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[Display omitted] • A simple single step multicomponent ugi type reaction was carried out to yield N-(tert-butyl)-2-(furan-2-yl)imidazo[1,2- a ]pyridine-3-amine (TBFIPA). • The synthesized TBFIPA was characterized using 1H NMR, 13C NMR and HRMS spectroscopic methods. • The selective & sensitive detection was identified using hypsochromic shift (lab : 335nm → 285nm) & fluorescence quenching. • The proposed mechanism is evident from Job plot, 1H NMR titration, ESI-MS data and theoretical DFT calculation. • The Cr3+ ion-selective TBFIPA was successfully applied in the design of a user-friendly silica-based portable test kits. • Also, the fluorescence quenching ability of TBFIPA in presence of Cr3+ ions are validated by imaging onion epidermal cells. • Real samples contaminated with Cr3+ ions were identified using TBFIPA with an appropriated relative error percentage. A simple single step one pot multicomponent reaction was performed to synthesize N-(tert -butyl)-2-(furan-2-yl)imidazo[1,2- a ]pyridine-3-amine (TBFIPA). The synthesized TBFIPA was subjected to library of cations to study its ability for selective and sensitive detection of specific metal ions. Selective detection of chromium ions by TBFIPA were found from the significant hypsochromic shift (335 nm → 285 nm) in the UV–Visible spectra. The fluorescent TBFIPA displays complete quenching of fluorescence under UV lamp (365 nm) only in the presence of chromium without the interference of common metal ions. Binding constant (k a) obtained from Benesi-Hildebrand plot is 0.21 × 105 M−1, limit of detection (LOD) and limit of quantification (LOQ) of TBFIPA toward Cr3+ ions are 4.70 × 10−7 M and 1.56 × 10−7 M, respectively. The mechanism proposed during complex formation were supported by stoichiometric Job continuous variation plot, 1H NMR titration and ESI-MS spectroscopic data. All the experimental confirmation for complex formation were corroborated with theoretical DFT studies optimized using RB3LYP/6-31G(d) basis set. The selectivity and sensitivity of TBFIPA toward Cr3+ ions are found suitable to design a user-friendly silica based portable test kit. Alongside, TBFIPA was successfully utilized for imaging onion epidermal cells. Furthermore, the results obtained for biological, environmental, and industrial samples provided solid evidence to estimate chromium ions using TBFIPA in these real samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel aggregation-induced emission active chemosensor has been developed. • The sensor could detect Cu2+ and S2− with low detection limit (34.6 nM and 1.15 μM, respectively) in an almost neat aqueous solution. • The sensor has been successfully applied to imaging of Cu2+ and S2− in living cells and zebrafish. A simple reversible fluorescent chemosensor 1 was constructed using a coumarin backbone, which displayed notable aggregation-induced emission. Particularly, Cu2+ could selectively and sensitively induce fluorescence quenching of sensor 1 in an almost neat aqueous solution. Furthermore, addition of S2− to 1 -Cu2+ system could specifically restore the fluorescence emission of 1 by snatching Cu2+ ion from its complex. The detection limits of sensor 1 towards Cu2+ and S2− were 34.6 nM and 1.15 μM, respectively. Notably, sensor 1 was successfully applied to detect Cu2+ and S2− in living cells and zebrafish owing to its remarkable fluorescence behavior and low cytotoxicity. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new BODIPY derivative 1 behaves as an “on–off” fluorescent sensor of Cu2+. [•] Complex 1·Cu 2+ displays “off–on” fluorescent spectral response to biothiols and S2−. [•] 1·Cu 2+ complex can better recognize glutathione compared with cysteine and homocysteine. [•] 1 exhibits high sensitivity for Cu2+ under physiological conditions and in living cells. [•] 1 can locates in lysosome used as fluorescent dye in cell imaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel colorimetric and fluorescent chemosensor based on diaminopyrimidine (DAPCS) was designed and synthesized. • DAPCS was applied for the highly selective and ultra-sensitive detection of Cu2+ ion in aqueous media and living cell. • The probe DAPCS for Cu2+ showed a linear correlation, and LOD was calculated as 0.014 µM. • DAPCS-based test strips were fabricated and applied to the detection of Cu2+ ions in solutions. In this paper, a new and effective diaminopyrimidine-based chemosensor (DAPCS) was developed for the highly selective and ultra-sensitive detection of Cu2+ ion in aqueous media and living cell. Characterization and structure determining of DAPCS was determined by UV–Vis, FTIR and NMR analyses. It is observed that DAPCS and Cu (II) forms a ligand to metal charge transfer (LMCT) complex which produces distinguishable red color. The results also indicate that the DAPCS easily interacts with Cu2+ ion to form a 1:1 stoichiometry complex (DAPCS -Cu2+), resulting in a bathochromic shift in absorption maximum (429 nm to 449 nm) and remarkable quenching fluorescence intensity at the wavelength of 501 nm in DMSO-H 2 O solution. Furthermore, the detection limit of DAPCS towards Cu2+ was calculated to be 3.19 µM. Meanwhile, DAPCS was applied as fluorescent probe for detection of Cu2+ ions with the detection limit of 0.014 µM. The optimal pH range of probe DAPCS for quantitative analysis of Cu2+ ions was 9–11, which renders it suitable for detection of Cu2+ under physiological conditions. Additionally, the DAPCS could be applied to detect Cu2+ in real water samples and in HeLa cells, indicating the practical uses of DAPCS in real analyses. [ABSTRACT FROM AUTHOR]

This paper's emphasis is on the development of a fluorescent chemosensor for Fe3+ ions in an aqueous solution, using hydrophilic carbon dots (O-CDs). A simple, cost-effective, and environmentally friendly one-step hydrothermal synthesis method was used to synthesize fluorescent hydrophilic O-CDs from Oxalis corniculata (Family; Oxalidaceae). The graphitic structure and size distribution of the O-CDs was verified by X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy studies. The resulting O-CDs had a near-spherical shape and an adequate degree of graphitization at the core, with an average diameter of 4.5 nm. X-ray photoelectron and Fourier transform infrared spectroscopy methods revealed the presence of several hydrophilic groups (carbonyl, amine, carboxyl, and hydroxyl, along with nitrogen and oxygen-rich molecules) on the surface of O-CDs. The synthesized hydrophilic O-CDs with excitation wavelength-dependent emission fluorescence characteristics showed a high quantum yield of about 20%. Besides this, the hydrophilic O-CDs exhibited a bright and controllable fluorescence with prolonged stability and photo-stability. These fluorescent hydrophilic O-CDs were used as a nanoprobe for the fluorometric identification of Fe3+ ions in an aqueous solution, with high sensitivity and selectivity. By quenching the blue emission fluorescence of this nanosensor, a highly sensitive Fe3+ ion in the range of 10–50 µM with a minimum detection limit of 0.73 µM was achieved. In addition, the developed nanosensor can be used to sense intracellular Fe3+ ions with high biocompatibility and cellular imaging capacity, and it has a lot of potential in biomedical applications. [ABSTRACT FROM AUTHOR]