Pulse Radiolysis of trans-Stilbene in Tetrahydrofuran. Spektral Shift and Decay Kinetics of the Radical Anions in the Presence of Quaternary Ammonium Salts

Article abstract of DOI:10.1021/j100400a035

Pulse radiolysis of trans-stilbene (St) in tetrahydrofuran (THF) solution was carried out in the presence of quaternary ammonium salts, such as Bu4NPF6, Bu4NI, Bu4NBPh4, CeMe3NPF6, PhMe3NPF6, and BzMe3NPF6 (Bu, butyl; Ce, cetyl; Me, methyl; Ph, phenyl; and Bz, benzyl).The absorption peak of the radical anions, St^-., was shifted to shorter wavelengths in the presence of the salts.The magnitude of the shift depends on the substituent groups of the quaternary ammonium cations.It is suggested that St^-. forms contact ion pairs with the quaternary ammonium cations.The decay rate of St^-. decreases with increasing salt concentration and becomes steady.The rate constants for the neutralization reaction of St^-. with the solvent counterions, THF(H⁺), have been determined in the absence and presence of Bu4NPF6; in the latter case, the reaction occurs between the ion pairs St^-./Bu4N⁺ and THF(H⁺)/PF6^-.The results for other aromatic compounds such as bibhenyl, anthracene, and pyrene are also presented.Comparison was made with the effect of NaBPh4.