Stilbene Radical Anions in the Excited Doublet State

This is the authors' abstract. We don't add key points for this paper.

Stilbene radical anions (St •- ) in the second excited doublet state generated by a pulse radiolysis−laser flash photolysis combined method undergo unimolecular isomerization from c -St •- to t -St •-, photoelectron ejection, and electron transfer to biphenyl added as a quencher. From the selective electron transfer from the St •- D 2 states to biphenyl (Bp), k Bp τ = 10.7 and 17.8 M -1 were obtained where k Bp and τ denote the rate constants of the electron transfer and the lifetimes of the c -St •- and t -St •- D 2 states, respectively. The τ values are estimated to be approximately 1.5 ± 0.4 ns and 2.5 ± 0.7 ns for the c -St •- and t -St •- D 2 states, respectively, from k Bp τ assuming the diffusion-controlled rate constant for k Bp . The shorter τ of the c -St •- D 2 state is attributed to isomerization via twisting about the central C C double bond. The τ values of the c -St •- and t -St •- D 2 states are 1 order of magnitude longer than those of c -St •+ and t -St •+ D 2 states. The transient phenomena of the D 2 states of c -St •- and t -St •- are discussed in terms of their lifetimes, structures, energies, and reaction processes.