The effect of metal chelate complexation on the reactivity and absorption spectra of 1,2-naphthoquinones: the synthesis of new types of near i.r. absorbing dyes

Abstract

The reactions of sodium 1,2-naphthoquinone-4-sulphonate with various arylamines and 1,1-bis[p-(dimethylamino)phenyl]ethylene were efficiently promoted by nickel(II) ions to give 4-aminated, 4-arylated, and 4-vinylated 1,2-naphthoquinones with absorption bands at larger wavelengths and with increased intensities on metal complex formation, with absorption maxima in the near i.r. region.