From 8-hydroxy-5-sulfoquinoline to new related fluorogenic ligands for complexation of aluminium(III) and gallium(III)

Launay, Franck; Alain, Valérie; Destandau, Émilie; Ramos, Nathalie; Bardez, Élisabeth; Baret, Paul; Pierre, Jean‐Louis

doi:10.1039/b103406p

Cited by 50 publications

(49 citation statements)

References 28 publications

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“…The corresponding stability constants for the 1:1 and 1:2 chelates were reported to be either a little larger [32], or somewhat smaller [37] than the stability constants of the aluminium chelates. Nevertheless, fluorogenic ligands of Al(III) are fluorogenic ligands of Ga(III), the properties of the absorption bands and of the fluorescence emission being generally quite similar [19]. Thus, we observed the chelation of Ga(III) by chromotropic acid in both the absorption and fluorescence spectra, the corresponding bands turning out to be exactly identical with those of the aluminium chelate.…”

Section: Interfering Cationssupporting

confidence: 48%

“…Another application of fluorogenic ligands is chemical sensing with optical fibre sensors, allowing in situ determination of aluminium [16]. With this ultimate objective in mind, we thoroughly investigated 8-hydroxyquinoline [17,18] before using it as a bidentate subunit in the design of an hexadentate ligand, O-Trensox [19]. Other fluorogenic subunits can be proposed, in particular dihydroxy derivatives, because of the strong affinity of hydroxyl groups for Al(III).…”

Section: Introductionmentioning

confidence: 99%

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Chromotropic acid, a fluorogenic chelating agent for aluminium(III)

Destandau

Alain

Bardez

2004

Analytical and Bioanalytical Chemistry

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Complexation of aluminium(III) with the fluorogenic ligand chromotropic acid (4,5-dihydroxynaphthalene-2,7-disulfonic acid) has been revisited with the aim of using enhancement of the fluorescence intensity as an analytical tool. Complexation at the optimum pH approximately 4 was shown to lead to a 1:1 complex with a stability constant log beta110=18.4 +/- 0.7. The fluorogenic effect was thoroughly investigated. Nearly selective excitation of the chelate rather than the ligand could be achieved at wavelengths longer than 360 nm. For analytical purposes the main interfering ion was Ga3+. The strongest competing ligand was shown to be citric acid. Competitive complexation by acetate or formate ions can also make their use in a buffer at the usual concentration, 0.2 mol L(-1), questionable, whereas a 10(-2) mol L(-1) formic acid buffer was shown to be a good alternative. The calibration plot showed that the dependence of response on Al(III) concentration was linear up to 500 microg L(-1); the detection limit was 0.65 microg L(-1) (3 SDblank, n=10, SD= +/- 1.4% at 10 microg L(-1) and +/- 0.8% at 100 microg L(-1)). The analytical procedure was successfully applied to several samples of tap water and the results were in good agreement with those from AAS determination.

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Section: Interfering Cationssupporting

confidence: 48%

Section: Introductionmentioning

confidence: 99%

Chromotropic acid, a fluorogenic chelating agent for aluminium(III)

Destandau

Alain

Bardez

2004

Analytical and Bioanalytical Chemistry

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“…Elemental analyses were performed by the microanaly-sis service of the Department of Molecular Chemistry of Grenoble. 8-Hydroxyquinoline-7-carboxylic acid [20,21] and 1-n-butyl-5-sulfo-8-hydroxyquinoline-7-carboxamide (Q S4 ) [15] were prepared as described in the literature. Stock solutions of Fe 3+ were prepared by dissolving the appropriate amount of iron perchlorate xH 2 O in standardized perchloric acid or sodium perchlorate in water.…”

Section: Methodsmentioning

confidence: 99%

“…Data analysis performed with the Specfit [14] program by using Equations (1) and (2) yielded the values: pK a1 = 6.77(1) and pK a2 = 2.60(3). pK a values for Q S4 were published elsewhere: [15] pK a1 = 6.80 and pK a2 = 2.80. pK a1 is assigned to the hydroxy proton and pK a2 to the pyridine nitrogen proton. These values are lower than those of other sulfonated 8-hydroxyquinoline derivatives, because of the electron-withdrawing character of the carbonyl group, which increases the mobility of the leaving protons.…”

Section: Ligand Pk a Determinationmentioning

confidence: 99%

From Molecular to Nanostructured Iron Complexes of Amphiphilic Chelators Based on 8‐Hydroxyquinoline Subunits – Evidence of Self‐Assembled Edifices Mimicking Siderophores from Marine Bacteria

et al. 2008

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Amphiphilic iron chelators based on the 8-hydroxyquinoline moiety were synthesized in order to study their potential trend to aggregate into more complex structures. The Q S10 and Q S4 ligands only differ by the length of the lipophilic alkyl chain (C10 and C4, respectively) tethered to the chelating subunit. Physicochemical investigations in aqueous solution were performed to determine the global stability constants of the iron complexes. At physiological pH, the [Fe(Q S10 ) 3 ] 3-predominant species undergoes time-dependent reorganization, as evidenced by cryogenic transmission electron microscopy: after a few hours of equilibration, iron-

