CONCERNING THE MECHANISM OF DISPLACEMENT OF NITRO-GROUPS FROM ACTIVATED AROMATED SYSTEMS

The photostimulated reactions of p-nitrobenzophenone and p-nitrobenzon itrile with a variety of nucleophiles have been investigated. Displace ment of the nitro group is observed in all cases. The rates of the rea ctions were measured by FT-IR. The rates were slowed by substances suc h as sulfur, air, Galvinoxyl and p-benzoquinone. In several cases rate s of loss of starting material were monitored by quenching the reactio n mixtures and isolating product and starting material. These reaction s also showed inhibition of their rates in the presence of inhibitors. These results indicate that the reactions are chain processes. It is concluded that the substrates are converted into their corresponding r adical anions which then react with the nucleophiles in a bimolecular displacement reaction. The alternate mechanism, which involves dissoci ation of the radical anions, is precluded because they are known not t o dissociate.