S. Niizuma et H. Kawata, CIDEP STUDY OF RADICALS PRODUCED PHOTOCHEMICALLY IN THE ORGANIC SOLUTION OF 9-ACRIDONE AND PHENOLS, Bulletin of the Chemical Society of Japan, 66(6), 1993, pp. 1627-1632
The photoreaction of the solution systems of 9-acridone (or N-methyl-9
-acridone) and phenols was investigated by optical spectroscopy, ESR,
and time-resolved CIDEP techniques. CIDEP signals of acridone semiquin
one and phenoxyl radicals were detected together and the hyperfine cou
pling constants of acridone semiquinone were determined for the first
time by simulation method. It was also clarified that radical pair mec
hanism (RPM) with triplet precursor and triplet mechanism (TM) were th
e main spin polarization mechanisms in these systems. The results indi
cate that the excited triplet state of acridone abstracts a hydrogen o
f phenols. Temperature, phenol concentration, light intensity and time
dependence of the phenoxyl CIDEP signal intensity and/or pattern supp
orted the conclusion.