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A cleverish fluorescence probe based on coumarin was developed, exhibiting remarkable color change, strong fluorescence enhancement and fast response when it interacts with hydrazine in water solution. The limit of detection (LOD) is 5.59 × 10 - 6  M for ultraviolet analysis and 8.18 × 10 - 8  M for fluorescence analysis, respectively. Taking advantage of good sensitivity and short response time, the probe was applied to test hydrazine in water and to observe hydrazine in living cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A simple coumarin-based Schiff base (probe L) was successfully developed. It showed strong green fluorescence emission at 527 nm with a 70.3% of fluorescence quantum efficiency (Φ F ). However, after the addition of common metal ions, probe L can only combine with Cu 2+ ions and displayed significant fluorescence quenching of > 96.2% (Φ F  = 2.7%) due to the paramagnetic quenching action from Cu 2+ . Conversely, by the coordination action of cysteine (Cys) and histidine (His), the quenching fluorescence of the complex (L-Cu 2+ ) between probe L and Cu 2+ ions was recovered mostly because the Cys and His can usurp Cu 2+ of L-Cu 2+ and led to the liberation of probe L. Based on the fluorescence changes of probe L with the actions of Cu 2+ , Cys, and His, an on-off-on reversible fluorescence probe for sensitive and specific monitoring Cu 2+ , Cys, and His has been prepared. More importantly, the probe L and L-Cu 2+ ensemble can be used, respectively, to test Cu 2+ and Cys/His in live cells and human urine samples with great reliability.

An excellent fluorescent probe with "turn on" phenomenon for sensitive monitoring hypochlorite (ClO - ) was prepared using the mild condensation reaction between coumarin and hydroxylamine (NH 2 OH). The probe possessed potent selectivity to ClO - with obvious color changes from yellow to light yellow and green to blue fluorescence emission, which could be noticed by the naked eye. Moreover, the probe has been succeeded in imaging ClO - in living A549 cells and thus has the potential prospect in the visual detection of intracellular ClO - ., (Copyright © 2018. Published by Elsevier Inc.)

A turn on fluorescence probe was designed cleverly and synthesized simply through the condensation reaction between coumarin derivative and barbiturate, for sensitively specific recognition of hypochlorite ion (ClO−). This probe displayed a transient monitor process (about 5 min) to ClO− in a wide range of pH values (3‐10), and the monitor limit could be estimated as low as 0.73μM. What's more, this probe could perform fluorescence imaging of ClO− in living cells, and make ClO− in aqueous solution appear on the convenient test strip visually. [ABSTRACT FROM AUTHOR]

A simple Schiff base was prepared by mild condensation reaction between a coumarin fluorescent group and diaminomaleonitrile, and it could serve as an excellent fluorescent probe for fast detection of ClO− with high selectivity and sensitivity. Along with addition of ClO−, this probe fleetingly showed noteworthy “turn-on” phenomenon accompanied by an increase of fluorescence intensity and the change of emission color from yellow to blue. This change of fluorescence is so significant that it can be observed by the naked-eye under a handheld ultraviolet light of 365 nm. However, other common reactive oxygen species exhibited no or very little fluorescent response under the same conditions. The limit of detection of this probe toward ClO− had a sensitivity feature as low as 9.6 nM. On account of these excellent features of short response time, remarkable fluorescence and color signal changes, high sensitivity and selectivity, this probe was effectively used for the fluorescence detection of ClO− in water samples. The values of the relative standard deviation were between 1.41% and 2.91%. More importantly, this probe displays excellent imaging capability in cytoplasm as well as very low cell toxicity and was unambiguously applied to image ClO− in living cells.A fluorescent probe based on coumarin for detection of ClO- was successfully developed, which can besuccessfully used for the detection of ClO− in living cells and in water sample because of the excellentfeatures including short response time, remarkable fluorescence and color signal changes, high sensitivityand selectivity [ABSTRACT FROM AUTHOR]

Three new coumarin–based derivatives with similar molecular structure were synthesized through a simple Schiff base reaction and their fluorescent properties were investigated in detail. Among of the compounds showed aggregation–induced emission (AIE) characteristics and high quantum efficiency ( Φ F ), of which compound 1 powder showed the strongest emission peak 570 nm ( Φ F = 25.3%), compound 2 solid exhibited 610 nm fluorescence emission peak ( Φ F = 3.3%), while the maximum emission wavelength of compound 3 powder red–shift to 640 nm ( Φ F = 16.8%). Meanwhile, compounds 1–3 showed long fluorescence lifetimes with respective 8.86 μs, 8.97 μs and 8.51 μs. The appearance of fluorescence properties can be attributed to efficient the excited state intramolecular proton transfer (ESIPT) and the twisted intramolecular charge transfer (TICT). Furthermore, due to the good luminescent properties, high stabilities and the large Stokes–shifts, the three compounds were ideal candidates for promising applications in organic lightemitting diodes (OLEDs). [ABSTRACT FROM AUTHOR]

The probe CT was synthesized and investigated as a novel label-free chemosensor for Ga 3 + detection in water. Probe CT showed remarkable selectivity and sensitivity for Ga 3 + in Tris–HCl aqueous buffer solution (pH 7.0). The chemosensor responded rapidly to Ga 3 + with a 1:1 stoichiometry. Meanwhile, the unapparent changes of fluorescence lifetime decays suggest the turn-on process of probe CT by Ga 3 + which appears to be a static mechanism. [ABSTRACT FROM AUTHOR]

A coumarin-based chemosensor was developed with excellent dual-mode detection capability for ClO− and N 2 H 4 based on different reaction mechanisms, which provides a strategy for the design of dual-channel responsive chemosensor for visualizing ClO− and N 2 H 4 in environment and biological samples. • A dual responsive chemosensor for hypochlorite and hydrazine was developed. • Different response signals based on different reaction mechanisms for hypochlorite and hydrazine. • A user-friendly test paper strip soaked with the chemosensor for hypochlorite. • Good recovery was achieved in real water samples for detecting hydrazine. A chemosensor was synthesized conveniently by the condensation between 7-diethylaminocoumarin and barbituric acid, which was used successfully for the detection of hypochlorite and hydrazine with excellent performances. This chemosensor underwent remarkable color change and turn off fluorescence in solution, while revealed turn on fluorescence on the filter paper in the presence of hypochlorite. In addition, it exhibited obvious fluorescence enhancement in solution, while no fluorescence change on the test paper after addition of N 2 H 4. As a result, this chemosensor could be a potential candidate for hypochlorite and hydrazine in different media through two distinct response modes. It could realize the detection of hypochlorite in water with a low detection concentration of 2 μM by test strip, and trace hydrazine in aqueous solution and living HepG2 cells by the mean of fluorescence signal. Moreover, the sensing mechanisms of this chemosensor towards hypochlorite and hydrazine were suggested by HRMS and 1H NMR spectra, in which the coumarin structure was destroyed by hypochlorite and the barbituric acid was removed by hydrazine, respectively. [ABSTRACT FROM AUTHOR]