查看更多>>摘要：Multi-faceted bending elastic organic single crystals are extremely rare and have potential applications in optical communication,mechanically tunable flexible fluorochromic materials,etc.,which have attracted great atten-tion of researchers.Herein,we reported two compounds with simple structures,namely 1,3-dimethylbarbituric acid(DMBA)and its derivative(TPABA).Under stress,both(200)and(002)faces of TPABA crystal could undergo reversible elastic deformation,possessing rare multi-faceted bending properties.The abundant weak isotropic intermolecular interactions(such as H-bonding,etc.)in crystal could buffer mechanical stress and prevent crystal fracture.Fortunately,TPABA crystals showed multi-directional flexible optical waveguide characteristics.The corresponding optical loss coefficients were 0.57 dBmm~(-1)(582 nm,straight line),0.75W dBmm~(-1)(583 nm,(002)face bending),and 0.58 dBmm~(-1)(587 nm,(200)face bending).Unlike TPABA crystals,under stress,the(040)and(200)faces of the DMBA crystal underwent plastic deformation and fracture,respectively,showing the characteristics of single-faceted plastic deformation.
查看更多>>摘要：Five large size polycyclic aromatic hydrocarbons(PAHs)obtained through convergence of tetraphenylethene(TPE)onto pentacenediene or bianthracenylidene cores were synthesized and fully characterized.Such convergence strategy yielded AIEgens with aggregation-induced emission enhancement(AIEE)effect and improved fluorescence quantum yields compared with a bisect strategy where pentacenediene and anthrace-nylidene were inserted into bisected TPE-AIEgens.Single crystal structure and DFT calculations of such large size AIE compounds indicate that the intermolecular interactions play an important role on the quantum yields and other physiochemical properties.
查看更多>>摘要：A series of novel D-jc-A type thermally activated delayed fluorescence(TADF)emitters,namely DTPTCzDP,DTPTCzDP-CN and DTPTCzDP-Py,were developed with 2,4-di-tert-butyl-1,3,5-triazine(DTPT)as electron acceptors and N3,N3,N6,N6-tetraphenyl-9H-carbazole-3,6-diamine(DAC-II)as donors.The π-bridge was varied from phenylene to cyanophenylene or pyridyl to tune the electronic and luminescence properties.The strong electron-donating DAG-II groups disperse the highest occupied molecular orbital(HOMO)and guarantee the effective separation of frontier molecular orbitals and the TADF feature despite the small dihedral angles Incorporation of electron-withdrawing cyano or pyridyl on or as the jr-bridge enhanced the triazine acceptor strength,not only leading to bathchromatic shift of the TADF,but also reducing the singlet and triplet energy splitting(ΔE_(St))and increasing the reverse intersystem crossing rate constant(Jcrisc).Particularly DTPTCzDP-CN exhibited high radiation rate constant kr>10~7 s~(-1)and k_(RISC)>10~6 s~(-1)simultaneously.The greenish-blue organic light-emitting diode of DTPTCzDP realized a maximum EQE of 20.13%(53.57 cd A~(-1))while the pale yellow device of DTPTCzDP-CN exhibited an EQE of 17.81%.All these devices showed slow efficiency roll-off,benefitting from the steric hindrance effect and intrinsic chemical stabilities of the bulky DTPT and DAC-II units in these emitters.
查看更多>>摘要：In this work,the effect of reaction conditions on the preparation of CQDs by pyrolysis was studied.More spe-cifkally,CQDs-1 with single emission peak of blue fluorescence and CQDs-2 with double emission peak of yellow fluorescence were prepared by pyrolysis methods in a closed and open environment,respectively.The media-nism of the difference in optical properties of the two types of CQDs had been systematically studied.The results showed that the difference in the degree of graphitization and surface state was the main reason for the dif-ference in the optical properties of the two types of CQDs.The CQDs-2 with dual emission characteristics was used for high sensitivity and high selectivity detection of cephalosporin antibiotics based on the inner-filter effect(IFE).The limit of detection(LOD)was 0.87-2.78 μM,with a good recovery rate(99.4-102%)in the milk spike recovery test.Additionally,the cytotoxicity and cell imaging showed that CQDs-1 and CQDs-2 have potential applications in biological systems.
查看更多>>摘要：Introduced oligo(ethylene glycol)(OEG)chains into high-performance donor-acceptor(D-A)type conjugated polymers is a promising strategy to control the π-π stacking,energy levels,solubility,and electrical properties.In this work,a series of novel PDTBF polymers(PDTBF-DTh,PDTBF-ThSe,and PDTBF-Th)were synthesized based on the typical benzothiadiazole-thiophene(BT-Th)-based polymer substituted with OEG side chains to investi-gate their electrochromic(EC)and photovoltaic performance.The resultant PDTBF polymers had fast switching speed(i.e.,chlorobenzene-prepared PDTBF-Th EC film:Tc~(0.9)= 1.8 s,Tb~(0.9)= 1.0 s),and high coloration effi-ciencies(i.e.,chlorobenzene-prepared PDTBF-ThSe EC film:255.50 cm~2 C~(-1)).Moreover,the PDTBF~DTh:Y6-based device shows a power conversion efficiency(PCE)of 3.11%.Due to the induced amphiphilic OEG side chains on the backbone of the conjugated polymer,these materials also exhibited green solvent processing potential.It is worth noting that these PDTBF polymers exhibited much wider optical bandgaps(1.95 eV-2.16 eV)than other reported PDTBF polymers(mostly narrow band gaps:1.40-1.70 eV),due to the format of linkage I between OEG side chains and thiophene units.It is an effective strategy to control the optical properties of the I conjugated polymers using OEG side chain engineering investigation.
