Efficient room temperature phosphorescence (RTP) is rarely observed in pure organic luminogens. However, we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatogra...Efficient room temperature phosphorescence (RTP) is rarely observed in pure organic luminogens. However, we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography (TLC) plates, but become highly phosphorescent in crystal state at room temperature, exhibiting typical crystallization-induced phosphorescence (CIP) characteristics. The CIP phenomenon is ascribed to the restriction of intramolecular rotations in crystals owing to effective intermolecular interactions. Such intermolecular interactions greatly rigidify the molecular conformation and significantly decrease the nonradiative deactivation channels of the triplet excitons, thus giving boosted phosphorescent emission at room temperature.展开更多
The luminescent liquid crystals (LLCs) are expected to solve the conflicts between the aggregation caused quenching and the requirement of aggregation or self-organization for LCs. Herein, we developed a new strategy ...The luminescent liquid crystals (LLCs) are expected to solve the conflicts between the aggregation caused quenching and the requirement of aggregation or self-organization for LCs. Herein, we developed a new strategy of applying aggregation-induced emission (AIE) phenomenon to the molecular design of LCs towards LLCs. In this report, a calamitic liquid crystal based on tolane with AIE characteristics was successfully synthesized and the chemical structure was characterized by 1H, 13C NMR, and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) high-resolution mass spectra. The fluorescence behavior was studied by fluorescence spectroscopy and the liquid crystal phase behaviors were investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM). The crystal structure was obtained by X-ray diffraction crystallography with P1 space group. Results demonstrated that the sample was AIE active and the LC phases sequence during cooling was nematic, smectic C and smectic B phase.展开更多
Efficient room temperature phosphorescence(RTP)is rarely observed in pure organic luminogens.However,we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography(...Efficient room temperature phosphorescence(RTP)is rarely observed in pure organic luminogens.However,we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography(TLC)plates,but become highly phosphorescent in crystal state at room temperature,exhibiting typical crystallization-induced phosphorescence(CIP)characteristics.The CIP phenomenon is ascribed to the restriction of intramolecular rotations in crystals owing to effective intermolecular interactions.Such intermolecular interactions greatly rigidify the molecular conformation and significantly decrease the nonradiative deactivation channels of the triplet excitons,thus giving boosted phosphorescent emission at room temperature.展开更多
An amphiphilic polymer bearing tetraphenylethene (TPE) moiety was synthesized by convenient reactions. The polymer exhibits unique aggregation-induced emission (AIE) characteristics and can self-assemble to size-tunab...An amphiphilic polymer bearing tetraphenylethene (TPE) moiety was synthesized by convenient reactions. The polymer exhibits unique aggregation-induced emission (AIE) characteristics and can self-assemble to size-tunable particles in DMF/water mixtures. The polymer nanoparticles can be used for cell imaging, which provides a potential stable fluorescent tool to monitor the distribution of drugs and bioconjugates in living cells.展开更多
Regioseletive 1,3-dipolar polycycloadditions of 4,4'-isopropylidenediphenyl dipropiolate (1) and tetraphenylethene (TPE)-containing diazides (2) are carried out in polar solvents such as DMF/toluene at a moderate ...Regioseletive 1,3-dipolar polycycloadditions of 4,4'-isopropylidenediphenyl dipropiolate (1) and tetraphenylethene (TPE)-containing diazides (2) are carried out in polar solvents such as DMF/toluene at a moderate temperature of 100℃ for 6 h,producing poly(aroxycarbonyltriazole)s (PACTs) P3 with high molecular weights (Mw up to 23900) and regioregularities (F1,4 up to ~90%) in high yields (up to ~99%).These metal-free click polymerizations can propagate smoothly in an open atmosphere without protection from oxygen and moisture.The obtained polymers are soluble in common organic solvents and thermally stable at temperatures up to 375℃.Thanks to their contained TPE moieties,the PACTs show aggregation-induced emission and can serve as fluorescent chemosensors for superamplified detection of explosives.展开更多
Efficient room temperature phosphorescence is observed in natural compounds and polymers such as starch, cellulose, bovine serum albumin (BSA), and some other carbohydrates. Whereas being practically nonluminescent in...Efficient room temperature phosphorescence is observed in natural compounds and polymers such as starch, cellulose, bovine serum albumin (BSA), and some other carbohydrates. Whereas being practically nonluminescent in solutions and TLC plates, they emit bright phosphorescence in the crystalline states with lifetime up to microseconds, exhibiting crystallization-induced phosphorescence (CIP) characteristics. The CIP of these natural products without any conventional chromophores offers a new platform for the exploration of conceptually novel luminogens.展开更多
