查看更多>>摘要：The photoswitchable system with color and multi-state fluorescence changes is the key to the realization of advanced multi-level information storage, and its application potential has far exceeded the monochromatic fluorescent system. Herein, we introduced a novel multi-state photoswitchable fluorescent polymeric nanoparticles, which contains two energy-matched photoswitchable fluorescent molecules, i.e. diarylethene derivative (BH, donor) and spiropyran derivative (SPMA, acceptor), to construct a tunable fluorescence resonance energy transfer (FRET) system. By optimizing the feeding ratio of the two photochromic molecules to control die efficiency of energy transfer, the fluorescence of the nanoparticles can be reversibly switched among none, red, orange, and green by adjusting the wavelength of light stimuli. In addition, the nanoparticles display good water dispersibility, high brightness, fast responsiveness, excellent photoreversibility, and long-term fluorescence stability. We also verified that the system has great potential in optical data storage, multi-layer information encryption, and anti-counterfeiting.
查看更多>>摘要：Therapeutic resistance caused by hypoxia tumor microenvironment (TME) is one of the main challenges for the development of nanoscale delivery systems, particular for the photodynamic agents. In this work, porphyrin-based metal-organic frameworks composite ACF@PCN-222@MnO2-PEG (APM) with the mimetic sea cucumber morphology was post-synthesized for using in photodynamic therapy (PDT) against hypoxia. Besides the good colloidal stability, as-synthesized APM nanoparticles also exhibited the well biocompatibility and H2O2-triggered drug releasing. After being reacted with endogenous H2O2, the amorphous Mn02 layer on the APM outersurface could quickly decompose to produce abundant oxygen, self-compensating for the consumption of photodynamic process. Meanwhile, the highly loaded hypoxia inhibitors acriflavine (ACF) of 18.7 wt% in APM was released to down-regulate the expression level of hypoxia-inducible factors (HIF). Combining with the self-generating oxygen and ACF inhibitors, the tumor hypoxia could be greatly relieved and the better tumor suppression effect by PDT have been demonstrated in vivo. This self-suppling oxygen nanosystem triggered by endogenous tumor markers proves a feasible way for remodeling the hypoxia TME and to achieve better therapeutic performances.
查看更多>>摘要：For the electrochemical determination of indigo carmine (Ic), which is a common and toxic dyestuff, a nano-composite (LB/MWCNTs) was prepared with chiral amine-bis(phenolate) boron complex containing N, N-Diethyl-p-phenylenediamine (LB), and multi-walled carbon nanotubes (MWCNTs). Chiral amine-bis(phenolate) boron-based electrochemical sensor (LB/MWCNTs/GCE) was designed by modifying the glassy carbon electrode with LB/MWCNTs composite and characterized by scanning electron microscope (SEM) and Fourier transforms infrared spectroscopy (FT-IR). Cyclic voltammograms of bare GCE, LB/GCE, MWCNTs/GCE, LB/MWCNTs/GCE electrodes in neutral ferrocene, cationic Ru(NH3)6~(+3), and anionic Fe(CN6)~3 probes were recorded. Also, their electrochemical behavior was evaluated by comparing with the theoretical values calculated in the Randies Sevcik equation. The active surface areas of bare GCE and LB/MWCNTs/GCE electrodes were found to be 1.039 cm2 and 2.401 cm2, respectively. LB/MWCNTs nanocomposite showed a high electrocatalyric activity on the electrochemical behavior of Ic in pH 2.0 phosphate buffer solution. A very low detection limit (0.019 μM) and linearity over a wide linear range (0.1 μM-30.0 μM) were obtained for Ic using square-wave voltammetry. Chiral amine-bis(phenolate)boron-based electrochemical sensor performance was examined in real samples such as river water, tap water, orange juice, and candy-coated chocolate. The results revealed that the chiral amine-bis(phenolate) boron-based electrochemical sensor can be successfully used as an alternative to the existing analytical techniques used for the quantification of Ic.
查看更多>>摘要：Four novel D-A-7t-A metal-free organic sensitizers QL1-4 with the fused azacycle units as donors have been designed and synthesized to investigate the relationship between both the sizes and conjugations of azacycle and performances of dye-sensitized solar cells systematically. QL1 with the five-membered azacycle, i.e., with carbazole (Cz) as donor, exhibits the smallest molar extinction coefficients (e). QL2 and QL3 with the seven-membered azacycle, i.e. with N-phenyl-iminostilbene (ISB) and JV-phenyl-iminodibenzyl (IDB) as donors, respectively, show the red-shifted absorption spectra and higher e compared to QL1. However, QL2 and QL3 with an only distinction in a single or double bond, display distinctive PCEs. QL4 with the six-membered azacycle, i.e., 9,9,10-triphenyl-9,10-dihydroacridine (TDD), exhibits a blue-shifted absorption spectrum due to a big dihedral angle, resulting in a lower photovoltaic performance. Especially, QL3 with the ISB donor is conducive to achieving a PCE of 6.22%, which is higher than QL2, due to its better planar structure and more conjugation. When co-adsorbed with CDCA, QL3 exhibits the highest PCE of 7.14% among all dyes, and up to 8.26% by co-sensitizing with dye WL5, which surpasses that of the reference dye N719 (7.75%). The results indicate that the size and conjugation of the fused azacycle donors may affect the photovoltaic performance significantly, and the ISB unit is demonstrated as a promising donor for efficient organic dyes.
