- Copper(II)-Silver(I) Macrocyclic Metal-Organic Framework: A Highly Efficient Reusable Triplet Oxygen Collector and Singlet Oxygen Generator
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The generation of highly reactive oxygen (1O2) is very significant for a variety of applications such as degradation, bleaching, chemical synthesis, photodynamic therapy for tumor treatment, and others. Herein, we report a novel peroxide-dianion-embedded bimetallic macrocycle, [O22-@Ag4Cu4L4]2+ (2), that can completely release the inserted peroxide dianion as the singlet oxygen (1O2) via a H+-assisted disproportionation process in methanol. Notably, the resulting empty Ag4Cu4L4(ClO4)4 (3) is able to trap oxygen (3O2) from air and fixes it in the macrocycle host as a peroxide dianion; furthermore, it releases it as 1O2 again in the presence of H+. So, the bimetallic macrocycle [Ag4Cu4L4]4+ herein behaves as a highly efficient reusable triplet oxygen receptor and singlet oxygen generator.
- Wang, Jian-Cheng,Yang, Jing,Wang, Shen-Qing,Ma, Jian-Ping,Dong, Yu-Bin
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- Stopped-flow enzyme assays on a chip using a microfabricated mixer
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This paper describes a microfabricated enzyme assay system including a micromixer that can be used to perform stopped-flow reactions. Samples and reagents were transported into the system by electroosmotic flow (EOF). Streams of reagents were merged and passed through the 100-pL micromixer in a system of roughly 6 nL volume. β-Galactosidase (β-Gal) was chosen as a model enzyme for these studies and was used to convert the substrate fluorescein mono-β-D-galactopyranoside (FMG) into fluorescein. Results obtained with microfabricated systems using the micromixer compared well to those obtained with an external T mixing device. In contrast, assays performed in a microfabricated device by merging two streams and allowing mixing to occur by lateral diffusion did not compare well. Using the microfabricated mixer, Km and kcat values of 75 ± 13 μM and 44 ± 3 s-1 were determined. These values compare well to those obtained with the conventional stopped-flow apparatus for which Km was determined to be 60 ± 6 μM and kcat was 47 ± 4 s-1. Enzyme inhibition assays with phenylethyl-β-D-thiogalactoside (PETG) were also comparable. It was concluded that kinetically based, stopped-flow enzyme assays can be performed in 60 s or less with a miniaturized system of roughly 6 nL liquid volume when mixing is assisted with the described device.
- Burke, Brian J.,Regnier, Fred E.
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- Combinatorial discovery of peptide dendrimer enzyme models hydrolyzing isobutyryl fluorescein
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Two 6750-membered one-bead-one-compound peptide dendrimer combinatorial libraries L (X4)8(LysX3)4(LysX 2)2LysX1 (X1-4 = 14 different amino acids or deletion, Lys = branching lysine residue) and AcL (with N-terminal acetylation) were prepared by split-and-mix solid phase peptide synthesis. Screening toward fluorogenic substrates for esterase and aldolase activities using the in silica off-bead assay (N. Maillard et al., J. Comb. Chem.2009, 11, 667-675) and bead decoding by amino acid analysis revealed histidine containing sequences active against fluorescein diacetate. Isobutyryl fluorescein, a related hydrophobic fluorogenic substrate, was preferentially hydrolyzed by dendrimers from library AcL containing hydrophobic residues such as AcH3 (AcHis)8(LysLeu)4(LysVal)2LysLysOH, compared to simple oligohistidine peptides as reference catalysts. Polycationic dendrimers from library L with multiple free N-termini such as H8 (His) 8(LysβAla)4(LysThr)2LysaProNH2 (aPro = (2S,4S)-4-aminoproline) showed stronger reactivity toward 8-acetoxypyrene-1,3,6-trisulfonate with partial acylation of N-termini. These experiments highlight the role of noncatalytic amino acids to determine substrate selectivity in peptide dendrimer esterase models.
- Maillard, Noelie,Biswas, Rasomoy,Darbre, Tamis,Reymond, Jean-Louis
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- Extension of the applicable range of fluorescein: A fluorescein-based probe for Western blot analysis
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(Chemical Equation Presented) The new star of Westerns: A highly sensitive fluorescence probe for alkaline phosphatase (ALP) based on a fluorescein derivative has been prepared and found to be suitable for use in Western blot analysis. The probe 1 is nonf
- Kamiya, Mako,Urano, Yasuteru,Ebata, Nobuyoshi,Yamamoto, Masami,Kosuge, Jyunichi,Nagano, Tetsuo
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- Peptide dendrimer enzyme models for ester hydrolysis and aldolization prepared by convergent thioether ligation
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Peptide dendrimers with multiple histidines or N-terminal prolines efficiently catalyze ester hydrolysis or aldol reactions in aqueous medium. Part of the catalytic proficiency of these dendritic enzyme models stems from multivalency effects observed in G2, G3 and G4 dendrimers displaying multiple catalytic groups in their branches. To study multivalency in higher generation systems, G4, G5 and G6 peptide dendrimers were prepared by a convergent assembly. Thus, peptide dendrimers bearing four or eight chloroacetyl groups at their N-termini underwent multiple thioether ligation with G2 and G3 peptide dendrimers with a cysteine residue at their focal point, to give G4, G5 and G6 dendrimers containing up to 341 amino acids, including multiple histidines or N-terminal prolines. While the efficiency of the esterase catalysts was comparable to that of their lower generation analogs, a remarkable reactivity increase was observed in G5 and G6 aldolase dendrimers.
