Oxidative nitration reaction of antiaromatic 5,15-dioxaporphyrin

Abstract

Upon oxidation of 20[Formula: see text]-electron antiaromatic 5,15-dioxaporphyrin (DOP) using nitrosonium ions as oxidants, a tetrakis-[Formula: see text]-nitrated compound was formed instead of the expected 18[Formula: see text]-electron aromatic dication species via an oxidative nitration reaction mechanism. Compared with the original DOP, this tetranitro DOP product exhibited a blue shift of absorption and downfield shifts of the [Formula: see text]-pyrrolic proton signals. The unique antiaromatic electronic structure of the tetranitro DOP was disclosed experimentally by electrochemistry and theoretically by DFT and NICS calculations.