Photo-switchable molecular magnets are promising in the applications of molecular spintronics,memory and switching devices.Introducing photo-responsive metal-to-metal electron transfer units into the molecular magnets...Photo-switchable molecular magnets are promising in the applications of molecular spintronics,memory and switching devices.Introducing photo-responsive metal-to-metal electron transfer units into the molecular magnets provides a feasible means of controlling the magnetic and related physical properties.Here,we assembled the redox-active octacyanotungstate building block[W^(Ⅴ)(CN)_(8)]^(5-)with Co^(Ⅱ)ion to obtain the metal-to-metal electron transfer(MMET)molecular magnets.Four structure-related twodimensional(2D)compounds 1-4 derived from[W(CN)_8]_(2)[Co_(3)(L)_(12)]·solv(L=1-phenylimidazole)were constructed by modifying phenylimidazole ligands with substituent R at the para position of the aromatic ring(R=CN(L1),NO_(2)(L2),F(L3)and Cl(L4)).Structural analysis indicated that 1-4 underwent a thermal-induced single-crystal to single-crystal(SCSC)phase transition to the desolvated 1a-4a,accompanied by the MMET from(Co_(LS)^(Ⅲ))_(2)-W_(2)^(Ⅳ)-Co_(HS)^(Ⅱ)(LS:low-spin)phase to(Co_(HS)^(Ⅱ))_(2)-W_(2)~Ⅴ-Co_(HS)^(Ⅱ)(HS:high-spin)phase.1a-4a also exhibited incomplete(Co_(HS)^(Ⅱ))_(2)-W_(2)~Ⅴ-Co_(HS)^(Ⅱ)(HS)phase(Co_(LS)^(Ⅲ))_(2)-W_(2)^(Ⅳ)-Co_(HS)^(Ⅱ)(LS)phase transition with thermal hysteresis loops.Photomagnetic characterizations revealed that 1-4 and 1a-4a exhibited a reversible light-induced interconversion between the HS^(*(*):metastable phase generated by light irradiation)state and LS*state.Moreover,for 1,1a and 2,their magnetic hysteresis can be reversibly produced and eliminated by alternating the 946-and 671-nm light irradiations,respectively,showing the photo-switchable molecular magnet behavior.The compared magnetostructural analysis indicated that the intermolecularπ···πstacking interactions between modified phenylimidazole ligands can be modulated by the different electronic and steric hindrance effects of substituents,which regulate the distortion degree of the CoN_(6)octahedron and ligand field around the cobalt ions.The anomalous increase of octahedral distortion parameter Σ_(Co),which increases as the interlayerπ···πinteraction weakens,not only affects the transition temperature,but also plays an important role in stabilizing the photoexcited metastable state.This study demonstrates the feasibility of regulating intermolecular interactions through molecular engineering strategy in developing photo-responsive molecular magnetic materials with enhanced photo operating temperatures,and may offer new insights for advancing the construction of photo-switchable 2D magnets and related molecule-based spintronic devices.展开更多
Photo-switchable metal-organic frameworks(PMOFs)as energy-saving adsorbents for tailorable vip capture show admirable potentials for various applications like adsorptive desulfurization.However,the regulation behavi...Photo-switchable metal-organic frameworks(PMOFs)as energy-saving adsorbents for tailorable vip capture show admirable potentials for various applications like adsorptive desulfurization.However,the regulation behavior of most reported PMOFs is based on weak physical interaction,and it is highly desired to introduce specific active sites to satisfy the demand of higher adsorption capacity and selectivity.Herein,for the first time,we prepared the PMOFs,azobenzene-functionalized HKUST-1(HK-Azo),simultaneously decorated with Cu_(2)O active sites that possess strong interaction with vip molecules.Due toπ-complexation interaction of Cu^(+)with aromatic sulfur compounds,the obtained HK-Azo shows obviously higher adsorption capacity on benzothiophene compared with HKUST-1.Upon ultraviolet(UV)and visible irradiation,azobenzene moieties in the PMOFs can transform their configuration freely and reversibly.Such trans/cis isomerization of azobenzene causes exposure/shelter of Cu_(2)O active sites,leading to controllable benzothiophene capture.The HK-Azo exhibits the change of benzothiophene uptake up to 29.7%upon trans and cis isomerization,which is obviously higher than HKUST-1 with negligible change.This work may inspire the development of new adsorption process regulated by light for adsorptive desulfurization that is impossible to realize by conventional PMOFs.展开更多
