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Mchedlov‐Petrossyan, Nikolay O.; Vodolazkaya, Natalya A.; Дорошенко, А. О.

doi:10.1023/a:1025089916356

Cited by 82 publications

(59 citation statements)

References 55 publications

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“…16 The species RB ± is unstable in aprotic solvents, like cyclohexane, where the RB ± concentration is less than 0.5% that of RB . 14,16 Since none of the RB solutions shows visible absorptions 16,19 or fluorescence emissions, 19 the drops in the absorbance and the emission intensity of RB in the reversed micellar solutions could be ascribed to a shift in the tautomeric equilibrium toward the right, resulting in RB formation, if the RB ± is presumed to be situated outside the water pools, as mentioned above. It was proposed that the fraction of RB molecules existing as RB ± in a given solvent could be determined from the apparent molar extinction coefficient of RB in the visible region in the solvent relative to the 100% RB ± standard.…”

Section: Effect Of Hydrogen Ion Concentrationmentioning

confidence: 98%

“…It was estimated that in water the fraction of RB molecules existing as lactone RB equals ca. 0.5 -1%, 19 and thus RB is present mainly as RB ± . In non-aqueous solvents, on the other hand, it was demonstrated that the position of the Eq.…”

Section: Effect Of Hydrogen Ion Concentrationmentioning

confidence: 99%

“…19 The fluorescence maximum shifts to longer wavelength with increasing solvent polarity or dielectric constant, and the effect is larger for the zwitterion form compared to the protonated form. 32 This is due to the solute-solvent, dipole-dipole reorientation of the polar solvent molecules around the increased (relative to the ground state) dipole moment of the excited state.…”

Section: Effect Of the Molar Concentration Ratio [H2o]/[ctac]mentioning

confidence: 99%

“…The photophysics of rhodamine B, RB, which is a xanthane dye, in a homogenous aqueous solution, [13][14][15][16][17] in homogenous organic solvents 14,[16][17][18] and in aqueous micelles, 19 are well known. The spectroscopic and photophysical properties of RB are nevertheless still the subject of numerous research and controversies.…”

Section: Introductionmentioning

confidence: 99%

“…These observations suggested that the interaction of RB with CTAC or the CTAC reverse micelles occurred in the solution at a lower Xh. Since the acid-base property of RB is sensitive to the nature of the microenvironment, 19 the dye is expected to behave differently depending on its place of location within the reverse micelles. This study was thus carried out to examine the acid-base behavior and distribution of RB in the CTAC reversed micellar system by means of absorption and fluorescence spectroscopy, using 1-hexanol and its mixture with cyclohexane as reversed micellar bulk solvents.…”

Section: Introductionmentioning

confidence: 99%

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Acid-Base Behavior of Rhodamine B in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane/Water

2010

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The latter neutral form is represented by an equilibrium mixture of the colored and fluorescent zwitterions RB ± and the colorless lactones RB , which exist in some solvents, but not in water, where the fraction of RB species is too small to be registered experimentally. In this work, the RB dye was used as a probe to understand the properties of the reversed micellar interface; also, the change in the location of RB in the CTAC reversed micellar media was investigated 2010 © The Japan Society for Analytical Chemistry † To whom correspondence should be addressed. E-mail: tfuji@sci.hiroshima-u.ac.jp The acid-base behavior of rhodamine B (RB) in reversed micellar solutions of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water was investigated through absorption and fluorescence measurements under varying the hydrogen-ion concentration in a water pool, the mole fraction of 1-hexanol in a bulk solvent and the water to surfactant molar concentration ratio. RB exhibited equilibria between the cationic, zwitterion and lactone forms of the dye as a cause of the spectral changes, indicating a change in the RB distribution among the reversed micellar water pool, interface and bulk solvent. Furthermore, RB was used as a probe to develop a method for determining the critical micelle concentration (CMC) in CTAC solutions. Abrupt variations in the intensities and wavelengths of the absorption and emission maxima of RB were observed at the CMC. The standard free energy of micellization was also evaluated from the CMC data.

