Laser Flash Photolysis of Chloranil in Solution

Chloranil (2,3,5,6‐tetrachloro‐2,5‐cyclohexadiene‐1,4‐dione; C ) in deoxygenated acetonitrile shows transient absorptions which are assigned to the radical anion \documentclass{article}\pagestyle{empty}\begin{document}$ \rm {C}^{- \kern-4pt {.}} $\end{document} and to the triplet 3 C *. The absorption due to \documentclass{article}\pagestyle{empty}\begin{document}$ \rm {C}^{- \kern-4pt {.}} $\end{document} rises ‘instantly’ during the 12 ns laser flash and then more gradually in a time of μs. This observation is explained as electron capture from neat acetonitrile by photoexcited C taking place from both its singlet and triplet states with rate constants estimated as 10 9 and 10 4 s −1 M −1 , respectively.