查看更多>>摘要：To develop new luminophores,three imidazobenzothiadiazole(ImBTD)fluorescent dyes(4a,4b,and 4c)have been successfully synthesized and characterized.Interestingly,the introduction of imidazole groups at the 5-and 6-positions of benzothiadiazole can effectively enhance the fluorescence in both solid and aqueous solution and lead to a fluorescence response to acid.Modification of different aromatic groups at position 4 and 8 of ImBTD can produce tunable mechanochromic luminescence(MCL),which has been studied by theoretical calculations,single crystal X-ray diffraction(XRD),powder XRD analysis,and differential scanning calorimeter(DSC).More importantly,the neutral dyes 4a-c show mitochondrial staining comparable to commercially positively charged dyes.As a novel multifunctional fluorescent dye,it has application value in the fields of solid-state fluorescence and biological imaging.
查看更多>>摘要：A new fluorometric sensor based on salicylideneaniline derivative for the detection of Cu~(2+)ion in aqueous media was developed and synthesized.The sensor showed strong absorption and fluorescence emission in an aqueous system through ESIPT and ICT characters.The greenish yellow fluorescence emission quenching and color change from bright yellow to pale yellow were observed after complexation with Cu~(2+)via the chelation-enhanced quenching(CHEQ)process.The sensor can recognize Cu~(2+)ion with high sensitivity and specificity over potential interfering ions as well as a low detection limit of 0.87 ppb,which was lower than the limit level concentration of Cu~(2+)in drinking water by the United States Environmental Protection Agency(U.S.EPA)and World Health Organization(WHO).The Job's plot,X-ray Absorption Spectroscopy(XAS),and NMR illustrated the chelating mode between PS and Cu~(2+)ion in 1:1 stoichiometric complexation.The DFT calculations revealed ligand-to-metal charge transfer(LMCT)phenomena upon the Cu~(2+)binding of PS.Moreover,this fluorescence sensor was successfully employed for analyzing Cu~(2+)concentration in real water samples as well as living cells.
查看更多>>摘要：As one of the most widely used azo synthetic dyes,long-term consumption of excessive amaranthcan cause a threat to health.It is very urgent to establish high selective and sensitive method for amaranth detection.Orange fluorescent carbon dots utilizing l-methionine and o-phenylenediamine as raw materials,namely S,N-CDs,were prepared via one-step hydrothermal method.Dialysis,thin layer chromatography and chromatographic column were employed for further purification.The purified dual-mode nanoprobe based on fluorescent and UV absorption was successfully established.For fluorescent,excellent linear ranges of 5-70 μM and 110-195 μM were obtained,and low detection limit was 345.22 nM.For UV absorption,excellent linear ranges of 0-155 μM with low detection limit 12.70 nM.It revealed that inner filter effect and static quenching dominated in amaranth quenching the fluorescent of S,N-CDs.Furthermore,the dual-mode nanoprobe could be efficiently applied to determine amaranth in fruit juice,carbonated drink,and strawberry jam samples.It provided a new insight on the purification of carbon dots and detection of amaranth by dual-mode nanoprobe.
查看更多>>摘要：Organic fluorescent materials have been widely used in various fields including visualization of latent fingerprints and imaging of lysosomes.High-performance organic fluorescent molecules based on simple molecular structures are still limited and highly demanded for high-definition and high-contrast imaging of latent fingerprints and lysosomes.In this work,two organic fluorescent molecules(DANPAN and DANBEN)were developed based on dimethylamino naphthalenyl phenylethene structure.These two molecules have quite different fluorescent properties,and the position of cyano group significantly affects the optical properties of these dimethylamino naphthalenyl phenylethene derivatives.Compound DANPAN shows strong yellow emission in solid state,while compound DANBEN has strong fluorescent emission in organic solutions.In addition to these differences,both compounds have large Stokes shifts and positive solvatochromic properties.Further studies showed that these compounds could be used to display latent fingerprints on various substrate surfaces.The obtained fingerprint images have excellent contrast and high resolution.It is also found that these molecules could specifically stain lysosomes in living cell within short incubation time.This work provides a series of new high-performance organic fluorescent materials with diverse applications.
查看更多>>摘要：Environment-sensitive fluorescence ligands based on twisted intramolecular charge transfer(TICT)are often applied to target relevant biomacromolecules.In this work,several imidazole-based"D-π-A"fluorescent ligands with different amine side chains have been designed,which showed sensitivity toward solvent polarity and viscosity.The binding of obtained ligands with lipase led to enhancement of emission intensity.Results from binding parameters exhibited that the ligands bound with lipase in a 1:1 stoichiometry,and the flexible amine side chain appended ligand was more sensitive to lipase.The fluorescence quenching experiments of ligands with lipase suggested the involvement of a static quenching mechanism in the binding process.From the estimated thermodynamic parameters,complexation between the ligands and lipase was found to occur primarily via Van der Waals forces and hydrogen bonds formation.Observations from synchronous,3D fluorescence and CD spectra pointed that the binding of ligands to lipase impacted the microenvironment around tyrosine and typ-tophan residues,but was not enough to change the secondary structure of lipase.Moreover,modeling calculation demonstrated that ligands were mainly located within the hydrophobic pockets of lipase.This study provides evidence for expanding the application of environment-sensitive fluorescent ligands for probes or drug candidates targeting lipase.
