A Kinetic study on the Spin Polarization Switching of Benzil in the Presence of Triethylamine

摘要

Dual spin polarizaiton of CIDEP signal of radicals produced in benzil/triethylamine in the benzene system was investigated by the time-resolved ESR and transient absorption technique. CIDEP signals showed absorption or emission depending on the concentration of triethylamine. Emissive CIDEP signal was observed below 10~(-3) M of triethylamine, whereas absorptive signal was observed above 10~(-1) M. The dual CIDEP signal was explkained by the triplet mechanism (TM) and the radical-triplet pair mechanism (RTPM); the absorptive polarized TM signal was generated from the reaction of free triplet benzil with triethylamine, whereas the emissive polarized CIDEP signal was generated through the interaction between triplet benzil and benzil ketyl radical produced from the benzil-triethylamine complex.