Micellar structure and micellar control of photochemical reactions

Ramnath, N.; Ramesh, V.; Ramamurthy, V.

doi:10.1016/0047-2670(85)85076-0

Cited by 29 publications

(10 citation statements)

References 91 publications

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“…The anionic emission was only observed in highly alkaline media outside the pH scale (KOH 14 mol/L) (28), but the cationic micellar media facilitates the adsorption of the anionic species of harmane and harmine as a consequence of the increase of local concentration of OH − ions (32). Besides, in micellar solution this anionic band appears resolved into two peaks, as a consequence of the compartimentalization effect of the micelles (31). The anionic band disappears as a consequence of the addition of NaCl to adjust the ionic strength.…”

Section: Resultsmentioning

confidence: 99%

“…Considering that, at this pH value, the rapid proton transfer in the excited state produces the emission of the cationic species of harmane, and harmine, the nature and properties of micellar media exert an important influence. Micellar solutions dissolve these aromatic alkaloids and exert an important compartimentalization effect in a local hydrophobic environment (31). If the alkaloids are in the core of the different micelles, the polarity of the environment is lower than in the bulk aqueous phase and the emission of the neutral species should be observed, as in organic Fluorescence quenching of β-carboline alkaloids in micellar media ORIGINAL RESEARCH 157 ORIGINAL RESEARCH 157 solvents.…”

Section: Resultsmentioning

confidence: 99%

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Fluorescence quenching of β‐carboline alkaloids in micellar media. A study to select the adequate surfactant to use in analytical techniques

et al. 2005

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The study of fluorescence quenching of the fluorophores allows the localization of the alkaloids (harmane and harmine) in the micelles (SDS, CTAB, Brij-35) to be established. In aqueous micellar solutions (SDS and Brij-35) at pH 13.0, emission corresponding to the neutral or zwitterionic forms can be observed. In the presence of CTAB (pH = 13.0) it was possible to observe the emission of anionic form. These species are not present in buffered aqueous solutions at these pH values. Bromide ion was added to the different surfactant solutions and the quenching effect was studied according to the Stern-Volmer equation. In the presence of SDS the quenching effect is considerably reduced compared to the aqueous solutions without surfactants, while for Brij-35 micelles were similar to those observed in homogeneous aqueous solution. For CTAB micelles a notable fluorescence quenching was observed for the different pH values studied. The fluorescence quenching studies show that the neutral species are associated inside the micelles, instead of the ionic species (cationic, zwitterionic or anionic) remaining on the surface of the micelles. The anionic surface of SDS micelles prevents the quenching effect by anionic quenchers for both neutral and charged species.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Fluorescence quenching of β‐carboline alkaloids in micellar media. A study to select the adequate surfactant to use in analytical techniques

et al. 2005

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“…For both phenanthre n e and pyrene, PAH photolysis rates increase in the micellar LiFOS solutions relative to water and monomeric LiFOS solutions. The photoreactivity of p h e n a n t h rene and pyrene appears to be more favorable in LiFOS micelles than in water due to micellar effects (i.e., cage, microviscosity, localization, compartmentalization, preorientation, polarity and counterion effects), which were reviewed in detail by Ramnath, et al [30]. The faster photolysis rate of p y rene than phenanthrene is probably due to its greater solubilization by LiFOS micelles.…”

Section: Pah Degradation By Direct Photolysis (Uv Only)mentioning

confidence: 99%

Photochemical treatment of a mixed PAH/surfactant solution for surfactant recovery and reuse

2001

Environ. Prog.

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“…[17À19] Micelles can also have a major influence on photochemical reactions. [20,21] An interesting advantage in using micelles in electron transfer reactions is that the rate of the reaction can be altered to measure conveniently.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanism of electron transfer reaction of single and double chain surfactant cobalt(III) complex by Fe²⁺ions in liposome (dipalmitoylphosphotidylcholine) vesicles: effects of phase transition

Nagaraj

Murugan²,

Thangamuniyandi

2015

Phase Transitions

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In this study, we report the kinetics of reduction reactions of single and double chain surfactant cobalt(III) complexes of octahedral geometry, cis-[Co(en) 2 (4AMP)(DA)] (ClO 4 ) 3 and cis-[Co(dmp) 2 (C 12 H 25 NH 2 ) 2 ](ClO 4 ) 3 (en D ethylenediamine, dmp D 1,3-diaminopropane, 4AMP D 4-aminopropane, C 12 H 25 NH 2 D dodecylamine) by Fe 2C ion in dipalmitoylphosphotidylcholine (DPPC) vesicles at different temperatures under pseudo first-order conditions. The kinetics of these reactions is followed by spectrophotometry method. The reactions are found to be second order and the electron transfer is postulated as outer sphere. The remarkable findings in the present investigation are that, below the phase transition temperature of DPPC, the rate decreases with an increase in the concentration of DPPC, while above the phase transition temperature the rate increases with an increase in the concentration of DPPC. The main driving force for this phenomenon is considered to be the intervesicular hydrophobic interaction between vesicles surface and hydrophobic part of the surfactant complexes. Besides, comparing the values of rate constants of these outer-sphere electron transfer reactions in the absence and in the presence of DPPC, the rate constant values in the presence of DPPC are always found to be greater than in the absence of DPPC. This is ascribed to the double hydrophobic fatty acid chain in the DPPC that gives the molecule an overall tubular shape due to the intervesicular hydrophobic interaction between vesicles surface and hydrophobic part of the surfactant complexes more suitable for vesicle aggregation which facilitates lower activation energy, and consequently higher rate is observed in the presence of DPPC. The activation parameters (DS # and DH # ) of the reactions at different temperatures have been calculated which corroborate the kinetics of the reaction.

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Micellar structure and micellar control of photochemical reactions

Cited by 29 publications

References 91 publications

Fluorescence quenching of β‐carboline alkaloids in micellar media. A study to select the adequate surfactant to use in analytical techniques

Fluorescence quenching of β‐carboline alkaloids in micellar media. A study to select the adequate surfactant to use in analytical techniques

Photochemical treatment of a mixed PAH/surfactant solution for surfactant recovery and reuse

Kinetics and mechanism of electron transfer reaction of single and double chain surfactant cobalt(III) complex by Fe²⁺ions in liposome (dipalmitoylphosphotidylcholine) vesicles: effects of phase transition

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Micellar structure and micellar control of photochemical reactions

Cited by 29 publications

References 91 publications

Fluorescence quenching of β‐carboline alkaloids in micellar media. A study to select the adequate surfactant to use in analytical techniques

Fluorescence quenching of β‐carboline alkaloids in micellar media. A study to select the adequate surfactant to use in analytical techniques

Photochemical treatment of a mixed PAH/surfactant solution for surfactant recovery and reuse

Kinetics and mechanism of electron transfer reaction of single and double chain surfactant cobalt(III) complex by Fe2+ions in liposome (dipalmitoylphosphotidylcholine) vesicles: effects of phase transition

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Kinetics and mechanism of electron transfer reaction of single and double chain surfactant cobalt(III) complex by Fe²⁺ions in liposome (dipalmitoylphosphotidylcholine) vesicles: effects of phase transition