STUDIES OF PHOTOCHEMICAL-REACTION BY CIDNP-DETECTED ESR-SPECTRUM

CIDNP-detected ESR spectroscopy was applied to the study of photochemi cal reaction. In the CIDNP-detected ESR spectroscopy, the spectrum due to intermediate radical pairs and the spectrum due to free (escaped) radicals can be separately observed. The spectrum due to radical pairs is called stimulated nuclear polarization (SNP), and the spectrum due to free radicals is called dynamic nuclear polarization (DNP). The me thod was applied to the study of photochemical reaction of 2,6-dichlor obenzoquinone and the isomerization of quadricyclane assisted by photo induced electron transfer, and the chemical species of the intermediat e radical pair and of the radical were clarified.