查看更多>>摘要：Trace water is known to be an impurity in organic solvents, having an adverse effect on the chemical reaction or environmental safety. Developing a green, facile and non-toxic method for detecting trace water in various organic solvents is still a challenge. Distinct form conventional fluorescent probes, room-temperature phosphorescence (RTP) test paper (TP) has aroused wide concern owing to its characteristic optical performance, including long afterglow and non-background interference. Herein, we fabricated a new kind of RTP-TP on the basis of chitosan carbon dots (CDs). The anchoring effect of polyvinyl alcohol (PVA) promoted the restriction of vibration/rotation and hindered the non-irradiative quenching of CDs by forming intermolecular hydrogen bonds. However, water molecules could interrupt these hydrogen bonds and therefore the RTP phenomenon would be disappeared. Further, the RTP-TP was used to detect trace water in various organic solvents with high efficiency, excellent stability, and reliability. In addition, the CDs-PVA solution can be also used as anti-counterfeiting ink via various printing methods.
Zubair Khalid Baig MoghalRamalingam ManivannanYoung-A Son
10页
查看更多>>摘要：9-arylated acridine-based derivatives (AUPAO & AUEA) with high visibility, fluorescence, and excellent light-fastness were synthesized in good yield. The molecules were characterized by ~1H NMR, ~(13)C NMR, HRMS and further investigated for photophysical properties. Initially, absorption and emission studies were carried out in wide-ranging polarity solvents to choose a solvent of interest for further investigations. Concentration-dependent studies were carried out in ethanol to determine an optimized concentration to study lightfastness studies. These molecules showed excellent lightfastness properties in solution form when compared to commercially available acridine orange. pH-dependent studies were also carried out to observe the behavior of cationic dyes in a wide range of pH to optimize pH for dyeing. The presence of extended conjugation at the 9th position and additional four mefhoxy groups resulted in highly fluorescent dyes with excellent quantum yield. The steric interactions, higher twist, and unrestricted rotation of the conjugation pathway between the aromatic ring at the 9th position and the acridine core decreased the transition probability and energy transfer tiiat helped improve the lightfastness. The introduction of a hydroxyl group in AUEA increased the solubility and helped in controlled dispersion while dyeing. Further, they were dyed on modacrylic fabric as high visibility fluorophores, and later the color coordinates, color strengths were measured.
Paltan LahaFalguni ChandraAhmad Husain c Department of Chemistry, DAV University Jalandhar, Jalandhar, 144012, Punjab, India
11页
查看更多>>摘要：Herein, we present synthesis, photophysical and photocatalytic aspects of four mononuclear luminescent iridium complexes ([1]~+-[4]~+) incorporating cyclometallating benzimidazole-based (L~1 and L~2) and phenanthroline pyrazine-based (L3-L5) ligands. Several analytical techniques were used for the characterization of the complexes. The structural elucidation of [2]~ and [3]+ using x-ray crystallography show a distorted Of, structure with nitrogen donors of cyclometallating ligands are in trans-direction. All the complexes are emitting in the orange-red region and displayed moderately good quantum yield. The complexes have also shown moderately good luminescence lifetime (z = 80-1900 ns) in different solvents. Importantly, the complex [3]+ exhibits comparative longer emission lifetime (Y = 1800 ns) in water at ambient condition. The complexes have shown moderately good photocatalytic efficacy towards azo dyes degradation in aqueous solution. The mechanistic investigation suggests that in the presence of light in aqueous medium the complexes induce the generation of (HO*/(O2) species which is responsible for the photodecomposition of azo dyes.
查看更多>>摘要：We describe herein synthesis of novel hydroxy-bis-2,5-disubstituted-l,3,4-oxadiazoles and their ability to emit green light, through ESIPT mechanism. Unlike previous reports, our compounds exhibit very good quantum yields, most likely avoiding the presumed intramolecular fluorescence quenching in presence of the second oxadiazole moiety. Studies regarding behaviour of the compounds in polar and non-polar solvents are also described, indicating the possibility to modulate the emission according to the environment. The solid-state structural analysis, corroborated with fluorescence data, suggest the importance of the tert-butyl group in preservation of the luminescent properties. The corresponding benzyl-protected compounds, precursors to the target hydroxy-bis-2,5-disubstituted-l,3,4-oxadiazoles were also investigated for their optical properties and found to display very intense blue emission, with quantum yields values in dichloromethane (between 0.423 and 0.499) almost equal to the standard quinine sulfate.
查看更多>>摘要：Bioactive small molecules, hypochlorous acid (HCIO) and sulfur dioxide (SO2), play vital roles in the maintenance of normal physiological function of living organisms. Once their balance is interrupted, it would cause oxidative stress and various diseases. Therefore, monitoring the change of HCIO and SO2 in cellular levels and in vivo is of great significant for exploring their physiological and pathological roles. Herein, we present a dual-site and dual-tum-on fluorescence probe PTBI that could simultaneously monitor HCIO and SO2 in mitochondria by two well-separated emission channels with a difference of 115 nm. The probe exhibited fast response (HCIO: < 5 s, SO2: <1 min) and low detection limits with 45.8 and 53.2 nM for HCIO and SO2, respectively. Using the single fluorescence molecule, we not only realized the detection of the basal and exogenous/endogenous levels of HCIO and SO2, but also achieved the monitoring mitochondrial oxidative stress induced by HCIO in living cells and zebrafish.
查看更多>>摘要：A triphenylamine with three benzothiophene rings was designed and successfully synthesized in 87% yield. The compound showed absorption at 386 nm and blue emission at around 442 nm, with a fluorescence quantum yield of 0.57. The compound showed high thermostability. The radical cation obtained by one-electron oxidation was stable in solution and showed a significant absorption in die NIR-II region U_(max) = 1213 nm). DFT calculations confirmed die experimental data.
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