Electronic absorption spectroscopy of polycyclic aromatic hydrocarbons (PAHs) radical cations generated in oleum: a superacid medium

Spectrochim Acta A Mol Biomol Spectrosc. 2010 Dec;77(5):998-1004. doi: 10.1016/j.saa.2010.08.037. Epub 2010 Sep 21.

Abstract

Oleum (fuming sulphuric acid), a well known superacid, was used as medium for the generation of the radical cation of a series of selected PAHs. The resulting radical cation spectra were studied by electronic absorption spectroscopy. Not only common PAHs like naphthalene, anthracene, tetracene, pentacene, perylene, pyrene, benzo[a]pyrene, phenanthrene and picene were studied but also the less common and very large PAHs relevant also for the astrochemical research, like coronene, hexabenzocoronene, quaterrylene, dicoronylene and a coronene oligomer. A correlation between the first ionization potential (IP1) of the PAHs studied and the energy to the so-called A-type band of the radical cations observed in oleum has led to the equation IP1=1.30EA+4.39 (in eV) which permits to estimate the energy of the PAHs radical cation transition (EA) in the VIS-NIR knowing the relative ionization potential or vice versa.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption
  • Anthracenes / chemistry
  • Cations / chemistry
  • Cations / pharmacokinetics
  • Models, Biological
  • Naphthacenes / chemistry
  • Naphthalenes / chemistry
  • Oxidation-Reduction
  • Photoelectron Spectroscopy / methods*
  • Polycyclic Aromatic Hydrocarbons / chemistry*
  • Polycyclic Aromatic Hydrocarbons / pharmacokinetics*
  • Sulfuric Acids / chemistry*
  • Sulfuric Acids / metabolism*

Substances

  • Anthracenes
  • Cations
  • Naphthacenes
  • Naphthalenes
  • Polycyclic Aromatic Hydrocarbons
  • Sulfuric Acids
  • decalin
  • pentacene
  • anthracene
  • sulfuric acid
  • naphthacene