- Uhlich, Nicolas A.,Darbre, Tamis,Reymond, Jean-Louis
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- A fluoresceinylcarbonate-based fluorescent probe for the sensitive detection of biothiols in a HEPES buffer and its cellular expression
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A fluoresceinylcarbonate-based fluorescent probe (1) with a disulfide bond was designed for the detection of biothiols in an aqueous solvent. The probe showed a more rapid and sensitive response to biothiols than other various amino acids through the disulfide bond cleavage and the subsequent intramolecular cyclization. When glutathione was added to the probe, fluorescence of 1 was significantly enhanced and was observable with the naked eye and in living cells. The Royal Society of Chemistry 2014.
- Hong, Keum-Hee,Kim, Dae Il,Kwon, Hyockman,Kim, Hae-Jo
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Read Online
- Controlled initiation of enzymatic reactions in micrometer-sized biomimetic compartments
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We present a technique to initiate chemical reactions involving few reactants inside micrometer-scale biomimetic vesicles (10-12 to 10-15 L) integral to three-dimensional surfactant networks. The shape of these networks is under dyna
- Karlsson, Anders,Sott, Kristin,Markstr?m, Martin,Davidson, Max,Konkoli, Zoran,Orwar, Owe
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Read Online
- Readily Available Fluorescent Probe for Carbon Monoxide Imaging in Living Cells
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Carbon monoxide (CO) is an important gasotransmitter in living systems and its fluorescent detection is of particular interest. However, fluorescent detection of CO in living cells is still challenging due to lack of effective probes. In this paper, a readily available fluorescein-based fluorescent probe was developed for rapid detection of CO. This probe can be used to detect CO in almost wholly aqueous solution under mild conditions and shows high selectivity and sensitivity for CO with colorimetric and remarkable fluorescent turn-on signal changes. The detection limit of this probe for CO is as low as 37 nM with a linear range of 0-30 μM. More importantly, this probe (1 μM dose) can be conveniently used for fluorescent imaging CO in living cells.
- Feng, Weiyong,Liu, Dandan,Feng, Shumin,Feng, Guoqiang
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Read Online
- A general strategy to quantify analytes through fluorescence chromaticity and luminosity
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To realize a fast, easy-operation and precise way using fluorescence probes to quantify analytes is a goal to facilitate detection, especially in situ. Herein, we are reporting an approach which can be generally employed for the differentiation and quanti
- Liang, Tianyu,Yang, Peiwei,Wu, Tianhong,Shi, Menghan,Xu, Xiayu,Qiang, Taotao,Sun, Xiaolong
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p. 2975 - 2979
(2020/07/20)
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- Protein Spherical Nucleic Acids for Live-Cell Chemical Analysis
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We report the development of a new strategy for the chemical analysis of live cells based on protein spherical nucleic acids (ProSNAs). The ProSNA architecture enables analyte detection via the highly programmable nucleic acid shell or a functional protein core. As a proof-of-concept, we use an i-motif as the nucleic acid recognition element to probe pH in living cells. By interfacing the i-motif with a forced-intercalation readout, we introduce a quencher-free approach that is resistant to false-positive signals, overcoming limitations associated with conventional fluorophore/quencher-based gold NanoFlares. Using glucose oxidase as a functional protein core, we show activity-based, amplified sensing of glucose. This enzymatic system affords greater than 100-fold fluorescence turn on in buffer, is selective for glucose in the presence of close analogs (i.e., glucose-6-phosphate), and can detect glucose above a threshold concentration of ~5 μM, which enables the study of relative changes in intracellular glucose concentrations.
- Samanta, Devleena,Ebrahimi, Sasha B.,Kusmierz, Caroline D.,Cheng, Ho Fung,Mirkin, Chad A.
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p. 13350 - 13355
(2020/09/09)
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- PROCESS FOR PREPARING FLUORESCEIN QUINOID FORM
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The present invention relates to a process for preparing fluorescein quinoid form of Formula (I): Furthermore, the present invention relates to a new solid fluorescein form and a process for the preparation thereof. The present invention also relates to the use of said new solid fluorescein form in the synthesis of fluorescein quinoid form.
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Paragraph 0054
(2020/02/19)
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- Boronate ester cross-linked PVA hydrogels for the capture and H2O2-mediated release of active fluorophores
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A new set of PVA hydrogels were formed using the boronate ester fluorescent probe PF1 and the novel boronate fluorescent probe PT1 as the covalent crosslinkers. Treatment with aqueous H2O2 allowed triggered release of the fluorescent dye accompanied by complete dissolution of the hydrogel.
- Williams, George T.,Sedgwick, Adam C.,Sen, Sajal,Gwynne, Lauren,Gardiner, Jordan E.,Brewster, James T.,Hiscock, Jennifer R.,James, Tony D.,Jenkins, A. Toby A.,Sessler, Jonathan L.
