A turn-on Schiff base fluorescence sensor for zinc ion

A T-shaped triazatruxene probe for the naked-eye detection of HCl gas with high sensitivity and selectivity

A T-shaped Schiff-base triazatruxene derivative (TATNFF) was designed, synthesized, and explored as a sensitive probe to detect HCl gas by the naked eye. The remarkable color change of TATNFF with turn-on behavior in the presence of a trace amount of HCl gas was obviously observed by the naked eye, which opens up a new strategy to explore a novel set of smart responsive materials for sensing applications.

A triazole Schiff base-based selective and sensitive fluorescent probe for Zn²⁺: A combined experimental and theoretical study

A triazole-Schiff base, 4-(5-Chloro-2-hydroxybenzylideneamino)-1H-1,2,4-triazole-5(4H)-thione (HL), exhibits the high selectivity and sensitivity for Zn(2+) in the fluorescence spectrometry over other common metal ions, especially Cd(2+) in DMSO:H2O (1:9, v/v) solution. A 1:1 binding ratio of Zn(2+)/L for the complex has been obtained by Uv-Vis titration experiments and Job's plot with the detection limit of 51 nmol/L. The coordination mode of the complex in solution was further confirmed by density functional theory (DFT) calculations. Time-dependent density functional theory (TD-DFT) calculations indicate that a chelation-enhanced fluorescence (CHEF) effect occurs in the process of detecting Zn ion.

Two Schiff-base fluorescent sensors for selective sensing of aluminum (III): Experimental and computational studies

Two Schiff-base fluorescent sensors have been synthesized, which both can act as fluorescent probes for Al(3+), upon addition of Al(3+), they exhibit a large fluorescence enhancement which might be attributed to the formation of 1:1 ligand-Al complexes which inhibit photoinduced electron transfer (PET) progress, and that the proposed binding modes of the sensors and Al(3+) are identified by theoretical calculations.

Fluorescent organic nanoparticles (FONs) for selective recognition of Al3+: application to bio-imaging for bacterial sample

(a) Changes in fluorescence upon successive addition of Al³⁺ ions to salpn-ONPs; (b) titration profile of fluorescence; (c) recognition of Al³⁺ through bio-fluorescence Staphylococcus aureus bacterial cells.

Tuning of azine derivatives for selective recognition of Ag+ with the in vitro tracking of endophytic bacteria in rice root tissue

X-ray structurally characterized probes to track Ag⁺ in in vitro endophytic bacteria at rice root tissue and human breast cancer cells (MCF7).

Detection of potentially toxic metals by SERS using salen complexes

Four metal ions have been clearly discriminated using SERS by coordinating each species to salen. The spectra acquired demonstrated characteristic differences, allowing identification of each metal ion.

A novel fluorescent sensor based on imidazo[1,2-a]pyridine for Zn2+

A novel chemosensorL1for the detection of Zn²⁺based on imidazo[1,2-a]pyridine in C₂H₅OH–H₂O (9 : 1, v/v) buffer solution was designed and synthesized.

A novel 2-(2′-aminophenyl)benzothiazole derivative displays ESIPT and permits selective detection of Zn2+ ions: experimental and theoretical studies

Synthesis of a novel 2-(2′-aminophenyl)benzothiazole based probe (1) and demonstration of excited state intramolecular proton transfer (ESIPT) with a large Stokes shift (∼246 nm) are presented.

Optical sensor: a promising strategy for environmental and biomedical monitoring of ionic species

In this review, we cover the recent developments in fluorogenic and chromogenic sensors for Cu²⁺, Fe²⁺/Fe³⁺, Zn²⁺and Hg²⁺.

A highly selective fluorescent chemosensor based on a quinoline derivative for zinc ions in pure water

A water-soluble fluorescent sensor with a low detection limit could be used to detect and quantify Zn²⁺in water samples.

X-ray structurally characterized sensors for ratiometric detection of Zn2+ and Al3+ in human breast cancer cells (MCF7): development of a binary logic gate as a molecular switch

A very simple molecule derived from salicylaldehyde and N-phenyl ethylenediamine (L1) functions as a dual-mode ratiometric fluorescence “turn on” sensor for Zn²⁺ and Al³⁺ at two different wavelengths.

A highly selective CHEF-type chemosensor for monitoring Zn2+ in aqueous solution and living cells

A new quinolone-based chemosensor was synthesized and successfully applied to quantify and image Zn²⁺ in water samples and living cells.

Fluorescent sensor for selective detection of Al(3+) based on quinoline-coumarin conjugate

A fluorescence probe, 8-formyl-7-hydroxyl-4-methyl coumarin - (2'-methylquinoline-4-formyl) hydrazone (L) has been synthesized. The chemosensor is found preferential binding to Al(3+) in presence of other competitive ions with associated changes in its optical and fluorescence spectra behavior. Upon addition of Al(3+) to a solution of L, it shows 200-fold enhancement of fluorescence intensity which might be attributed to form a 2:1 stoichiometry of the binding mode of LAl(III) and the chelation enhanced fluorescence (CHEF) process at 479nm in ethanol. The lowest detection limit for Al(3+) is determined as 8.2×10(-7)M.

