Anodic voltammetry of phenol and benzenethiol derivatives.

Stradins, J.; Hasanli, Beibala

doi:10.1016/0022-0728(93)80286-q

Cited by 52 publications

(17 citation statements)

References 19 publications

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“…The CTB derivative 1 H 6 incorporates three phenol‐like and three benzylic thiol functions, which have similar p K a values (ca. 10.5 and 9.4, respectively), and are deprotonated in 0.1 m alkali hydroxide solutions. Earlier Cs + binding studies of deprotonated cryptophanols incorporating O(CH 2 ) 2 O bridges (derivatives of cryptophane‐A) were performed in 0.1 m LiOD.…”

Section: Resultsmentioning

confidence: 99%

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Generation of Cryptophanes in Water by Disulfide Bridge Formation

Brégier¹,

Hudeček

Chaux³

et al. 2017

Eur J Org Chem

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International audienceCryptophanes are receptors consisting of two bridging concave cyclotribenzylene (CTB) subunits. The formation of cryptophanes in basic aqueous solutions (0.1 M MOD; M = Li, Na, K, and Cs) by disulfide bridge formation has been investigated. Two original CTBs, 1H(6) and 2H(6), derived from cyclotriphenolene through the introduction of mercaptomethyl and mercapto substituents, respectively, were synthesized. Cryptophane formation by slow oxygenation of 1(6-) was observed only in the presence of Me4N+ as template, which yielded the diastereomeric forms in a ratio of around 82:18. By contrast, the rigid CTB 2H(6) yielded a cryptophane stereoselectively without a template. Interestingly, air oxidation of a 1:1 mixture of 1(6-) and 2(6-) in the presence of Me4N+ (0.5-1 equiv./1(6-)) in 0.1 m LiOD led to the exclusive formation of the cryptophane complex [(1.1)(6-)superset of+NMe4], (2.2)(6-) being formed only in very minor amounts. No mixed species were detected in the reaction mixtures. The stabilities of the diastereomers of the protonated cryptophanes were calculated in the gas phase by DFT at the omega B97XD 6-311G(d,p) level of theory

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Section: Resultsmentioning

confidence: 99%

“…The CTB derivative 2 H 6 incorporates three phenol‐like and three thiophenol‐like functions, the p K a values of which, 9.4 and 6.6, respectively, indicate that they are deprotonated in 0.1 m alkali hydroxide solution. Compound 2 H 6 (ca.…”

Section: Resultsmentioning

confidence: 99%

Generation of Cryptophanes in Water by Disulfide Bridge Formation

Brégier¹,

Hudeček

Chaux³

et al. 2017

Eur J Org Chem

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“…In the alkaline medium HNN was completely deprotonated and no protons were involved in a redox reaction (pH>10.0). The intersection of linear parts of the plot in Figure a could be approximated as a dissociation constant of hydroxyl group at around 9.7 in this specific BR buffer – DMSO medium (9 : 1).…”

Section: Resultsmentioning

confidence: 99%

Voltammetry of a Novel Antimycobacterial Agent 1‐Hydroxy‐N‐(4‐nitrophenyl)naphthalene‐2‐carboxamide in a Single Drop of a Solution

et al. 2017

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The aim of this study is the development of a miniaturized voltammetric method for the determination of an antimycobacterial agent 1-hydroxy-N-(4-nitrophenyl)naphthalene-2-carboxamide (HNN) in a single drop (20 mL) of a solution by cathodic and anodic voltammetry at a glassy carbon electrode. Cyclic voltammetry was used to investigate its redox properties followed by the optimization of differential pulse voltammetric determination in a regular 10 mL volume. The optimal medium for the analytical application of both cathodic and anodic voltammetry was found to be Britton-Robinson buffer pH 7.0 and dimethyl sulfoxide (9 : 1, v/v). HNN gave one cathodic peak at around À0.6 V and one anodic peak at around + 0.2 V vs. Ag j AgCl (3 mol L À1 KCl) reference electrode. Determination of HNN in a 10 mL volume gave the limit of quantification around 10 nmol L À1 by both adsorptive stripping anodic and cathodic voltammetry. Afterwards, miniaturized voltammetric methods in a single drop of solution (20 mL) were investigated. This approach requested some modifications of the cell design and voltammetric procedures. A novel method of removing dissolved oxygen in a single drop had to be developed and tested. Developed miniaturized voltammetric methods gave parameters comparable to the determination of HNN in 10 mL. The applicability of the miniaturized method was verified by the determination of HNN in a drop of a bacterial growth medium.

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“…3 and 4, are presented in Tables 1 and 2. With two of the [53], were expected to undergo deuteration as shown in Eq. 11.…”

Section: Kineticsmentioning

confidence: 99%

Quenching of diphenylmethyl radical fluorescence by cyanoaromatics and phenols

Cyr

Das

2015

Res Chem Intermed

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We have used double-laser nanosecond laser flash photolysis to study the kinetics of bimolecular quenching of the lowest doublet excited state of the transient diphenylmethyl radical ( 2 Ph 2 CH Á ) in acetonitrile at 25°C. We chose a series of cyanoaromatic compounds as acceptor-type quenchers and a series of 4-substituted phenols as donor-type quenchers. The observed bimolecular quenching rate constants (k Q ) are in the range 2 9 10 6 -2 9 10 10 M -1 s -1 for cyanoaromatics and 1 9 10 5 -3 9 10 9 M -1 s -1 for phenols. The Hammett plots of the k Q values for these two series have positive and negative slopes, respectively, and establish the enhanced behavior of the photo-excited diphenylmethyl radical as both a donor and an acceptor. For cyanoaromatics, the trend in the dependence of 2 Ph 2 CH Á * quenching rate constants on the free energy change of electron transfer (DG el ) coincides well with that of RehmWeller data on acceptor-type and donor-type quenchers of singlet excited states. An approximate fit of the k Q data for cyanoaromatics to the Agmon-Levine model of electron transfer gave a value of 4.5 kcal mol -1 for the free energy of activation at DG el = 0. For phenols, the trend in the dependence of k Q on the free energy change of electron transfer deviates significantly from that of cyanoaromatics data. This deviation was traced to the use of irreversible oxidation potentials of phenols to calculate DG el . No isotope effect is observed from substitution of phenolic hydrogen by deuterium, i.e., k Q,H /k Q,D & 1. Phenolate ions quench 2 Ph 2 CH Á * with large rate constants, 1-2 9 10 10 M -1 s -1 , i.e., well in the limit of diffusion control.

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Anodic voltammetry of phenol and benzenethiol derivatives.

Cited by 52 publications

References 19 publications

Generation of Cryptophanes in Water by Disulfide Bridge Formation

Generation of Cryptophanes in Water by Disulfide Bridge Formation

Voltammetry of a Novel Antimycobacterial Agent 1‐Hydroxy‐N‐(4‐nitrophenyl)naphthalene‐2‐carboxamide in a Single Drop of a Solution

Quenching of diphenylmethyl radical fluorescence by cyanoaromatics and phenols

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