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Abstract A simple naphthalene derivative, 6-hydroxy-2-naphthohydrazide (NAH), was designed and synthesized through two facile steps reactions with the 6-hydroxy-2-naphthoic acid (NCA) as the starting material. In neat H 2 O (10% 0.01 M HEPES buffer, v/v, pH = 7.4), probe NAH showed a highly selective and sensitive response towards Fe3+ via perceptible color change and displayed "turn-on" dual-emission fluorescence response for Cu2+. The binding stoichiometry ratio of NAH /Cu2+ and NAH /Fe3+ were all confirmed as 1:1 by the method of fluorescence job's plot and UV–Vis job's plot, respectively. Probe NAH can be used over a wide pH range for the determination of Fe3+ (2.0–10.0) and Cu2+ (6.0–10.0) without interference from other co-existing metal ions. A possible detection mechanism was the hydrolysis of NAH upon the addition of Fe3+ or Cu2+, thereby leading to the formation of 6-hydroxy-naphthalene-2-carboxylic acid (NCA) which was further confirmed by the various spectroscopic techniques including FT-IR, 1H NMR titration and HRMS. Moreover, NAH was successfully applied to the detection of Cu2+ and Fe3+ in tap water, ultrapure water and BSA. Graphical Abstract Unlabelled Image Highlights • A novel probe 6-hydroxy-2-naphthohydrazide (NAH) was synthesized and characterized. • NAH showed a highly selective and sensitive response towards Fe3+ and displayed "turn-on" fluorescence response for Cu2+. • The detection limit of NAH towards Fe3+ and Cu2+ was 1.74 × 10−5 M and 4.51 × 10−8 M, respectively. • The hydrolysis of compound NAH to produce NCA in the presence of Fe3+ or Cu2+. [ABSTRACT FROM AUTHOR]

Abstract A new naphthalene-quinoline based chemosensor L was prepared and structurally characterized. L exhibited excellent selectivity and sensitivity to Al3+ through distinct fluorescence enhancement (335-fold) and ratiometric detection in DMF/H 2 O (v/v, 1/9) based on the combined mechanisms of ESIPT and CHEF. The recognizing behavior of L toward Al3+ had been investigated in detail through Job's Plot, FT-IR, HNMR, and HRMS analysis. The limit of detection (LOD) for Al3+ was as low as and 3.67 × 10−8 M. L was successfully applied in real sample detection and construction of molecular logic gate. Moreover, L was verified to be of low cytotoxicity and good imaging characteristics for the detection of Al3+ in cells HSC. Graphical abstract Unlabelled Image Highlights • A naphthalene-quinoline based chemosensor L was prepared and structurally characterized. • L exhibited excellent selectivity and sensitivity to Al3+ through fluorescence enhancement (335-fold) and ratiometric detection. • The limit of detection (LOD) for Al3+ was determined as 3.67 × 10−8 M. • L was successfully applied in the detection of Al3+ in cells HSC. [ABSTRACT FROM AUTHOR]

A series of benzothiazole-based compounds were synthesized and characterized. Among them, probe Z showed significant dual-functional performance which was capable of sensing pH change and Cu2+. Probe Z displayed fluorescent turn-on under alkaline conditions due to deprotonation of the hydroxyl group along with the obviously color change from colorless to mint green. Interestingly, it further achieved in ratiometric detection of Cu2+ through absorbance or fluorescence signals in strong alkaline condition. The limit of detection was calculated correspondingly as 0.37 μM and 1.35 μM, respectively. Especially, the combination of the XNOR and INHIBIT logic gates could be used to confirm that one medium was in neutrality or alkalinity condition. Moreover, Z was successfully used in real water samples and test paper for fast identification of Cu2+, respectively. Unlabelled Image • A dual-functional chemosensor Z was synthesized and characterized. • Z was successfully in sensing pH change through significant color chang. • Z was achieved in ratiometric detection of Cu2+ with detection limit as low as 1.35 μM. • Z was successfully used in real water samples and test paper for fast identification of Cu2+. [ABSTRACT FROM AUTHOR]