查看更多>>摘要：Mono-deprotonated HIndigo~-anions have been selectively generated by a direct interaction of H2Indigo with cesium metal in toluene.Following interaction with cryptand allows one to isolate crystalline complex {cryptand(Cs~+)}(Cs~+HHmdigo~-]2-C6H4Cl2(1).Methods for preparation of chelated complexes of HIndigo~-with cobalt(II)and nickel(II)halides have also been developed allowing structure and properties of crystalline {CV~+} [HIndigo(Co~(II)Cl2)]~--C6H4Cl2@and {cryptand(K~+)}[Hrndigo(Ni~(II)Cl2)]~@to be studied.Tetrahedral Co~(II)atoms in 2 have high-spin S = 3/2 state which is evidenced from corresponding EPR spectra and SQUID measurements.Molecular structure and properties of HIndigo~-anions have been studied in the obtained complexes and compared with those of mono-reduced HIndigo~(·-)radical anions.It is shown that absorption bands of HIndigo"are red-shifted relative to those of HIndigo~(·-)allowing reduced and deprotonated forms of irans-indigo to be distinguished.HIndigo"anions are EPR silent and diamagnetic in contrast to paramagnetic HIndigo~(·-)radical anions.
查看更多>>摘要：Two new water-soluble PAH-substituted(PAH-polyaromatic hydrocarbon)naphtho[1,2-d] [1,3]oxazole dyes 1-2 were synthesized and investigated for intramolecular charge transfer(ICT)behavior,aggregation,and ability to fluorescent staining and photosensitization on living cancer cells of HeLa and Vero cultures.To make clear this behavior a detailed analysis of the relationship between the structure and photophysical properties 1-2 were carried out based on experimental and computation data.As a result of the staining experiment,there was a diffuse distribution in the cytoplasm of 2-(9-anthracenyl)-containing naphthoxazole 1 as a hydrophilic fluo-rophore.Whereas 2-(1-pyrenyl)-derivative 2 showed accumulation in the endoplasmic reticulum,as well as additional distribution in lipid bilayers.Photodynamic activity of type II was confirmed for the cationic exogenous photosensitizer 2:the IC_(50)value in the case of HeLa cell culture was 0.50 μM.The radical mechanism of photodynamic activity was determined by the EPR method.
查看更多>>摘要：Most of panel paintings in Cambodia were destroyed by climate,insects and war;especially during Khmer Rouge(1975-1979).A few paintings were studied for materials and techniques.In this research,we focus on the pigment analyses of the early 20th century Cambodian panel paintings on the wooden doors and windows in the gallery of bronze,National Museum of Cambodia.The EDX and XRD techniques were applied to determine the elemental compositions and identities of the pigments used in the paintings.The results suggested the presence of lead white,calcite,Prussian blue,red cinnabar,red ochre,red lead,gypsum,emerald green(clinoclase),organic black,organic brown with the base of blanc fixe and gold leaf in the paintings.The cross sections of paint samples showed various layers;wood support,ground and paint layers.The ground layer was composed of kaolin while various white pigments like calcite,lead white,blanc fixe and gypsum were found in the paint layer.This indicated the use of white pigment(s)in combination with another colored pigment(s).
查看更多>>摘要：Five triphenylmethine dyes were designed and synthesised for the blue colour conversion layer of virtual and augmented reality displays.To form subpixel patterns suitable for high-brightness microdisplay panels,the prepared dyes must exhibit high solubility,colour strength,durability,and colour purity.For this purpose,three major strategies were introduced:dimerisation of triphenylmethine,chlorination,and counterion exchange.The electrostatic and spectroscopic characteristics of the synthesised dyes were investigated and predicted using computational calculations.The counter anion-modified dyes exhibited superior optical properties and thermal-and photo-stabilities compared to their parent dyes.The modified dyes also showed enhanced solubility toward industrial solvents because of their highly twisted chemical structures and weakly coordinating counter anion substituents.The synthesised dyes were chlorinated to optimise blue colour tuning and prevent the agglomer-ation of dyes.DTPM-C1-HFPSI was selected as the main colourant,and EV-HFPSI was selected as the colour-matching colourant to manufacture optimal deep blue colour resists.The optimised spin-coated films exhibi-ted high transmittance in the blue region and excellent properties in terms of brightness and colour purity by absorption over a wide and appropriate visible region.