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“…Em meio ácido o decréscimo da adsorção pode ser atribuído à protonação dos sítios de complexação do SX e dos grupos amino remanescentes da QTS, uma vez que o agente complexante SX apresenta duas constantes de acidez referentes ao nitrogênio piridínico e ao grupamento fenólico, pK 1 = 4,0 e pK 2 = 8,5, respectivamente. 2,17 Em meio muito alcalino as soluções foram tamponadas com agentes complexantes auxiliares, a fim de se evitar a precipitação dos íons Cu(II) na forma de hidróxidos. Porém, os compostos presentes nas soluções tampão formam complexos com o metal estudado provocando uma diminuição na adsorção dos íons pelo adsorvente o que pode justificar a diminuição da adsorção observada em pH maiores que 6,0.…”

Section: Dependência Do Ph Na Adsorçãounclassified

Microencapsulação do agente quelante sulfoxina em microesferas de quitosana preparadas por spray drying como novo adsorvente para íons metálicos

Vitali¹,

Laranjeira²,

Fávere³

et al. 2008

Quím. Nova

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Recebido em 26/7/07; aceito em 14/3/08; publicado na web em 26/8/08 MICROENCAPSULATION OF THE CHELATING AGENT SULFOXINE INTO MICROSPHERES OF CHITOSAN PREPARED BY SPRAY DRYING AS A NEW ADSORBENT FOR METALIC IONS.In this work, a new adsorbent was prepared by microencapsulation of sulfoxine into chitosan microspheres by the spray drying technique. The new adsorbent was characterized by Raman spectroscopy, scanning electron microscopy and microanalysis of energy dispersive X-rays. The Cu(II) adsorption was studied as a function of pH, time and concentration. The optimum pH was found to be 6.0. The kinetic and equilibrium data showed that the adsorption process followed the pseudo second-order kinetic model and the Langmuir isotherm model over the entire concentration range. An increase of 8.0% in the maximum adsorption capacity of the adsorbent (53.8 mg g -1 ) was observed as compared to chitosan glutaraldehyde crosslinked microspheres.Keywords: microencapsulation; chitosan; sulfoxine. INTRODUÇÃOA contaminação de ambientes aquáticos com íons metálicos tóxicos é um problema complexo e a remediação desses ambientes vem recebendo atenção de muitos pesquisadores nos últimos anos.1 O aumento da concentração destes metais tóxicos pode ser atribuído principalmente às intensas atividades industriais e agrícolas. Muitos destes cátions metálicos são tóxicos mesmo em baixas concentrações e deveriam ser removidos para a remediação dessas águas. 2,3O cobre é um elemento potencialmente tóxico devido ser um dos metais mais utilizados, principalmente nas indústrias elétricas, de galvanoplastia, de fertilizantes, em atividades de mineração, fundição e refino de metais, além de estar presente na composição de pigmentos, fungicidas e pesticidas. A toxicidade deste metal está relacionada com a capacidade que o elemento possui de catalisar a formação de radicais livres. De acordo com a Agência de Proteção Ambiental Americana, a concentração máxima permitida de cobre em água potável é de 1,3 mg dm A adsorção ou extração em fase sólida é uma técnica que vem sendo muito utilizada para a remoção de metais de águas contaminadas. Algumas das importantes vantagens da adsorção em relação às técnicas comumente usadas são: a baixa quantidade de resíduo gerado, fácil recuperação dos metais e a possibilidade de reutilização do adsorvente. [5][6][7] O desenvolvimento de adsorventes preparados pela microencapsulação de agentes complexantes orgânicos surge como uma alternativa de grande potencial de aplicação em Química Analítica.8 O uso destes adsorventes modificados com o objetivo de separar e pré-concentrar traços de íons metálicos apresenta inúmeras vantagens: o agente complexante pode ser substituído facilmente e, portanto, o mesmo adsorvente pode ser usado para diferentes propósitos. Por exemplo, um agente complexante seletivo pode ser microencapsulado, obtendo-se então seletividade para um íon metálico específico; este pode ser facilmente substituído ou recuperado propiciando uma maior flexibilidade das condições de trabalho, devido o complexan...

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From 8-hydroxy-5-sulfoquinoline to new related fluorogenic ligands for complexation of aluminium(III) and gallium(III)

Cited by 50 publications

References 28 publications

Chromotropic acid, a fluorogenic chelating agent for aluminium(III)

Chromotropic acid, a fluorogenic chelating agent for aluminium(III)

From Molecular to Nanostructured Iron Complexes of Amphiphilic Chelators Based on 8‐Hydroxyquinoline Subunits – Evidence of Self‐Assembled Edifices Mimicking Siderophores from Marine Bacteria

Microencapsulação do agente quelante sulfoxina em microesferas de quitosana preparadas por spray drying como novo adsorvente para íons metálicos

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