Gas phase adiabatic electron affinities of cyclopenta-fused polycyclic aromatic hydrocarbons

Todorov, Petar D.; Koper, Carola; Lenthe, Joop H. van; Jenneskens, Leonardus W.

doi:10.1016/j.cplett.2008.01.065

Cited by 4 publications

(2 citation statements)

References 33 publications

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“…The EAs for the series of acenes (anthracene, tetracene, pentacene, etc.) are well-known to be generally higher than the EAs for the more compact PAHs (Modelli et al 2006), as are the EAs for PAHs comprising one or more five-membered rings (Todorov et al 2008) and fullerenes. The EA for the compact and highly symmetric coronene molecule (C 24 H 12 ) has been established at about 0.5 eV (Betowski et al 2006;Carelli & Gianturco 2012;Chen et al 1996;Denifl et al 2005;Duncan et al 1999;Malloci et al 2005).…”

Section: Electron Affinity: Stability Of [Pah -H]mentioning

confidence: 99%

Laboratory Infrared Spectroscopy of Gaseous Negatively Charged Polyaromatic Hydrocarbons

Gao

Berden

2014

ApJ

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Based largely on infrared spectroscopic evidence, polycyclic aromatic hydrocarbon (PAH) molecules are now widely accepted to occur abundantly in the interstellar medium. Laboratory infrared spectra have been obtained for a large variety of neutral and cationic PAHs, but data for anionic PAHs are scarce. Nonetheless, in regions with relatively high electron densities and low UV photon fluxes, PAHs have been suggested to occur predominantly as negatively charged ions (anions), having substantial influence on cloud chemistry. While some matrix spectra have been reported for radical anion PAHs, no data is available for even-electron anions, which are more stable against electron detachment. Here we present the first laboratory infrared spectra of deprotonated PAHs ( [PAH -H] − ) in the wavelength ranges between 6 and 16 μm and around 3 μm. Wavelength-dependent infrared multiple-photon electron detachment is employed to obtain spectra for deprotonated naphthalene, anthracene, and pyrene in the gas phase. Spectra are compared with theoretical spectra computed at the density functional theory level. We show that the relative band intensities in different ranges of the IR spectrum deviate significantly from those of neutral and positively charged PAHs, and moreover from those of radical anion PAHs. These relative band intensities are, however, well reproduced by theory. An analysis of the frontier molecular orbitals of the even-and odd-electron anions reveals a high degree of charge localization in the deprotonated systems, qualitatively explaining the observed differences and suggesting unusually high electric dipole moments for this class of PAH molecules.

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Section: Electron Affinity: Stability Of [Pah -H]mentioning

confidence: 99%

Laboratory Infrared Spectroscopy of Gaseous Negatively Charged Polyaromatic Hydrocarbons

Gao

Berden

2014

ApJ

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“…Externally cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAH) are important in several contexts. 1,2 Compounds from this class are abundant combustion effluents, observed as products of the incomplete combustion of hydrocarbon fuels. 3 CP-PAH are also important environmental pollutants because of their genotoxicity.…”

Section: Introductionmentioning

confidence: 99%

Local aromaticity of the five-membered rings in acenaphthylene derivatives

Radenković

Đurđević

Bultinck

2012

Phys. Chem. Chem. Phys.

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In this paper, a detailed study of the local aromaticity in a series of cyclopenta-fused linear polyacenes (acenaphthylene derivatives) was performed using several different criteria of aromaticity. Namely, the energy effect (ef), bond resonance energy (BRE), harmonic oscillator model of aromaticity (HOMA) index, multi centre delocalization indices (MCI), electron density at ring critical points ρ(r(C)), nucleus independent chemical shifts (NICS) and ring current maps were employed. All these methods agree that the extent of aromaticity of the five-membered ring in the acenaphthylene molecule is quite small. On the other hand, it was shown that the aromatic character of the five-membered rings depends on the size of the polyacenic part and on the position of the five-membered ring along the polyacenic part of the given acenaphthylene derivatives. According to energetic, electron delocalization and geometrical indices, the aromatic character of the pentagons in some higher acenaphthylene congeners is of the same order of magnitude as the aromatic character of some hexagons in the respective molecules. Ring current maps revealed the existence of a weak paratropic (antiaromatic) circulation in the five-membered rings which, in the case of higher members of the homolog series, becomes weaker. In contrast, the NICS indices showed a significant antiaromatic character of the five-membered rings in higher members of the acenaphthylene series.

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Ambipolar organic semiconductors from electron-accepting cyclopenta-fused anthracene

Xia

Liu

et al. 2013

Chem. Commun.

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Gas phase adiabatic electron affinities of cyclopenta-fused polycyclic aromatic hydrocarbons

Cited by 4 publications

References 33 publications

Laboratory Infrared Spectroscopy of Gaseous Negatively Charged Polyaromatic Hydrocarbons

Laboratory Infrared Spectroscopy of Gaseous Negatively Charged Polyaromatic Hydrocarbons

Local aromaticity of the five-membered rings in acenaphthylene derivatives

Ambipolar organic semiconductors from electron-accepting cyclopenta-fused anthracene

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