A cap-type Schiff base acting as a fluorescence sensor for zinc(II) and a colorimetric sensor for iron(II), copper(II), and zinc(II) in aqueous media

A simple and low cost chemosensor is described. This sensor could simultaneously detect three biologically important metal ions through fluorogenic (Zn(2+)) and chromogenic (Fe(2+), Cu(2+), and Zn(2+)) methods in aqueous solution. The sensor could function as a "turn-on" fluorescence receptor only to Zn(2+) ions. In addition, the sensor could be successfully applied to the detection of intracellular Zn(2+). Meanwhile, the sensor displayed an obvious red color upon selective binding with Fe(2+). Therefore, the sensor could serve as a useful tool for the discrimination of Fe(2+) from Fe(3+) in aqueous media. Moreover, the sensor also showed color changes from yellow to colorless upon selective binding with Zn(2+) and Cu(2+), respectively. The detection limit of the sensor for Cu(2+) (1.5 μM) is far below the guidelines of the World Health Organization (30 μM) as the maximum allowable copper concentration in drinking water, and therefore it is capable of being a practical system for the monitoring of Cu(2+) concentrations in aqueous samples. These results provide a new approach for selectively recognizing the most important three trace elements in the human body simultaneously, for Zn(2+) by emission spectra and Fe(2+), Cu(2+), and Zn(2+) by the naked eye.

Sensing of Zn²⁺ ion by N-furfurylsalicylaldimine based on CHEF process

The recognition ability of N-Furfurylsalicylaldimine (HL) toward various cations (Pb(2+), Hg(2+), Ba(2+), Cd(2+), Ag(+), Zn(2+), Cu(2+), Ni(2+), Co(2+), K(+), Sr(2+), and Na(+)) has been studied by UV-Vis and fluorescence spectroscopy. The compound showed highly selective fluorescence signaling behaviour for Zn(2+) ions in methanol-water medium based on CHEF process and is capable of distinguishing Zn(2+) from Cd(2+) ion. From single crystal X-ray analysis it is revealed that a Zn(2+) ion binds two ligand molecules through imine nitrogen and phenolate oxygen atom.

A new turn-on fluorescence probe for Zn(2+) in aqueous solution and imaging application in living cells

We designed and synthesized a new pyrazoline-based turn-on fluorescence probe for Zn(2+) by the reaction of chalcone and thiosemicarbazide. The structure of the probe was characterized by IR, NMR and HRMS spectroscopy. The probe (L) exhibits high selectivity and sensitivity for detecting Zn(2+) in buffered EtOH/HEPES solution (EtOH/HEPES=1/1, pH 7.2) with 80-fold fluorescence enhancement, which is superior to previous reports. Job's plot analysis revealed 1:1 stoichiometry between probe L and Zn(2+) ions. The association constant estimated by the Benesi-Hildebrand method and the detection limit were 3.92×10(3)M(-1) and 5.2×10(-7)M, respectively. A proposed binding mode was confirmed by (1)H NMR titration experiments and density functional theory (DFT) calculations. The probe is cell-permeable and stable at the physiological pH range in biological systems. Because of its fast response to Zn(2+), the probe can monitor Zn(2+) in living cells. Moreover, the selective binding of L and Zn(2+) was reversible with the addition of EDTA in buffered EtOH/HEPES solution and Zn(2+) could be imaged in SH-SY5Y neuron cells.

Zinc 2-((2-(benzoimidazol-2-yl)quinolin-8-ylimino)methyl)phenolates: synthesis, characterization and photoluminescence behavior

A series of 2-(2-(1H-benzoimidazol-2-yl)quinolin-8-yliminomethyl)phenol derivatives and their zinc complexes (C1-C5) were synthesized and fully characterized. The molecular structure of the representative complex C2 was determined by single crystal X-ray diffraction, which revealed that the zinc was five-coordinated with the tetra-dentate ligand and a methanol bound to the metal to afford a distorted square-pyramidal geometry. The UV-Vis absorption and fluorescence spectra of the organic compounds and their zinc complexes were measured and investigated in various solvents such as methanol, THF, dichloromethane, and toluene; significant influences by solvents were observed on their luminescent properties; red-shifts for the zinc complexes were clearly observed in comparison to the free organic compounds.

A selective NIR-emitting zinc sensor by using Schiff base binding to turn-on excited-state intramolecular proton transfer

A rational design has led to a highly selective and cell-permeable zinc sensor, which exhibits not only a large fluorescence turn-on at ~545 nm but also the desirable NIR emission (~720 nm) with a large Stokes' shift, providing a practical sensor platform with two emission channels for reliable zinc detection.

Zn(ii) promoted dramatic enhancement in the enantioselective fluorescent recognition of functional chiral amines by a chiral aldehyde

The addition of Zn²⁺ to the methanol solution of a BINOL-based chiral dialdehyde leads to dramatically enhanced enantioselective fluorescent responses toward various functional chiral amines, representing one of the first chiral aldehydes capable of such recognition.

A single chemosensor for multiple analytes: fluorogenic detection of Zn2+ and OAc− ions in aqueous solution, and an application to bioimaging

A single fluorescent chemosensor 1 for multiple analytes (Zn²⁺ and OAc⁻) has been developed and it can monitor Zn²⁺ ions in living cells.