查看更多>>摘要：Fluoride is an essential trace element in the human body and plays an essential role in various physiological processes.However,fluoride ion detection in vivo remains challenging due to the lack of probes that can enter the organism and emit at the near infrared region(NIR).Herein,we developed a boron-dipyrromethene(BODIPY)-based NIR probe that takes advantage of the high resolution and deep penetration of photoacoustic imaging,which can produce high NIR absorption at 803 nm in the presence of fluoride ions,resulting in a strong photoacoustic signal in the NIR region.In addition,the probe exhibits high selectivity for fluoride ions.In view of these outstanding features,the probe was then successfully applied to fluoride ion imaging in living mice,proving that a probe is a promising tool for fluoride ion detection in vitro and in vivo.
查看更多>>摘要：In this paper,a water-soluble CsPbBr3 perovskite nanocrystals(PNCs)probe with high photoluminescence was prepared and its analytical application for penicillamine detection was studied after an anion exchange process.The result indicated that the CsPbBr3 PNCs probe after iodide anion exchange(CsPbX3,X = Br/I)had a sensitive optical property that can be changed by penicillamine.The fluorescence intensity of the CsPbX3 PNCs increased and the maximum emission peak of the CsPbX3 blue-shifted in the presence of a lower concentration of penicillamine.By optimizing the degree of anion exchange and the experimental condition,penicillamine in the concentration from 5.0 to 35.0 nM can be linearly detected by the luminescence changes of the CsPbX3 PNCs probe.The color change of the PNCs probe was just right in the red and green bands that can be easily recognized by the naked eyes under 365 nm UV lamps.The mechanism of the phenomenon was further studied and the results indicated the interaction of the sulfhydryl group in the penicillamine with the iodide exchanged in the perovskite is the cause of spectral changes.The CsPbX3 PNCs probe prepared here also had a similar response to other sulfur compounds.Thus,the method proposed here has the potential to establish a universal analytical method for the visualization of sulfur-containing substances in water environments.
查看更多>>摘要：Two red-emitting Ir~(III)(C^N)2(P-donor ligand)Cl-type complexes bearing(~(III)(C^N ligands with carbazole functional group have been successfully prepared with different P-donor ligands of triphenylphosphine and triethylphos-phine,respectively.The investigation of their phosphorescent behavior in the mixture of THF and water to reveal their aggregation induced phosphorescent emission(AIPE)ability,which is also indicated by their much higher phosphorescent quantum yield(Φp)in doped film than those in the dilute solution.Mainly,their AIPE are induced by the blocked stretching motion of aromatic segments in CN ligand and restrained the deformation of their coordinating skeletons.The AIPE complexes can possess AIE factor(α_(AIE))of ca.7.4.In addition,the carbazole group can effectively promote hole transporting ability of the concerned AIPE emitters,which can benefit their electroluminescent ability.Hence,the I~(III)(C^N)2(P-donor ligand)Cl-type complexes can show decent EL efficiencies in the solution-processed red-emitting organic Light-emitting diodes(OLEDs)with a maximum external quantum efficiency(η_(ext))of 8.5%,a maximum current efficiency(η1)of 22.0 cd A~(-1)and a maximum power efficiency(ηp)of 15.9 lm W~(-1).Furthermore,as long-wavelength emitter,solution-processed white OLEDs(WOLEDs)have been constructed based on the red-emitting AIPE Ir~(III)(C^TN)2(P-donor ligand)Cl-type complexes,which can play critical role in achieving stable white electroluminescent spectra at high luminescence.The concerned WOLEDs can show attractive EL efficiencies of 6.6%,23.7 cd A~(-1)and 16.0 lm W~(-1).All these results can provide valuable information for developing new AIPE materials with high EL ability.
查看更多>>摘要：Fluorescent imidazole-triazole based ligands L1 and L2 have been designed as chemical push-pull chemosensors for divalent metal ions and synthesized through palladium-catalyzed cross-coupling reactions using indium or-ganometallics and click chemistry.The novel ligands exhibit intense absorption in the ultraviolet region with high molar extinction coefficients,and strong fluorescence emission with large Stokes displacements.On the basis of UV-Vis absorption spectroscopy and fluorescence emission data in acetonitrile,L1 is shown as a bifuncional chemosensor with differential response for Fe~(2+)and Cu~(2+)over a range of selected 3d divalent and other metal ions.The binding site of the ligand was established by single-crystal X-ray diffraction and ~1H NMR spectroscopy studies.The association constants,determined by spectrofluorimetric titrations,show a steady binding affinity of L1 for Cu~(2+)and Fe~(2+)in comparison with other previously reported fluorescent bidentate chemosensors,offering the lowest limit of detection(LOD)with Cu~(2+).DFT calculations provide a rationale properly understanding and interpreting the experimentally observed results.Indeed,a mechanism of the different optical responses of LI towards 3d divalent metal ions is proposed.
查看更多>>摘要：Cell membrane is the barrier between cell and environment,which is an important structural basis for maintaining cell environment stability and regulating cell normal life activities.There are important active molecules in the cell membrane,so it is of great biological and medical significance to explore the physiological functions of active molecules in the cell membrane.In this work,probe that co-regulating cell membrane targeting by pyridine salts and lipid chains was developed.In this probe,using pyridine salt as receptor and coumarin derivatives as donor constructed a ratiometric fluorescent probe MCP based on ICT for specific recognition of SO2 derivatives.MCP was selected the cyanide group as the SO_3~(2-)response site,and the introduction of pyridine propyl,which regulates hydrophobicity,so as to achieve efficient targeting of cell membranes.MCP showed high sensitivity and selectivity for SO_3~(2-).Moreover,MCP showed a fast response time(30 s)and red fluorescence emission wavelength(645 nm).In addition,MCP can successfully applying to detect endogenous SO2 on the cell membranes.
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