Applications to Reaction Mechanism Studies of Organic

Abstract

Many organic M e+/ e-can be generated at high concentration of 10-6-10-3 M from electrochemical reactions and chemical oxidation by using one-electron oxidants. However, heterogeneous formation on the electrode and subsequent two-electron oxidation are involved in the former oxidation, and the kinetic measurements is essentially not possible in the latter oxidation. Therefore, both methods can be used for the generation of M e+/ e_, but not for the kinetic study involving M e+/ e-. Photochemical reactions such as photoinduced electron transfer (PET) and resonant two-photon ionization (RTPI) are used to generate Me +/e-and Me +, respectively. Laser flash photolysis (LFP) is a useful technique for the kinetic study involving Me +/e_. However, generation of Me +/e_ in solution by PET must be accompanied by ion pair formation, e.g., Me +/e_, Me +janion, etc. Because solvated electron (e;) is also generated together with Me + in RTPI, recombination of e; and Me + decreases the yield of Me +. Such accompanied species influence the transient behavior ofM e+/ e-. Moreover, M is limited for PET and RTPI, in which M should have appropriate character such as lower oxidation potential (Eox) and strong absorption at the laser wavelength (A).