On the exciplex formation in the energy transfer from aromatic hydrocarbons to crystal violet

The interaction of a triphenyl methane (TPM) dye: crystal violet (CV) with the triplet state (S-3*) Of the aromatic molecules biphenyl, p-terphenyl or anthracene was studied by pulse radiolytic kinetic spectrophotometry. in each case, studies of time-resolved spectra and kinetics showed that an exciplex between sensitiser triplet and ground state of CV is formed as an intermediate before the former dissociates to give triplet state of CV, [S-3* + CV (kb)reversible arrow(kf) (3)(S..CV)* -->(k3) S + (CV)-C-3*]. A detailed kinetic analysis has been carried out to evaluate various kinetic kb parameters. The equilibrium constant, K (k(f)/k(b)), was found to be 1.8 X 10(4) dm(3) mol(-1), 1.53 X 10(4) dm(3) mol(-1) and 1.32 X 10(4) dm(3) mol(-1) in the case of biphenyl, p-terphenyl and anthracene sensitiser triplet states, respectively. (C) 1998 Elsevier Science S.A.