Oscillator strengths and excited-state lifetimes for the cations of 2,6-diarylpyrylium salts

Measurements have been made on the absorption spectra in acetonitrile for 2,6-diarylpyrylium salts. It is found that the addition of various radicals to the 2,6-diphenylpyrylium cation influences the excited-state lifetimes and the oscillator strengths for the various absorption bands. The largest increase in the sum of the oscillator screngths for all the absorption bands occurs when phenyl or oxalkyl radicals are attached to the cation.