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supporting information
p. 5516 - 5519
(2020/06/10)
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- Fat mass and obesity-associated protein (FTO) inhibitors prepared from 9-(2-carboxyphenyl) xanthene compounds and therapeutic effects thereof
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The invention relates to usage of the following general formula I as a drug for diseases targeting fat mass and obesity-associated protein (FTO), and provides usage of 9-(2-carboxyphenyl) xanthene compounds in preparation of FTO inhibitors. Specifically, the invention discloses usage of the 9-(2-carboxyphenyl) xanthene compounds as shown in the formula (I), as well as derivatives and pharmaceutically acceptable salts thereof, in preparation of the FTO inhibitors or pharmaceutical compositions for treating FTO-related diseases.
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Paragraph 0055-0058
(2020/07/13)
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- Photocatalysis Enables Visible-Light Uncaging of Bioactive Molecules in Live Cells
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The photo-manipulation of bioactive molecules provides unique advantages due to the high temporal and spatial precision of light. The first visible-light uncaging reaction by photocatalytic deboronative hydroxylation in live cells is now demonstrated. Using Fluorescein and Rhodamine derivatives as photocatalysts and ascorbates as reductants, transient hydrogen peroxides were generated from molecular oxygen to uncage phenol, alcohol, and amine functional groups on bioactive molecules in bacteria and mammalian cells, including neurons. This effective visible-light uncaging reaction enabled the light-inducible protein expression, the photo-manipulation of membrane potentials, and the subcellular-specific photo-release of small molecules.
- Wang, Haoyan,Li, Wei-Guang,Zeng, Kaixing,Wu, Yan-Jiao,Zhang, Yixin,Xu, Tian-Le,Chen, Yiyun
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p. 561 - 565
(2019/01/04)
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- Fluorogenic hydrogen sulfide (H2S) donors based on sulfenyl thiocarbonates enable H2S tracking and quantification
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Hydrogen sulfide (H2S) is an important cellular signaling molecule that exhibits promising protective effects. Although a number of triggerable H2S donors have been developed, spatiotemporal feedback from H2S release in biological systems remains a key challenge in H2S donor development. Herein we report the synthesis, evaluation, and application of caged sulfenyl thiocarbonates as new fluorescent H2S donors. These molecules rely on thiol cleavage of sulfenyl thiocarbonates to release carbonyl sulfide (COS), which is quickly converted to H2S by carbonic anhydrase (CA). This approach is a new strategy in H2S release and does not release electrophilic byproducts common from COS-based H2S releasing motifs. Importantly, the release of COS/H2S is accompanied by the release of a fluorescent reporter, which enables the real-time tracking of H2S by fluorescence spectroscopy or microscopy. Dependent on the choice of fluorophore, either one or two equivalents of H2S can be released, thus allowing for the dynamic range of the fluorescent donors to be tuned. We demonstrate that the fluorescence response correlates directly with quantified H2S release and also demonstrate the live-cell compatibility of these donors. Furthermore, these fluorescent donors exhibit anti-inflammatory effects in RAW 264.7 cells, indicating their potential application as new H2S-releasing therapeutics. Taken together, sulfenyl thiocarbonates provide a new platform for H2S donation and readily enable fluorescent tracking of H2S delivery in complex environments.
- Zhao, Yu,Cerda, Matthew M.,Pluth, Michael D.
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p. 1873 - 1878
(2019/02/15)
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- Plasmonically Coupled Nanoreactors for NIR-Light-Mediated Remote Stimulation of Catalysis in Living Cells
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Artificial nanoreactors that can facilitate catalysis in living systems on-demand with the aid of a remotely operable and biocompatible energy source are needed to leverage the chemical diversity and expediency of advanced chemical synthesis in biology and medicine. Here, we designed and synthesized plasmonically integrated nanoreactors (PINERs) with highly tunable structure and NIR-light-induced synergistic function for efficiently promoting unnatural catalytic reactions inside living cells. We devised a synthetic approach toward PINERs by investigating the crucial role of metal-tannin coordination polymer nanofilm - the pH-induced decomplexation-mediated phase-transition process - for growing arrays of Au-nanospheroid-units, constructing a plasmonic corona around the proximal and reactant-accessible silica-compartmentalized catalytic nanospace. Owing to the extensive plasmonic coupling effect, PINERs show strong and tunable optical absorption in the visible to NIR range, ultrabright plasmonic light scattering, controllable thermoplasmonic effect, and remarkable catalysis; and, upon internalization by living cells, PINERs are highly biocompatible and demonstrate dark-field microscpy-based bioimaging features. Empowered with the synergy between plasmonic and catalytic effects and reactant/product transport, facilitated by the NIR-irradiation, PINERs can perform intracellular catalytic reactions with dramatically accelerated rates and efficiently synthesize chemically activated fluorescence-probes inside living cells.
- Kumar, Amit,Kumar, Sumit,Kumari, Nitee,Lee, Seon Hee,Han, Jay,Michael, Issac J.,Cho, Yoon-Kyoung,Lee, In Su
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p. 977 - 990
(2019/01/15)
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- Fluorescence Detection of Prostate Cancer by an Activatable Fluorescence Probe for PSMA Carboxypeptidase Activity
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Prostate cancer (PCa) is a common malignant tumor among adult males, and convenient intraoperative detection of PCa would reduce the risk of leaving positive surgical margins, especially during nerve-sparing procedures. To achieve rapid, fluorescence-based visualization of PCa, we focused on the glutamate carboxypeptidase (CP) activity of prostate-specific membrane antigen (PSMA), a type II transmembrane glycoprotein that is attracting attention as a PCa biomarker. Based on our finding that aryl glutamate conjugates with an azoformyl linker are recognized by PSMA and have a sufficiently low LUMO (lowest unoccupied molecular orbital) energy level to quench the fluorophore through photoinduced electron transfer, we designed and synthesized a first-in-class activatable fluorescence probe for CP activity of PSMA. The developed probe allowed us to visualize the CP activity of PSMA in living cells and in clinical specimens from PCa patients and is expected to be useful for rapid intraoperative detection and diagnosis of PCa.
