Formation of the Radical Cations of Some Tetracyclic Aromatic Hydrocarbons in Boric Acid Glass

Abstract

The radical cations of tetracene, chrysene, 1,2-benzanthracene, and 3,4-benzphenanthrene have been produced in boric acid glass by u.v. irradiation. Their electronic spectra are recorded in the region 200–1400 nm and show a close resemblance to the available data for the cations reported earlier.

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

“…Therefore, oleum is an ideal medium to generate radical cations of organic substrates like PAHs whose ionization potential is below 10 eV [11,12]. As we will show, oleum is an ideal medium to generate radical cations at room temperature avoiding the use of more sophisticated reaction media [8] or even ionizing radiation normally used for the production of the radical cations [6,27,28] or the use of boric acid matrix [23][24][25]29,30]. Thus, in response to the reduction of disulphuric acid as shown in reaction (3) the correspondent oxidation reaction of the organic substrate can be represented schematically as follows:…”

“…Shida et al report two transitions at 459 and 487 nm for the radical cation of picene [6,27], in line with our results permitting us to confirm the assignment. The radical cation electronic transitions of [n]phenacenes in general are not particular intense in acidic media like for instance in boric acid glass [29,30]; although oleum is a superacid, the behaviour of [n]phenacenes in the radical cation formation appear very similar to that in boric acid.…”