Time-dependent spectral changes of some ferrocene derivatives in halocarbon solvents after removal of photoexcitation

The time-dependent changes in the electronic absorption spectra (UV–vis) of some ferrocene derivatives in the halocarbon solvents chloroform and carbontetrachloride have been investigated after removal of the photoexcitation by monochromatic radiation (UV) in nitrogen atmosphere. The spectral responses with time after removal of photoexcitations are entirely different for the two solvents. Except for a little exception, it has been observed that in general, in the case of the ferrocene derivatives under study the absorbance of new bands appeared due to photoexcitation increases in chloroform and decreases in carbontetrachloride with time after removal of photoexcitation. Our previous study has indicated the photoinduced charge-transfer between a particular ferrocene derivative and halocarbon solvent. The results of this present study indicate that some sort of secondary thermal reaction continued even after the removal of photoexcitation and the secondary thermal reaction depends significantly on the ferrocene derivative and also the nature of the halocarbon solvent used.