We report a fluorescence "turn-on" method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mech...We report a fluorescence "turn-on" method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mechanism (aggregation-induced emission, or AIE) to determine the CMC values, and the results are consistent with the data obtained by the classical techniques. In addition, this method renders the convenient detection of the CMC values. Any large and professional instruments are unnecessary, instead, a portable UV lamp and an ultrasonic generator are enough to carry out the detection in an ordinary laboratory. Considering that micelles are interesting entities and have found applications in many important fields such as emulsion polymerization, template of nanosized materials synthesis, controllable drug delivery and macromolecular self-assembling. Our experimental results may offer a facile, sensitive and promising method to detect the formation of micelles constructed by the new amphiphilic molecules and macromolecules.展开更多
Fluorescent probes play a key role in modern biomedical research. As compared to inorganic quantum dots (QDs) composed with heavy metal elements, organic dye-based fluorescent nanoparticles have higher biocompatibilit...Fluorescent probes play a key role in modern biomedical research. As compared to inorganic quantum dots (QDs) composed with heavy metal elements, organic dye-based fluorescent nanoparticles have higher biocompatibility and are richer in variety. However, traditional organic fluorophores tend to quench fluorescence upon aggregation, which is known as aggregation-caused quenching (ACQ) effect that hinders the fabrication of highly emissive fluorescent nanoparticles. In this work, we demonstrate the synthesis of organic fluorescent dots with aggregation-induced emission (AIE) in far-red/near-infrared (FA/NIR) region. A conventional ACQ-characteristic fluorescent dye, 3,4:9,10-tetracarboxylic perylene bisimide (PBI), is converted into an AIE fluorogen through attaching two tetraphenylethylene (TPE) moieties. The fluorescent dots with surface folic acid groups are fabricated from PBI derivative (DTPEPBI), showing specific targeting effect to folate receptor-overexpressed cancer cells. In vivo studies also suggest that the folic acid-functionalized AIE dots preferentially accumulate in the tumor site through enhanced permeability and retention (EPR) effect and folate receptor-mediated active targeting effect. The low cyto-toxicity, good FR/NIR contrast and excellent targeting ability in in vitro/in vivo imaging indicate that the AIE dots have great potentials in advanced bioimaging applications.展开更多
The research on using thiol-ene click reaction to synthesize sulfur-containing polymers with topological structures and advanced functional properties is a hot topic. However, the application of the thiol-yne reaction...The research on using thiol-ene click reaction to synthesize sulfur-containing polymers with topological structures and advanced functional properties is a hot topic. However, the application of the thiol-yne reaction in the functional polymer preparation is limited and the thiol-yne click polymerization is to be further developed. In this review, we summarized recent research efforts on using thiol-yne click polymerization to synthesize polymers with topological structures. The sulfur-containing polymers were facilely prepared by photo-and thermo-initiated, amine-mediated, and transition-metal-catalyzed thiol-yne click polymerizations. These polymers are promising to be used as drug-delivery vehicles, high refractive index optical materials, photovoltaic materials, and biomaterials etc.展开更多
A photochromic rhodamine B-based material containing Cd(Ⅱ)as bridge was facilely prepared.The 4-methoxylsalicylaldehyde rhodamine B hydrazone Cd(Ⅱ)complex displayed unusual ring-open response upon 365 nm UV irradiat...A photochromic rhodamine B-based material containing Cd(Ⅱ)as bridge was facilely prepared.The 4-methoxylsalicylaldehyde rhodamine B hydrazone Cd(Ⅱ)complex displayed unusual ring-open response upon 365 nm UV irradiation,exhibiting long photochromic lifetime and good fatigue resistance.The UV-induced ring-open of the complex led to a distinct color and fluorescence change in acetonitrile.A new mechanism was put forward:salicylaldehyde part in the complex underwent UV-promoted isomerization from enol-form to keto-form,enhancing the chelation of Cd(Ⅱ)and yielding the ring-opening rhodamine B part.Compared to other reported photochromic systems,this new photochromic material offered attractive new insights into the development of low cost photochromic materials with good performance.展开更多
The research on aggregation-induced emission (AIE) has drawn increasing interests in the past decade. With the efforts scientists paid, a variety of AIE systems have been developed, among which the tetraphenylethelene...The research on aggregation-induced emission (AIE) has drawn increasing interests in the past decade. With the efforts scientists paid, a variety of AIE systems have been developed, among which the tetraphenylethelene and silole derivatives are the most studied. Development of new AIE systems could further enrich the AIE molecules and promote the development of AIE area. In this communication, we prepared a new AIE system based on 1,2,4,6-tetraphenylpyridinium ions according to the restriction of intramolecular rotation mechanism. These molecules could be facilely synthesized via one-step and one-pot reaction. The ionic AIE-active molecules could find wide application in sensing and optoelectronic areas.展开更多
