Tetramethylbenzidine Photoionization Research Articles

Electron spin resonance and proton matrix electron nuclear double resonance studies of N,N,N',N'-tetramethylbenzidine photoionization in sodium and lithium dodecyl sulfate micelles: structural effects of crown ethers

The study of model membrane systems enjoys increasing attention within the area of solar energy research. An electron nuclear double resonance and electron spin resonance study of photogenerated N,N,N[prime],N[prime]-tetramethylbenzidine (TMB) cation in frozen suspensions of lithium (LDS) and sodium (SDS) dodecyl sulfate micelles containing various concentrations of cyclic polyethers was undertaken. The relative location of the TMB cation within the organic aggregate was determined from the proton matrix ENDOR line width at 142 K. A broader line width was observed in LDS compared to SDS micelles, which is due to the fact that the larger lithium cation opens the micellar interface resulting in increased hydration and deeper solubilization of TMB. The proton matrix ENDOR line width decreased upon addition of crown ethers. This decrease may be explained by displacement of the TMB toward the interface as a result of the decrease in ionic strength caused by the complexation of the countercations. The photoyield shows a slight increase with addition of crown ethers. This increase is most likely caused by the increase in the effective anionic charge of the micelle effected by the complexation of the sodium or lithium ions by the crown ethers. This increase in the anionic charge mitigatesmore » the rate of thermal back electron transfer resulting in an increased photoyield. 54 refs., 6 figs., 2 tabs.« less

Electron paramagnetic resonance and proton matrix electron nuclear double resonance studies of N,N,N′,N′-tetramethylbenzidine photoionization in sodium dodecyl sulfate micelles: structural effects of added alcohols

An electron nuclear double resonance and electron paramagnetic resonance study of photogenerated N,N,N′,N′-tetramethylbenzidine (TMB) cation in frozen suspensions of sodium dodecyl sulfate micelles containing various concentrations of alcohols has been undertaken. The alcohols used in the study were ethanol, propan-2-ol, butan-1-ol and octan-1-ol. Experiments were performed with both the deuteriated and protonated analogues of these molecules. The photoyields were determined from double integration of the first-derivative electron paramagnetic resonance spectra. The location of the TMB cation relative to the micelle interface was determined from the proton matrix electron nuclear double resonance (H-ENDOR) linewidth at 140 K. In general, the TMB radical cation was observed to have a broader H-ENDOR linewidth for samples in which the protonated alcohol was used. This difference increased when longer-chained alcohols were used. The results demonstrate that the shorter chain length alcohols are located at the micellar interface, whereas both butan-1-ol and octan-1-ol intercalate deeper into the hydrocarbon interior of the micelle. The photoyield grew with alcohol addition up to 50 mmol dm–3, after which the yield decreased. The maximum yield was obtained in samples with short-chain alcohols. These results showed that the yield depended on the degree of disruption of the micelle/water interface. Although hydration of the interface stabilizes the photogenerated cation thus increasing the yield, this effect competes with the disruption of the interfacial region and concomitant decrease of the negative surface charge. The lower negative surface charge helps increase back electron transfer. The results from this ENDOR study are consistent with recent work involving electron spin echo modulation spectroscopy, which showed greater water penetration into the micellar interface upon addition of alcohol.

Effects of crown ethers on the interfacial structure of micelles and vesicles

Crown-ether (CE) compounds are able to capture the counter-ions near the micellar or vesicular interfaces. The concentration effect of CE addition on the interfacial structure of sodium lauryl sulfate (NaLS) micelles and dihexadecyl phosphate (DHP) vesicles, is studied through two electron transfer reactions: the N, N, N′, N′-tetramethylbenzidine (TMB) photoionization and the photocation (TMB +) decay. Previous studies have shown a linear dependence of the photoionization yield vs. the interfacial electrical potential (ΔΨ) in negatively charged micelles or vesicles. A relationhip between TMB + dark decay rate and ΔΨ has also been demonstrated. In the present study, photoionization yield and TMB + decay rate display an opposite variation vs. CE concentration. The results are discussed in terms of ΔΨ variations.

