Reichardt betaines as combined solvatochromic and acid-base indicators in microemulsions

Mchedlov‐Petrossyan, Nikolay O.; Isaenko, Yu.V.; Goga, Sergey T.

doi:10.1007/s11176-005-0093-5

Cited by 12 publications

(8 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Betaine dyes, such as compound 1 , have also been used as probes to investigate microemulsions. , Recently, Sarkar et al synthesized AOT-derived surface active ILs and used them to produce IL-in-oil microemulsions, which were characterized using dye 1 , as well as employing other techniques. The influence of an increase in the amount of c ([C 4 mim][BF 4 ]) in the [C 4 mim][BF 4 ]/[C 4 mim][AOT]/benzene microemulsion on the solvatochromic band of the dye was studied.…”

Section: Pyridinium N-phenolate Dyes In the Study Of Microheterogeneo...mentioning

confidence: 99%

PyridiniumN-Phenolate Betaine Dyes

2014

View full text Add to dashboard Cite

Introduction 10429 2. Historical Contextualization 10431 3. Synthesis of Pyridinium N-Phenolate Dyes 10433 4. Solvatochromic Properties of Pyridinium N-Phenolate Dyes 10435 4.1. X-ray Crystallographic Studies of the Molecular Structures of Pyridinium N-Phenolate Dyes 10437 4.2. Quantum Chemical Calculations Involving Pyridinium N-Phenolate Dyes 10438 4.3. The E T (30) and E T N Solvent Polarity Scale 10440 4.4. Multiparametric Approaches to the Analysis of the E T (30) and E T N Scale 10441 5. Secondary Solvatochromic Pyridinium N-Phenolate Dyes 10442 6. Investigation of the Physical Properties of Room-Temperature Ionic Liquids 10443 7. Thermosolvatochromism of Pyridinium N-Phenolate Dyes 10450 8. Halochromism of Pyridinium N-Phenolate Dyes 10451 9. Piezosolvatochromism of Pyridinium N-Phenolate Dyes 10452 10. Pyridinium N-Phenolate Dyes in the Investigation of Solvent Mixtures 10453 11. Application of Pyridinium N-Phenolate Dyes in the Construction of Chromogenic Chemosensors 10455 11.1. Chirosolvatochromism of Pyridinium N-Phenolate Dyes 10456 11.2. Chromoionophores 10456 11.3. Chromogenic Chemosensors for Anionic Species 10457 11.4. Chromogenic Chemosensors for Neutral Analytes 10458 12. Pyridinium N-Phenolate Dyes as Probes To Measure the Polarity of Solid Surfaces 10459 13. Pyridinium N-Phenolate Dyes in the Study of Microheterogeneous Systems 10460 13.1. Investigation of Surfactants in Aqueous and Organic Media 10462 13.2. Pyridinium N-Phenolate Dyes in the Investigation of Cyclodextrins in Solution 10463 13.

show abstract

Section: Pyridinium N-phenolate Dyes In the Study Of Microheterogeneo...mentioning

confidence: 99%

PyridiniumN-Phenolate Betaine Dyes

2014

View full text Add to dashboard Cite

show abstract

“…This value is higher than reported for water solution 8.85 or 9.12 , what can be addressed to alteration of solution polarity. Indeed, as it was documented beforehand the presence of alcohol is expected to increase pK values of thymol blue (10.48–10.99).…”

Section: Resultsmentioning

confidence: 99%

Structural origin of apparent surface basicities of p‐aminosulanamide polymorphs

Cysewski

2013

Crystal Research and Technology

View full text Add to dashboard Cite

Perichromism of two polymorphic forms of p-aminosulfonamide (SNM) affecting spectroscopic properties of adsorbed thymol blue (TB) was studied. The consistent protocol for assessment of indicator interactions with solids was proposed and validated. This relies on the deconvolution of spectra into individual contributions both in solution and on the surface. The obtained relationships between pH and degree of protonation of indicator allows for surface basicity quantification. It has been found that γ -SNM is significantly more basic than β-form with difference exciding 3 pH units. Besides, the signal profiles measured in solution and adsorbed on either of SNM form were used for examination of TB perichromism. Although, only small red-shift has been notices, this effect is not identical for both polymorphs. The differences in apparent surface pH of polymorph are explained in terms of structural properties. The morphology analysis allows for identification of habits responsible for structural origin in observed differences of polymorphs basicities. The noticed coincidental distributions of active centres of TB conformers and amine basic/acidic sites on γ -polymorph might be considered as the source of apparent pH differences. Thus, basicities of studied system are to be related to morphology differences of polymorphs and recognition by iorn-pairs formation rather than changes in characters of proton donating or accepting sites.

