Electrochemically generated free radicals

Il'yasov, A. V.; Kargin, Yu. M.; Sotnikova, N.; Kondranina, V. Z.; Mel'nikov, B. V.; Vafina, A. A.

doi:10.1007/bf00862182

Cited by 5 publications

(10 citation statements)

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“…Thus N(id3-id2) --IR is a measure of the extent of the isomerization reaction, and the isomerization collection efficiency parameter, nk, defined in [10] can be nk = N --IR/(id8 --id2) [10] used to determine k;. Thus N(id3-id2) --IR is a measure of the extent of the isomerization reaction, and the isomerization collection efficiency parameter, nk, defined in [10] can be nk = N --IR/(id8 --id2) [10] used to determine k;.…”

Section: Methodsmentioning

confidence: 99%

“…R ----n-C4H9 di-n-butyl R ----n-C4H9 di-n-butyl fumarate (DBF) (DBM) studies (7)(8)(9)(10) have shown that in aprotic media the fumarates on reduction form the trans-radical anion (F-) which undergoes a relatively slow coupling reaction to a dimeric dianion (D 2-) which ultimately produces hydrodimer, while the F + e--> F- [1] 2F---> D 2- [2] maleates form the cis-radical anion (M-) which isomerizes to F-and also couples much more rapidly to produce the dimeric dianion M + e --> M-[3]…”

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confidence: 99%

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Rotating Ring‐Disk Electrodes: V . Isomerization and Reductive Coupling of Dialkyl Maleates

Yeh

Bard

1977

J. Electrochem. Soc.

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The rates of isomerization and coupling of the radical anions produced on electroreduction of several dialkyl maleates [methyl (DMM), ethyl (DEM), n-butyl (DBM)] in N,N-dimethylformamide solutions were investigated at the rotating ring-disk electrode (RRDE). Digital simulation methods were employed to obtain appropriate working curves and techniques were established to obtain both the first order isomerization constant (kD and the second order dimerization constant (k2) from collection efficiency measurements. The measured kl values; DMM, 2.2; DEM, 6.0; and DBM, 6.7 (sec -1) show an increasing isomerization rate with increasing size of alkyl substituent (R). The coupling rates decrease with irmreasing R; the k2 values are: DMM, 1.9 • 105; DEM, 9.1 • 104; and DBM, 6.9 • 104 (M -x sec-D. Comparison of these results to previous measurements of the coupling rates of the corresponding trans-species (i.e., fumarates) indicate that the c/s-radical anions couple about two thousand times faster than do the trans.The rotating ring-disk electrode has been useful in the investigation of the kinetics of electrode reactions, even for rather complicated mechanisms involving parallel reaction paths and higher order reactions [see (1-6) and references therein]. A particularly interesting electrochemical reaction scheme involves the difference in behavior upon reduction of the cisand trans-isomeric dialkyl fumarates and dialkyl maleates.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Rotating Ring‐Disk Electrodes: V . Isomerization and Reductive Coupling of Dialkyl Maleates

Yeh

Bard

1977

J. Electrochem. Soc.

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“…The structure and dynamic process of 1 were intensively investigated by Mislow et al [2] as a part of study on crowded triaryl derivatives [3], and have been discussed since then [4]. Redox properties and radical cation of the crowded triarylphosphines represented by 1 were extensively studied by Tordo [5] and Russian groups [6]. We have been involved in functional-material oriented research on phosphorus compounds and constructed the phosphorus redox systems such as phosphaquinoid compounds [7] and (aminoaryl)diphosphenes [8].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure and Properties of Crowded Triarylphosphines

Sasaki¹,

Yoshifuji

2007

COC

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“…Some of them have large C−P−C bond angles around phosphorus and are reversibly oxidized to stable radical cations because of their high HOMOs arising from structural changes around the phosphorus and the steric protection by the bulky substituents . Trimesitylphosphine ( 1 ) has long been known as a representative compound (Chart ). Tris(9-anthryl)phosphine has been reported to have a crowded structure as well as unique photophysical properties arising from the anthryl groups .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Properties of Sterically Crowded Triarylphosphines Bearing Naphthoquinone Moieties

et al. 2010

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Sterically crowded triarylphosphines bearing naphthoquinone moieties were synthesized by the Suzuki-Miyaura coupling of the corresponding (phosphinoaryl)boronic acid derivatives with 2,3dichloro-1,4-naphthoquinone. The triarylphosphine-naphthoquinone unit can be extended by employing a triarylphosphine bearing a chloronaphthoquinone moiety as a substrate. As an example, an oligomer bearing three triarylphosphine and two naphthoquinone moieties was synthesized. The triarylphosphines bearing naphthoquinone moieties exhibited purple to blue colors arising from intramolecular charge transfer. A systematic study of various derivatives showed that the corresponding absorption shifted toward longer wavelengths as the difference between the oxidation potential of the triarylphosphine moieties and the reduction potential of the naphthoquinone moieties becomes smaller. On the other hand, the intensity of the charge transfer absorption depends on the number of interacting triarylphosphine-naphthoquinone units. The purple color of the charge transfer turned to pale yellow after protonation of the phosphorus atom with trifluoroacetic acid, while deprotonation by addition of triethylamine regenerated the color as well as the phosphine. The intramolecular charge transfer is sensitive to structural changes, as insertion of a 1,4-phenylene spacer between the triarylphosphine and naphthoquinone moieties leads to a loss of the purple color.

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Electrochemically generated free radicals

Cited by 5 publications

References 1 publication

Rotating Ring‐Disk Electrodes: V . Isomerization and Reductive Coupling of Dialkyl Maleates

Rotating Ring‐Disk Electrodes: V . Isomerization and Reductive Coupling of Dialkyl Maleates

Synthesis, Structure and Properties of Crowded Triarylphosphines

Synthesis and Properties of Sterically Crowded Triarylphosphines Bearing Naphthoquinone Moieties

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