A push–pull azobenzene is mercurated twice at the ring with less electron density

Treatment of N,N-dialkyl-4-[4-nitrophenyl)diazenyl] anilines with a mercury(II) salt in anhydrous trifluoroacetic acid results in single and double metallation of the ring with less electron density. The seemingly counterintuitive outcome of the reaction was rationalized through experimental and computational investigations of the reaction mechanism.

Experimental and computational investigations identified kinetic control of the process as the likely explanation for such a counterintuitive result. Figure optionsDownload as PowerPoint slideHighlights
► Reaction of push–pull azodyes with mercury (II) salts.
► Metallation of the ring with less electron density.
► Kinetically controlled process.