查看更多>>摘要：In the present study,we developed a novel fluorescent chemosensor with a hybrid structure of 3-pyridinonitriie-coumarin derivatives by molecular design strategy that can effectively label intracellular lipid droplets.Interestingly,the probe ATOP-LD also exhibited polarity-sensitive properties,which may be attributable to its own strong electron-giving and electron-absorbing moieties.In addition,the probe exhibited excellent interference resistance,pH stability and low biotoxicity and had been successfully applied to cell imaging.Also,probe ATOP-LD could discriminate dead and living zebrafish or its embryos.These satisfactory properties prove that the probe is useful and possesses great potential for application.
查看更多>>摘要：A series of novel V-shaped D-π-A-π-D push-pull chromophores,containing two aminoaryl electron donors(D),1,5-thiophenylene π-conjugated spacer and a 6-cyano-or 6,7-difluoroquinoxaline electron acceptor(A),was designed,synthesized,and characterized.6-Cyano derivatives demonstrated red shift of absorption and emission maxima compared with 6,7-difluoro counterparts.The compounds displayed positive emission solvatochromism with increasing solvent polarity.Additionally,emission behavior of all compounds in THF/water mixture and solid state was investigated.Moreover,the two-photon excited fluorescence(2 PE)spectra of carbazolyl-containing chromophores were measured.Replacement of 6,7-difluoroquinoxaline core by 6-cyanoquinoxaline increases two-photon absorption cross section(δ_(2PA))value by more than 10 times.6,7-Difluoroquinoxalines demonstrated changes in emission maxima or/and intensity after mechanic stimulation.Electronic-structure calculations with the use of quantum-chemistry methods were performed to have a deeper insight into experi-mental data.In summary,the obtained results show multifunctional nature of V-shaped 2,3-bis(5-arylthiephen-2-yl)quinoxalines and their potential utility in diverse applications.
查看更多>>摘要：As a vital reactive oxygen species(ROS),endogenous hypochlorous acid(HOCl)deeply engaged in masses of pathophysiological processes owing to its high reactivity,thus the detection of HOCl is awfully valuable for elucidating HOCl-related pathophysiology mechanism.Despite the extensive development of outstanding HOCl fluorescent probes so far,very few of them could be applied for monitoring HOCl in the pure water system.Herein,we present a novel rhodol-based fluorescent probe 6 for the unambiguous detection of HOCl in pure water,which was effectively designed and synthesized by using the spirocyclic hydrazide group as the HOCl sensitive site and introducing two hydroxyethyl groups for obtaining high hydrophilicity into the rhodol skeleton,a unique rhodamine structure.Compared to the control compound 5 without hydrophilic groups only capable to be used in the aqueous system containing organic solvent,6 achieves the detection of HOCl not only in the above regular system but also in pure water,indicating that the introduction of hydrophilic hydroxyethyl group is an effective and reasonable approach to achieve the broader-spectrum detection of HOCl.More importantly,different with 5,highly water-soluble 6 regardless of dissolving in the regular system or pure water system can achieve the visual monitoring of HOCl with prominent sensitivity and high spatiotemporal resolution in living HepG2 cells and zebrafish,confirming the robust imaging ability of our probe 6 to HOCl in complex biosystem.
查看更多>>摘要：In this study,the bi-functional material with both aggregation induced emission(AIE)character and catalytic activity was proposed.The material was prepared by integrating Zr(IV)ions and tetraphenyl ethylene(TPE)derivatives that functionalized with four carboxylic acid groups.The TPE-Zr~(4+)aggregates showed typical AIE effect with a blue emission peak centered at 470 nm.On the other side,the TPE-Zr~(4+)aggregates retained the phosphatase-like catalytic activity of Zr~(4+)ions,which could catalyze the hydrolysis of fluorescent substrate fluorescein diphosphate(FDP)to generate green fluorescence centered at 513 nm.It is interesting that both the AIE character and catalytic activity of TPE-Zr~(4+)aggregates are highly sensitive to pH values.The unique property makes TPE-Zr~(4+)aggregates a promising material for ratiometric pH sensing and intracellular imaging.
查看更多>>摘要：In this work,we designed and synthesized a turn-on fluorescent probe for detecting H2O2.The results demonstrated that probe JQ-1 exhibited a high selectivity for H2O2.In addition,probe JQ-1 exhibited excellent sensitivity(detection limit:87 nM)and a fast response time(~10 min).Organelle co-localization experiment showed that JQ-1 mainly targeted mitochondria,which provided possibility to detect change of H2O2 level in mitochondria.JQ-1 can be used to image exogenous and endogenous H2O2 in vitro and vivo.Meanwhile,we used JQ-1 as fluorescence dye to investigate the change of H2O2 level during immunogenic cell death for the first time by confocal laser scanning microscopy and flow cytometry,and the results showed that H2O2 level had negligible change in process.Therefore,the results suggested that this probe is a reliable chemical tool for monitoring both endogenous and exogenous H2O2.
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