In this study,we present an in-depth exploration of charge transport phenomena and variable photo-switching characteristics in a novel double-perovskite-based three-terminal device.The Cs_(2)AgBiBr_(6) thin film(TF)wa...In this study,we present an in-depth exploration of charge transport phenomena and variable photo-switching characteristics in a novel double-perovskite-based three-terminal device.The Cs_(2)AgBiBr_(6) thin film(TF)was synthesized through a three-step thermal evaporation process followed by precise open-air annealing,ensuring superior film quality as confirmed by structural and morphological characterizations.Photoluminescence spectroscopy revealed distinct emissions at 2.28 and 2.07 eV,indicative of both direct and indirect electronic transitions.Our device exhibited space-charge limited current(SCLC)behaviour beyond 0.35 V,aligning with the relationship Current(I)∝Voltage(V)^(m),where the exponent m transitioned from≤1 to>1.Detailed analysis of Schottky parameters within the trap-filled limit(TFL)regime was conducted,accounting for variations in temperature and optical power.Significantly,the self-powered photodetector demonstrated outstanding performance under illumination.The sensitivity of the device was finely tunable via the applied bias voltages at the third terminal.Notably,an optimal bias voltage of±100μV yielded maximum responsivity(R)of 0.48 A/W and an impressive detectivity(D*)of 1.07×10^(9) Jones,highlighting the potential of this double-perovskite-based device for advanced optoelectronic applications.展开更多
Many azo compounds and their intermediates are toxic and have been linked to various health issues,representing a growing global problem.Molecular engineering for selective encapsulation of azobenzene compounds is cri...Many azo compounds and their intermediates are toxic and have been linked to various health issues,representing a growing global problem.Molecular engineering for selective encapsulation of azobenzene compounds is critical,given their significant use in smart materials and prevalence as environmental micropollutants released from the food and dye industries.However,the current host molecules catering to azobenzene compounds are mainly limited to cyclodextrins,pillar[n]arenes and cucurbit[n]urils,demonstrating a moderate affinity.This report describes that a novel 3,3'-bipyridinium-based cyclophane was capable of encapsulating anionic azobenzene compounds in water with high binding affinity and pH stability through electrostatic attraction-enhanced mechanism,surpassing the extensively reported supramolecular systems.1D&2D NMR experiments,UV-vis spectrum,X-ray crystallography and computational modeling were carried out to understand the host-vip complexation.It's worth noting that the tetracationic cyclophane exhibited good selective and anti-interference encapsulation properties in binary,ternary and seawater systems.Furthermore,upon UV/white light irradiation,the reversible conversion between(E)-4,4'-azobisbenzoate and(Z)-4,4'-azobisbenzoate triggers the dissociation/recomplexation of the host-vip complex within 3 min.This reversible photo-switchable(E)-disodium 4,4'-azobisbenzoateBPy-Box^(4+)supramolecular system holds promise for designing novel materials for extraction/release of azo compounds and other small smart materials.展开更多
Stochastic optical reconstruction microscopy(STORM),as a typical technique of single-molecule localization microscopy(SMLM),has overcome the diffraction limit by randomly switching fluorophores between fluorescent and...Stochastic optical reconstruction microscopy(STORM),as a typical technique of single-molecule localization microscopy(SMLM),has overcome the diffraction limit by randomly switching fluorophores between fluorescent and dark states,allowing for the precise localization of isolated emission patterns and the super-resolution reconstruction from millions of localized positions of single fluorophores.A critical factor influencing localization precision is the photo-switching behavior of fluorophores,which is affected by the imaging buffer.The imaging buffer typically comprises oxygen scavengers,photo-switching reagents,and refractive index regulators.Oxygen scavengers help prevent photobleaching,photo-switching reagents assist in facilitating the conversion of fluorophores,and refractive index regulators are used to adjust the refractive index of the solution.The synergistic interaction of these components promotes stable blinking of fluorophores,reduces irreversible photobleaching,and thereby ensures high-quality super-resolution imaging.This review provides a comprehensive overview of the essential compositions and functionalities of imaging buffers used in STORM,serving as a valuable resource for researchers seeking to select appropriate imaging buffers for their experiments.展开更多