- Kawatani, Minoru,Yamamoto, Kyoko,Yamada, Daisuke,Kamiya, Mako,Miyakawa, Jimpei,Miyama, Yu,Kojima, Ryosuke,Morikawa, Teppei,Kume, Haruki,Urano, Yasuteru
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supporting information
p. 10409 - 10416
(2019/07/04)
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- Design and evolution of an enzyme with a non-canonical organocatalytic mechanism
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The combination of computational design and laboratory evolution is a powerful and potentially versatile strategy for the development of enzymes with new functions1–4. However, the limited functionality presented by the genetic code restricts the range of catalytic mechanisms that are accessible in designed active sites. Inspired by mechanistic strategies from small-molecule organocatalysis5, here we report the generation of a hydrolytic enzyme that uses Nδ-methylhistidine as a non-canonical catalytic nucleophile. Histidine methylation is essential for catalytic function because it prevents the formation of unreactive acyl-enzyme intermediates, which has been a long-standing challenge when using canonical nucleophiles in enzyme design6–10. Enzyme performance was optimized using directed evolution protocols adapted to an expanded genetic code, affording a biocatalyst capable of accelerating ester hydrolysis with greater than 9,000-fold increased efficiency over free Nδ-methylhistidine in solution. Crystallographic snapshots along the evolutionary trajectory highlight the catalytic devices that are responsible for this increase in efficiency. Nδ-methylhistidine can be considered to be a genetically encodable surrogate of the widely employed nucleophilic catalyst dimethylaminopyridine11, and its use will create opportunities to design and engineer enzymes for a wealth of valuable chemical transformations.
- Burke, Ashleigh J.,Lovelock, Sarah L.,Frese, Amina,Crawshaw, Rebecca,Ortmayer, Mary,Dunstan, Mark,Levy, Colin,Green, Anthony P.
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p. 219 - 223
(2019/06/13)
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- A photocaged fluorescent probe for imaging hypochlorous acid in lysosomes
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By combining the advantages of the photocaging technology and traditional analyte-responsive fluorescent probes, we designed and synthesized the first photocaged lysosomal-targeted fluorescent HOCl probe (PL-HA). The new caged PL-HA probe was capable of remote light-controlled recognition of HOCl in lysosomes.
- Ren, Mingguang,Li, Zihong,Nie, Jing,Wang, Li,Lin, Weiying
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p. 9238 - 9241
(2018/08/23)
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- Allyl Fluorescein Ethers as Promising Fluorescent Probes for Carbon Monoxide Imaging in Living Cells
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Recently, the fluorescent detection of carbon monoxide (CO) in living cells has attracted great attention. However, due to the lack of effective ways to construct fluorescent CO probes, fluorescent detection of CO in living cells is still in its infancy.
- Feng, Shumin,Liu, Dandan,Feng, Weiyong,Feng, Guoqiang
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p. 3754 - 3760
(2017/05/08)
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- HKOH-1: A Highly Sensitive and Selective Fluorescent Probe for Detecting Endogenous Hydroxyl Radicals in Living Cells
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The hydroxyl radical (.OH), one of the most reactive and deleterious reactive oxygen species (ROS), has been suggested to play an essential role in many physiological and pathological scenarios. However, a reliable and robust method to detect e
- Bai, Xiaoyu,Huang, Yueyang,Lu, Mingyang,Yang, Dan
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supporting information
p. 12873 - 12877
(2017/09/25)
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- A Fluorescein-Based Colorimetric and Fluorescent Probe for Hydrazine and its Bioimaging in Live Cells
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A turn-on fluorescent probe (FN) for detection of hydrazine has been developed. Probe FN exhibited high selectivity and excellent sensitivity towards hydrazine with a detection limit as low as 4.6?×?10?10?M. Probe FN selectively reacts with hydrazine (N2H4) in a physiological environment, leading to an off-on fluorescence response along with the color change from colorless to yellow, allowing colorimetric detection of hydrazine by the naked eye. Furthermore, probe FN was successfully applied for visualizing hydrazine in living cells.
- Li, Gongchun,Liu, Yongxiang,Song, Jianhua,Ye, Yong
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p. 323 - 329
(2017/02/05)
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- Evaluation of the Ser-His Dipeptide, a Putative Catalyst of Amide and Ester Hydrolysis
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Efficient hydrolysis of amide bonds has long been a reaction of interest for organic chemists. The rate constants of proteases are unmatched by those of any synthetic catalyst. It has been proposed that a dipeptide containing serine and histidine is an effective catalyst of amide hydrolysis, based on an apparent ability to degrade a protein. The capacity of the Ser-His dipeptide to catalyze the hydrolysis of several discrete ester and amide substrates is investigated using previously described conditions. This dipeptide does not catalyze the hydrolysis of amide or unactivated ester groups in any of the substrates under the conditions evaluated.
- Macdonald, Melissa J.,Lavis, Luke D.,Hilvert, Donald,Gellman, Samuel H.