Two derivatives of tetraphenylethene (TPE) were synthesized through one step cross McMurry coupling reaction. Both luminogens exhibit aggregation-induced emission (AIE) and crystallization induced emission enhancement...Two derivatives of tetraphenylethene (TPE) were synthesized through one step cross McMurry coupling reaction. Both luminogens exhibit aggregation-induced emission (AIE) and crystallization induced emission enhancement (CIEE). The emissions of both luminogens could be switched between blue and green through reversible modulation of morphology with thermal, organic solvent fuming and mechanical stimuli. Thus we provide a possible design strategy for emission switching materials.展开更多
Near-infrared(NIR)lights are powerful tools to conduct deep-tissue imaging since NIR-Ⅰ wavelengths hold less photon absorption and NIR-Ⅱ wavelengths serve low photon scattering in the biological tissues compared wit...Near-infrared(NIR)lights are powerful tools to conduct deep-tissue imaging since NIR-Ⅰ wavelengths hold less photon absorption and NIR-Ⅱ wavelengths serve low photon scattering in the biological tissues compared with visible lights.Two-photon fluorescence lifetime microscopy(2PFLM)can utilize NIR-Ⅱ excitation and NIR-Ⅰ emission at the same time with the assistance of a well-designed fluorescent agent.Aggregation induced emission(AIE)dyes are famous for unique optical properties and could serve a large two-photon absorption(2PA)cross-section as aggregated dots.Herein,we report two-photon fluorescence lifetime microscopic imaging with NIR-Ⅱ excitation and NIR-Ⅰ emission using a novel deep-red AIE dye.The AIE-gens held a 2PA cross-section as large as 1.61×10^(4)GM at 1040 nm.Prepared AIE dots had a two-photon fluorescence peak at 790 nm and a stable lifetime of 2.2 ns under the excitation of 1040 nm femtosecond laser.The brain vessels of a living mouse were vividly reconstructed with the two-photon fluorescence lifetime information obtained by our home-made 2PFLM system.Abundant vessels as small as 3.17µm were still observed with a nice signal-background ratio at the depth of 750µm.Our work will inspire more insight into the improvement of the working wavelength of fluorescent agents and traditional 2PFLM.展开更多
A novel luminogen, CZ2TPAN, with typical D-A architecture was obtained. It shows intramolecular charge transfer and aggregation-induced emission characteristics with high solid-state efficiency of 65.3%. Moreover, it ...A novel luminogen, CZ2TPAN, with typical D-A architecture was obtained. It shows intramolecular charge transfer and aggregation-induced emission characteristics with high solid-state efficiency of 65.3%. Moreover, it exhibits reversible mechanochromic behavior between crystalline and amorphous states with remarkable emission color change from green (504 nm) to yellow (545nm).展开更多
We report a novel strategy to study the chain dynamics of poly(acrylic acid) (PAA) in a relative concentrated solution (1.0 g/L). The strategy is based on the fluorescent probe (DCTPE) with unique aggregation-induced ...We report a novel strategy to study the chain dynamics of poly(acrylic acid) (PAA) in a relative concentrated solution (1.0 g/L). The strategy is based on the fluorescent probe (DCTPE) with unique aggregation-induced emission (AIE) characteristics. Free DCTPE molecules are non-emissive in aqueous solution, but they become highly emissive when trapped in polymer coils. The fluorescence intensity is proportional to the efficiency of trapping DCTPE molecules in polymer coils. By correlation the change of fluorescence intensity with the variation of pH value (from 1.78 to 12.06), the PAA chain's dynamics in the relatively concentrated solution have been elucidated into three processes. In the pH range from 12.06 to 6.0, PAA chains take an extended and non-folding conformation. Changing pH from 6.0 to 3.86, PAA chains are partially protonated and loosely packed polymer coils are formed. Further lowering the pH value of the solution (from 3.86 to 1.78), protonated segments dominate the PAA chains, and at the same time, the intermolecular hydrogen bonding takes effect, thus the polymer chains posses in the conformation of more compact coils.展开更多
Fluorescent probes play a key role in modern biomedical research.As compared to inorganic quantum dots(QDs)composed with heavy metal elements,organic dye-based fluorescent nanoparticles have higher biocompatibility an...Fluorescent probes play a key role in modern biomedical research.As compared to inorganic quantum dots(QDs)composed with heavy metal elements,organic dye-based fluorescent nanoparticles have higher biocompatibility and are richer in variety.However,traditional organic fluorophores tend to quench fluorescence upon aggregation,which is known as aggregation-caused quenching(ACQ)effect that hinders the fabrication of highly emissive fluorescent nanoparticles.In this work,we demonstrate the synthesis of organic fluorescent dots with aggregation-induced emission(AIE)in far-red/near-infrared(FA/NIR)region.A conventional ACQ-characteristic fluorescent dye,3,4:9,10-tetracarboxylic perylene bisimide(PBI),is converted into an AIE fluorogen through attaching two tetraphenylethylene(TPE)moieties.The fluorescent dots with surface folic acid groups are fabricated from PBI derivative(DTPEPBI),showing specific targeting effect to folate receptor-overexpressed cancer cells.In vivo studies also suggest that the folic acid-functionalized AIE dots preferentially accumulate in the tumor site through enhanced permeability and retention(EPR)effect and folate receptor-mediated active targeting effect.The low cytotoxicity,good FR/NIR contrast and excellent targeting ability in in vitro/in vivo imaging indicate that the AIE dots have great potentials in advanced bioimaging applications.展开更多
