ORGANIC PHOTOCHEMISTRY .8. PHOTOCHEMICAL REDUCTION OF NITRO-COMPOUNDS

Aromatic nitro-compounds, when irradiated with u.v. light in organic solvents containing abstractable hydrogen atoms, give rise to reduction products, the relative proportion of which depends on the solvent and the wavelength of the exciting radiation. The overall reaction is shown to involve a sequence of photochemical and thermal steps the first of which is a hydrogen abstraction probably by a 3(ππ*) excited state of the nitrocompound. SCF-MO and zero-order HMO calculations lend support to this view.