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A new fluorescent emitter based on π-extended benzothiadiazole was synthesized. The emitter exhibited a large molar extinction coefficient, a high quantum yield of 98% and a large radiative decay rate of 108 s−1. Moreover, the obtained TADF-sensitized fluorescent OLED displayed excellent device performance with a high EQEmax of 14.3%. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel fluorescent probe was synthesized for detecting H 2 S based on PET-effect. • The probe based on pyrazole effectively avoids the interference of biothiol. • The probe can be used to detect cellular exogenous and endogenous H 2 S. • The probe can be used in portable test paper to detect H 2 S in solution and various water samples. Fluorescent probes for H 2 S are often interfered by other thiols. In this work, a coumarin-pyrazole dye with 2,4-dinitrosulfonyl group was designed for the detection of H 2 S. The probe exhibits weak fluorescence in water due to the photo induced electron transfer (PET) by 2,4-dinitrosulfonyl. After the sulfonyl group is cleaved off by H 2 S, strong fluorescence appears. The probe can specifically detect H 2 S without being interfered by other biological thiols, and shows a wide applicable pH range, low detection and wide detection range. The excellent detection properties of the probe can also be used to detect endogenous and exogenous H 2 S in cells. In addition, the probes can be made into portable test paper for the detection of H 2 S in solutions and can detect H 2 S in different water samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A NIR fluorescence probe based on hemicyanine derivative is prepared for biothiols detection. • This probe shows high selectivity and sensitivity for biothiols with low detection limit. • This probe is capable of detecting endogenous and endogenous biothiols in mitochondria with low cytotoxicity. • This probe successfully visualized biothiols fluctuations induced by Ag+ in mitochondria. • This probe confirmed the relationship between oxidative stress and thiols levels by stimulation with Ag+ and H 2 O 2 in mitochondria. A novel near-infrared fluorescent probe CySNC based on hemicyanine was developed to monitor fluctuations of biothiols in response to oxidative stress caused by heavy metal ion poisoning. In the presence of biothiols, CySNC showed "turn-on" fluorescence at 772 nm with low limits of detection (0.12 μM for Cys, 0.15 μM for Hcy and 0.14 μM for GSH). The probe CySNC had excellent fluorescence response to Cys/Hcy/GSH under physiological conditions and the response time for Cys/Hcy/GSH was 15 min, 35 min and 28 min, respectively. In addition, CySNC was applied for detecting endogenous and exogenous biothiols in mitochondria with low cytotoxicity. More importantly, CySNC successfully visualized biothiols fluctuations induced by Ag+ in mitochondria and confirmed the relationship between oxidative stress and biothiols levels by stimulation with Ag+ and H 2 O 2 in mitochondria, which provided a new train of thought to unravel the mechanisms of heavy ion poisoning. [ABSTRACT FROM AUTHOR]

To develop new luminophores, three imidazobenzothiadiazole (ImBTD) fluorescent dyes (4a , 4b , and 4c) have been successfully synthesized and characterized. Interestingly, the introduction of imidazole groups at the 5- and 6-positions of benzothiadiazole can effectively enhance the fluorescence in both solid and aqueous solution and lead to a fluorescence response to acid. Modification of different aromatic groups at position 4 and 8 of ImBTD can produce tunable mechanochromic luminescence (MCL), which has been studied by theoretical calculations, single crystal X-ray diffraction (XRD), powder XRD analysis, and differential scanning calorimeter (DSC). More importantly, the neutral dyes 4a - c show mitochondrial staining comparable to commercially positively charged dyes. As a novel multifunctional fluorescent dye, it has application value in the fields of solid-state fluorescence and biological imaging. [Display omitted] • Three fluorescent dyes based on imidazobenzothiadiazole (ImBTD) have been successfully synthesized. • Modification of different aromatic groups can turn the emission wavelength from green to red with tunable MCL properties. • Imidazole effectively improve fluorescence in solid and aqueous solutions, and result in sensitivity to acid. • The neutral dyes show mitochondrial staining which is comparable to commercial dyes with positive charge. [ABSTRACT FROM AUTHOR]

Three mechanochromic luminescent (MCL) materials were obtained by modifying the 5, 6 and 4, 7 positions of benzothiadiazole (BTD) with two sterically hindered amides and two aromatic groups, respectively. The Stokes shifts of the compounds were larger in different solvents (>6000 cm−1), especially 3c in dimethyl sulfoxide up to 8900 cm−1. Upon response to mechanical force, the fluorescence of 3c had high contrast (75 nm) before and after milling, and the emission changed from bright yellow light (533 nm) to orange-red light (608 nm). Meanwhile, strong fluorescence emission intensities were observed before and after grinding (quantum yield: 56%, 46% respectively). The MCL reasons of the compounds were explained in detail by theoretical calculation, single crystal X-ray diffraction (XRD), powder XRD and differential scanning calorimetry (DSC) analysis. In addition, the MCL materials also showed fluorescence responsiveness to the vapor of volatile acids. [Display omitted] • Three solid fluorescent materials were designed by modifying the 5, 6 and 4, 7 positions of benzothiadiazole. • The materials show high-contrast mechanochromic luminescence properties and high quantum yield. • The MCL mechanism were carried out by theoretical calculation, single crystal XRD and powder XRD. • The materials are sensitive to acid in solution and in the gaseous state. [ABSTRACT FROM AUTHOR]

[Display omitted] • A fluorescence probe based on coumarin β-diketone is prepared for hydrazine detection. • This probe shows high selectivity and sensitivity for hydrazine with significant fluorescence enhancement. • This probe can be easily prepared with good water solubility. • This probe is capable of quantitative determination of hydrazine in real water samples. • This probe can be applied to imaging hydrazine in MCF-7 cells. Herein, a new "turn on" fluorescent probe C-1 is developed to specifically detect hydrazine using coumarin nucleus as the fluorophore and β-diketone as the recognition group. The probe shows high selectivity towards hydrazine over other common ions and amine-containing species, as well as good water solubility and quantitative detectability of hydrazine in concentration range of 1–200 μM. The detection limit is as low as 1.89 ppb, which is lower than the threshold set by EPA (10 ppb). Probe-coated filter papers are confirmed to detect gaseous hydrazine successfully through obvious fluorescence color changes. In addition, the probe has been verified to detect hydrazine in actual water environment and living cells. [ABSTRACT FROM AUTHOR]

To develop new dyes with mitochondria staining capacity, a series of zwitterionic dyes of hybrid coumarin-difluoroboron have been synthesized. The hybrid dyes are conjugated by 7-diethylaminocoumarin, difluoroboron (BF 2) β-diketone and electron-donating group. The dyes show deep-red emission (600–680 nm) and high fluorescence quantum yield in organic solvents. The nature of ICT and zwitterion has been fully researched by TD-DFT and ESP calculations. Co-staining with the Mito–Tracker Green shows staining capability to mitochondria in living cells by confocal cell imaging experiments. This work can provide a new strategy for the design of neutral cellular probes for mitochondria staining. Image 1 • Zwitterionic dyes of hybrid coumarin-difluoroboron have been synthesized for mitochondria staining. • The dyes show deep-red emission and high fluorescence quantum yield in organic solvents. • The nature of ICT and zwitterion has been fully researched by TD-DFT and ESP calculations. • Co-staining with the Mito–Tracker Green show staining capability to mitochondria in living cells. [ABSTRACT FROM AUTHOR]