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supporting information
p. 3518 - 3521
(2016/08/16)
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- High efficient probes with Schiff base functional receptors for hypochlorite sensing under physiological conditions
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A series of novel and convenient fluorescent probes with Schiff base functionality were presented for direct detection of OCl- via the irreversible OCl--promoted oxidation and hydrolyzation reaction in formation of the ring-opened pr
- Huang, Yang-Yang,Wang, Meng-Jia,Yang, Zheng,She, Meng-Yao,Wang, Shu,Liu, Ping,Li, Jian-Li,Shi, Zhen
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p. 1077 - 1081
(2014/08/18)
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- Fluorescein-derived fluorescent probe for cellular hydrogen sulfide imaging
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In this work, a fluorescein-derived fluorescent probe for H2S based on the thiolysis of dinitrophenyl ether is reported. This probe exhibits turn-on fluorescence imaging of H2S in living cells and bulk solutions with excellent selectivity. The reaction mechanism was explained by means of absorption, fluorescence and HPLC-MS.
- Liu, Hui-Ying,Zhao, Miao,Qiao, Qing-Long,Lang, Hai-Jing,Xu, Jing-Zhe,Xu, Zhao-Chao
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p. 1060 - 1064
(2014/08/18)
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- Effects of artemisinin antimalarials on Cytochrome P450 enzymes in vitro using recombinant enzymes and human liver microsomes: Potential implications for combination therapies
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1. Cytochrome P450 enzyme system is the most important contributor to oxidative metabolism of drugs. Modification, and more specifically inhibition, of this system is an important determinant of several drug-drug interactions (DDIs). 2. Effects of the antimalarial agent artemisinin and its structural analogues, artemether, artesunate and dihydroartemisinin, on seven of the major human liver CYP isoforms (CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6 and 3A4) were evaluated using recombinant enzymes (fluorometric assay) and human liver microsomes (LC-MS/MS analysis). Inhibitory potency (IC50) and mechanisms of inhibition were evaluated using nonlinear regression analysis. In vitro-in vivo extrapolation using the [I]/Ki ratio was applied to predict the risk of DDI in vivo. 3. All compounds tested inhibited the enzymatic activity of CYPs, mostly through a mixed type of inhibition, with CYP1A2, 2B6, 2C19 and 3A4 being affected. A high risk of interaction in vivo was predicted if artemisinin is coadministrated with CYP1A2 or 2C19 substrates. 4. With respect to CYP1A2 inhibition in vivo by artemisinin compounds, our findings are in line with previously published data. However, reported risks of interaction may be overpredicted and should be interpreted with caution.
- Ericsson, Therese,Sundell, Jesper,Torkelsson, Angelica,Hoffmann, Kurt-Jürgen,Ashton, Michael
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p. 615 - 626
(2014/06/23)
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- A reductive ligation based fluorescent probe for S-nitrosothiols
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A reductive ligation based fluorescent probe (SNOP1) for the detection of S-nitrosothiols (SNO) was developed. The probe showed good selectivity and sensitivity for SNO. The Royal Society of Chemistry 2014.
- Zhang, Di,Chen, Wei,Miao, Zhengrui,Ye, Yong,Zhao, Yufen,King, S. Bruce,Xian, Ming
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supporting information
p. 4806 - 4809
(2014/05/06)
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- NBD-based colorimetric and fluorescent turn-on probes for hydrogen sulfide
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Hydrogen sulfide (H2S) is an important endogenous signalling molecule and also an important environmental target for detection. New reaction-based colorimetric and fluorescent turn-on probes based on selective thiolyling of NBD (7-nitro-1,2,3-benzoxadiazole) ether were explored for sensing of H2S in aqueous buffer. The syntheses of both probes are simple and quite straightforward. The probes are highly sensitive and selective toward H2S over other biologically relevant species. Probe 1 can be used to directly visualize H2S by the naked eye and shows more than 1000-fold fluorescence increase upon reaction with H2S. Probe 2 is a near-infrared fluorescent sensor for H2S at physiological pH.
- Wei, Chao,Zhu, Qing,Liu, Weiwei,Chen, Wenbin,Xi, Zhen,Yi, Long
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supporting information
p. 479 - 485
(2014/01/06)
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- Monogalactopyranosides of fluorescein and fluorescein methyl ester: Synthesis, enzymatic hydrolysis by biotnylated β-galactosidase, and determination of translational diffusion coefficient
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Fluorescein monoglycosides (d-galactopyranoside (FMG) and d-glucopyranoside) and their methyl ester (MFMG) have been prepared from acetobromoglucose/galactose and fluorescein methyl ester in good yields. Enzymatic hydrolysis experiments (using biotinylated β-galactosidase) of the galacto derivatives have been performed and kinetic parameters were calculated. A 15-20 times increase of the fluorescence intensity has been observed during the hydrolysis. A linear increase of fluorescence has been noted at short time and low concentration of substrate, making these compounds useful and sensitive probes for galactosidases. The magnitude of the Michaelis-Menten constant (Km) value for MFMG is higher than that of FMG suggesting a possible conformational change of the fluorogenic substrate. Km value for biotinylated β-Gal with FMG is lower than that for the native enzyme. This observation indicates higher substrate affinity of the biotinylated enzyme in comparison to the native enzyme. Translational diffusion coefficients have been measured, for both fluorogenic substrates and both the products, employing fluorescence correlation spectroscopy. Translational diffusion coefficients for fluorogenic substrates and the enzymatic hydrolysis products have been measured to be similar, in the range of 3.5-4.5 × 10-10 m2 s-1. Thus an enhancement or retardation of the enzymatic kinetics due to difference in translational mobility of substrate and product is not that apparent.
