Matrix isolation studies of transients produced in the γ-radiolysis of decafluorobenzophenone: Spectral relaxation of anion and ketyl radical formation

Absorption spectra of the anion radical of decafluorobenzophenone (DFB) obtained on γ-radiolysis in various matrices were found to be blue shifted on warming. Spectra of the anion is blue shifted by as much as 0.32eV in MTHF matrix containing 0.7M ethanol (EtOH). In nonpolar 3 MP matrix containing 0.5 M isopropylalcohol (iPrOH) the extent of blue shift was found to be much lower, viz. 0.12 eV. Ketyl radical absorption obtained on warming results from protonation of the anion radical. The fact that warming of the matrix is a prerequisite for the ketyl radical formation seems to indicate that proton involved must be arising out of an ion-molecule reaction rather than the matrix itself. The formation of anion radical of DFB in 3 MP was found to be possible only in the presence of solute such as isopropylalcohol and triethylamine (TEA) where the positive hole is concomitantly trapped by the solute.