A chemodosimeter for the ratiometric detection of hydrazine based on return of ESIPT and its application in live-cell imaging

A novel fluorescein-based "turn-on" probe for the detection of hydrazine and its application in living cells

We constructed a novel probe for hydrazine detection based on ICT and PET mechanism. Phthalimide and acetyl ester groups were used as the recognition units. Addition of hydrazine produced a turn-on fluorescence at 525nm along with the fluorescent color change from dark to yellow. The probe could selectively detect hydrazine over other related interfering species. The detection limit of the probe for hydrazine was calculated to be 0.057μM which was lower than the EPA standard (0.320μM). Furthermore, the probe could also be applied for the imaging of hydrazine in living cells.

A highly sensitive and selective off-on fluorescent chemosensor for hydrazine based on coumarin β-diketone

A coumarin-based sensor C1, namely 3-acetoacetylcoumarin was designed, synthesized and applied for hydrazine detection. Hydrazinolysis of the chemosensor gives a fluorescent coumarin-pyrazole product C1-N₂H₄ [3-(3-methyl-1H-pyrazol-5-yl)coumarin], and thus resulting in a prominent fluorescence off-on response toward hydrazine under physiological conditions. The probe is highly selective toward hydrazine over cations, anions and other biologically/environmentally abundant analytes. The detection limit of the probe is 3.2ppb. The sensing mechanism was supported by ¹H NMR, IR, MS and DFT calculation. The application of the fluorescent probe in monitoring intracellular hydrazine in glioma cell line U251 was also demonstrated.

A renewable test strip combined with solid-state ratiometric fluorescence emission spectra for the highly selective and fast determination of hydrazine gas

We developed a new technique combining a renewable test strip and solid-state ratiometric fluorescence readout for the fast capture and quantification of N₂H₄ gas.

A highly sensitive naked-eye fluorescent probe for trace hydrazine based on ‘C-CN’ bond cleavage

The ‘C–CN’ bond cleavage was applied to the recognition of N₂H₄ for the first time; the obvious change in color could be used for “naked-eye” detection; the corresponding detection limit was found to be 5.81 × 10⁻⁸ M (1.65 ppb); the probe could be applied for N₂H₄ detection in real water samples.

Colorimetric detection of iron and fluorescence detection of zinc and cadmium by a chemosensor containing a bio-friendly octopamine

A chemosensor containing a bio-friendly octopamine was developed for the colorimetric detection of iron and fluorescence detection of zinc and cadmium.

Mitochondria-targeted ratiometric fluorescent detection of hydrazine with a fast response time

A fluorescent hydrazine-probe was synthesized, which exhibited high sensitivity, excellent selectivity and anti-interference ability.

A highly selective long-wavelength fluorescent probe for hydrazine and its application in living cell imaging

A highly selective long-wavelength turn-on fluorescent probe has been developed for the detection of N₂H₄. The probe was prepared by conjugation the tricyanofuran-based D-π-A system with a recognizing moiety of acetyl group. In the presence of N₂H₄, the probe can be effectively hydrazinolysized and produce a turn-on fluorescent emission at 610nm as well as a large red-shift in the absorption spectrum corresponding to a color change from yellow to blue. The sensing mechanism was confirmed by HPLC, MS, UV-vis, emission spectroscopic and theoretical calculation studies. The probe displayed high selectivity and sensitivity for N₂H₄ with a LOD (limit of detection) of 0.16μM. Moreover, the probe was successfully utilized for the detection of hydrazine in living cells.

A novel ratiometric fluorescent probe based on 1, 8-naphthalimide for the detection of Ho3+ and its bioimaging

A ratiometric fluorescent probe for the detection of Ho³⁺ in DMSO-aqueous medium was designed and synthesized based on 1, 8-naphthalimide. The probe displayed response to Ho³⁺ with a fluorescence decrease at 512nm and enhancement at 480nm, accompanying with a distinct fluorescence change from bright yellow-green to cyan. Besides, the probe exhibited a lower detection limit (6×10^-8M) and could be used in intracellular fluorescence imaging. To the best of the knowledge, it was the first ratiometric fluorescent probe for Ho³⁺ detection. This probe was expected to be a useful tool for further elucidating the roles of Ho³⁺ in materials, biology and environment.