查看更多>>摘要：In this study,three molecules with distorted asymmetric D-A-D'structure were synthesized by one-step nude,ophilic substitution reaction using different fluorophores(carbazole,phenoxazine,phenothiazine)as electron donors and benzophenone with distorted conformation as electron acceptor.The target compounds were all confirmed by ~1H NMR,~(13)C NMR and EI-MS.In addition,the molecular skeleton of the target compound con-taining a phenothiazine donor group was further confirmed by X-ray single-crystal diffraction analysis.Com-bined with the results of UV-vis absorption spectra and fluorescence emission spectra,we found that the differet electron donating ability of donor parts(carbazole,phenoxazine and phenothiazine)led to the blue,green and light yellow fluorescence of these compounds in the solid states.Subsequent studies showed that these three compounds all showed remarkable solvatochromism in different organic solvent due to the intramolecular charge transfer(ICT)effect,and the increase of solvent polarity induces a red-shift in the emission wavelength,The results of mechanochromic properties confirmed that only the compound containing phenothiazine flud-rophore showed obvious reversible mechanochromic properties.Compounds containing carbazole and pheno-thiazine groups showed aggregation-induced enhanced emission(AIEE),while compound bearing phenoxazine showed typical aggregation-induced emission(AIE)behavior.Through powder X-ray diffraction(XRD)analysis experiment,crystal structure analysis and theoretical calculation,the relationship between the structure and properties of these molecules was discussed.Finally,we also preliminarily explored the application of these molecules in biological imaging,which exhibited excellent biocompatibility and cell permeability in living cells.In brief,through reasonable molecular design,the luminescent properties and solvatochromism properties of these compounds can be regulated,which provides a theoretical basis for the rational design of molecules with excellent photophysical properties.
查看更多>>摘要：Two novel ethyne-linked polymers(PI and P2)were synthesized and characterized.Via femtosecond Z-scan,their nonlinear optical properties were investigated.Both polymers exhibit obvious reverse saturable absorption and self-defocusing.Using phase object pump-probe method,their transient absorption and refraction dynamic traces are measured and the mechanism of their optical nonlinearities is analyzed.The results indicate that two-photon absorption(TPA)mainly dominants nonlinear absorption of PI and P2.The TPA coefficients are approximate 24.7 × 10~(-2)cm/GW for PI and 3.12 × 10~(-2)cm/GW for P2.Through the extrapolation fitting,the estimated OL threshold for PI is on the order of 10~(-2)J/cm~2.On the other hand,both polymers display negative excited-sate refraction which is strong enough to dominate the transient nonlinear refraction over solvent effect.The refractive volumes of each effective state are determined.Our results indicate that ethyne-linked polymers have good nonlinear optical properties under femtosecond pulse excitation.
查看更多>>摘要：The design,synthesis,and bio-applicability of a series of 8 near-infrared(NIR)molecular probes with tunable hydrophilic/hydrophobic properties are described in this paper.The title dyes comprise of symmetric hepta-methine cyanines with various N-quaternary heterocyclic moieties including indole,benzo[e]indol,benzothia-zole and naphtho[1,2-d]thiazole,along with an extra positive charge in close proximity to the polymethine backbone.Combined UV-Vis and spectrofluorimetric techniques in both organic and aqueous-buffered solutions were employed to investigate the optical properties of the NIR chromophores.Two of the fluorophores emerged remarkable fluorescence quantum yield(Φ=0.083),while their brightness was found up to 3-fold that of the FDA approved Indocyanine green-ICG(Φ = 0.027).What is more,two of the dyes appear to outperform the later clinical benchmark fluorophore in terms of photostability.While the ICG was completely faded after 1 h of constant irradiation,nearly 70% of the original emission signal could be observed for one of the novel molecular probes.The log P_(ow)values determined by a combination of HPLC and UV-Vis(partition between 1-octanol/water)cover a relatively large range,from-2.14 up to 7.92.Investigation on the cytotoxicity by means of the MTT assay revealed,that present dyes are suitable for bioanalytical purposes and are safe to use.This paper also includes fluorescence imaging and cellular applications,such as labeling of HeLa cervical cancer cells.The results from the confocal microscopy reveal the superior staining capability of current heptamethines since they show significantly brighter signal than the commercial ICG probe.An organelle-selective fluorescent staining was achieved depending on the dye chemical structure.Co-localization within the intracellular microenvironment(linear or granular-cytosol,mitochondria,lysosome,endoplasmatic reticulum or Golgi apparatus)was confirmed without interference,employing several conventional organelle dye trackers.To the best of our knowledge,heptamethine dyes represent the first example of a series NIR emitting probes,that exhibit rational structural modifications aiming to fine-tune the hydrophilic/hydrophobic properties furnishing organelle-targeted staining.