Planarized intramolecular charge transfer(PLICT)state can facilitate the fluorescence process thanks to the relative excellent planarity.Recently,we have discovered that the excited state quinone-conformation induced ...Planarized intramolecular charge transfer(PLICT)state can facilitate the fluorescence process thanks to the relative excellent planarity.Recently,we have discovered that the excited state quinone-conformation induced planarization(ESQIP)occurring on tetraphenylpyrazine(TPP)based derivatives could furnish them with PLICT feature.Unlike to the well-known intramolecular charge transfer,strengthening the electron-donating nature on the donor(D)moiety did not impair the PLICT.The calculation results showed that planarization of the TPP based compounds scarcely accompanied with energy wastage while amount of energy was required for the torsion on geometries.In the polar solvents,the energy consumption for planarization could further decrease,but that for twisting structure would increase.To take advantage of the transformation of the frontier orbitals'distribution,the PLICT type materials would perform a potential application on organic light-emitting diodes(OLEDs).展开更多
In this work,a fluorescent probe(TPEBe-I)was developed for adenosine triphosphate(ATP)detection based on the synergetic effect of aggregation-induced emission and counterion displacement.TPEBe-I gave weak emission in ...In this work,a fluorescent probe(TPEBe-I)was developed for adenosine triphosphate(ATP)detection based on the synergetic effect of aggregation-induced emission and counterion displacement.TPEBe-I gave weak emission in aqueous solution due to the heavy-atom effect of counter iodide ion.However,upon the addition of ATP,the new aggregate complex(TPEBe-ATP)was formed between the cationic unit of TPEBe-I and ATP through electrostatic interactions,which not only restricted the intramolecular motion of luminogen but also eliminated the quenching effect of iodide ion.As a result,the fluorescent light-up detection for ATP was successfully achieved.Moreover,TPEBe-I exhibited high selectivity towards ATP and showed a wide linear detection region towards the logarithm of ATP concentration(5—600µmol/L)with a detection limit of 1.0µmol/L,enabling TPEBe-I as a promising probe for ATP quantitative analysis.展开更多
Mechanistic studies promote scientific development from phenomena to theories.Aggregation-induced emission(AIE),as an unusual photophysical phenomenon,builds the bridge between molecular science and aggregate mesoscie...Mechanistic studies promote scientific development from phenomena to theories.Aggregation-induced emission(AIE),as an unusual photophysical phenomenon,builds the bridge between molecular science and aggregate mesoscience.With the twenty-year development of AIE,restriction of intramolecular motion(RIM)has been verified as the working mechanism of AIE effect.In this review,these mechanistic works about RIM are summarized from experimental and theoretical perspectives.Thereinto,the experimental studies are introduced from three parts:external rigidification,structural modification and structural characterization.In the theoretical part,calculations on the low-frequency motion of AIEgens have been performed to prove the RIM mechanism.By virtue of the theoretical calculations,some new mechanisms are proposed to supplement the RIM,such as restriction of access to conical intersection,suppression of Kasha transition,restriction of access to dark state,etc.It is foreseeable that the RIM mechanism will unify the photophysical theories for both molecules and aggregates,and inspire more progress in aggregate science.展开更多
We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes(PAs,P3) through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants.The precursor ...We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes(PAs,P3) through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants.The precursor PA(P2) was derived by desilylation of the pristine PA with trimethylethynylsilane side chains(P1).P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane(M) under the promotion of WCl6-Ph4Sn catalyst.Two synthetic routes,i.e.two-steps(from P1 to P3 via precursor P2) and one-pot(from P1 to P3 without separation and purification of P2) were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2.By using the techniques such as GPC,FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized.展开更多
基金the National Natural Science Foundations of China (21104044)the National Basic Research Program of China (973 Program, 2013CB834701 and 2013CB834704)+1 种基金the Ph.D. Programs Foundation of Ministry of Education of China (20110073120040)the Shanghai Leading Academic Discipline Project (B202). W.Z.Y. thanks the Start-up Foundation and SMC-Chenxing Young Scholar Pro- gram of Shanghai Jiao Tong University.
文摘Efficient room temperature phosphorescence (RTP) is rarely observed in pure organic luminogens. However, we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography (TLC) plates, but become highly phosphorescent in crystal state at room temperature, exhibiting typical crystallization-induced phosphorescence (CIP) characteristics. The CIP phenomenon is ascribed to the restriction of intramolecular rotations in crystals owing to effective intermolecular interactions. Such intermolecular interactions greatly rigidify the molecular conformation and significantly decrease the nonradiative deactivation channels of the triplet excitons, thus giving boosted phosphorescent emission at room temperature.