Series of azobenzene-bridged pillar[5]arene-based [3]rotaxanes with different alkyl chain length of vip molecules were constructed by threading-endcapping method with alkylenetriazole as axile and tetrahydrochromene...Series of azobenzene-bridged pillar[5]arene-based [3]rotaxanes with different alkyl chain length of vip molecules were constructed by threading-endcapping method with alkylenetriazole as axile and tetrahydrochromene as endcapping group.The encapsulation of pillar[5]arenes were proved by highresolution mass,^(1) H NMR and NOESY spectra.The photo-responsive property were examined by irradiation of the synthesized [3]rotaxanes with 365 nm and blue light LED,which caused trans to cis and cis to trans isomerization,respectively.Irradiation of corresponding model vip compounds without pillar[5]arene encapsulation resulted in near completely trans to cis and cis to trans isomerization,indicating the existence of pillar[5]arenes is the determining factor for the comprised photo isomerization efficiency.展开更多
Light-induced switching of drug activity can be used to realize spatio-temporal control of biological activity in cells and in vivo.In our study of light-switchable derivatives of immunosuppressive drug cyclosporin A(...Light-induced switching of drug activity can be used to realize spatio-temporal control of biological activity in cells and in vivo.In our study of light-switchable derivatives of immunosuppressive drug cyclosporin A(CsA)in their inhibition of protein phosphatase calcineurin(CaN),we have discovered that 7-methyl-6-thioguanosine(MESG)inhibits CaN under light irradiation through a photo-crosslinking mechanism.The inhibition has shown selectivity over other enzymes such as phosphatase PP2A,protease chymotrypsin,and cyclophilin 18,the receptor protein for CsA.The discovery could pave the way to discover new covalent inhibitors for protein phosphtase,to design immunophilin-independent CaN inhibitors,and to design new light controlled inhibitors to modulate signal transduction.展开更多
基金supported by the National Natural Science Foundation of China(22025101,22222103,22173015,22103009)the Fundamental Research Funds for the Central Universities(DUT22LAB606)the Liaoning Binhai Laboratory,China(LBLE-2023-02)。
文摘Photo-switchable molecular magnets are promising in the applications of molecular spintronics,memory and switching devices.Introducing photo-responsive metal-to-metal electron transfer units into the molecular magnets provides a feasible means of controlling the magnetic and related physical properties.Here,we assembled the redox-active octacyanotungstate building block[W^(Ⅴ)(CN)_(8)]^(5-)with Co^(Ⅱ)ion to obtain the metal-to-metal electron transfer(MMET)molecular magnets.Four structure-related twodimensional(2D)compounds 1-4 derived from[W(CN)_8]_(2)[Co_(3)(L)_(12)]·solv(L=1-phenylimidazole)were constructed by modifying phenylimidazole ligands with substituent R at the para position of the aromatic ring(R=CN(L1),NO_(2)(L2),F(L3)and Cl(L4)).Structural analysis indicated that 1-4 underwent a thermal-induced single-crystal to single-crystal(SCSC)phase transition to the desolvated 1a-4a,accompanied by the MMET from(Co_(LS)^(Ⅲ))_(2)-W_(2)^(Ⅳ)-Co_(HS)^(Ⅱ)(LS:low-spin)phase to(Co_(HS)^(Ⅱ))_(2)-W_(2)~Ⅴ-Co_(HS)^(Ⅱ)(HS:high-spin)phase.1a-4a also exhibited incomplete(Co_(HS)^(Ⅱ))_(2)-W_(2)~Ⅴ-Co_(HS)^(Ⅱ)(HS)phase(Co_(LS)^(Ⅲ))_(2)-W_(2)^(Ⅳ)-Co_(HS)^(Ⅱ)(LS)phase transition with thermal hysteresis loops.Photomagnetic characterizations revealed that 1-4 and 1a-4a exhibited a reversible light-induced interconversion between the HS^(*(*):metastable phase generated by light irradiation)state and LS*state.Moreover,for 1,1a and 2,their magnetic hysteresis can be reversibly produced and eliminated by alternating the 946-and 671-nm light irradiations,respectively,showing the photo-switchable molecular magnet behavior.The compared magnetostructural analysis indicated that the intermolecularπ···πstacking interactions between modified phenylimidazole ligands can be modulated by the different electronic and steric hindrance effects of substituents,which regulate the distortion degree of the CoN_(6)octahedron and ligand field around the cobalt ions.The anomalous increase of octahedral distortion parameter Σ_(Co),which increases as the interlayerπ···πinteraction weakens,not only affects the transition temperature,but also plays an important role in stabilizing the photoexcited metastable state.This study demonstrates the feasibility of regulating intermolecular interactions through molecular engineering strategy in developing photo-responsive molecular magnetic materials with enhanced photo operating temperatures,and may offer new insights for advancing the construction of photo-switchable 2D magnets and related molecule-based spintronic devices.
