Synthesis and photochromic properties of ferrocenyl-substituted benzo- and dibenzochromenes

The synthesis, photochromic behaviour, photodegradation parameters and fluorescence spectra of a range of benzo- and dibenzochromenes substituted by a ferrocenyl group in the 2-position have been investigated. The ferrocenyl group leads to two absorption bands in the visible spectrum bf the photomerocyanine Species, in contrast to the single band observed with corresponding phenyl substituted derivatives. It also increases the thermal rate of bleaching of the photomerocyanine.