基金the National Natural Science Foundation of China (21074073, 21104044)Shenzhen Science and Technology Bureau (ZYC201105130112A, JC201105130384A)
文摘The luminescent liquid crystals (LLCs) are expected to solve the conflicts between the aggregation caused quenching and the requirement of aggregation or self-organization for LCs. Herein, we developed a new strategy of applying aggregation-induced emission (AIE) phenomenon to the molecular design of LCs towards LLCs. In this report, a calamitic liquid crystal based on tolane with AIE characteristics was successfully synthesized and the chemical structure was characterized by 1H, 13C NMR, and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) high-resolution mass spectra. The fluorescence behavior was studied by fluorescence spectroscopy and the liquid crystal phase behaviors were investigated by differential scanning calorimetry (DSC), polarized optical microscopy (POM). The crystal structure was obtained by X-ray diffraction crystallography with P1 space group. Results demonstrated that the sample was AIE active and the LC phases sequence during cooling was nematic, smectic C and smectic B phase.
文摘Efficient room temperature phosphorescence(RTP)is rarely observed in pure organic luminogens.However,we have newly observed that benzil and its derivatives are nonluminescent in solvents and thin layer chromatography(TLC)plates,but become highly phosphorescent in crystal state at room temperature,exhibiting typical crystallization-induced phosphorescence(CIP)characteristics.The CIP phenomenon is ascribed to the restriction of intramolecular rotations in crystals owing to effective intermolecular interactions.Such intermolecular interactions greatly rigidify the molecular conformation and significantly decrease the nonradiative deactivation channels of the triplet excitons,thus giving boosted phosphorescent emission at room temperature.
基金supported by the National Natural Science Foundation of China (20974028, 20974098, and 21174120)the National Basic Research Program of China (2009CB623605)+1 种基金the Research Grants Council of Hong Kong (603509, HKUST2/CRF/10, 604711, and N_HKUST620/11)B.Z.T. thanks the support from the Cao Guangbiao Foundation of Zhejiang University
文摘An amphiphilic polymer bearing tetraphenylethene (TPE) moiety was synthesized by convenient reactions. The polymer exhibits unique aggregation-induced emission (AIE) characteristics and can self-assemble to size-tunable particles in DMF/water mixtures. The polymer nanoparticles can be used for cell imaging, which provides a potential stable fluorescent tool to monitor the distribution of drugs and bioconjugates in living cells.
基金supported by the National Natural Science Foundation of China (20634020,50703033,20974098 and 20974028)the Ministry of Science and Technology of China (2009CB623605)+4 种基金the University Grants Committee of Hong Kong ( AoE/P-03/08)the Research Grants Council of Hong Kong (603509,601608 and 602707)the Innovation and Technology Fund of Hong Kong (ITS/168/09). A.J.Q. and B.Z.T acknowledge the supports from the Postdoctoral Research Foundation of China (20081461)the Fundamental Research Funds for the Central Universities (2010KYJD005)the CAO GuangBiao Foundation of Zhejiang University,respectively
文摘Regioseletive 1,3-dipolar polycycloadditions of 4,4'-isopropylidenediphenyl dipropiolate (1) and tetraphenylethene (TPE)-containing diazides (2) are carried out in polar solvents such as DMF/toluene at a moderate temperature of 100℃ for 6 h,producing poly(aroxycarbonyltriazole)s (PACTs) P3 with high molecular weights (Mw up to 23900) and regioregularities (F1,4 up to ~90%) in high yields (up to ~99%).These metal-free click polymerizations can propagate smoothly in an open atmosphere without protection from oxygen and moisture.The obtained polymers are soluble in common organic solvents and thermally stable at temperatures up to 375℃.Thanks to their contained TPE moieties,the PACTs show aggregation-induced emission and can serve as fluorescent chemosensors for superamplified detection of explosives.
基金the National Natural Science Foundations of China (21104044)the National Basic Research Program of China (973 Program, 2013CB834701 and 2013CB834704)+1 种基金the Ph.D. Programs Foundation of Ministry of Education of China (20110073120040)the Shanghai Leading Academic Discipline Project (B202)
文摘Efficient room temperature phosphorescence is observed in natural compounds and polymers such as starch, cellulose, bovine serum albumin (BSA), and some other carbohydrates. Whereas being practically nonluminescent in solutions and TLC plates, they emit bright phosphorescence in the crystalline states with lifetime up to microseconds, exhibiting crystallization-induced phosphorescence (CIP) characteristics. The CIP of these natural products without any conventional chromophores offers a new platform for the exploration of conceptually novel luminogens.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 50573065 & 50873086)the Natural Science Foundation of Zhejiang Province (Grant No. Z406018)
文摘We report a fluorescence "turn-on" method to detect the critical micelle concentration (CMC) of surfactants. This method works well for both cationic and anionic surfactants. It employs an unprecedented mechanism (aggregation-induced emission, or AIE) to determine the CMC values, and the results are consistent with the data obtained by the classical techniques. In addition, this method renders the convenient detection of the CMC values. Any large and professional instruments are unnecessary, instead, a portable UV lamp and an ultrasonic generator are enough to carry out the detection in an ordinary laboratory. Considering that micelles are interesting entities and have found applications in many important fields such as emulsion polymerization, template of nanosized materials synthesis, controllable drug delivery and macromolecular self-assembling. Our experimental results may offer a facile, sensitive and promising method to detect the formation of micelles constructed by the new amphiphilic molecules and macromolecules.
