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A novel oxime-based fluorescent chemosensor (E)-2-(4′-(7,8,13,14-tetrahydrodibenzo[a,i]phenanthridin-5-yl)-[1,1′-biphenyl]-4-yl)ethen-1-ol (PBO) has been developed for the fluorimetric detection of hypochlorite ion (OCl−). On account of the optical behavior of the sensor PBO, distinctive spectral alterations in the presence of OCl− were detected. Furthermore, an obvious fluorescent color change from cyan to blue was also observed. An explicit linear relationship was found between the fluorimetric ratio of PBO and the concentration of OCl−. The detection limit (LOD) of PBO was evaluated to be 8 nM. The optical response was caused by the nucleophilic attack of OCl− on the imine group of the PBO probe, which stimulates intramolecular charge transfer. NMR titration investigation verified the detection mechanism. The PBO probe causes a quick spectral response towards OCl−, within 10 seconds. Furthermore, the practical utility of PBO was investigated through test paper analysis. The detection of OCl− in various water samples was also explored. The fluorescence bio-imaging experiment indicates the potential ability of the sensor PBO to detect OCl− in live E. coli cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Imidazole derived new chemosensor for selective detection of CN− ions. • Sensor BMA responds rapidly toward cyanide ions with a low LOD (7.87 nM). • The detection mechanism of BMA with CN− has been studied extensively. • The sensor BMA can detect cyanide ions in live cells and food samples. On account of the supreme toxicity of CN− ions in the physiological systems, it is essential to develop a sensitive chemosensor to detect cyanide ions. Herein, we designed a new 5-(3-(4,5-diphenyl-1H-imidazol-2-yl)-2-hydroxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (BMA) sensor, which exhibits tremendous colorimetric as well as fluorometric behaviour towards CN− ions. This could be due to the nucleophilic attack of CN− ions on the dione-vinyl site, which induces intramolecular charge transfer (ICT) capabilities. The cyanide recognition mechanism of BMA was verified by optical experiments such as UV–visible and fluorescence spectroscopy, NMR, and mass analysis. Moreover, the structural characterization was done by 1H NMR titration and HRMS analysis, and the molecular orbital interactions were studied by TDDFT calculations. The sensor BMA exhibited a rapid response towards CN− ions (10 sec) with low detection limit (7.87 nM), great pH stability in the physiologically applicable pH range (6–12) and had good sensitivity and selectivity towards CN− ions. Encouraged by these detection properties, we successfully used sensor BMA to determine CN− ions in real water and food samples. To validate the colorimetric behavior of the sensor BMA , test paper strip experiments were carried out in the laboratory. We also extensively studied the effect of the sensor in Escherichia coli (E.coli) bacterial cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new naphthalimide based "turn-on" fluorescent probe for detection of H 2 S has been designed and synthesised. • Probe NPN-N 3 exhibits very high selectivity and sensitivity towards H 2 S. The obtained Limit of Detection (LOD) for H 2 S is found to be 1.2 μM. • Probe NPN-N 3 can successfully detect H 2 S levels in wine, beer and various environmental water samples. • Probe NPN-N 3 was successfully implemented in bioimaging application. A novel fluorescent sensor based on intramolecular charge transfer (ICT) for detecting the H 2 S ion has been successfully designed and developed. The H 2 S amount was determined using a sensor probe of 6-azido-2-(pyridin-2-ylmethyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (NPN-N 3) with high selectivity. The fluorescence intensity ratio of NPN-N 3 was shown to be linearly related to the concentration of H 2 S, with a LOD of 1.2 μM. Besides that, there was an apparent fluorescent colour changes from colorless to green. Fluorescence bio-imaging with various emission channels could be used with the current sensor probe to detect H 2 S ions in living cells. The real-time application of H 2 S was proved by test strip experiments. [ABSTRACT FROM AUTHOR]

