- A highly selective 7-hydroxy-3-methyl-benzoxazinone based fluorescent probe for instant detection of thiophenols in environmental samples
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A new 7-hydroxy-3-methyl-benzoxazinone based fluorescent probe for thiophenols has been designed and synthesized. The probe displays highly selective and sensitive detection to thiophenols over other common analytes with instant response and remarkable large Stokes shift. It's noteworthy that biothiols, aliphatic thiols, and reducing anions do not perturb the sensing of thiophenols. The limit of detection of the probe was calculated as low as 24 nM for thiophenols. Finally, the utility of probe was illustrated by the detection of thiophenol in real environmental water samples.
- An, Ruibing,Wei, Peng,Zhang, Datong,Su, Na
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- A Michael addition-cyclization-based switch-on fluorescent chemodosimeter for cysteine and its application in live cell imaging
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Based on a conjugate addition/intramolecular cyclization sequence, we designed and synthesized a fast response fluorescent probe, BTAC (benzothiazol-azacoumarin), for the discriminative detection of cysteine (Cys). The reaction of cysteine with BTAC results in the cleavage of the acrylate moiety from BTAC, thereby producing BTAC-OH, with a remarkable fluorescence enhancement at 560 nm. The probe exhibits high sensitivity and selectivity toward cysteine over homocysteine and glutathione and the detection limit reached as low as 124 nM for cysteine. The addition of Cys resulted in the color of the solution of BTAC changing from colorless to greenish yellow under the simulation of physiological conditions and BTAC could serve as a "naked-eye" indicator. The structure of BTAC was established by computational DFT (density functional theory) calculation and time dependent density functional theory (TDDFT) calculations were performed to demonstrate the electronic properties of BTAC and its product, BTAC-O-. Finally, the probe was successfully applied for the fluorescence bioimaging of cysteine owing to its photostability and low cytotoxicity.
- Manna, Srimanta,Karmakar, Parthasarathi,Ali, Syed Samim,Guria, Uday Narayan,Sarkar, Ripon,Datta, Pallab,Mandal, Debasish,Mahapatra, Ajit Kumar
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- Experimental and quantum chemical study on nano-copper immobilized on magnetic graphitic carbon nitride core shell particles; a reusable heterogeneous catalyst toward reduction of nitro arenes
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A new magnetic material, which named CuFe2O4?SiO2?g-C3N4/Cu with a core/shell morphology has been designed and synthesized. For the first time ever, the mixture of carbon and g-C3N4 layer was applied as an effective linker for immobilization of Cu metal on the catalyst. The physiochemical properties of the catalyst were identified by XRD, FT-IR, VSM, FE-SEM and TEM characterization techniques. The reduction of nitro compounds to the corresponding amines was investigated in the presence of NaBH4 at 55 °C in water. Quantum chemical study reveals that the addition of Cu atoms to the g-C3N4 layer induce a slight structural deformation via changing the bond lengths and bond orders, also the type of interaction of Cu atoms and nitrogen atoms of g-C3N4 is mainly electrostatic in nature. Induced pattern of charge distribution provided by Electrostatic Potential Map exhibits the attractive regions for electrophiles and nucleophiles interacting with this system.
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- A 7-hydroxybenzoxazinone-containing fluorescence turn-on probe for biothiols and its bioimaging applications
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In this work, a novel 7-hydroxybenzoxazinone-based fluorescent probe (PBD) for the selective sensing of biothiols is reported. Upon treatment with biothiols, PBD shows a strong fluorescence enhancement (up to 70-fold) and a large Stokes shift (155 nm). Meanwhile, this probe exhibits high resistance to interference from other amino acids and competing species. PBD features good linearity ranges with a low detection limit of 14.5 nM for glutathione (GSH), 17.5 nM for cysteine (Cys), and 80.0 nM for homocysteine (Hcy), respectively. Finally, the potential utility of this probe for biothiol sensing in living HeLa cells is demonstrated.