基金the Agency for Science Technology and Research Joint Council and Institute of Materials Research and Engineering of Singapore (IMRE/13-8P1104)the Singapore National Research Foundation (R-279-000-390-281)+1 种基金the Research Grants Council of Hong Kong (603509, HKUST2/CRF/10, 604711, N_HKUST620/11)the Guangdong Innovative Research Team Program (201101C0105067115)
文摘Fluorescent probes play a key role in modern biomedical research. As compared to inorganic quantum dots (QDs) composed with heavy metal elements, organic dye-based fluorescent nanoparticles have higher biocompatibility and are richer in variety. However, traditional organic fluorophores tend to quench fluorescence upon aggregation, which is known as aggregation-caused quenching (ACQ) effect that hinders the fabrication of highly emissive fluorescent nanoparticles. In this work, we demonstrate the synthesis of organic fluorescent dots with aggregation-induced emission (AIE) in far-red/near-infrared (FA/NIR) region. A conventional ACQ-characteristic fluorescent dye, 3,4:9,10-tetracarboxylic perylene bisimide (PBI), is converted into an AIE fluorogen through attaching two tetraphenylethylene (TPE) moieties. The fluorescent dots with surface folic acid groups are fabricated from PBI derivative (DTPEPBI), showing specific targeting effect to folate receptor-overexpressed cancer cells. In vivo studies also suggest that the folic acid-functionalized AIE dots preferentially accumulate in the tumor site through enhanced permeability and retention (EPR) effect and folate receptor-mediated active targeting effect. The low cyto-toxicity, good FR/NIR contrast and excellent targeting ability in in vitro/in vivo imaging indicate that the AIE dots have great potentials in advanced bioimaging applications.
基金supported by the National Natural Science Foundation of China(21222402,21174120)the National Basic Research Program of China(2009CB623605,2013CB834702)the Research Grants Council of Hong Kong(603509,HKUST2/CRF/10,604711,N_HKUST620/11)
文摘The research on using thiol-ene click reaction to synthesize sulfur-containing polymers with topological structures and advanced functional properties is a hot topic. However, the application of the thiol-yne reaction in the functional polymer preparation is limited and the thiol-yne click polymerization is to be further developed. In this review, we summarized recent research efforts on using thiol-yne click polymerization to synthesize polymers with topological structures. The sulfur-containing polymers were facilely prepared by photo-and thermo-initiated, amine-mediated, and transition-metal-catalyzed thiol-yne click polymerizations. These polymers are promising to be used as drug-delivery vehicles, high refractive index optical materials, photovoltaic materials, and biomaterials etc.
基金financially supported by the National Natural Science Foundation of China(21175079 and 21375074)
文摘A photochromic rhodamine B-based material containing Cd(Ⅱ)as bridge was facilely prepared.The 4-methoxylsalicylaldehyde rhodamine B hydrazone Cd(Ⅱ)complex displayed unusual ring-open response upon 365 nm UV irradiation,exhibiting long photochromic lifetime and good fatigue resistance.The UV-induced ring-open of the complex led to a distinct color and fluorescence change in acetonitrile.A new mechanism was put forward:salicylaldehyde part in the complex underwent UV-promoted isomerization from enol-form to keto-form,enhancing the chelation of Cd(Ⅱ)and yielding the ring-opening rhodamine B part.Compared to other reported photochromic systems,this new photochromic material offered attractive new insights into the development of low cost photochromic materials with good performance.
基金the National Science Foundation of China (21222402, 21174120, 20974098)the National Basic Research Program of China (2013CB834702, 2009CB623605)the Research Grants Council of Hong Kong (603509, HKUST2/CRF/10, 604711, NHKUST620/11)
文摘The research on aggregation-induced emission (AIE) has drawn increasing interests in the past decade. With the efforts scientists paid, a variety of AIE systems have been developed, among which the tetraphenylethelene and silole derivatives are the most studied. Development of new AIE systems could further enrich the AIE molecules and promote the development of AIE area. In this communication, we prepared a new AIE system based on 1,2,4,6-tetraphenylpyridinium ions according to the restriction of intramolecular rotation mechanism. These molecules could be facilely synthesized via one-step and one-pot reaction. The ionic AIE-active molecules could find wide application in sensing and optoelectronic areas.
