查看更多>>摘要：Developing a variety of organic compounds with bright solid-state emission is highly advantageous,provided they exhibit stimuli-responsive properties.Such'smart'materials offer a remarkable role in sensing,digital machinery,material science,and the biomedical field.Taking this into account,two phenothiazines(PT)appended vinyl-linked aryl unit(mesitylene/phenyl)two based D-rc-A structures have been synthesized.The derivatives have exhibited remarkable luminescence characteristics in a diverse set of solvents due to the twisted intramolecular charge transfer(TICT)state and aggregation-induced emission enhancement properties.Sur-prisingly,between them,only the mesitylene derivative displays significant and highly reversible mechano-fluorochromic(MFC)activity by exhibiting an emission shift from sky blue(467 nm)to cyan(482 nm).The mechanistic insight obtained from P-XRD analysis suggests crystal to amorphous transition causes bathochromic shift upon grinding.SEM analysis reveals two discrete morphologies of the MFC compound in its pristine and ground states.Additionally,DFT and TD-DFT calculations provide insight into their electronic energy levels.Furthermore,results from the electrochemical experiment indicate that they are potential candidates for developing optoelectronic devices.
查看更多>>摘要：Polymorphic luminogens not only provide ideal models to study the relationship between packing patterns and emission properties,but also facilitate the design of new high performance luminogens.Intermolecular interactions,such as π-π stacking,hydrogen bonding are widely involved to explain the relationships between crystals and emissions,while intramolecular effects,especially the torsion angels between the donor and the fluorophore have not been fully recognized.In this paper,a new coumarin derivative coumarinopyrone(GP)was synthesized and four crystals(CP-G1,CP-G2,CP-R and CP-O)were obtained by recrystallizing.These four crystals with different stacking modes or molecular conformations elicited bright fluorescent emissions varied from 520 nm to 620 nm.The relationship of fluorescent emissions with the intra-/intermolecular interactions was revealed through single crystals analysis.Interestingly,crystals CP-0(emission at 580 nm)and CP-R(emission at 620 nm)had nearly identical stacking mode,but differentiated at tiny torsion angel between the diethylamino donor and the coumarin fluorophore.It may provide crystal-level evidence to explain the effect of the rotation of one donor on fluorescence properties.The emissions of CP could be reversibly switched among blue and orange through recrystallizing or solvent fuming.CP-G2 and CP-O exhibited fluorescence response to NH3,and CP-O was further expected to be a food spoilage sensor.
查看更多>>摘要：The quick coupled reaction of nitric oxide(NO)with superoxide free radicals(·O_2~-)produces peroxynitrite(ONOO~),it is a powerful biological oxidant.And according to interact with proteins,lipids,nucleic acids and other organisms,the ONOO~ eventually leads to all sorts of diseases,for instance,Alzheimer's disease,diabetes,cancer,inflammation.To fully understand the multiple pathological processes of ONOCT in vivo,it is imperative to exploit effective tools to realize the precise,fast and sensitive detection of endogenous ONOCT.We described novel fluorescent probe named YV in this work,covering the synthesis,characterization and biological appli cation.YV can detect ONOO-by means of fluorescence imaging.Because of the borate group cleavage,YV exhibited a fluorescence intensity change toward ONOO-.It was,the principle of ESIPT that resulted in fluo-rescence enhancement.The probe YV shows a series of advantages such as high selectivity,fast response,sig-nificant Stokes shift and low detection limit.Fluorescence imaging can be used to identify variations in ONOO~-in Hela cells and zebrafish.YV will be a robust imaging tool for detecting endogenous ONOO".
查看更多>>摘要：Inorganic-organic photochromic hybrid materials have attracted attention in different research fields,since they have a wide potential application in optical memories,sensors,filters,lenses,pigments,and decoration.In this work,the photochromism of the l-(2-Hydroxyethyl)-3,3-dimethylindolino-6/-nitrobenzopyrylospiran dye was investigated through the preparation of hybrid pigments based on raw and pillared saponites at pH 2 and pH 13 at 25 ℃.The second group of pigments was prepared at pH 2 and 25 ℃ by in-situ hydrolysis of TEOS in the presence of the same dye.All prepared solids were characterized by X-Ray diffraction,~(13)C CP/MAS NMR and thermogravimetry,and were submitted to irradiation under visible light.The results suggested both intercalation and/or adsorption of the dye onto clay mineral surface via hydrogen bonds for the saponite based pigments.Concerning the hybrids obtained from TEOS hydrolysis reaction,the dye acts as a template resulting in a higher photostability of the resulting pigment compared to those prepared with clay minerals.In general,all hybrid pigments presented photoreversible capacity after light exposure and subsequent time-out in the dark.The findings of this study proposed the multicolored prepared hybrids as promising materials to be applied in photochromic systems as smart pigments.
查看更多>>摘要：The substitution reaction of 3-N-(2-chloroacetamido)benzanthrone with a number of the amino acids is reported.The possibility of using this halogenated benzanthrone for fluorescent labelling of amino acids has been studied.Arginine is the most reactive amino acid in the reaction,as it was found in the study.The spectral behavior of new benzanthrone derivatives depends on the polarity of the medium,exhibiting fluorescent solvatochromism due to intramolecular charge transfer from the substituted amino group to the carbonyl group.The results obtained indicate that the synthesized compounds are promising for studying peptides and proteins,as well as for visualizing biological objects.
