查看更多>>摘要：A series of donor-acceptor-donor'(D-A-D')type compounds with aggregation-induced emission(AIE)were designed and synthesized by using imidazole as an acceptor and triphenylamine and indolocarbazole as different donors.The non-coplanar structure could effectively eliminate the molecular aggregation-caused quenching(ACQ).Meanwhile,the electron push-pull character could be adjusted by introducing different substituents to achieve the high-efficiency fluorescence from its locally excited(LE)state.The electronic structures,electrochemical behavior,thermal stability,photophysical properties and electroluminescence(EL)performance of these compounds were systematically studied.Four new materials were evaluated as the blue emitters in non-doped OLEDs,and all devices present stable blue emissions with premium EL performance.Furthermore,a hybrid white organic light-emitting diode(WOLED)was prepared by using the compound 5b as the double blue emitting layer and the compound 5d as the host doping with phosphorescent dye.The maximum current efficiency and external quantum efficiency of the device were 67.6 cd/A and 24.3%,respectively.Especially,the WOLED showed ultra-stable CIE coordinates of(x = 0.337 ± 0.003,y = 0.341 ± 0.002)as the driving voltage increases from 5 V to 12 V.This work provides an idea for the design of AIE molecules and a practical strategy to achieve multifunctional light-emitting devices.
查看更多>>摘要：Detecting viscosity is vital for pathological investigation since subtle changes in cellular microviscosity are related to pathologies and diseases.In this work,five cationic Ir(III)complexes Irl-Ir5 with the formulas as[Ir(ppy)2L]PF6 have been synthesized,where L1-L5 are a family of coplanar bithiazole derivatives having versatile donor/acceptor tails(proton,bromo,tetraphenylethylene,benzothiophene,ethyl benzoate).Fluorescent experiment shows that L1-L5 have a fluorescent activity with high quantum yields(Φ>33%).However,the quantum yields of Ir1-Ir5 are weak in the range from 2.7% to 7.7%.There is a linear relationship between Log(I_(620)nm)and Log(viscosity),which can quantitatively measure viscosity in the range of 1.36-669 cP.Furthermore,a cell colocalization experiment has been performed using commercial nuclear dye(DAPI),lysosomal dye(LysoGreen),and mitochondrial dye(MitoGreen)to explore the subcellular localization ability of Irl in living cells,indicating that the probe Irl can easily pass through the cell membrane,and can accurately target lyso-somes in living cells.In addition,complex Irl can quantitatively detect viscosity and target lysosomes,possessing the potential for practical application in intracellular viscosity detection.
查看更多>>摘要：The specific recognition and long-term continuously monitoring of antibiotics in water is extremely i ecosystem and human health.Herein,we report a two-dimensional blue photoluminescence polymer CdL·H2O(1)based on 9H-carbazole-2,7-dicarboxylic acid(H2L),emission of which cou cantly quenched only by aztreonam(ATM)among thirteen antibiotics in aqueous media.By the titration experiments,the linear Stern-Volmer plot between emission intensities of 1 and ATM cc was observed in the concentration range of 20-100 μM with K_(sv)of 1.12×10~4 M~(-1).Besides high se sensitivity,good anti-interference ability and repeatability for ATM detection were also confirmed,we immersed 1 into the ATM solution for 60 days,and during this period the fluorescence quenchin of ATM for 1 almost unchanged.This result indicates that 1 could be used as a stable high-perfo rescence sensing material for the specific recognition and long-term continuously monitoring of ATI is also the first fluorescent material that can detect ATM in water.The fluorescence quenching me attributed to photoinduced electron transfer(PET)from 1 to ATM.
