Photochemical Debromination of Meso-Substituted Bromoanthracenes Studied by Steady-State Photolysis and Laser Photolysis

Article abstract of DOI:10.1021/j150663a039

Debrominations of 9-bromoanthracene (BA) and 9,10-dibromoanthracene (DBA) in acetonitrile containing triethylamine (TEA) or N,N-dimethylaniline (DMA) have been studied by means of steady-state photolysis and laser photolysis.By the addition of TEA, the decay constants of the lowest excited singlet states of BA and DBA increase and the maximum yields of the triplet states decrease.The singlet quenching rate constants by TEA are calculated to be of the order of 1E10 M^-1 s^-1, showing that the reactions are diffusion controlled.Compared with the result of γ-radiolysis and pulse radiolysis, it is suggested that the photochemical debrominations of BA and DBA in the presence of amines take place via the anion radicals which are produced through exciplexes between amines and the lowest excited singlet states of bromoanthracenes.