Electronic absorption spectra and photodecomposition of some substituted ferrocenes

Abstract

The photostabilities of various ferrocene derivatives in solution have been studied as a function of solvent and, to a lesser extent, of incident wavelength. Some substituted ferrocenes, like ferrocene itself, did not decompose in methanol solution on exposure to near-ultraviolet light or sunlight; the remainder decomposed rapidly. Solutions of some derivatives in a number of other solvents also proved susceptible to photolysis. Qualitative evidence suggests that solute–solvent interaction leads to photo-chemically unstable species. Ferric ions do not appear to be formed in significant quantities during the degradative processes.Of the substituted ferrocenes investigated in this work, p-acetophenylferrocene appears to have considerable merit as a relatively stable and therefore protective light absorber. None of the derivatives, however, is as stable as ferrocene, which is prohibitively volatile for most practical applications.