基金supproted by the National Science Fund for Distinguished Young Scholars(No.22125804)the National Natural Science Foundation of China(Nos.22001122,22178163,22078155,and 21878149)we were also grateful to the High Performance Computing Center of Nanjing Tech University for providing the computational resources.
文摘Photo-switchable metal-organic frameworks(PMOFs)as energy-saving adsorbents for tailorable vip capture show admirable potentials for various applications like adsorptive desulfurization.However,the regulation behavior of most reported PMOFs is based on weak physical interaction,and it is highly desired to introduce specific active sites to satisfy the demand of higher adsorption capacity and selectivity.Herein,for the first time,we prepared the PMOFs,azobenzene-functionalized HKUST-1(HK-Azo),simultaneously decorated with Cu_(2)O active sites that possess strong interaction with vip molecules.Due toπ-complexation interaction of Cu^(+)with aromatic sulfur compounds,the obtained HK-Azo shows obviously higher adsorption capacity on benzothiophene compared with HKUST-1.Upon ultraviolet(UV)and visible irradiation,azobenzene moieties in the PMOFs can transform their configuration freely and reversibly.Such trans/cis isomerization of azobenzene causes exposure/shelter of Cu_(2)O active sites,leading to controllable benzothiophene capture.The HK-Azo exhibits the change of benzothiophene uptake up to 29.7%upon trans and cis isomerization,which is obviously higher than HKUST-1 with negligible change.This work may inspire the development of new adsorption process regulated by light for adsorptive desulfurization that is impossible to realize by conventional PMOFs.
基金Research Board(SERB),a statutory entity of the Department of Science and Technology(DST),Ministry of Science and Technology,India(File No:CRG/2021/000255)provided financial support to one of the authors.
文摘In this study,we present an in-depth exploration of charge transport phenomena and variable photo-switching characteristics in a novel double-perovskite-based three-terminal device.The Cs_(2)AgBiBr_(6) thin film(TF)was synthesized through a three-step thermal evaporation process followed by precise open-air annealing,ensuring superior film quality as confirmed by structural and morphological characterizations.Photoluminescence spectroscopy revealed distinct emissions at 2.28 and 2.07 eV,indicative of both direct and indirect electronic transitions.Our device exhibited space-charge limited current(SCLC)behaviour beyond 0.35 V,aligning with the relationship Current(I)∝Voltage(V)^(m),where the exponent m transitioned from≤1 to>1.Detailed analysis of Schottky parameters within the trap-filled limit(TFL)regime was conducted,accounting for variations in temperature and optical power.Significantly,the self-powered photodetector demonstrated outstanding performance under illumination.The sensitivity of the device was finely tunable via the applied bias voltages at the third terminal.Notably,an optimal bias voltage of±100μV yielded maximum responsivity(R)of 0.48 A/W and an impressive detectivity(D*)of 1.07×10^(9) Jones,highlighting the potential of this double-perovskite-based device for advanced optoelectronic applications.
