Synthesis of Naphthidines

Significance

The synthesis along with electrochemical and spectral properties of seven novel N,N′-substituted naphthidines are reported. The synthesis presented proceeds first with Ni(0)-catalyzed amination of 1-chloronaphthalene, followed by TiCl₄-induced oxidative dimerization. This pathway represents the first efficient method of accessing this class of compounds. Through cyclic voltammetry, UV-Vis and EPR spectrometry, it was noted that the naphthidines formed unusually stable di(radical cations). Theoretical studies carried out on the compounds showed that, while the neutral naphthidines prefer a twisted conformation, the oxidized versions adopt a more planar conformation in order to better delocalize the charge.