Pyrene Dimer Cation as Studied by Pulse Radiolysis

Kira, Akira; Arai, Shigeyoshi; Imamura, Masashi

doi:10.1063/1.1674767

Cited by 81 publications

(47 citation statements)

References 18 publications

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“…This tripl t state is considered to be produced by recombination of pyrene cation and the counter anion. However, the bands at 390nm and 510nm, indicating dimer cation formation, 16 were not detected.…”

Section: Resultsmentioning

confidence: 92%

“…Not only the singlet excimer but also the dimer cation is observed in intermolecular systems, and it was confirmed that the formation enthalpy of the latter was almost equal to that of the former. 16 In addition, intramolecular triplet excimer was observed in the compact geometry of bis[ 1-( lpyrenyl)ethyl]ethers.8 The differences between the present and other systems may be ascribed to geometrical structure of dipeptides. According to recent detailed fluorescence studies, 15 an excimer common to threo-and erythro-BIPyA is formed from two conformers in the ground state.…”

Section: Resultsmentioning

confidence: 97%

See 1 more Smart Citation

Absorption Spectra of N-Acetyl-bis(1-pyrenylalanine)methylester in the Excited and Ionic States

Tanaka

Masuhara

Mataga

et al. 1986

Polym J

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ABSTRACT:Absorption spectra of the excited and ionic states of threo-and erythro-Nacetyl(l-pyrenylalanine)methylester were measured by ps and ns laser photolysis methods. Interchromophoric interaction affecting the absorption spectrum was observed only in the excited singlet state, while neither triplet excimer nor dimer cation was detected. The present results are quite different from those of other bichromophoric systems, which were ascribed to rather distant structures of relevant chromophores in dipeptides. recently that meso-and rac-2,4-diarylpentanes are more appropriate model compounds. Excellent examples are 2,4-diphenylpentane for polystyrene and 2,4-di(N-carbazolyl)-pentane for poly(N-vinylcarbazole) and their photophysical aspects have been studied in detail. 3 The influence of the conformational distribution on the dynamics of their excited singlet states has been elucidated by single photon counting measurement. On the other hand, the triplet, cationic, and anionic states can be studied with a laser photolysis method, previously demonstrated in the systematic study on di(N-carbazolyl) compounds. 4 Bipyrenyl and binaphthyl compounds are being studied in detail as the next target systems, 5 -7 since pyrene and naphthalene are molecules showing typically distinct intermolecular interactions in the excited singlet and cationic states. Excimer formation and decay dynamics of bis [l-(1-pyrenyl)ethyl]ethers as well as 2,4-di(l-pyrenyl)pentane, and N-acetylbis(l-pyrenylalanine )methylester are closely related to the conformational and configurational aspects of vinyl polymers and polypeptides. Recently, we succeeded in measuring for the first time absorption spectra of the triplet excimer of pyrene, examining bis[l-(1-pyrenyl)ethyl]ethers. 8 Intramolecular association of two pyrenyl chromophores in the

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 97%

Absorption Spectra of N-Acetyl-bis(1-pyrenylalanine)methylester in the Excited and Ionic States

Tanaka

Masuhara

Mataga

et al. 1986

Polym J

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“…Particularly attractive among these are charged PAH clusters. However, because of the experimental inaccessibility of these highly unusual and reactive species, there is no gas phase spectroscopic data available to the best of our knowledge with which to test this hypothesis [PAH dimer cations have been characterized in solution (21,22) but are subject to strong solvation effects]. To make progress, we explore the spectroscopic properties of various charged PAH clusters by using ab initio quantum chemical calculations and show that a unique class of closed-shell charged dimers can account for the ERE.…”

Section: T He Extended Red Emission (Ere) Was Discovered In 1975 Bymentioning

confidence: 99%

Charged polycyclic aromatic hydrocarbon clusters and the galactic extended red emission

Rhee

Lee²,

Gudipati³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

117

114

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The species responsible for the broad extended red emission (ERE), discovered in 1975 and now known to be widespread throughout the Galaxy, still is unidentified. Spanning the range from Ϸ540 to 900 nm, the ERE is a photoluminescent process associated with a wide variety of different interstellar environments. Over the years, a number of plausible candidates have been suggested, but subsequent observations ruled them out. The objects that present the ERE also emit the infrared features attributed to free polycyclic aromatic hydrocarbon (PAH) molecules, suggesting that closely related materials are plausible ERE carriers. Here, we show that the peculiar spectra and unique properties of closed-shell cationic PAH dimers satisfy the existing observational constraints and suggest that emission from mixtures of charged PAH clusters accounts for much of the ERE. This work provides a view into the structures, stabilities, abundances, and ionization balance of PAH-related species in the emission zones, which, in turn, reflects physical conditions in the emission zones and sheds fundamental light on the nanoscale processes involved in carbon-particle nucleation and growth and carbonaceous dust evolution in the interstellar medium.dimer ͉ excited state ͉ interstellar medium ͉ nanoparticles T he extended red emission (ERE) was discovered in 1975 by Cohen et al. (1) in the peculiar object known as the Red Rectangle. Subsequent observations have shown that it is a widespread interstellar photoluminescent phenomenon. Witt and coworkers established that the ERE is associated with reflection nebulae (2, 3), carbon-rich planetary nebulae (4), and the interstellar medium of the Galaxy (5), whereas Darbon, Perrin, Sivan, and coworkers have detected the ERE in galactic HII regions and other galaxies (6-8). A detailed review can be found elsewhere (9).The ERE is a broad emission band starting near 540 nm that extends into the near infrared (IR). For most objects, the peak wavelength varies between 600 and 700 nm (3), although in the HII region of the Orion nebula, the band seems to peak near 800 nm (8). These variations are thought to arise from modest changes in chemical make-up and differing radiation fields and not from fundamental changes in the nature of the carrier. In some cases, structure appears superposed on the band (10, 11). Over the years a number of possible explanations have been suggested, including photoluminescence from species such as neutral polycyclic aromatic hydrocarbon (PAH) molecules (12), organic residues (13), neutral PAH clusters (14), hydrogenated amorphous carbon particles (15, 16), and silicon nanoparticles (17). Although a carbon-rich carrier was implicated by cosmic abundance constraints, all of these materials have been found wanting in light of subsequent observations. The case for each of these suggestions and the observational difficulties they encounter are summarized nicely by Witt et al. (18). Recently, observational constraints have been determined that are especially important in revealing t...

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“…9 The temperature was controlled by a flow of cooled or heated nitrogen gas in a thermostatic box with a thin aluminum window to admit the electron beam and a quartz evacuated cell as a window for the analyzing light beam.…”

mentioning

confidence: 99%

Thermodynamic Constants and Rate Constants of the Formation of the Pyrene Dimer Cation

Arai

Kira

Imamura

1972

The Journal of Chemical Physics

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Pyrene Dimer Cation as Studied by Pulse Radiolysis

Cited by 81 publications

References 18 publications

Absorption Spectra of N-Acetyl-bis(1-pyrenylalanine)methylester in the Excited and Ionic States

Absorption Spectra of N-Acetyl-bis(1-pyrenylalanine)methylester in the Excited and Ionic States

Charged polycyclic aromatic hydrocarbon clusters and the galactic extended red emission

Thermodynamic Constants and Rate Constants of the Formation of the Pyrene Dimer Cation

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