Synthesis and reactivity of a chlorinated 1,8-bis(diarylmethylium)naphthalenediyl dication.

[Reaction: see text] 1,8-Bis(bis(p-chlorophenyl)methylium)naphthalenediyl dication has been prepared by treatment of the corresponding diol with a mixture of [HBF4]aq and (CF3CO)2O. The proximity of the methylium centers leads to strong electrostatic repulsions that are exacerbated by the electron-withdrawing p-chloro substituents. As indicated by cyclic voltammetry, this dication is the strongest oxidant of the 1,8-bis(methylium)naphthalenediyl series. It undergoes a reductive chlorination with chloride and reacts with bromide or iodide to afford the corresponding acenaphthenes.