A new Intramolecular charge transfer (ICT) based fluorescent sensor for recognizing Th 4+ ions has been successfully designed and developed. Sensor probe of 2-methyl-4-(4-(7,8,13,14-tetrahydrodibenzo[a,i]phenanthridin-5-yl)phenyl)but-3-yn-2-ol (1a) and 5-(4-ethynylphenyl)-7,8,13,14-tetrahydrodibenzo[a,i]phenanthridine (1b) selectively determined Th 4+ ion with an instant color change from colorless to blue in CH 3 CN:H 2 O (9:1) solvent system. The detection limit (1a : 3.4 × 10−8 M and 1b: 1.4 × 10−8 M) for Th 4+ ion was below the U.S Environmental Protection Agency's (EPA) permissible level in drinking water. In addition, 1a was applied to quantify thorium ions in natural water samples. The present sensor probe could detect thorium ions in biological cells using fluorescence bio-imaging with different emission channels. The detailed sensing mechanisms of 1a and 1b for Th 4+ ion have been investigated from NMR titrations, FTIR, Electrospray ionization (ESI)-Mass, and theoretical calculation techniques. [Display omitted] • New hydroxy and ethynyl substituted phenanthridine-based "turn-on" fluorescence sensor for detection of thorium ions were developed • Probe 1a was also tested to detect thorium ion in environmental water samples • The present sensor probes were successfully applied to detect thorium ion in biological cell using fluorescence bio-imaging • Sensor probes 1a-b -based test paper strips were used to detect efficiently thorium ion in water under UV lamp at 365 nm • The low detection limit sensors of 1a-b for thorium ion are 34 nM and 14 nM respectively [ABSTRACT FROM AUTHOR]

The studied materials, Cadmium (Cd2+) and Chromium (Cr3+) are highly toxic, and it focuses on investigating various environmental sources, such as industrial processes and waste water. When quantities of Cr3+ and Cd2+ exceed the allowable limit, biological toxicity and hazardous environmental pollution are unavoidable. In order to address this problem, we introduce 5-(5-(4-([2,2':6′,2″-terpyridin]-4′-yl) phenyl) thiophen-2-yl)-7,8,13,14-tetrahydrodibenzo [ a,i ] phenanthridine (TPTP), a dual-emission response chemosensor that employs a colorimetric and fluorescence turn-on approach for the rapid, sensitive, and discriminate detection of Cr3+ and Cd2+ ions. We created a newly designed luminous TPTP sensor based on intramolecular charge transfer (ICT). TPTP sensor probe specifically determined Cr3+ and Cd2+ ions with an immediate colour shift from cyan to green and orange in CH 3 CN: H 2 O (6:4) solvent solution. The permissible level set by the Environmental Protection Agency (EPA) of the United States for the presence of Cr3+ and Cd2+ ions in drinking water was higher than the detection level of 3.5 and 9.7 nM, by this sensor respectively. NMR titrations, HRMS, and theoretical calculation methods were employed to examine the accurate sensing processes of TPTP and complexes. This is an effective method of detecting Cr3+ and Cd2+ ions in an environmental system using a ratiometric methodology. In addition, TPTP was used to determine the concentration of Cr3+ and Cd2+ ions in natural water and food samples. Fluorescent bio-imaging studies revealed that the present sensor TPTP could identify Cr3+ and Cd2+ ions inside living HeLa cells. A paper kit analysis has been done on TPTP , which has a time-to-result of less than 1 s and offers a cost-effective assay. As a result, the platform offers portability. [Display omitted] • A ratiometric probe for Cd2+ and Cr3+ ions based on a thiophene-extended conjugate terpyridine with phenanthridine functionality has been developed. • The sensor TPTP has a good selectivity for detecting Cd2+ and Cr3+ ions and a low detection limit. • The sensing mechanism was confirmed by a 1H NMR titration experiment and a DFT calculation. • The probe worked well for fluorescent bio-imaging of the Cd2+ and Cr3+ ions in both living cells and real resources. [ABSTRACT FROM AUTHOR]