查看更多>>摘要：This article describes a new chemosensor,2-(benzo[d]thiazol-2-yl)-6-(7,8,13,14-tetrahydrodibenzo[a,i] phenanthridin-5-yl)phenol(BTPP),which is based on the combination of phenanthridine and benzothiazole groups for the sensitive and selective detection of Cu~(2+).Following the successful synthesis of BTPP in a single step,the molecular structure of BTPP was verified by NMR,~(13)C NMR,mass spectrometry,and X-ray single-crystal analysis.These sensors exhibit high optical selectivity for the Cu~(2+)ion across a broad spectrum of other common metal ions in ACN/H2O(1:1)solution,resulting in an extraordinary fluorescence off-on response with a very low Limit of Detection(LOD)value.When Cu~(2+)was added to the compound BTPP,it displayed outstanding properties such as bright yellow emission,rapid reaction time(10 s),detection over a wide pH range(pH = 6-12),and reversibility with glutathione(GSH).FT-IR analysis,~1H NMR titration experiments,HRMS,and Job's plot analysis were used to determine the mechanism of BTPP's binding to Cu~(2+).Inspired by these remarkable sensing characteristics,we successfully used BTPP to detect Cu~(2+)in paper strip-based detection,ambient water samples,and fluorescent bio-imaging in E.coli bacteria with satisfying results.
查看更多>>摘要：Three novel carboline-based benzothiadiazole compounds,αCB,βCB,and γCB,bearing α-,β-,and γ-carboline,respectively,were synthesized and characterized.The molecular structures of aCB and yCB in the crystalline state were analyzed using single-crystal X-ray diffraction.The UV-vis absorption and photoluminescence spectra of all compounds displayed typical intramolecular charge transfer(ICT)characteristics,resulting in clear sol-vatochromic effects in various organic solvents.Theoretical calculations also verified that the major electronic transitions of the three compounds could be assigned to the ICT transition between the carboline moiety(as the electronic donor,D)and benzothiadiazole center(as the acceptor,A).The unit cell of the crystal structure of aCB revealed two solvent(chloroform)molecules residing in the space between the two α-carboline moieties via hydrogen bonding,which could inhibit the structural fluctuation of this compound.Given this feature,aCB demonstrated higher emissive efficiency and a lower nonradiative decay process compared with βCB and γCB.Interestingly,the crystalline powders of aCB,including the solvent molecules in its unit cell,demonstrated a high-contrast and reversible mechanochromic phenomenon,which originated from the conversion of the compound from a crystalline state to a randomly aggregated one.The above findings provide insights into the molecular design of carboline-based D-A-D-type organic fluorophores with high emissive efficiency and intriguing functional characteristics.
查看更多>>摘要：The novel,selective and pH-resistant AIE type chemosensor,based on pyridine,containing a tetracyanobuta-diene moiety(4-CN-TCPy)for turn on detection of Ag~+,as well as for turn-off detection of I~-and mercapto-carboxylic acids was developed.On the example of both tumor and non-tumor cells,it was shown that developed sensor can be used for fluorescent imaging of tissues.
查看更多>>摘要：Sulfatase plays a pivotal role in the regulation of biologically active metabolites associated with various diseases.In particular,the up-regulation of steroid sulfatase activity has a positive correlation with breast cancer due to the increment of estrone levels via the desulfation reaction of estron 3-sulfate.Despite the high association between sulfatase activity and disease occurrence,there has been little progress in the discovery of sulfatase inhibitors,possibly due to the lack of robust activity-based assays.To design a sulfatase activity probe,we examined the binding between four fluorophores(coumarin,BODIPY,rhodol,and tricyanofuran[TCF])and three isoforms of sulfatase using docking simulations and found that the rhodol and TCF scaffolds exhibited stable binding.To avoid the charge-driven organelle accumulation bias,we chose TCF as the core structure and designed two probes containing sulfate(TCF-OSulf and TCF-NCOO-OSulf).The TCF probes showed clear colorimetric response and 2.7-fold and 5-fold fluorescence enhancements in vitro.In addition,the probes detected the inhibition of the enzyme by estrone-O-sulfamate(EMATE)in a time-dependent manner.Since cell-based screening has many advantages over the traditional high-throughput assay in vitro,we further examined TCF probes for the inhibitor assay for sulfatase activity in live cells.Based on our observations,TCF-NCOO-OSulf could be used to monitor sulfatase activity in live cells at a concentration of 5 ^iM.This is the first sulfatase activity-based probe that can visualize activity and inhibition in live cell conditions.
