Electrochemical behaviour of chlorobenzenesulphonamide derivatives at the mercury electrode in non-aqueous solvents
TL;DR: In this paper, the analysis of polarographic and coulometric results showed that the overall reduction mechanism of chlorobenzenesulphonamide derivatives occurs with the cleavage of the CCl bond followed by the reduction of the BN bond breaking.
About: This article is published in Electrochimica Acta.The article was published on 1988-08-01. It has received 5 citations till now.
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TL;DR: In this article, the electrochemical behavior of polychlorobenzene derivatives is discussed on the basis of calculated quantum-mechanical indexes (CNDO/2, MNDO, AM1 methods) and of pure structural parameters reckoned by means of graph theory.
Abstract: The electrochemical behaviour of 12 polychlorobenzene derivatives is discussed on the basis of calculated quantum-mechanical indexes (CNDO/2, MNDO, AM1 methods) and of pure structural parameters reckoned by means of graph theory (Wierner, Balaban, Randic, PID and Wrms numbers). Even the existence of good relationships between reduction potentials and energies of virtual molecular orbitals, π* or σ*(closed-shell calculations), does not account for the details of the electron uptake at the molecular level. Open-shell calculations (MNDO) regarding unrelaxed radical anions are much more promising in this respect, the occurrence of the so-called ‘ortho effect’ can be so justified. The reductive process (at least in the experimental conditions considered here) is shown to be scarcely affected by solvent-shell or internal molecular rearrangements; this view is supported by the good description of the process, strictly on structural grounds regarding the whole of the molecule, provided by the graph-theoretical indexes.
22 citations
TL;DR: In this article, the electrochemical dehalogenation of a variety of halogenated aromatic compounds is studied by means of semi-empirical (AM1) and ab initio (ROHF 3-21G*) calculations.
Abstract: The electrochemical dehalogenation of a variety of halogenated aromatic compounds is studied by means of semiempirical (AM1) and ab initio(ROHF 3-21G*) calculations. Comparison of the electrochemical half-wave potential values (E1/2) and calculated theoretical indices indicates the formation of a π radical following the electron uptake. Moreover, the relationship observed between the half-wave potential, in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and the electron affinity suggests that the reduction potential is determined by the first electron uptake and that kinetic factors play a minor role, their influence being constant or negligible.
12 citations
TL;DR: In this article, the electroreductive potential values of the o-, m- and p- dibromobenzenes (DBBs) follow an unusual pattern in that, unlike the structurally related dichlorobenzene (DCB) derivatives, these three isomers exhibit a strong "ortho effect" and are accompanied by a large difference in the E1/2 values.
Abstract: The electroreductive potential values of the o-, m- and p- dibromobenzenes (DBBs) follow an unusual pattern in that, unlike the structurally related dichlorobenzene (DCB) derivatives, these three isomers exhibit a strong ‘ortho effect’ and are accompanied by a large difference in the E1/2 values. Any interference with the mechanism of reduction on the part of the chemical environment can be safely ruled out, given the consistency of the E1/2 values obtained in four different solvents. The use of theoretical indices calculated by the PM3 method enables the experimental behaviour of the DBBs to be rationalised on the basis of the electronic structure of the neutral isolated molecule. Remarkably, PM3 indicates the formation of a σ-type radical anion in the case of the reduction of the bromobenzene derivatives.
3 citations
TL;DR: The analysis of the polarographic, voltammetric and coulometric results showed that the overall reduction mechanism of benzamide occurs with the cleavage of the CN bond as mentioned in this paper.
2 citations
TL;DR: In this article, the electrochemical behavior of 2-methylsulphonyl-3-phenyloxaziridine (1) and 2-tbutyl-3 -phenyl oxaziridis (2) has been investigated by polarographic techniques in aprotic solvent.
2 citations
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TL;DR: In this article, the reduction of a wide series of p- and m-substituted benzophenones and 2-substantituted fluorenones is studied in dimethylformamide.
91 citations
TL;DR: In this article, three methodes electrochimiques were used for determiner les reactivites d'une serie de 26 couples radical aryl-nucleophile.
Abstract: Utilisation de 3 methodes electrochimiques pour determiner les reactivites d'une serie de 26 couples radical aryl-nucleophile
72 citations
TL;DR: In this paper, the electrochemical reduction of allyl iodide, allyl bromide and allyl anion was studied in dry acetonitrile with TBAP as supporting electrolyte by means of cyclic voltammetry.
Abstract: The electrochemical reduction of allyl iodide ( la ) , allyl bromide ( l b ) , (E)-3-bromo-l-phenyl-l-propene (IC), and (E)-5-bromo-2,2,6,6-tetramethyl-3-heptene ( Id ) was studied in dry acetonitrile with TBAP as supporting electrolyte by means of cyclic voltammetry and coulometry at mercury, platinum, and vitreous carbon electrodes. Compounds la-c showed multiple waves on platinum and mercury because of halide surface effects. However on vitreous carbon la-d gave single reduction waves, with half-peak potentials of -1.38, -1.64, -1 .1 I , and -1.89 V (vs. SCE), respectively. Apparent coulometric n values of 1 for la-c were shown to arise from rapid nucleophilic substitution of the allyl anion intermediates with starting halide to give electroinactive dimers. Sterically hindered Id showed an napp of 2 and did not exhibit surface interactions with Hg and Pt. Thus allyl halides, contrary to previous statements in the literature, are reduced via a two-electron electrode reaction and the reduction of the allyl radical to the allyl anion cannot be seen as a separate step. Evidence was also obtained for the formation of the allyl anion by reduction of l a and I b with solvated electrons in liquid ammonia; the electrochemical oxidation of this species in this medium occurred at ca. -1.2 V.
53 citations
38 citations
TL;DR: In this paper, the overall reduction process on an Hg electrode depends on the protonicity of the solvent and on the number of substituents on the N1 nitrogen (mono- or disubstituted).
17 citations