基金partially supported by the National Natural Science Foundation of China(51173018)National Basic Research Program of China(2013CB834704,2011CB935702)+1 种基金the Fundamental Research Funds for the Central Universities,RPC Grants of HKUST(RPC11SC09)the Research Grants Council of Hong Kong(HKUST2/CRF/10)
文摘Two derivatives of tetraphenylethene (TPE) were synthesized through one step cross McMurry coupling reaction. Both luminogens exhibit aggregation-induced emission (AIE) and crystallization induced emission enhancement (CIEE). The emissions of both luminogens could be switched between blue and green through reversible modulation of morphology with thermal, organic solvent fuming and mechanical stimuli. Thus we provide a possible design strategy for emission switching materials.
基金This work was supported by the National Natural Science Foundation of China(Nos.61735016,61975172)the Natural Science Foundation of Zhejiang Province of China(No.LR17F050001)+1 种基金the Fundamental Research Funds for the Central Universities of China(No.2020-KYY-511108-0007)the Open Fund of Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregate,South China University of Technology,China(No.2019B030301003).
文摘Near-infrared(NIR)lights are powerful tools to conduct deep-tissue imaging since NIR-Ⅰ wavelengths hold less photon absorption and NIR-Ⅱ wavelengths serve low photon scattering in the biological tissues compared with visible lights.Two-photon fluorescence lifetime microscopy(2PFLM)can utilize NIR-Ⅱ excitation and NIR-Ⅰ emission at the same time with the assistance of a well-designed fluorescent agent.Aggregation induced emission(AIE)dyes are famous for unique optical properties and could serve a large two-photon absorption(2PA)cross-section as aggregated dots.Herein,we report two-photon fluorescence lifetime microscopic imaging with NIR-Ⅱ excitation and NIR-Ⅰ emission using a novel deep-red AIE dye.The AIE-gens held a 2PA cross-section as large as 1.61×10^(4)GM at 1040 nm.Prepared AIE dots had a two-photon fluorescence peak at 790 nm and a stable lifetime of 2.2 ns under the excitation of 1040 nm femtosecond laser.The brain vessels of a living mouse were vividly reconstructed with the two-photon fluorescence lifetime information obtained by our home-made 2PFLM system.Abundant vessels as small as 3.17µm were still observed with a nice signal-background ratio at the depth of 750µm.Our work will inspire more insight into the improvement of the working wavelength of fluorescent agents and traditional 2PFLM.
基金supported by the National Natural Science Foundation of China(21104044)the National Basic Research Program of China(2013CB834704)+1 种基金the Ph.D.Programs Foundation of Ministry of Education of China(20110073120040)the Start-up Foundation for New Faculties of Shanghai Jiao Tong University
文摘A novel luminogen, CZ2TPAN, with typical D-A architecture was obtained. It shows intramolecular charge transfer and aggregation-induced emission characteristics with high solid-state efficiency of 65.3%. Moreover, it exhibits reversible mechanochromic behavior between crystalline and amorphous states with remarkable emission color change from green (504 nm) to yellow (545nm).
基金the National Science Foundation of China (21074113)the Key Project of the Natural Science Foundation of Zhejiang Province (Z4110056)
文摘We report a novel strategy to study the chain dynamics of poly(acrylic acid) (PAA) in a relative concentrated solution (1.0 g/L). The strategy is based on the fluorescent probe (DCTPE) with unique aggregation-induced emission (AIE) characteristics. Free DCTPE molecules are non-emissive in aqueous solution, but they become highly emissive when trapped in polymer coils. The fluorescence intensity is proportional to the efficiency of trapping DCTPE molecules in polymer coils. By correlation the change of fluorescence intensity with the variation of pH value (from 1.78 to 12.06), the PAA chain's dynamics in the relatively concentrated solution have been elucidated into three processes. In the pH range from 12.06 to 6.0, PAA chains take an extended and non-folding conformation. Changing pH from 6.0 to 3.86, PAA chains are partially protonated and loosely packed polymer coils are formed. Further lowering the pH value of the solution (from 3.86 to 1.78), protonated segments dominate the PAA chains, and at the same time, the intermolecular hydrogen bonding takes effect, thus the polymer chains posses in the conformation of more compact coils.
文摘Fluorescent probes play a key role in modern biomedical research.As compared to inorganic quantum dots(QDs)composed with heavy metal elements,organic dye-based fluorescent nanoparticles have higher biocompatibility and are richer in variety.However,traditional organic fluorophores tend to quench fluorescence upon aggregation,which is known as aggregation-caused quenching(ACQ)effect that hinders the fabrication of highly emissive fluorescent nanoparticles.In this work,we demonstrate the synthesis of organic fluorescent dots with aggregation-induced emission(AIE)in far-red/near-infrared(FA/NIR)region.A conventional ACQ-characteristic fluorescent dye,3,4:9,10-tetracarboxylic perylene bisimide(PBI),is converted into an AIE fluorogen through attaching two tetraphenylethylene(TPE)moieties.The fluorescent dots with surface folic acid groups are fabricated from PBI derivative(DTPEPBI),showing specific targeting effect to folate receptor-overexpressed cancer cells.In vivo studies also suggest that the folic acid-functionalized AIE dots preferentially accumulate in the tumor site through enhanced permeability and retention(EPR)effect and folate receptor-mediated active targeting effect.The low cytotoxicity,good FR/NIR contrast and excellent targeting ability in in vitro/in vivo imaging indicate that the AIE dots have great potentials in advanced bioimaging applications.