A highly selective fluorescent probe based on coumarin for the imaging of N2H4 in living cells

A turn-on fluorescence probe for highly sensitive and selective detection of N₂H₄ was developed based on hydrazine-triggered a substitution- cyclization-elimination cascade. Upon the treatment with N₂H₄, probe 1, 4-methyl-coumarin-7-yl bromobutanoate, displayed a remarkable fluorescence enhancement (25-fold) with a maximum at 450nm. This probe can quantitatively detect N₂H₄ with a extremely low detection limit as 7×10^-8M. Moreover, cell imaging experiments have indicated that probe 1 has potential ability to detect and image N₂H₄ in biological systems.

Triphenylamine–benzimidazole based switch offers reliable detection of organophosphorus nerve agent (DCP) both in solution and gaseous state

Triphenylamine-conjugated imidazole dye acts as a potential sensor for the liquid and vapour phase detection of nerve agent simulantDCP.

A highly sensitive and selective fluorescent probe for N2H4 in air and living cells

A new colorimetric and fluorescent probe developed for the sensitive and selective detection of N₂H₄ in air and aqueous solution.

A new near-infrared ratiometric fluorescent probe for hydrazine

Under mild conditions, a novel near-infrared ratiometric and on–off fluorescent probe was synthesized, which can detect hydrazine with high selectivity and anti-interference over other amines, biological species, anions and metal ions.

Ratiometric luminescence detection of hydrazine with a carbon dots–hemicyanine nanohybrid system

Under mild conditions, a novel ratiometric fluorescent probe containing CDs and a hemicyanine derivative was fabricated for reliable, selective, and sensitive sensing of hydrazine.

A new hydroxynaphthyl benzothiazole derived fluorescent probe for highly selective and sensitive Cu(2+) detection

A new reactive probe, 1-(benzo[d]thiazol-2-yl)naphthalen-2-yl-picolinate (BTNP), was designed and synthesized. BTNP acts as a highly selective probe to Cu(2+) in DMSO/H2O (7/3, v/v, Tris-HCl 10mM, pH=7.4) solution based on Cu(2+) catalyzed hydrolysis of the picolinate ester moiety in BTNP, which leads to the formation of an ESIPT active product with dual wavelength emission enhancement. The probe also possesses the advantages of simple synthesis, rapid response and high sensitivity. The pseudo-first-order reaction rate constant was calculated to be 0.205min(-1). Moreover, application of BTNP to Cu(2+) detection in living cells and real water samples was also explored.

A novel fluorescent probe for sensitive detection and imaging of hydrazine in living cells

A turn-on fluorescent probe (Naphsulf-O) for hydrazine was developed by protecting the hydroxy group of the fluorophore 6-acetyl-2-hydroxynaphthalene via O-4-nitrobenzenesulfonylation, where 4-nitrobenzene was used as a fluorescence quenching moiety as well as an electrophile. Upon nucleophilic aromatic substitution (NAS) reaction of hydrazine toward the probe, the protecting group was removed and fluorophore was released. The probe exhibits a large Stokes shift, excellent selectivity and high sensitivity for hydrazine detection in aqueous solution with a detection limit of 0.716 ppb (22nM), which is of great importance in both environmental and biological system. Furthermore, it was successfully applied to imaging of hydrazine in living cells.