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Section: Effect Of Hydrogen Ion Concentrationmentioning

confidence: 98%

Section: Effect Of Hydrogen Ion Concentrationmentioning

confidence: 99%

Section: Effect Of the Molar Concentration Ratio [H2o]/[ctac]mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Acid-Base Behavior of Rhodamine B in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane/Water

2010

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Gas phase sensors for bases using rhodamine B in nafion films

Hwang

Levitsky

Euler

2010

J of Applied Polymer Sci

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A sensor and dosimeter specific to inorganic and organic amine bases composed of Rhodamine B dissolved in Nafion is prepared and evaluated. UV-vis, emission, and IR spectroscopies are used to monitor the presence of a variety of analytes, including aliphatic and aromatic amines. The Rhodamine B serves as a visual indicator of the presence of an analyte by turning from brown to pink upon exposure to aliphatic amines after sufficient exposure, thus acting as a visual monitor. The Rhodamine B also acts as a fluorescent sensor, which turns on upon exposure to the analyte. The sulfonic acid groups in the Nafion protonate the bases, giving unique signatures in the IR spectra allowing for differentiation of the bases.

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Fluorescent Sensors for Hg²⁺ in Micelles: A New Approach that Transforms an ON–OFF into an OFF–ON Response as a Function of the Lipophilicity of the Receptor

Pallavicini

Fernandez

Foti

et al. 2006

Chemistry A European J

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A new approach to the use of micelles in the fluorescent sensing of metal cations is proposed and applied to the case of Hg2+. We demonstrate how it is possible to transform a system from an ON–OFF to an OFF–ON sensor by changing the length of the chain used to lipophilise a ligand that resides inside TritonX‐100 micelles together with pyrene as the fluorophore. Three tetrathia‐monoaza macrocyclic ligands have been synthesised with the same ring but functionalised on the nitrogen atom with a methyl (C1‐NS4), an n‐butyl (C4‐NS4) or an n‐dodecyl (C12‐NS4) chain. The three ligands have been fully characterised in water containing TritonX‐100 micelles by means of potentiometric titrations and their apparent protonation and complexation constants with Hg2+ were determined. On the basis of the distribution diagrams obtained, the more lipophilic C12‐NS4 has been developed as an ON–OFF fluorescent sensor for mercury: working at pH<4, in the absence of Hg2+ the ligand is inside the micelles, protonated and non‐quenching, while on addition of mercury the [C12‐NS4Hg]2+ complex forms which remains inside the micelles and is quenching. On the other hand, the ligand of intermediate chain length, C4‐NS4, can be used to obtain an OFF–ON sensor at 7.07.0 the ligand is unprotonated, it stays inside the micelles and is quenching, while addition of Hg2+ in the 7.0–9.5 pH range results in the formation of [C4‐NS4Hg]2+, which is hydrophilic enough to leave the micelles and to be released into the bulk solution where it is no longer capable of quenching pyrene fluorescence. Additional studies on C1‐NS4, C3‐NS4 and C8‐NS4 indicate that the optimal chain length to observe this OFF–ON behaviour is C3–C4.

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Cited by 82 publications

References 55 publications

Acid-Base Behavior of Rhodamine B in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane/Water

Acid-Base Behavior of Rhodamine B in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane/Water

Gas phase sensors for bases using rhodamine B in nafion films

Fluorescent Sensors for Hg²⁺ in Micelles: A New Approach that Transforms an ON–OFF into an OFF–ON Response as a Function of the Lipophilicity of the Receptor

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Untitled

Cited by 82 publications

References 55 publications

Acid-Base Behavior of Rhodamine B in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane/Water

Acid-Base Behavior of Rhodamine B in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane/Water

Gas phase sensors for bases using rhodamine B in nafion films

Fluorescent Sensors for Hg2+ in Micelles: A New Approach that Transforms an ON–OFF into an OFF–ON Response as a Function of the Lipophilicity of the Receptor

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Product

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Fluorescent Sensors for Hg²⁺ in Micelles: A New Approach that Transforms an ON–OFF into an OFF–ON Response as a Function of the Lipophilicity of the Receptor