查看更多>>摘要：In this work,deformable and chromatic hydrogel triggered by multi-stimuli was fabricated.This hydrogel was composed of N-isopropylacrylamide(NIPAAm),acryl-6-aminocaproic acid(A6ACA),and spiropyran(SP)derivatives,which possessed ferric ion(Fe~(3+))and temperature-triggered shape deformations properties as well as chromatic behavior.Under ultraviolet light irradiation,the SP isomer in the hydrogel transformed to the mer-ocyanine(MC)isomer,and the hydrogel showed the characteristic UV-Vis absorption peak of MC at 540 nm.The hydrogel revealed the selective chromatic response to Fe~(3+)with the disappearance of the absorption peak of MC.Using ionoprinting technology,the hydrogel deformed programmatically in the presence of Fe~(3+).Moreover,owing to the anisotropic structure of the chromatic hydrogel,it realized reversible bending deformation triggered by temperature.The behaviors of hydrogels in response to dual stimuli(Fe~(3+)and temperature)were further investigated,and the hydrogel showed programmable,spatiotemporal,and complex deformation behaviors,accompanying by the color change.This hydrogel will have great application potential in soft robotics,soft actuators,and environmental sensors.
查看更多>>摘要：It is still a meaningful and challenging task to prepare ultralong-lived(phosphorescence lifetime τp>100 ms)pure organic phosphorescence materials emitting at room temperature,let alone at high temperature(e.g.100 ℃).Herein,l-methyl-4-phenylpyridin-l-ium salts(PMX,X = CI,PF6,Br and I)without afterglow are tightly encapsulated into the cavity of phCB[6](a CB[6] derivative)to form amorphous ultralong-lived host-guest I phosphorescence complexes PMCl/phCB [6](1.57 s),PMPF6/phCB [6](1.35 s)and PMBr/phCB[6](0.51 s)with green afterglow lasting for 9-10 s under ambient conditions.More importantly,the green phosphorescence is still visible to the naked eyes even at 100 ℃,exhibiting excellent high-temperature tolerance.Such an encapsulation strategy for obtaining high-temperature phosphorescent materials has not been reported yet and would pave a new road for its further applications.
查看更多>>摘要：In photovoltaic technologies,hole-transporting materials(HTMs)play a critical role in realizing highly efficient performance of perovskite solar cells(PSCs).Herein,a series of fluorine substituted small molecules based on triphenylamine backbone are designed by controlling fluorine atoms number and position.A comprehensive study on the structural modification is carried out to reveal the effect of fluorine substitution of HTMs.The energy level alignment,reorganization energy and the charge-transport properties are explored based on Quantum-chemical calculations.It is found that all difluorinated molecules have lower HOMO levels,which indicates that perovskite solar cells with two fluorine substituted hole-transporting materials may have higher open-circuit voltages.Moreover,the UV-vis absorption spectra of the studied molecules are slightly red-shifted with the increase of fluorine atoms.To further understand the effect of fluorine substitution on the hole transport properties,the hole mobilities of all HTMs are evaluated quantitatively using the Marcus theory and Einstein relation.The calculated results show that difluorinated molecules TPB-m~(-2)F exhibit relatively higher hole mobility owing to efficient intermolecular interactions.As for monofluorinated molecules TPB-lF-a and TPB-1F-b,TPB-lF-a with fluorine atoms substituted on the inside position exhibit higher hole-transporting performance.Overall,we conclude that suitable modification of fluorine substitution is expected to improve the electrochemical and hole transport property of HTMs.We hope our theoretical investigation provide useful information for further improving the photovoltaic performance of PSCs.
查看更多>>摘要：The advent of A-DA'D-A non-fullerene acceptors(NFAs)containing electron-deficient A'unit such as benzo-thiadiazole(BT),benzotriazole(BTA)and quinoxaline(Qx)has driven the significant development of organic solar cells(OSCs)using donor-acceptor(D-A)type polymer as electron donor.However,how to use A-DA'D-A type NFAs to accelerate the development of poly(3-hexylthiophene)(P3HT)device is still not determined,because only limited BT-based A-DA'D-A molecules have been used in P3HT-based devices.Herein,a new A-DA'D-A molecule named TPBTA-RCN with BTA as the A'unit and 2-(l,l-dicyanomethylene)rhodanine(RGN)as the A unit was designed.On the basis of our previous report,we concluded here that the terminal group plays a larger role than the central fused A'unit in regulating charge generation and recombination processes of P3HT:A-DA'D-A-type NFA systems.In summary,we not only demonstrate the broad prospects of A-DA'D-A NFAs to pair with P3HT,but also illustrates further synthetic directions of this kinds of materials,which will greatly facilitate the progress of P3HT-based OSCs.
查看更多>>摘要：Four-coordinated organoboron compounds have drawn intense attention as light-emitting and/or electron-transporting layers in organic light-emitting diodes(OLEDs)due to their remarkable solid-state luminescence and electron-transporting properties.During the past dozen years,by exploring the conjugating ligand moieties,a variety of fascinating four-coordinated boron-containing compounds have been constructed,mainly including N,0(nitrogen,oxygen)-,N,JV-,0,0-chelated types.These compounds are promising emissive materials for OLEDs:they have been shown to be superior highly efficient and full-colour emitters for OLEDs with some TADF emitters based on these ligands achieving high external quantum efficiencies over 20% in devices.This review focuses on the significant advances in four-coordinated organoboron emitters over the past dozen years,with emphases on material design and OLED performance.The molecular structures summarized here are compre-hensive and up-to-date,covering compounds with traditional fluorescence,phosphorescence,and thermal-activated delayed fluorescence(TADF).
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