- Mandal, Prasun K.,Bensimon, David,Cattiaux, Laurent,Mallet, Jean-Maurice
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p. 40 - 46,7
(2020/07/30)
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- Design and performance of supported Lewis acid catalysts derived from metal contaminated biomass for Friedel-Crafts alkylation and acylation
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The main goal of this work was to prove the interest of metal hyperaccumulator plants in supported Lewis acid catalysis. Friedel-Crafts alkylation and acylation reveal the great catalytic activity of different plant extracts. This approach is a green solution with chemical benefits including high yield, excellent regioselectivity, small amounts of catalyst, mild conditions and concrete perspectives towards the depletion of mineral resources. The results also constitute an incentive for the development of phytoextraction programs on metal-bearing soils.
- Losfeld, Guillaume,Escande, Vincent,Vidal De La Blache, Paul,L'Huillier, Laurent,Grison, Claude
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scheme or table
p. 111 - 116
(2012/09/08)
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- Photocontrollable analyte-responsive fluorescent probes: A photocaged copper-responsive fluorescence turn-on probe
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Analyte-responsive fluorescent probes are valuable chemical tools for dissecting complex living systems. However, the major shortcoming of fluorescent probes is that once they enter the cells, control over them is basically lost. It is critical to regulat
- Yuan, Lin,Lin, Weiying,Cao, Zengmei,Long, Lingliang,Song, Jizeng
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supporting information; experimental part
p. 689 - 696
(2011/03/19)
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- A palette of fluorescent probes with varying emission colors for imaging hydrogen peroxide signaling in living cells
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We present a new family of fluorescent probes with varying emission colors for selectively imaging hydrogen peroxide (H2O2) generated at physiological cell signaling levels. This structurally homologous series of fluorescein- and rhodol-based reporters relies on a chemospecific boronate-to-phenol switch to respond to H2O2 over a panel of biologically relevant reactive oxygen species (ROS) with tunable excitation and emission maxima and sensitivity to endogenously produced H2O 2 signals, as shown by studies in RAW264.7 macrophages during the phagocytic respiratory burst and A431 cells in response to EGF stimulation. We further demonstrate the utility of these reagents in multicolor imaging experiments by using one of the new H2O2-specific probes, Peroxy Orange 1 (PO1), in conjunction with the green-fluorescent highly reactive oxygen species (hROS) probe, APF. This dual-probe approach allows for selective discrimination between changes in H2O2 and hypochlorous acid (HOCl) levels in live RAW264.7 macrophages. Moreover, when macrophages labeled with both PO1 and APF were stimulated to induce an immune response, we discovered three distinct types of phagosomes: those that generated mainly hROS, those that produced mainly H2O2, and those that possessed both types of ROS. The ability to monitor multiple ROS fluxes simultaneously using a palette of different colored fluorescent probes opens new opporunities to disentangle the complex contributions of oxidation biology to living systems by molecular imaging.
- Dickinson, Bryan C.,Huynh, Calvin,Chang, Christopher J.
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scheme or table
p. 5906 - 5915
(2010/07/13)
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- Rose Bengal analogs and vesicular glutamate transporters (VGLUTs)
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Vesicular glutamate transporters (VGLUTs) allow the loading of presynaptic glutamate vesicles and thus play a critical role in glutamatergic synaptic transmission. Rose Bengal (RB) is the most potent known VGLUT inhibitor (K i 25 nM); therefore we designed, synthesized and tested in brain preparations, a series of analogs based on this scaffold. We showed that among the two tautomers of RB, the carboxylic and not the lactonic form is active against VGLUTs and generated a pharmacophore model to determine the minimal structure requirements. We also tested RB specificity in other neurotransmitter uptake systems. RB proved to potently inhibit VMAT (Ki 64 nM) but weakly VACHT (Ki >9.7 μM) and may be a useful tool in glutamate/acetylcholine co-transmission studies.
- Pietrancosta, Nicolas,Kessler, Albane,Favre-Besse, Franck-Cyril,Triballeau, Nicolas,Quentin, Thomas,Giros, Bruno,Mestikawy, Salah El,Acher, Francine C.
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experimental part
p. 6922 - 6933
(2010/10/19)
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- Mild synthesis of asymmetric 2′-carboxyethyl-substituted fluoresceins
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(Chemical Equation Presented) Asymmetric fluoresceins bearing a carboxyethyl group in the chromophoric portion of the dyes were prepared by a reaction of substituted phthalic anhydride with a carboxyethyl substituted resorcinol analogue followed by a condensation with a second resorcinol analogue. In order to avoid an accumulation of symmetric side products, the second step was performed in two substeps: acid-catalyzed formation of a triphenylmethyl intermediate followed by base-catalyzed cyclization which furnished the desired dyes.
- Lukhtanov, Eugeny A.,Vorobiev, Alexei V.
