Novel electron-beam-induced reaction of a sulfonium salt in the solid state

Enomoto, Kazuyuki*; Moon, S.*; Maekawa, Yasunari; Shimoyama, Junji*; Goto, Kazuyuki*; Narita, Tadashi*; Yoshida, Masaru

The electron beam (EB)-induced reaction of triphenylsulfonium methanesulfonate (1-Ms) in the solid state afforded the benzene-substituted product, biphenyldiphenylsulfonium methanesulfonate (2-Ms), which has not been observed by either photolysis or EB-induced reaction in a solution. The kinetic data revealed that the biphenyl salt 2-Ms exhibited 3.7 times greater kinetic constants for consumption than that of 1-Ms. The EB-induced reaction of benzene-substituted triphenylsulfonium salts, p-biphenyldiphenylsulfonium methanesulfonate (2p-Ms) and (4-phenylthiophenyl)diphenyl- sulfonium methanesulfonate (7) showed the consumption rates of 3.8 and 5.7 times greater than that of 1-Ms. The sulfonium salts with aromatic counter anions showed somewhat higher reactivity than those with aliphatic counter anions. Accordingly, it is concluded that the triphenylsulfonium salts having aryl groups, which exhibit lower ionization potential (Ip), in both cation and anion moieties should exhibit greater decomposition rates.