查看更多>>摘要：Fluorescence probes have shown great potential in lipid droplets(LDs)imaging,whereas the imaging perfor mance of the present commercial dyes is far from ideal.In addition,there still is lack of an effective strategy for designing LDs specific probes with satisfactory imaging performance.In this work,we have provided a novel method and probes based on donor(D)-acceptor(A)structure with nitrobenzoxadiazole(NBD)as the A unit and benzene derivatives as the D units,which are expected to show strong emission in lipid environment.Four probes(N-B,N-MeB,N-MeOB and N-Me2NB)with increasing electron-donating ability were prepared,whose fluorescence-emission changed from aggregation-induced emission(AIE)(N-B and N-MeB)to aggregation-caused quenching(ACQ)(N-MeOB and N-Me2NB).Intriguingly,the emission of these probes in oil changed from blue region to red(652 nm)with the increase of electron-donating ability from N-B to N-Me2NB,indicating the great emission regulable ability of this strategy.Moreover,these probes could specifically stain the intracellular and tissular LDs,which had shown considerable performance in the studying of LDs spatial distributions in mice and human atherosclerosis plaques.Impressively,N-Me2NB with the strongest electron-donating group of N-dimethylaniline showed negligible emission in aqueous solution but remarkable enhanced emission in oil,which could still efficiently stain the intracellular LDs at 200 nM.This novel con struction strategy would provide new ideas for preparation of LDs specific probes.
查看更多>>摘要：The analysis of 28 specimens of some of the first Portuguese postage stamps,dated from 1853 to 1894,undertaken with non-destructive techniques:X-Ray fluorescence(XRF),Attenuated Total Reflection Fou Transform Infrared(ATR-FTIR)and Ultraviolet-Visible Reflectance Spectroscopy(UV-Vis).Ink,paper cancellation of the postage stamps were analysed,and the pigments,binders and fillers identified.Prussian 1 was found present in all blue and also in green and brown specimens.Chrome and zinc yellow,lead sulphate mars red were also found in other of the investigated postage stamps.Binders consist mostly of protein g Fillers such as calcite and kaolinite were found dominant.The presence of the latter served as an indicator distinguishing between genuine and forged samples.UV-Vis spectra also proved useful for the same purpose,the above information was processed and organized using chemometric techniques.These include mainly erarchical Cluster Analysis(HCA),for clustering stamps of similar composition,and Principal Compor Analysis(PCA)for mapping the samples and identifying the more relevant variables.The latter are,in the pa content of calcium,potassium,sulphur and silicon and,in the dye pigment area,of iron,zinc and lead cont The study introduces an approach in which,by combination of non-destructive multi analytical techniques v chemometric analysis,extensive information on different aspects of the composition of the studied post stamps is provided,including that of paper and dyes.
查看更多>>摘要：As a representative of the third generation of bisphosphonate drugs,zoledronic acid(ZA)is clinically used to treat osteolytic bone metastases from malignant tumors and osteoporosis.Herein,a novel signal-on strategy for highly selective detection of ZA is proposed,employing Fe~(3+)-mediated fluorescent sulfur quantum dots(SQDs)as a probe.Specifically,Fe~(3+)can induce the aggregation of SQDs in aqueous solution and strongly quench their fluorescence,however,which recovers again in the presence of ZA owing to its emulative complexation with Fe~(3+).The complex ratio and binding mode between ZA and Fe~(3+)are also theoretically simulated.This method exhibits the merits of rapidness,high selectivity,reliability,and with no need of derivatization for ZA detection,with a detectable range of 5-200 μM and a detection limit of 1.7 μM.It has also been successfully applied to determine ZA in real samples including human serum,urine,and drugs.
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