Kensy, UweGrellmann, Karl-HeinzMosquera González, Manuel2018-07-272018-07-271993Kensy, U., Grellmann, K.-H. & Mosquera González, M. (1993). Competition between tunnel- and viscosity-effects on bimolecular hydrogen-transfer reaction. Pure and Applied Chemistry, Vol. 65, No. 8, pp. 1625–1628. https://doi.org/10.1351/pac1993650816250033-4545http://hdl.handle.net/10347/17085The photocyclization of a methylsubstituted diphenylamine results in the formation of a transient zwitterionic dihydrocarbazole. The transient converts into a stable dihydrocarbazole by an intramolecular, sigmatropic hydrogen shift and by an intermolecular hydrogen exchange reaction. The rates of both reactions are governed by hydrogen tunnel effects. The intermolecular hydrogen exchange is the first example for a bimolecular reaction where tunnel effects have been observed. The role of solvent viscosity is discussedeng@ 1993 IUPACjournal article10.1351/pac1993650816251365-3075open access