Resonance-Assisted Hydrogen Bonding as a Driving Force in Synthesis and a Synthon in the Design of Materials

Resonance-assisted hydrogen bonding (RAHB), a concept introduced by Gilli and co-workers in 1989, concerns a kind of intramolecular H-bonding strengthened by a conjugated π-system, usually in 6-, 8-, or 10-membered rings. This Review highlights the involvement of RAHB as a driving force in the synthesis of organic, coordination, and organometallic compounds, as a handy tool in the activation of covalent bonds, and in starting moieties for synthetic transformations. The unique roles of RAHB in molecular recognition and switches, E/Z isomeric resolution, racemization and epimerization of amino acids and chiral amino alcohols, solvatochromism, liquid-crystalline compounds, and in synthons for crystal engineering and polymer materials are also discussed. The Review can provide practical guidance for synthetic chemists that are interested in exploring and further developing RAHB-assisted synthesis and design of materials.

Molecular engineering of a dual emission near-infrared ratiometric fluorophore for the detection of pH at the organism level

A near-infrared ratiometric fluorophore (NIR-HBT) was rationally designed and constructed by expanding both the excitation and emission wavelength of the classical ratiometric fluorophore 2-(benzothiazol-2-yl)phenol (HBT) into the near-infrared region. The NIR-HBT was easily synthesized by incorporating the HBT module into the hemicyanine skeleton and showed evident NIR ratiometric fluorophore characteristics. Further application of the new fluorophore for pH detection demonstrated that NIR-HBT possesses superior overall analytical performance and NIR-HBT was successfully applied for detection of acidosis caused by inflammation in living animal tissue, which indicated the potential application value of NIR-HBT in biological imaging and sensing.

An ESIPT-based fluorescent probe for sensitive detection of hydrazine in aqueous solution

A fluorescent probe for sensitive detection of hydrazine based on an ESIPT mechanism and a substitution-cyclization-elimination cascade was developed. After the addition of hydrazine, an approximately 50-fold enhancement in fluorescence intensity at 465 nm was observed and the subsequent decrease at 375 nm was observed in 10 min with a detection limit of 0.147 μM. We also detected hydrazine in HeLa cells successfully.

Fluorescent oxazoles from quinones for bioimaging applications

This work describes a synthetic strategy for the syntheses of four new fluorescent excited state intramolecular proton transfer (ESIPT) prone oxazole derivatives synthesized from lapachol, a naturally occurring naphthoquinone isolated from the Tabebuia species (ipe tree).

Highly fluorescent extended 2-(2′-hydroxyphenyl)benzazole dyes: synthesis, optical properties and first-principle calculations

Restoration of ESIPT upon protonation was demonstrated in an extended-hydroxybenzothiazole derivative in which it was fully inhibited in the neutral state.

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.

A ratiometric fluorescent and colorimetric probe for selective detection of hydrazine

In aqueous DMSO solution, ratiometric fluorescent hydrazine probe COUMA2 undergoes hydrazinolysis affording deacetylation products displaying dual emissive peaks at 500 and 655 nm.

A highly sensitive fluorescent probe for detection of hydrazine in gas and solution phases based on the Gabriel mechanism and its bioimaging

A new probe 2-benzo[1,2,5]thiadiazol-4-yl-isoindole-1,3-dione (BTI) based on the Gabriel reaction was developed for hydrazine which shows promising selectivity towards hydrazine over other analytes.

Carbazole–benzimidazole based dyes for acid responsive ratiometric emissive switches

Three carbazole conjugated benzimidazole dyes have been synthesized and their acid/base induced photophysical properties have been studied.

AH, Taye N, Mogare DG, Chattopadhyay S, Das A. Specific receptor for hydrazine: mapping the in situ release of hydrazine in live cells and in an in vitro enzymatic assay

New chemodosimetric reagent for the specific detection of hydrazine in physiological conditions as well as for the mapping of its in situ generation in live Hct116 and HepG2 cells by enzymatic transformations.

FRET-based fluorescence ratiometric and colorimetric sensor to discriminate Fe3+ from Fe2+

A new benzothiazole–quinoline–rhodamine-6G-based probe was synthesised. The probe can exclusively detect Fe³⁺ through a ratiometric manner in a mixed aqueous system with a detection limit in the 10⁻⁸ M range.