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p. 2424 - 2427
(2008/09/19)
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- Approaches for scale-up of microwave-promoted reactions
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In this report, we look at a range of classes of reaction involving microwave heating and show how different processing techniques can be used to address scale-up needs. We look at both batch and continuous-flow processing. We have shown that when using batch methodologies working using an open reaction vessel offers operational advantages while still giving good yields of desired products. In cases where open-vessel conditions are not amenable or where particularly volatile or toxic reagents are used, parallel sealed vessels can offer an alternative approach. For continuous-flow processing, homogeneity of the reaction mixture is key. When the mixture is homogeneous, it is possible to move from small-scale sealed-vessel conditions to the continuous-flow apparatus without any modification of reaction conditions or loss in product yield. When either the starting materials or the product mixture contains particulate matter, continuous processing can prove a challenge, but reoptimization of reaction conditions as well as reduction of the concentration may allow these difficulties to be overcome.
- Bowman, Matthew D.,Holcomb, Jennifer L.,Kormos, Chad M.,Leadbeater, Nicholas E.,Williams, Victoria A.
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- New monofunctionalized fluorescein derivatives for the efficient high-throughput screening of lipases and esterases in aqueous media
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Monoalkylation or acylation of fluorescein (1) with various acyloxymethyl or acyl halides afforded, respectively, a series of ether- (2) and ester-functionalized (3) fluorogenic probes. The highly reactive and water-soluble substrates release fluorescein
- Yang, Yongzheng,Babiak, Peter,Reymond, Jean-Louis
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p. 404 - 415
(2007/10/03)
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- Improved photostable FRET-competent biarsenical-tetracysteine probes based on fluorinated fluoresceins
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We have developed fluoro-substituted versions of the biarsenical-tetracysteine label FlAsH, exhibiting significant improvements in important properties over the original fluorescein derivative. In complexes with tetracysteine targets, F2FlAsH exhibits 50 times improved photostability, lower pH sensitivity, higher absorbance and quantum yield than FlAsH, and F4FlAsH adds a new color to the palette of biarsenical dyes. The two probes also provide a new FRET pair with a larger Ro value (54 A) than any previously obtained with biarsenical dyes. Copyright
- Spagnuolo, Carla C.,Vermeij, Rudolf J.,Jares-Erijman, Elizabeth A.
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p. 12040 - 12041
(2007/10/03)
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- SULFONATE COMPOUND AND FLUORESCENT PROBE USING THE SAME
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The present invention provides a sulfonate compound, including a structure represented by a general formula (I) below, where, in the formula (I), an atomic group A-O is an atomic group that forms a fluorescent compound upon cleavage of a covalent bond between the atomic group A-O and a sulfonyl group, one or a plurality of atomic groups B-SO3- are bonded to an atomic group A, B is a ring that is substituted by one or a plurality of electron-withdrawing groups, the electron-withdrawing group is at least one selected from the group consisting of an alkyl halide group, a nitro group and a cyano group, and B may be the same or different in kind in the case where the plurality of B exist.
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Page/Page column 21-22
(2008/06/13)
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- A design of fluorescent probes for superoxide based on a nonredox mechanism
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Fluorometric detection of O2-? is performed based on desulfonylation of 3 to the corresponding fluoresceins 4 through nucleophilic substitution, and this fluorescing process is quite specific toward O2-? over H
- Maeda, Hatsuo,Yamamoto, Kayoko,Nomura, Yoko,Kohno, Iho,Hafsi, Leila,Ueda, Noritsugu,Yoshida, Shoko,Fukuda, Masako,Fukuyasu, Yuka,Yamauchi, Yuji,Itoh, Norio
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- 2,4-Dinitrobenzenesulfonyl fluoresceins as fluorescent alternatives to Ellman's reagent in thiol-quantification enzyme assays
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(Chemical Equation Presented) Fluorescent sensor for thiols: Deprotection of nonfluorescent 1 by thiols (R′SH) proceeds rapidly and near-quantitatively in aqueous solution (pH 7.4) to produce highly fluorescent 2. Assays performed in the presence of 1 provide a rapid and simple method for the determination of inhibitory constants for inhibitors such as donepezil toward acetyl- and butyrylcholinesterases.
- Maeda, Hatsuo,Matsuno, Hiromi,Ushida, Mai,Katayama, Kohei,Saeki, Kanaka,Itoh, Norio
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p. 2922 - 2925
(2007/10/03)
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- Ship-in-a-bottle synthesis of fluorescence-labeled nanoparticles: Applications in cellular imaging
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Fluorescein (2-(6-hydroxy-3-oxo-(3H)-xanthen-9-yl)benzoic acid) has been prepared inside the pores of zeolite-Y via ship-in-a-bottle synthesis. Fluorescein, whose dimensions prevent it from entering through the ~7 A windows of the faujasite zeolite used, was prepared by the acid-catalyzed reaction of resorcinol and phthalic anhydride. In this article we report initial spectroscopic data as well as an example of the usefulness of these fluorescence-labeled nanoparticles for imaging applications such as confocal fluorescence microscopy. Encapsulated fluorescein shows a remarkable increase in photostability.