- Li, Bin,Zhang, Datong,An, Ruibing,Zhu, Yaling
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- Cobalt oxide NPs immobilized on environmentally benign biological macromolecule-derived N-doped mesoporous carbon as an efficient catalyst for hydrogenation of nitroarenes
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Highly nitrogen-doped mesoporous carbon (N-mC) material incorporated cobalt oxide nanoparticles was synthesized through simple pyrolysis of environmentally friendly chitosan-polyaniline-Co(OAc)2 precursor in one-step. The as-prepared catalyst named CoO&at;N-mC with 14.65 ?wtpercent nitrogen content was characterized by different analysis techniques. The heterogeneous catalyst exhibits outstanding catalytic activity for the reduction of a variety of nitroaromatic compounds in the presence of NaBH4 as a reducing agent in water as a green solvent at 75 ?°C. Utilization of natural biological macromolecules such as chitosan as green and cheap starting material with harmless aniline and earth-abundant cobalt salt, facile synthesis, excellent product yield, short reaction time, high chemoselectivity, sustainable and mild reaction condition, and reusability of catalyst for at least five cycles without any significant decline in the catalytic efficiency are some prominent merits of this new nanocatalyst.
- Elhampour, Ali,Nanadegani, Zahra Soleimani,Nemati, Firouzeh,Rangraz, Yalda
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- Optimization of the azobenzene scaffold for reductive cleavage by dithionite; development of an azobenzene cleavable linker for proteomic applications
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In this paper we conducted an extensive reactivity study to determine the key structural features that favour the dithionite-triggered reductive cleavage of the azo-arene group. Our stepwise investigation allowed identification of a highly reactive azo-arene structure 25 bearing a carboxylic acid, at the ortho position of the electron-poor arene and an ortho-Oalkyl-resorcinol as the electron-rich arene. Based on this 2(2′-alkoxy-4′-hydroxyphenylazo) benzoic acid (HAZA) scaffold, the orthogonally protected difunctional azo-arene cleavable linker 26 was designed and synthesized. Selective linker deprotection and derivatization was performed by introducing an alkyne reactive group and a biotin affinity tag. This optimized azo-arene cleavable linker led to a total cleavage in less than 10 s with only 1 mM dithionite. Similar results were obtained in biological media.
- Leriche, Geoffray,Budin, Ghyslain,Brino, Laurent,Wagner, Alain
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experimental part
p. 4360 - 4364
(2010/09/20)
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- One step hair coloring compositions using salts
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A hair coloring composition comprising the following two compositions which are mixed just prior to application to the hair: (a) a composition comprising a water-soluble peroxygen oxidizing agent; and (b) a composition comprising one or more oxidative hair coloring agents selected from the group consisting of an aromatic diamine, an amino phenol, a naphthol, a polyhydric phenol, a catechol and mixtures thereof; wherein the composition comprising one or more oxidative hair coloring agents further comprises al least one water soluble carbonate releasing salts; and optionally a water soluble ammonium salt, is described.
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- Transition metal complexes as dye forming catalysts in hair coloring compositions
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A hair coloring composition comprising a first composition which comprises: (a) a dye forming transition metal salt or complex; which is first applied to the hair; and a second composition which comprises the following two compositions which are mixed just prior to application to the hair: (a) a composition comprising a water-soluble peroxygen oxidizing agent; and (b) a composition comprising one or more oxidative hair coloring agents selected from the group consisting of an aromatic diamine, an aminophenol, a polyhydric phenol a catechol and mixtures thereof.
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- Enhanced color deposition for hair with sequestering agents
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Hair coloring compositions which comprise: (A) non-nitrogenous chelating agents from the group consisting of polyphosphate; phosphonates; hydroxycarboxylates; polyacrylates; zeolite; and mixtures thereof; (B) an oxidative dye primary intermediate; and (C) an oxidative dye coupler; (D) and water are described. The present invention also relates to a method for coloring hair which comprises contacting said hair with a hair coloring composition as described above.
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- POLAROGRAPHIC AND CYCLIC VOLTAMMETRIC BEHAVIOUR OF SOME AZO COMPOUNDS DERIVED FROM SULFONAMIDE IN DMF-AQUEOUS SOLUTIONS
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The polarographic and cyclic voltammetric behaviour of (2-hydroxyphenylazo)-4-benzenesulfonamide and some of its derivatives have been studied in Britton-Robinson buffer series containing 30 vol.percent of DMF.Over the entire pH range (2-12), the reduction pathway occurs through an irreversible 4-electron step corresponding to the reduction of N=N center to the amine stage.The voltammograms recorded in acidic and alkaline solution at different scan rates exhibit one or two cathodic peaks depending on the substituent and the pH of the medium.The electrode reaction mechanism was suggested, also the kinetic parameters were calculated.
- Mabrouk, El-Sayed M.,Killa, Hamada M.,Fattah, Abdel Fattah A. Abdel,Yasen, Shalaby A.
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p. 268 - 275
(2007/10/02)
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