Spectral properties of bis-9-anthryl derivatives immobilised in silica xerogel

Three bis-9-anthryl derivatives of the type Ant-R-Ant, where Ant is anthryl group and R is receptor spacer consisting of such donor atoms as N or N and O, were encapsulated in silica xerogel by the sol–gel method. Our recent studies in methanol solution show that these materials could be used as fluorosensors in chemical recognition phases for optical chemical sensor. Optical absorption spectra of the bis-anthryl derivatives are nearly the same in the solution and silica matrix. However, the free species entrapped in silica exhibit fluorescence emission spectra with a long wavelength tail, which is probably due to the presence of excimers in the excited state and/or heterogeneous environment of the emission centres in the amorphous silica matrix. The studied bis-anthryl derivatives undergo photochemical degradation during UV irradiation.