- Chretien, Michelle N.,Shen, Biao,Garcia, Hermenegildo,English, Ann M.,Scaiano
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p. 434 - 437
(2007/10/03)
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- Fluorescent probes for hydrogen peroxide based on a non-oxidative mechanism
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Highly selective detection of H2O2 through a non-oxidative mechanism has been achieved by desulfonylation of 1 to the corresponding fluorescein, This approach has been used for the intracellular formation of H2O2/sub
- Maeda, Hatsuo,Fukuyasu, Yuka,Yoshida, Shoko,Fukuda, Masako,Saeki, Kanako,Matsuno, Hiromi,Yamauchi, Yuji,Yoshida, Kenji,Hirata, Kazumasa,Miyamoto, Kazuhisa
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p. 2389 - 2391
(2007/10/03)
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- Ionization and Tautomerism of Hydroxyxanthenes and Some Other Dyes in Ethanol
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Protolytic equilibria of hydroxyxanthene dyes, Fluorescein and Eosin, as well as of some related compounds, in ethanol were studied by spectrophotometry. Stepwise ionization and tautomeric equilibrium constants were determined.
- Mchedlov-Petrosyan
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p. 267 - 274
(2007/10/03)
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- Designing the selectivity of the fluorescent detection of amino acids: A chemosensing ensemble for histidine
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The imidazole group of histidine deprotonates and bridges the two CuII centers of a dimetallic polyamine macrocyclic complex, displacing the previously bound and quenched fluorescent indicator I. Thus, histidine recognition is signaled by the revival of the fluorescence of I. Selectivity with respect to other natural amino acids is achieved by choosing an indicator of tuned affinity toward the dicopper(II) receptor. Copyright
- Hortala, Marta Ansa,Fabbrizzi, Luigi,Marcotte, Nathalie,Stomeo, Floriana,Taglietti, Angelo
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- Novel fluorogenic substrates for acid phosphatase
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Fluorinated versions of fluorescein diphosphate (FDP) can provide significantly enhanced fluorescence upon hydrolysis by acid phosphatase, as compared with FDP, when measured at the reaction pH.
- Gee, Kyle R.
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p. 1395 - 1396
(2007/10/03)
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- Organic sonoelectrochemistry. Reduction of fluorescein in the presence of 20 kHz power ultrasound: an EC' reaction
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The electro-reduction of the dye fluorescein at mercury electrodes in basic aqueous solution is known to produce the stable semi-fluorescein radical.When the electrolysis is exposed to power ultrasound of intensity up to ca. 65 W cm-2 the radic
- Eklund, John C.,Waller, David N.,Rebbitt, Thomas O.,Marken, Frank,Compton, Richard G.
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p. 1981 - 1984
(2007/10/03)
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- Extraordinary Character of the Solvent Influence on Protolytic Equilibria: Inversion of the Fluorescein Ionization Constants in H2O-DMSO Mixtures
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The protolytic equilibria of fluorescein and sulfonefluorescein in the H2O-DMSO system are studied spectrophotometrically.The pKa values, as well as the absorption spectra, attributed to individual ionic (molecular) forms of the dyes, are determined.The paH* scales used in pKa calculations were estimated by the indicator method (sulfonephthalein series) through the overlapping procedure.The character of the solvent influence on the fluorescein stepwise ionization (H3R(+) H2R HR(-) R(2-); Ka0, Ka1 and Ka2, respectively) results in extraordinary interrelations between the Ka constants, up to inversion: pKa1 > pKa2.The Ka1/Ka2 ratio changes gradually from 224 in H2O to 0.045 in 91percent DMSO; meanwhile the Ka0/Ka1 ratio increases from 204 to 7*1010.The anomalous character of the fluorescein pKa dependence on the content of DMSO (up to pKa1 > pKa2) is explained through the tautomeric equilibria shift and the nature of the functional groups.The tautomerization constants of the fluorescein neutral form are given as obtained on the basis of the extrathermodynamic assumption proposed previously (N.O.Mchedlov-Petrossyan, Zh.Anal.Khim. 1979, 34, 1055).This allowed calculation of the ionization microconstants (k), which were found to be in agreement with pKa values of model compounds.
- Mchedlov-Petrossyan, Nikolay O.,Mayorga, Rafael Salinas
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p. 3025 - 3032
(2007/10/02)
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- Photooxidation of Leuco Dyes. III. - Sensitized Photooxidation of Leuco Fluorescein
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Quantum yields of the sensitized photooxidation of leuco fluorescein are reported.Fluorescein and benzophenone were found to be efficient sensitizers of photooxidation of leuco fluorescein.There is a characteristic dependence of quantum yields on concentration of leuco fluorescein and oxygen in the solution.The results are discussed on the basis of a reaction scheme proposed for the sensitized formation of fluorescein.
- Langbein, H.,Paetzold, R.
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- Chemiluminescence of a Linear Fluorescein Hydrazide
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Die Chemilumineszenz des durch Kondensation von Fluorescein mit Hydrazinhydrat unter Druck synthetisierten Fluoresceinhydrazides wird angegeben.Die Reaktion in waessrig alkalischen Medium mit Wasserstoffperoxid und Haemin oder Ferricyanid gibt eine sehr s
- Nikokavouras, J.,Zois, J.,Vassilopoulos, G.,Perry, A.
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- Equilibre entre formes structurales de l'eosine et de la fluoresceine moleculaires. Influence des solvants
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The study of equilibrium between lactonic and amphoteric forms of molecular eosin and fluorescein proves that, in 11 organic solvents, the lactonic ring of fluorescein is more stable than eosin's while in solid state or in aqueous media, the contrary takes place.The influence of solvents is explained by taking account of their solubility parameters δA and δH.
- Fompeydie, Dominique,Levillain, Pierre
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p. 459 - 465
(2007/10/02)
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