Fluorescence Of Uranyl Ion Research Articles

Fluorescent Uranyl Ion Lidded Cucurbit[5]uril Capsule

A novel fluorescent complex {(UO(2))(2)(CB5)}(NO(3))(4)·4HNO(3).3H(2)O (U2CB5) is obtained from cucurbit[5]uril (CB5) and uranyl nitrate under ambient temperature conditions. The crystal structure revealed that two uranyl ions are coordinated to the two open portals of CB5 giving a closed molecular capsule, which further connected through CB5 molecules to give two-dimensional frameworks. The U2CB5 complex was further investigated by NMR, FTIR and TGA techniques. The Fluorescence of uranyl ion was found to be enhanced due to complexation with cucurbituril.

Fluorescence quenching of the uranyl ion by adamantylideneadamantane and its photosensitized oxidation products

The quenching of uranyl-ion fluorescence by adamantylideneadamantane and its photosensitized oxidation products (adamantilideneadamantan-1,2-dioxetane and adamantanone) in acetone solutions was studied. Possible mechanisms of the uranyl-photocatalyzed degradation of dioxetane are discussed. The photochemical quantum yield of dioxetane (φ = 0.55 ± 0.05) was determined, and an ion-radical oxidation mechanism involving the substrate radical cation and the superoxide ion was proposed.

Study of kinetic electrolyte effects on a fast reaction in solution: The quenching of fluorescence of uranyl ion up to high electrolyte concentration

The effect of an added electrolyte on the kinetics of fluorescence quenching of the uranyl ion by chloride anion is investigated. Various electrolytes have been used up to a maximum concentration of 9 mol dm−3. The description of the experimental results is examined using theoretical results of previous work and a new expression derived in this paper. The ability of two mechanisms to interpret the data is analysed. The results point to a diffusion-influenced process mainly controlled by a fast chemical reaction occurring between solvent-separated species.

Radioactive Origin of Emissions Observed from Uranium Compounds and Their Silica Cells.

Uranyl ion fluorescence at 520 nm has been recorded from solutions that were excited only by radioactive emanations from trace concentrations of a 232U impurity or added 225actinium nitrate. This fluorescence had also been observed by others from 233UO4·2H2O, but was attributed to a nuclear origin. Atomic oxygen emission was observed for a 233UO4·2H2O sample, as was a broad visible emission originating from the fused silica tube that contained the radioactive sample.

Flow fluorimetry of trace amounts of uranium(VI) after preconcentration on a tri-n-octylphosphine oxide/polyethylene column and elution with hydrogenphosphate solution

The fluorescence of uranyl ion is enhanced in phosphoric acid medium and in hydrogen-phosphate medium. The pH dependence of the fluorescence intensity showed maxima at pH 1–2 and pH 7–8. The concentration of phosphoric acid which gave maximum intensity was around 1 M, but in the hydrogenphosphate media an increase in the concentration lowered the intensity. The procedure was used in combination with preconcentration on a tri-n-octylphosphine oxide/polyethylene column. This simple system provided a limit of detection of 0.04 μg for uranium and the calibration graph was linear for the range 0.08–0.8 μg of uranium when 4–15 ml of sample solution was passed through the column. The flow fluorimetric method was applied to the determination of uranium in a spinel.

Selective detection of uranium by laser-induced fluorescence: a potential remote-sensing technique 1: Optical characteristics of uranyl geologic targets

The remote sensing of laser-induced uranyl ion fluorescence is examined as a potential indicator of uranium occurring in geologic materials at the earth's surface. The lifetime and brightness of the fluorescence from a wide variety of rocks, minerals, and soils are reported. The distinctive characteristics of uranyl ion absorption and fluorescence were observed in diverse geologic materials such as chalcedonies and opals containing 15-3000 ppm of uranium and in surface coatings of uranyl minerals such as metaautunite, liebigite, and an-dersonite. The conditions which permit the excitation and selective detection of uranyl ion fluorescence from such targets are described.

Selective detection of uranium by laser-induced fluorescence: a potential remote-sensing technique 2: Experimental assessment of the remote sensing of uranyl geologic targets

An analysis is presented of a method to detect selectively uranyl ion fluorescence from geologic targets. Limitations to the sensitivity which are imposed by system parameters and noise sources are discussed. A ground-based laser system designed and constructed as part of this study is described, and data obtained with this system are presented. Finally the operating criteria of a conceptual airborne system for regional mapping of uranyl fluorescence anomalies are considered.

Catalysis of ionic reactions by polyelectrolytes. III. Quenching of uranyl ion fluorescence by iron(II) ions in poly(vinylsulfonic acid) solution

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCatalysis of ionic reactions by polyelectrolytes. III. Quenching of uranyl ion fluorescence by iron(II) ions in poly(vinylsulfonic acid) solutionHerbert Morawetz and Issam A. I. TahaCite this: J. Am. Chem. Soc. 1971, 93, 4, 829–833Publication Date (Print):February 1, 1971Publication History Published online1 May 2002Published inissue 1 February 1971https://doi.org/10.1021/ja00733a005RIGHTS & PERMISSIONSArticle Views84Altmetric-Citations32LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (619 KB) Get e-Alerts Get e-Alerts

Photosensitization of vinyl polymerization by uranyl ions

AbstractMonomer acrylamide was used as quencher of uranyl ion fluorescence and Stern‐Volmer plots were constructed at three monochromatic wavelengths of exciting radiation. The results indicated that the reaction between excited uranyl ion and monomer is one of energy transfer. The rate parameters kp/kp½ and kd′/ki were calculated from the polymerization kinetics at high monomer concentrations. A general mechanism for the photopolymerization of vinyl monomers sensitized by uranyl ions is proposed and discussed.

Quenching of Fluorescence of Uranyl Ions by Organic Substrates

The quenching of uranyl ion fluorescence by formaldehyde, acetaldehyde, methanol and isopropanol in aqueous porchlolric acid solutions is studied at three monochromatic wavelengths, 165 mμ, 405 mμ, 4 mμ, STERN-VOLMER plots are drawn and the rate parameters are calculated and compared with those obtained from kinetics of photochemical oxidation of those substrates by uranyl ions. The mechanism of photochemical oxidation of substrates by uranyl ions is discussed in the light of the experimental results.