Reduction of tetranitromethane by electronically excited aromatics in acetonitrile: Spectra and molar absorption coefficients of radical cations of anthracene, phenanthrene and pyrene

Room temperature absorption spectra of the long-lived transient species produced by photolysing solutions containing tetranitromethane (TNM) or a TNM/arene mixture have been recorded with a multi-channel spectrophotometer, capable of μs time resolution and covering a wide spectral range (200–1010 nm). The arene was anthracene (A), naphthalene (N), phenanthrene (Φ), or pyrene (P). In methanol, A+, N+ and Φ+ disappear within the available time resolution, but all four cations live for tens or hundreds of μs in acetonitrile; the molar absorption coefficients of A+, Φ+ and P+ in the latter solvent match those of the respective anions in tetrahydrofuran.