Dimeric Radical Cation of 4,5,7,8‐Tetramethyl[2.2]paracyclophane

Bruhin, J.; Gerson, Fabian; Ohya-Nishiguchi, Hiroaki

doi:10.1002/hlca.19770600733

Cited by 19 publications

(6 citation statements)

References 9 publications

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“…spectrum of low intensity. It is noteworthy that, in contrast to 2 [ 5 ] , no dimeric radical cations were obtained by electrolysis of 3 and 4 in CH2C12/CF3COOH/(CF3C0)20.…”

Section: Introductionmentioning

confidence: 87%

The Radical Cations of 4,5,7,13,15,16‐Hexamethyl‐ and 4,5,7,8,12,13,15,16‐Octamethyl [2.2]paracyclophane

Gerson

Lopez

Hopf³

1982

Helvetica Chimica Acta

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4,5,7,13,15,16-Hexamethyl-(3) and 4,5,7,8,12,13,15,16-octamethyl[2.2]paracyclophane (4) have been oxidized to their radical cations in solution under relatively mild conditions. Substantial hyperfine splittings in the ESR. spectra of 3 9 and 4Q arise from the methyl protons, whereas those from methylene protons are very small. This result indicates that the ethano bridges, unlike the methyl substituents, are rather ineffective in delocalizing the positive charge in 3% and 4?. It is in line with the interpretation proposed previously to rationalize the gas-phase ionization potentials of multiply bridged [2N]cyclophanes and methyl derivatives of [2.2]paracyclophane. The 71-spin distributions in 39 and 49 are discussed in terms of a simple model in which the singly occupied orbitals are represented as the antibonding combinations of two benzene HOMO'S.Introduction. -[2.2]Paracyclophane (1) is relatively resistent to oxidation in solution, unless one or both of its benzene rings are substituted by several electrondonating groups. Recently, it has been reported that the radical cation of4,5,7,8-tetramethyl [2.2]paracyclophane (2) was generated under rather rigorous conditions [ 11. The present paper deals with the radical cations of more highly substituted derivatives of 1, namely the 4,5,7,13,15,16-hexamethyl-(3) and 4, 5,7,8,12,13,15,16octamethyl[2.2]paracyclophane (4) [2]. Both, 39 and 4? are prepared under milder

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“…spectrum of low intensity. It is noteworthy that, in contrast to 2 [ 5 ] , no dimeric radical cations were obtained by electrolysis of 3 and 4 in CH2C12/CF3COOH/(CF3C0)20.…”

Section: Introductionmentioning

confidence: 87%

The Radical Cations of 4,5,7,13,15,16‐Hexamethyl‐ and 4,5,7,8,12,13,15,16‐Octamethyl [2.2]paracyclophane

Gerson

Lopez

Hopf³

1982

Helvetica Chimica Acta

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“…ing with the electrolytic reduction [5] and oxidation [6]. radical ions in the temperature range from 163 to 273 K. Fig.3.…”

Section: Splitting Unresolved ")mentioning

confidence: 99%

Radical Ions in the Pentalene Series. Part. I. 1,3,5‐tri‐t‐butylpentalene

Fürderer

Gerson

Häfner

1978

Helvetica Chimica Acta

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SummaryThe ESR. spectra of the radical anion and cation of 113,5-tri-t-butylpentalene (IT) have been reexamined under higher resolution. With the assistance of the ENDOR. technique, the coupling constants of all protons in II? and 110 could be determined. The experimental data agree satisfactorily with the values predicted by the simple MO model which suggests that the n-spin distributions in 110 and 110 should not strongly differ from those in the corresponding radical ions of parent pentalene (I). As in the case of other non-alternant hydrocarbons, the proton coupling constants for 110 are very sensitive to experimental conditions, due to the association of the radical anion with its counterion. Spectra of 114' taken at low temperatures (down to 133 and 163 K for ESR. and ENDOR., respectively) have not revealed specific line-broadening which could arise from the bond shift between the two Kekulk-structures of pentalene.

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“…40 These species are only stable for a short time and at low temperatures. These structures are thought to involve a parallel layering of the aromatic units at a distance within 3 Å. Cation radicals of methylsubstituted paracyclophanes have been found to be dimeric, involving 4p-faces in the cation stabilization.…”

Section: Electrochemical Generation Of Cationsmentioning

confidence: 99%

Layered [3.3]Orthocyclophanes - Interesting Study Objects in π-π Interaction

Mataka

Thiemann

Taniguchi

et al. 2000

Synlett

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Small size meta-and paracyclophanes have been used in the study of p-p interactions in facing, closely layered p-systems. A complication in these studies stems from the fact that the p-systems in those structures are distorted. Access to closely layered non-distorted aromatic systems surprisingly comes from the area of the orthocyclophanes, molecules, which for the most part are known to be flexible and topologically uninteresting compounds. That specifically designed bridges can lead to rigid, layered orthocyclophanes will be described in this overview along with their physical properties. 5Outlook

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Dimeric Radical Cation of 4,5,7,8‐Tetramethyl[2.2]paracyclophane

Cited by 19 publications

References 9 publications

The Radical Cations of 4,5,7,13,15,16‐Hexamethyl‐ and 4,5,7,8,12,13,15,16‐Octamethyl [2.2]paracyclophane

The Radical Cations of 4,5,7,13,15,16‐Hexamethyl‐ and 4,5,7,8,12,13,15,16‐Octamethyl [2.2]paracyclophane

Radical Ions in the Pentalene Series. Part. I. 1,3,5‐tri‐t‐butylpentalene

Layered [3.3]Orthocyclophanes - Interesting Study Objects in π-π Interaction

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