Extended conjugation in di- and tri-arylmethanes. Part I. Electronic absorption spectra of 9,9-dimethylfluorene analogues of Crystal Violet and Malachite Green

Abstract

9,9-Dimethylfluorene analogues of some basic triphenylmethane dyes have been prepared and their absorption spectra have been determined. The extended quinonoid system in 9,9-dimethylfluorene is more energetically favoured than that in biphenyl, but in these dyes the mesomeric effect is not readily transmitted through the fluorenyl system.

The preparations of several 9,9-dimethylfluorene intermediates are described.