ESR spectra of anion radicals of phenazine derivatives

Brodskii, A.I.; Gordienko, L. L.; Kruglyak, Yu. A.

doi:10.1007/bf00523734

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…The HMO calculations for the substituted molecules were carried out using the parameters listed in Table 3, the parameters for -C1, -CH3, and -CH30 being taken from the tabulation of Purcell and Singer (14). The -NO2 parameters were based on those used by Brodskii et al (15) but were modified in order to obtain a better fit with the experimental data. A plot of the energy of the LVMO obtained in units of PC, (Table 1) us.…”

Section: Resultsmentioning

confidence: 99%

The Electroreduction of Substituted Benzofurazans

Fawcett¹,

Forte²,

Loutfy³

et al. 1972

Can. J. Chem.

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The electroreduction of 4-and 5-substituted benzofurazans was investigated at a platinum electrode in acetonitrile. Standard potentials for the reactions were linearly related to the energy of the lowest vacant molecular orbital as estimated by Hiickel theory. Standard rate constants for electron transfer decreased as standard potentials in the series became more cathodic. This decrease is attributed to a double layer effect. No correlation was obtained between standard rate constants and observed hyperfine splitting constants for the anion radicals.L'electrortduction des benzofurannes substituts en -4 et -5 a &ti. ttudite dans I'aci.tonitrile au moyen d'une tlectrode en platine. Les potentiels standard pour les rkactions ont &ti. relies d'une faqon lintaire aux orbitales moleculaires vacantes les plus basses telles qu'estimtes par la thtorie d'Hiickel. Les constantes de vitesse standard pour le transfert d'~1ectrons dkcroissent au fur et a mesure que les potentiels standard dans les series deviennent plus cathodiques. Cette diminution est attribuke A un effet de double couche. Aucune corrtlation n'a ete obtenue entre les constantes de vitesse standard et les constantes hyperfines de dtdoublement observtes pour les radicaux anioniques.

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Section: Resultsmentioning

confidence: 99%

The Electroreduction of Substituted Benzofurazans

Fawcett¹,

Forte²,

Loutfy³

et al. 1972

Can. J. Chem.

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“…7,11, 12 Nitroquinones have been investigated with special toxicological concern. Electroreduction of nitro derivatives of quinones has been described, [13][14][15][16][17][18] but, in the majority of cases, without considering any relationship with pharmacological activities and any evidence of mechanistic complications, as demonstrated in the case of 2-nitronaphthothiophen-4,9-quinone, 19 which carries two different electrochemically reducible sites and presents a conjugate interaction.…”

Section: Introductionmentioning

confidence: 99%

Inner reorganization during the radical–biradical transition in a nor-β-lapachone derivative possessing two redox centers

et al. 2008

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In this work, the electrochemical behaviour of an antitumoral nitro o-quinone derivative obtained from 3-bromo-nor-beta-lapachone was studied. Cyclic voltammetric experiments, in acetonitrile solution, revealed that both quinone and nitro functions are reduced independently as quasi-reversible one-electron transfer processes in this order. Depending on the reduction potential, a radical anion or a biradical dianion is obtained. The formation of these paramagnetic species was confirmed by performing in situ Electrochemical-Electron Spin Resonance (E-ESR) experiments. Analysis of the kinetics of electron transfer associated to those electron uptake processes, in terms of the Marcus-Hush-Levich model, revealed differences in the reorganization energy (lambda((k))) for both steps (lambda((I)): 1.07-1.11 eV; lambda((II)): 1.21-1.30 eV). By evaluating the conformations of the radical and biradical systems by calculations at the BLYP//TZVP level of theory, it was found that the inner component, for the second reduction process (lambda((II))) was approximately 72% of lambda((II)), reflecting modifications in the molecular structure during the radical anion-biradical dianion transition. This change is also reflected in the differences presented by line widths of the ESR signals of both electrogenerated radical and diradical species.

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ESR spectra of anion radicals of phenazine derivatives

Cited by 2 publications

References 4 publications

The Electroreduction of Substituted Benzofurazans

The Electroreduction of Substituted Benzofurazans

Inner reorganization during the radical–biradical transition in a nor-β-lapachone derivative possessing two redox centers

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