Replacement of sodium ions by cryptate (C222) complexed barium ions in sodium dodecyl sulfate micelles studied by electron spin resonance and electron spin-echo modulation of 5-doxylstearic acid and N,N,N',N'-tetramethylbenzidine photoionization and by viscosity measurements

Ultraviolet irradiation of solubilized N,N,N{prime},N{prime}-tetramethylbenzidine (TMB) and viscosity measurements have been carried out at room temperature in mixed micellar solutions of sodium dodecyl sulfate (SDS) and barium dodecyl sulfate (Ba(DS){sub 2}). The barium ions were complexed by the macrocyclic cryptate C222. The irradiations did not lead to constant photoionization yields in the barium/C222-containing solutions because of secondary reactions. The viscosity as a function of the Ba{sup 2+}/2 mole fraction (X) changed from 1.47 mPa s at X = 0 to 1.33 mPa s at X = 1, passing through a maximum at X = 0.2. At 77 K in frozen solutions the TMB photoionization yield as measured by electron spin resonance increased by a factor of 1.8 in the range X = 0-0.2 and leveled off at larger X. Deuterium modulation depths of electron spin-echo decay curves measured at 4.2 K for TMB{sup +} and 5-doxylstearic acid increase as a function of X in a similar way as the photoionization yields. The results indicate a higher local concentration of water molecules in the micellar surface region when the C222-complexed barium ions are present.

Electron spin resonance and electron spin echo modulation studies of N,N,N',N'-tetramethylbenzidine photoionization adsorbed at the interface of polymeric latices

Electron spin resonance (ESR) and electron spin echo modulation (ESEM) of photoionized N,N,N{prime},N{prime}-tetramethylbenzidine (TMB) cation adsorbed at the interface of butadiene-acrylonitrile-methacrylic acid and butadiene-styrene-acrylic acid polymeric latices have been studied as a function of sodium dodecyl sulfate (SDS) concentration adsorbed at the latex interface. The photoionization yield of TMB in frozen latices mainly depends on the strength of TMB{sup +}-water interactions, which are enhanced by added SDS as measured by ESEM. An increase in the negative surface potential of the latex particles, due to the adsorption of SDS at the latex surface, does not affect the photoionization yield, showing that the particle surface potential has, for negatively charged systems, a secondary role in promoting the photoionization yield. Differences in the TMB{sup +} yield are found for the two polymeric latices and are attributed to the different latex compositions and/or different interfacial structures.

Electron spin resonance and electron spin echo modulation of n-doxylstearic acid and N,N,N',N'-tetramethylbenzidine photoionization in sodium versus lithium dodecylsulfate micellar solutions: effect of 15-crown-5 and 18-crown-6 ether addition

Electron spin echo modulation and electron spin resonance spectra of photogenerated N,N,N',N'-tetramethylbenzidine (TMB) cation radical and n-doxylstearic acids (n-DSA) in frozen micellar solutions of sodium and lithium dodecyl sulfate containing 15-crown-5 and 18-crown-6 ethers in D/sub 2/O have been studied as a function of crown ether concentration. Modulation effects due to N-DSA with water deuteriums give direct evidence that both crown ethers are mainly located at the micellar interface and that this causes a decrease of the hydration of the micellar interface. Crown ether complexation constants for sodium and lithium micellar counterions are reported and show that 18-crown-6 > 15-crown-5 for sodium counterion and 15-crown-5 > 18-crown-6 for lithium counterion. Modulation effects from TMB/sup +/ interaction with water deuteriums indicate that the TMB molecule moves toward the micelle interfacial region when sodium or lithium cations are complexed by crown ethers. The TMB/sup +/ yield upon TMB photoionization increases by about 10% with crown ether addition for SDS and LDS micellar systems, but it is greater if the absolute values for the LDS system are compared to those for the SDS micellar system. This behavior correlates with the strength of TMB/sup +/-water interactions and suggests that the main factor in themore » photoionization efficiency is the photocation-water interaction.« less

ChemInform Abstract: ESR and Electron Spin‐Echo Modulation Studies of 5‐Doxylstearic Acid and N,N,N′,N′‐Tetramethylbenzidine Photoionization in Sodium Dodecylsulfate Micelles. Effects of 15‐Crown‐5 and 18‐Crown‐6 Ether Addition

ChemInform Abstract: ESR and Electron Spin‐Echo Modulation Studies of 5‐Doxylstearic Acid and N,N,N′,N′‐Tetramethylbenzidine Photoionization in Sodium Dodecylsulfate Micelles. Effects of 15‐Crown‐5 and 18‐Crown‐6 Ether Addition

Electron spin resonance and electron spin-echo modulation studies of 5-doxylstearic acid and N, N, N′, N′-tetramethylbenzidine photoionization in sodium dodecylsulphate micelles. Effects of 15-crown-5 and 18-crown-6 ether addition