基金support by the National Natural Science Foundation of China(No.52473225)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515110262)。
文摘Many azo compounds and their intermediates are toxic and have been linked to various health issues,representing a growing global problem.Molecular engineering for selective encapsulation of azobenzene compounds is critical,given their significant use in smart materials and prevalence as environmental micropollutants released from the food and dye industries.However,the current host molecules catering to azobenzene compounds are mainly limited to cyclodextrins,pillar[n]arenes and cucurbit[n]urils,demonstrating a moderate affinity.This report describes that a novel 3,3'-bipyridinium-based cyclophane was capable of encapsulating anionic azobenzene compounds in water with high binding affinity and pH stability through electrostatic attraction-enhanced mechanism,surpassing the extensively reported supramolecular systems.1D&2D NMR experiments,UV-vis spectrum,X-ray crystallography and computational modeling were carried out to understand the host-vip complexation.It's worth noting that the tetracationic cyclophane exhibited good selective and anti-interference encapsulation properties in binary,ternary and seawater systems.Furthermore,upon UV/white light irradiation,the reversible conversion between(E)-4,4'-azobisbenzoate and(Z)-4,4'-azobisbenzoate triggers the dissociation/recomplexation of the host-vip complex within 3 min.This reversible photo-switchable(E)-disodium 4,4'-azobisbenzoateBPy-Box^(4+)supramolecular system holds promise for designing novel materials for extraction/release of azo compounds and other small smart materials.
基金funded by the National Natural Science Foundation of China(No.62305041)the Natural Science Foundation of Liaoning Province(No.2023-MS-103)。
文摘Stochastic optical reconstruction microscopy(STORM),as a typical technique of single-molecule localization microscopy(SMLM),has overcome the diffraction limit by randomly switching fluorophores between fluorescent and dark states,allowing for the precise localization of isolated emission patterns and the super-resolution reconstruction from millions of localized positions of single fluorophores.A critical factor influencing localization precision is the photo-switching behavior of fluorophores,which is affected by the imaging buffer.The imaging buffer typically comprises oxygen scavengers,photo-switching reagents,and refractive index regulators.Oxygen scavengers help prevent photobleaching,photo-switching reagents assist in facilitating the conversion of fluorophores,and refractive index regulators are used to adjust the refractive index of the solution.The synergistic interaction of these components promotes stable blinking of fluorophores,reduces irreversible photobleaching,and thereby ensures high-quality super-resolution imaging.This review provides a comprehensive overview of the essential compositions and functionalities of imaging buffers used in STORM,serving as a valuable resource for researchers seeking to select appropriate imaging buffers for their experiments.
基金supported by the National Natural Science Foundation of China(Nos.21372192,21871227)the Natural Science Foundation of Jiangsu Province(No.BK20190905)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Series of azobenzene-bridged pillar[5]arene-based [3]rotaxanes with different alkyl chain length of vip molecules were constructed by threading-endcapping method with alkylenetriazole as axile and tetrahydrochromene as endcapping group.The encapsulation of pillar[5]arenes were proved by highresolution mass,^(1) H NMR and NOESY spectra.The photo-responsive property were examined by irradiation of the synthesized [3]rotaxanes with 365 nm and blue light LED,which caused trans to cis and cis to trans isomerization,respectively.Irradiation of corresponding model vip compounds without pillar[5]arene encapsulation resulted in near completely trans to cis and cis to trans isomerization,indicating the existence of pillar[5]arenes is the determining factor for the comprised photo isomerization efficiency.
文摘Light-induced switching of drug activity can be used to realize spatio-temporal control of biological activity in cells and in vivo.In our study of light-switchable derivatives of immunosuppressive drug cyclosporin A(CsA)in their inhibition of protein phosphatase calcineurin(CaN),we have discovered that 7-methyl-6-thioguanosine(MESG)inhibits CaN under light irradiation through a photo-crosslinking mechanism.The inhibition has shown selectivity over other enzymes such as phosphatase PP2A,protease chymotrypsin,and cyclophilin 18,the receptor protein for CsA.The discovery could pave the way to discover new covalent inhibitors for protein phosphtase,to design immunophilin-independent CaN inhibitors,and to design new light controlled inhibitors to modulate signal transduction.