show abstract

“…Moreover, it would not be an exaggeration to say that at least a dozen of publications give evidence for a more hydrated or more polar state of different molecular probes in SDS micelles as compared with those in the case of CTAB. Such information is provided by visible spectra of nitroxides [129], fluorescence of 3,3-dimethyl-2-pheny1-3H-indole [130], fluorescence of rose Bengal B [131], absorption and pK a of this dye [132], and position of the visible absorption maximum of the anion of 4-n-heptadecyl-7-hydroxy coumarin [133]. The formation of the nonpolar lactone of 5-(N-octadecanoyl)aminofluorescein is less expressed in the SDS micellar aqueous solution as compared with cationic and nonionic surfactants micellar systems [134].…”

Section: Hydrogen Bonding Of the Solvatochromic Betaine Dyes In Surfa...mentioning

confidence: 99%

“…From these positions, one may consider data for a variety of compounds: nitrophenols [148], hydroxyanthraquinones [149], substituted diarylamines [150], fluorescein dyes [17,18,132,134], rhodamines [31,[151][152][153][154][155], azo dyes [156]; acridines [157], and many other indicators [13,19,97,133,[140][141][142][143][144][145][146][147][158][159][160][161][162][163][164][165][166].…”

Section: Acid-base Indicators As Useful Tools For Studying Micelles 6...mentioning

confidence: 99%

See 1 more Smart Citation

Solvatochromic and Acid–Base Molecular Probes in Surfactant Micelles: Comparison of Molecular Dynamics Simulation with the Experiment

Mchedlov‐Petrossyan

Farafonov

Lebed

2023

Liquids

View full text Add to dashboard Cite

This article summarizes a series of seventeen publications by the authors devoted to molecular dynamics modeling of various indicator dyes (molecular probes) enclosed in surfactant micelles. These dyes serve as generally recognized tools for studying various types of organized solutions, among which surfactant micelles in water are the simplest and most explored. The modeling procedure involves altogether 50 to 95 surfactant molecules, 16 to 28 thousand water molecules, and a single dye molecule. The presentation of the simulation results was preceded by a brief review of the state of experimental studies. This article consists of three parts. First, despite numerous literature data devoted to modeling the micelles itself, we decided to revisit this issue. The structure and hydration of the surface of micelles of surfactants, first of all of sodium n-dodecylsulfate, SDS, and cetyltrimethylammonium bromide, CTAB, were studied. The values of the electrical potential, Ψ, were estimated as functions of the ionic strength and distance from the surface. The decrease in the Ψ value with distance is gradual. Attempts to consider both DS− and CTA+ micelles in water without counterions result in a decay into two smaller aggregates. Obviously, the hydrophobic interaction (association) of the hydrocarbon tails balances the repulsion of the charged headgroups of these small “bare” micelles. The second part is devoted to the study of seven pyridinium N-phenolates, known as Reichardt’s dyes, in ionic micelles. These most powerful solvatochromic indicators are now used for examining various colloidal systems. The localization and orientation of both zwitterionic and (colorless) cationic forms are generally consistent with intuitive ideas about the hydrophobicity of substituents. Hydration has been quantitatively described for both the dye molecule as a whole and the oxygen atom. A number of markers, including the visible absorption spectra of Reichardt’s dyes, enable assuming a better hydration of the micellar surface of SDS than that of CTAB. However, our data show that it is more correct to speak about the more pronounced hydrogen-bonding ability of water molecules in anionic micelles than about better hydration of the SDS micelles as compared to CTAB ones. Finally, a set of acid–base indicators firmly fixed in the micellar pseudophase were studied by molecular dynamics. They are instruments for estimating electrostatic potentials of micelles and related aggregates as Ψ= 2.303RTF−1 (pKai − pKaapp), where pKai and pKaapp are indices of so-called intrinsic and apparent dissociation constants. In this case, in addition to the location, orientation, and hydration, the differences between values of pKaapp and indices of the dissociation constants in water were estimated. Only a semi-quantitative agreement with the experimental data was obtained. However, the differences between pKaapp of a given indicator in two micellar solutions do much better agree with the experimental data. Accordingly, the experimental Ψ values of ionic micelles, as determined using the pKaapp in nonionic micelles as pKai, are reproduced with reasonable accuracy for the corresponding indicator. However, following the experimental data, a scatter of the Ψ values obtained with different indicators for given micelles is observed. This problem may be the subject of further research.

show abstract

Reichardt betaines as combined solvatochromic and acid-base indicators in microemulsions

Cited by 12 publications

References 20 publications

PyridiniumN-Phenolate Betaine Dyes

PyridiniumN-Phenolate Betaine Dyes

Structural origin of apparent surface basicities of p‐aminosulanamide polymorphs

Solvatochromic and Acid–Base Molecular Probes in Surfactant Micelles: Comparison of Molecular Dynamics Simulation with the Experiment

Contact Info

Product

Resources

About