Electron spin-echo modulation (e.s.e.m.) and electron spin resonance (e.s.r.) spectra of the photogenerated N, N, N′, N′-tetramethylbenzidine (TMB) cation radical and 5-doxylstearic acid (5-DSA) in frozen micellar solutions of sodium dodecylsulphate containing 15-crown-5 and 18-crown-6 ethers in D2O and H2O have been studied as a function of the crown ether concentrations. Modulation effects due to 5-DSA interactions with water deuteriums give direct evidence that both crown ethers are mainly located at the micellar interface and that their interaction causes a decrease of hydration of the micellar interface. Modulation effects from TMB+ interaction with water deuteriums indicate that the TMB molecule moves toward the interfacial region when the sodium cation is complexed by the crown ether to decrease the local ionic strength in the interfacial region. The efficiency of charge separation upon TMB photoionization increases ca. 10% with crown ether addition, and correlates with the increased TMB+–water interactions. The sodium cation complexation by the crown ether to change the charge distribution and ionic strength at the micellar interface seems to cause the interfacial hydration changes that promote the photoionization efficiency.

Electron spin resonance and electron spin echo modulation studies of N,N,N',N'-tetramethylbenzidine photoionization in sodium dodecyl sulfate micelles: structural effects of alcohol addition

Electron spin echo modulation (ESEM) and electron spin resonance (ESR) spectra of the photogenerated N,N,N′,N′-tetramethylbenzidine cation radical (TMB+) in frozen micellar solutions of sodium dodecylsulfate containing 2-propanol, 1-propanol, 1-pentanol, 1-octanol, 2-propanol-d7, 1-octanol-d17 in D2O and H2O or 15-crown-5, 18-crown-6 ethers in D2O have been studied as a function of the alcohol or crown ether concentration from 0 to 200 mM. Modulation effects due to the TMB+ interactions with deuteriums in D2O and in H2O in TMB/SDS/alcohol systems give direct evidence that 2-propanol is mainly located at the micellar interface, whereas the alkyl chain of 1-octanol is located deeper in the micelle. Alcohol addition leads to an increase of water penetration into the micellar interface in the order 1-propanol<2-propanol ≤ 1-pentanol<1-octanol. Modulation effects due to TMB+ in TMB/SDS/crown systems indicate that the TMB molecule moves toward the interfacial region when sodium cation is complexed by the crown ether. The efficiency of charge separation upon TMB photoionization increases with alcohols or crown ethers addition and correlates with the increased TMB+-water interactions.

Effects of added tetramethylammonium chloride on sodium dodecyl sulfate micellar structure: electron scavenging ability of doxylstearic acid spin probes and their reaction with N,N,N',N'-tetramethylbenzidine photogenerated cations studied by electron spin resonance

Electron spin resonance (ESR) studies are carried out for a series of chi-doxylstearic acids (chi = 5, 7, 10, 12, and 16) and photoproduced N,N,N'N'-tetramethylbenzidine (TMB) cations in sodium dodecyl sulfate micelles in order to investigate the effects of added tetramethylammonium chloride (TMACl) on the micellar structure at room temperature. It is observed that chi-doxylstearic acids not only act as electron acceptors for electrons produced by photoionization of TMB but also react with TMB cations to produce nonparamagnetic products. chi-Dependences of the reactivities of these two reactions suggest that chi-doxylstearic acids increase their average number of gauche conformations inside the micelles when TMACl is added to the micellar solution. It is concluded that tetramethylammonium cations act as spacers between head groups of surfactant molecules to become more disordered and loosely packed inside the micelles. This confirms previous electron spin echo modulation studies on frozen micellar solutions.

ChemInform Abstract: ESR and Electron Spin Echo Modulation Studies of N,N,N′,N′‐Tetramethylbenzidine Photoionization in Frozen Micellar Solutions: Structural Effect of 1‐Butanol Addition to Sodium and Tetramethylammonium Dodecylsulfate and Dodecyltrimethylammoninm Chloride Micelles.

ChemInform Abstract: ESR and Electron Spin Echo Modulation Studies of N,N,N′,N′‐Tetramethylbenzidine Photoionization in Frozen Micellar Solutions: Structural Effect of 1‐Butanol Addition to Sodium and Tetramethylammonium Dodecylsulfate and Dodecyltrimethylammoninm Chloride Micelles.

