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

Abstract: 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. [Copyright &y& Elsevier]