ELECTRONIC-SPECTRA OF RADICAL IONS OF CYCLIC POLYSILANES

The absorption spectra of the radical ions of cyclic polysilanes, (Me2Si)n, where n = 5, 6, and 7, formed by γ-irradiation have been recorded for rigid matrices at 77 K. The absorption maxima of radical anions of the cyclic polysilanes showed a red shift from 670 to 900 nm with increasing ring size. {A figure is presented} shows a broad single band at 720 nm, whereas {A figure is presented} shows two bands in the wavelength region from 500 to 1000 nm. A single peak is observed for {A figure is presented} at 900 nm. Ring-size reduction of the cyclic polysilanes with production of dimethylsilylene was not observed for the radical ions below 173 K, in sharp contrast to the behavior shown by the photoexcited states. © 1990.