Electron spin resonance and electron spin echo modulation studies of N,N,N',N'-tetramethylbenzidine photoionization in frozen micellar solutions: structural effect of 1-butanol addition to sodium and tetramethylammonium dodecylsulfate and dodecyltrimethylammonium chloride micelles

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron spin resonance and electron spin echo modulation studies of N,N,N',N'-tetramethylbenzidine photoionization in frozen micellar solutions: structural effect of 1-butanol addition to sodium and tetramethylammonium dodecylsulfate and dodecyltrimethylammonium chloride micellesEwa Szajdzinska-Pietek, Rene Maldonado, Larry Kevan, and Richard R. M. JonesCite this: J. Am. Chem. Soc. 1985, 107, 23, 6467–6470Publication Date (Print):November 1, 1985Publication History Published online1 May 2002Published inissue 1 November 1985https://doi.org/10.1021/ja00309a007RIGHTS & PERMISSIONSArticle Views53Altmetric-Citations17LEARN 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 (460 KB) Get e-Alerts Get e-Alerts

Electron spin resonance and electron spin echo modulation studies of N,N,N',N'-tetramethylbenzidine photoionization in anionic micelles: structural effects of tetramethylammonium cation counterion substitution for sodium cation in dodecyl sulfate micelles

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron spin resonance and electron spin echo modulation studies of N,N,N',N'-tetramethylbenzidine photoionization in anionic micelles: structural effects of tetramethylammonium cation counterion substitution for sodium cation in dodecyl sulfate micellesE. Szajdzinska-Pietek, Rene Maldonado, Larry Kevan, and Richard R. M. JonesCite this: J. Am. Chem. Soc. 1984, 106, 17, 4675–4678Publication Date (Print):August 1, 1984Publication History Published online1 May 2002Published inissue 1 August 1984https://doi.org/10.1021/ja00329a005RIGHTS & PERMISSIONSArticle Views115Altmetric-Citations39LEARN 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 (449 KB) Get e-Alerts Get e-Alerts

Optical absorption, electron spin resonance, and electron spin echo studies of the photoionization of tetramethylbenzidine in cationic and anionic synthetic vesicles: comparison with analogous micellar systems

The photoionization of N,N,N',N'-tetramethylbenzidine (TMB) in dihexadecylphosphate anionic vesicles and in dioctadecyldimethylammonium chloride cationic vesicles has been studied by optical absorption and electron spin resonance in liquid and frozen solutions. The TMB cation has been observed to be stabilized in both types of vesicles. The photoionization efficiency is about twofold greater in the cationic vesicles compared to the anionic vesicles. Shifts in the optical absorption maximum between micellar and vesicle solutions indicate that TMB is in a less polar environment in the vesicle systems. Electron spin echo modulation spectrometry has been used to detect TMB cation-water interactions that are found to be weaker than in previously studied micellar solutions. This is consistent with the optical absorption results and with an asymmetric solubilization site for TMB and TMB/sup +/ within the vesicular structure. A new absorption in the photoionized vesicles is assigned to a nonparamagnetic diamine-diimine charge-transfer complex between two TMB cations in the same vesicle. This complex is not formed in micellar systems. 5 figures.

Electron spin resonance and electron spin echo studies of the photoionization of tetramethylbenzidine in frozen aqueous anionic, cationic, and nonionic micellar solutions. Effect of micelle type and anionic micelle size

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron spin resonance and electron spin echo studies of the photoionization of tetramethylbenzidine in frozen aqueous anionic, cationic, and nonionic micellar solutions. Effect of micelle type and anionic micelle sizeP. A. Narayana, A. S. W. Li, and Larry KevanCite this: J. Am. Chem. Soc. 1982, 104, 24, 6502–6505Publication Date (Print):December 1, 1982Publication History Published online1 May 2002Published inissue 1 December 1982https://doi.org/10.1021/ja00388a004RIGHTS & PERMISSIONSArticle Views87Altmetric-Citations35LEARN 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 (496 KB) Get e-Alerts Get e-Alerts

Laser photoionization and light-initiated redox reactions of tetramethylbenzidine in organic solvents and aqueous micellar solution

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLaser photoionization and light-initiated redox reactions of tetramethylbenzidine in organic solvents and aqueous micellar solutionS. A. Alkaitis and M. GraetzelCite this: J. Am. Chem. Soc. 1976, 98, 12, 3549–3554Publication Date (Print):June 1, 1976Publication History Published online1 May 2002Published inissue 1 June 1976https://doi.org/10.1021/ja00428a027RIGHTS & PERMISSIONSArticle Views236Altmetric-Citations91LEARN 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 (734 KB) Get e-Alerts Get e-Alerts