Pyrene—naphthalene complex radical cations

Kira, Akira; Nakamura, Takashi; Imamura, Masashi

doi:10.1016/0009-2614(78)85292-0

Cited by 8 publications

(6 citation statements)

References 14 publications

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“…A longer wavelength shift of the CR band from 950 to 1050 nm indicates a slight decrease of ∆H from 15.0 to 13.6 kcal/mol for the nitrostyrylpyridinyl and dicyanovinylstyrylpyridinyl dimer radical cations, respectively. These values are larger than those (8-10 kcal/mol) of fused aromatic dimer radical cations such as pyrene 25,26,[31][32][33][34][35][36][37][38][39] and are comparable to that (15.3 kcal/mol) of the benzene dimer radical cation. 26,30 The stabilization energy of the dimer radical cation is determined by the attractive charge transfer interaction together with electronic and steric repulsive forces.…”

Section: Esr Spectroscopymentioning

confidence: 83%

“…The CR band has been observed for dimer radical cations formed by γ-radiolysis and pulse radiolysis in rigid matrices at or near 77 K , by chemical oxidation in solutions at low temperatures, and by nanosecond (ns) laser flash photolysis and nanosecond pulse radiolysis at room temperature in solution. [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] All of these dimer radical cations, except those found by us in nitrostyrylpyridinium salts [22][23][24] and that in ref 27, were formed between neutral parent molecules (M) and radical cations (M + ) generated from M. Ishitani and Nagakura reported the appearance of a CR band from paracyclophane anions chemically produced in solutions at low temperatures. 27 Itoh reported the intramolecular association of the pyridinyl radical and the pyridinium cation in the radical cations of bis(4-methoxycarbonylpyridinium iodides), connected with tri-and tetramethylenes, in solution at room temperature.…”

Section: Introductionmentioning

confidence: 99%

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Charge Resonance and Charge Transfer Interactions of Photogenerated Dicyanovinylstyrylpyridinyl Radicals in Solutions at Room Temperature

1996

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Charge resonance and charge transfer interactions of dicyanovinylstyrylpyridinyl radicals were observed at room temperature in organic solvents by steady photolysis with absorption and ESR spectroscopy. Excitation of dicyanovinylstyrylpyridinium salts with tetraphenylborate in less polar solvents resulted in photoinduced electron transfer reactions to form fairly stable dicyanovinylstyrylpyridinyl radicals. In addition to the remarkable color changes due to the characteristic absorption of dicyanovinylstyrylpyridinyl radicals in the visible region, a charge resonance absorption band (CR band) of dimer radical cations and a charge transfer band of radical dimers were observed in the near-infrared region with peaks at 1050 and 1120 nm, respectively. The rise of the CR band was observed in the pulse width of a nanosecond laser, which was as fast as that of the formation of radical itself.

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Section: Esr Spectroscopymentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Charge Resonance and Charge Transfer Interactions of Photogenerated Dicyanovinylstyrylpyridinyl Radicals in Solutions at Room Temperature

1996

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“…In a hetero-dimer ion comprised of dissimilar partners (X ≠ Y), the charge may stay mainly on the molecule with lower ionization potential (IP). A limited number of absorption spectra were reported for hetero-dimer ions of aromatic molecules in condensed phases [8,9].…”

Section: Introductionmentioning

confidence: 99%

Photodissociation spectroscopy of (benzene–toluene)+. Charge delocalization in the hetero-dimer ion

et al. 1998

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The electronic spectrum of the benzene-toluene hetero-dimer ion is measured in the 380-1400 nm region. The spectrum shows intense bands around 1175 and 670 nm and a weaker band around 920 nm, which correspond to charge resonance (CR) bands of homodimer ions. The observation indicates that the positive charge stays on the benzene part in some probability, although the ionization potential of benzene is 0.4162 eV higher than that of toluene. A local excitation band (LE) is observed around 420 nm, where a π ← π transition is locally excited in the charged benzene or toluene molecule. On the basis of the position of the CR-like bands as well as the intensity of the LE band relative to that of homo-dimer ions, the probability of finding the charge on the benzene molecule is analyzed to be approximately 36 %.

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“…Neusser and co-workers determined the dissociation energies of several aromatic dimer ions from the ionization potentials of neutral dimers and the appearance potentials for the dissociation of dimer ions (breakdown measurement). − The binding energies of hetero-dimer ions of benzene with other molecules were found to be smaller than that of the benzene homo-dimer ion. Both groups assigned the decreased bonding energy in hetero-dimer ions to the reduced resonance interaction. − Kira and co-workers first presented spectroscopic evidence for the formation of the intermolecular naphthalene−pyrene hetero-dimer ion in a low-temperature matrix . However, it was difficult to unambiguously identify the species responsible for the photoabsorption in the CR band region.…”

Section: Introductionmentioning

confidence: 99%

“…[11][12][13][14][15] Kira and co-workers first presented spectroscopic evidence for the formation of the intermolecular naphthalene-pyrene hetero-dimer ion in a lowtemperature matrix. 16 However, it was difficult to unambiguously identify the species responsible for the photoabsorption in the CR band region. Yamamoto and co-workers used bichromophoric compounds linked by a methylene chain as precursors of the dimer ions and studied intramolecular dimer ions by laser photolysis at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Charge Delocalization in Benzene−Naphthalene Hetero-Dimer Cation

et al. 1997

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The electronic spectrum of the benzene-naphthalene hetero-dimer cation is measured in the 400-1200 nm region by the photodissociation spectroscopy. Most intense band at 580 nm is assigned to a local excitation (LE) band of the naphthalene cation chromophore. In addition to this band, an LE band of the benzene cation chromophore of the hetero-dimer is observed at nearly the same position (430 nm) as that of the benzene homo-dimer cation. The observation indicates that the positive charge stays on the benzene molecule in some probability, although the ionization potential of benzene is by 1.10 eV higher than that of naphthalene. The spectrum of the hetero-dimer cation also shows an intermolecular charge transfer (CT) band around 920 nm. On the basis of the position of the CT band as well as the intensity of the LE band relative to that of the homo-dimer, the probability of finding the charge on the benzene molecule is analyzed to be approximately 9 %.

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Pyrene—naphthalene complex radical cations

Cited by 8 publications

References 14 publications

Charge Resonance and Charge Transfer Interactions of Photogenerated Dicyanovinylstyrylpyridinyl Radicals in Solutions at Room Temperature

Charge Resonance and Charge Transfer Interactions of Photogenerated Dicyanovinylstyrylpyridinyl Radicals in Solutions at Room Temperature

Photodissociation spectroscopy of (benzene–toluene)+. Charge delocalization in the hetero-dimer ion

Charge Delocalization in Benzene−Naphthalene Hetero-Dimer Cation

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