基金Supported by the National Natural Science Foundation of China(Nos.21788102,51673118,21975077)the Science&Technology Program of Guangzhou Province,China(Nos.201804010218,201804020027)+2 种基金the Project of the Innovation and Technology Commission of Hong Kong,China(No.ITC-CNERC14S01)the Fundamental Research Funds for the Central Universities,China(No.2019ZD04)the Fund of Key Laboratory of Luminescence from Molecular Aggregates of Guangdong Province,China(No.2019B030301003).
文摘Planarized intramolecular charge transfer(PLICT)state can facilitate the fluorescence process thanks to the relative excellent planarity.Recently,we have discovered that the excited state quinone-conformation induced planarization(ESQIP)occurring on tetraphenylpyrazine(TPP)based derivatives could furnish them with PLICT feature.Unlike to the well-known intramolecular charge transfer,strengthening the electron-donating nature on the donor(D)moiety did not impair the PLICT.The calculation results showed that planarization of the TPP based compounds scarcely accompanied with energy wastage while amount of energy was required for the torsion on geometries.In the polar solvents,the energy consumption for planarization could further decrease,but that for twisting structure would increase.To take advantage of the transformation of the frontier orbitals'distribution,the PLICT type materials would perform a potential application on organic light-emitting diodes(OLEDs).
基金This work was supported by the National Natural Science Foundation of China(No.21975149)the Funded Projects for the Academic Leaders and Academic Backbones,Shaanxi Normal University,China(No.18QNGG007)the Fundamental Research Funds for the Central Universities of China(No.GK202003036).
文摘In this work,a fluorescent probe(TPEBe-I)was developed for adenosine triphosphate(ATP)detection based on the synergetic effect of aggregation-induced emission and counterion displacement.TPEBe-I gave weak emission in aqueous solution due to the heavy-atom effect of counter iodide ion.However,upon the addition of ATP,the new aggregate complex(TPEBe-ATP)was formed between the cationic unit of TPEBe-I and ATP through electrostatic interactions,which not only restricted the intramolecular motion of luminogen but also eliminated the quenching effect of iodide ion.As a result,the fluorescent light-up detection for ATP was successfully achieved.Moreover,TPEBe-I exhibited high selectivity towards ATP and showed a wide linear detection region towards the logarithm of ATP concentration(5—600µmol/L)with a detection limit of 1.0µmol/L,enabling TPEBe-I as a promising probe for ATP quantitative analysis.
基金This work is supported by the National Natural Science Foundation of China(No.21788102)the Research Grants of Council of Hong Kong,China(Nos.16304819,16305618,N_HKUST609/19,C6009-17G)the Innovation of Technology Commission of Hong Kong,China(No.ITC-CNERC14SC01).
文摘Mechanistic studies promote scientific development from phenomena to theories.Aggregation-induced emission(AIE),as an unusual photophysical phenomenon,builds the bridge between molecular science and aggregate mesoscience.With the twenty-year development of AIE,restriction of intramolecular motion(RIM)has been verified as the working mechanism of AIE effect.In this review,these mechanistic works about RIM are summarized from experimental and theoretical perspectives.Thereinto,the experimental studies are introduced from three parts:external rigidification,structural modification and structural characterization.In the theoretical part,calculations on the low-frequency motion of AIEgens have been performed to prove the RIM mechanism.By virtue of the theoretical calculations,some new mechanisms are proposed to supplement the RIM,such as restriction of access to conical intersection,suppression of Kasha transition,restriction of access to dark state,etc.It is foreseeable that the RIM mechanism will unify the photophysical theories for both molecules and aggregates,and inspire more progress in aggregate science.
基金partially supported by the National Natural Science Foundation of China (21074113,20634020 & 20974028)the National Basic Research Program of China (973 Program,2009CB623605)+1 种基金the Research Grants Council of Hong Kong (603509 & HKUST2/CRF/10)the University Grants Committee of Hong Kong (AoE/P-03/08)
文摘We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes(PAs,P3) through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants.The precursor PA(P2) was derived by desilylation of the pristine PA with trimethylethynylsilane side chains(P1).P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane(M) under the promotion of WCl6-Ph4Sn catalyst.Two synthetic routes,i.e.two-steps(from P1 to P3 via precursor P2) and one-pot(from P1 to P3 without separation and purification of P2) were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2.By using the techniques such as GPC,FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized.