation of NBD-S-ONE in acetonitrile at lambda > 300 nm selectively excited the keto chromophore. After intersystem crossing, the triplet energy of the keto group was transferred to the NBD group with 18.6% efficiency via a through-bond mechanism, resulting in the isomerization of the latter group to the quadricyclane group.
文摘RGD peptides linked with a nonnatural amino acid, phenylazophenyl alaninine (azoAla), were synthesized and applied to cell adhesion inhibitors. The RGD peptides linked with azoAla at C terminal showed potent binding to the integrin on the surface of HeLa cells. Photoisomerization effect of the azobenzene side chain of synthesized peptides on the cell adhesion inhibition was further investigated. It was demonstrated that the cis form of azoAla linked RGD peptides revealed a little weak cell adhesion inhibition effect as compared with trans form of azoAla linked RGD peptide.
文摘Herein we have employed high-level multi-reference CASSCF and MS-CASPT2 electronic structure methods to systematically study the photochemical mechanism of intramolecularly hydrogen-bonded 2-（2＇-hydroxyphenyl）-4-methyloxazole. At the CASSCF level, we have optimized minima, conical intersections, minimum-energy reaction paths relevant to the excited-state intramolecular proton transfer （ESIPT）, rotation, photoisomerization, and the excited-state deactivation pathways. The energies of all structures and paths are refined by the MS-CASPT2 method. On the basis of the present results, we found that the ESIPT process in a conformer with the OH... N hydrogen bond is essentially barrierless process; whereas, the ESIPT process is inhibited in the other conformer with the OH... O hydrogen bond. The central single-bond rotation of the S1 enol species is energetically unfavorable due to a large barrier. In addition, the excited-state deactivation of the S1 keto species, as a result of the ultrafast ESIPT, is very efficient because of the existence of two easily-approached keto S1/S0 conical intersections. In stark contrast to the S1 keto species, the decay of the S1 enol species is almostly blocked. The present theoretical study contributes valuable knowledge to the understanding of photochemistry of similar intramolecularly hydrogen-bonded molecular and biological systems.
文摘The excited state characters of HY103 have been studied by means of time-resolved photon emission （time-correlated single photon counting） and time dependent density functional theory calculations. The experimental and theoretical results demonstrate that HY103 dyes undergo an efficient one-bond-flip motion after photoexicitation at room temperature, which leads to a very short lifetime of the normM fluorescence state, and a weak fluorescence emission around 670 am. However, when HY103 are excited in amorphous glasses at 77 K, the normal fluorescence emission is prolonged to nanoseconds time scale about 2 ns, and the fluorescence emission is enhanced. Furthermore, a new emission state is produced, which is characterized as a volume-conserved twisted （VCT） state. This is the first observation of a VCT state. The experiment indicates that the VCT motion of excited state of π-conjugated molecules in restricted environment can form a stable emission state, and the excited state character of π-conjugated molecules in restricted environment is complex.