查看更多>>摘要：Organic crystal with a high emission efficiency and excellent spectral stability is crucial for constructing low-threshold deep-blue organic laser.Here,we synthesized an organic lasing molecule(BPhDPF)with a steric diarylfluorene as the core building block,the single crystal of which has ultra-deep-blue emission with the photoluminescence quantum yield(PLQY)as high as 84.9%,as well as short lifetime and super-stable emission.Meanwhile,C-H ··· π interactions are easily observed in single crystal structure,contributing to the formation of BPhDPF polyhedral microcrystals by self-organize in solution.Interestingly,the intermolecular coupling and exited state were well inhibited by the large steric hindrance group at 9-position and 2-/7-flexible side-chain,which is critical to laser applications.Finally,the deep-blue emission organic laser was obtained with a peak located at 418 nm and very low threshold of P_(th)= 1.62 μJ cm~(-2).A novel organic lasing molecule has been developed,offering helpful information for further investigating organic lasers.
查看更多>>摘要：In this paper,ternary polymer solar cells(PSCs)consisting of two blend donors(FTAZ and PTB7-Th)and one acceptor(N3)with similar highest occupied molecular orbital(HOMO)energy levels,different absorption peaks and cascading lowest unoccupied molecular orbital(LUMO)energy levels are built.The ternary PSCs achieve higher photovoltaic performance and better thermal stability compared to the FTAZ:N3 binary PSCs.The A medium wavelength absorption FTAZ polymers and long wavelength absorption PTB7-Th polymers as the blend donor,and near-infrared wavelength absorption N3 as the acceptor.The optimize ternary PSCs exhibit a maximum power conversion efficiency of 15.65%,with an open-circuit voltage of 0.852 V,a short-circuit current of 25.25 mA cm~(-2),and an FF of 72.5%.This performance of device is attributed to more efficient exciton dissociation and suppression of charge recombination within ternary films.The ternary PSCs also show good crystallinity and surface morphology at room temperature and after thermal annealing for 20 h at 70 ℃,which is attribute to the better thermal stability of the ternary PSCs.
查看更多>>摘要：High-performance microscopy with organelle-targeting fluorescent probes has been an indispensable bioimaging tool for cell biology.Confocal or super-resolution imaging often requires highly magnified and/or longitudinal scanning conditions,necessitating the advent of photostable fluorophores.Herein,we report novel organelle-targeting fluorescent probes derived from a highly photostable fluorophoric skeleton,i.e.,1,5-naphthyridine-2,6-dione(NTD).With organelle-specific derivatization and π-conjugation extention,we developed NTD-based molecular probes with blue-to-red fluorescence tunability and intracellular organelle selectivity for staining,as well as minimal cytotoxicity,which allowed us to demonstrate intracellular differentiation of lysosomes and mitochondria by multi-color confocal imaging.Under the condition of longitudinal microscopic examination,these new probes showed excellent photostability of fluorescent signals as opposed to the rapid photobleaching of commercial trackers.By virtue of these beneficial properties,the NTD-based probes were successfully applied to super-resolution cell imaging by enduring the high-power illumination conditions of sub-diffraction microscopic techniques including stimulated emission depletion(STED)and structured illumination microscopy(SIM).
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