MAGNETIC-FIELD EFFECTS ON HYDROGEN ABSTRACTION OF TRIPLET XANTHONE WITH P-AMINOTHIOPHENOL IN AN SDS MICELLAR SOLUTION

The photoreduction of xanthone with p-aminothiophenol in a sodium dode cylsulfate solution was investigated with the aid of a nanosecond lase r flash photolysis technique at magnetic fields of 0-10 T. The lifetim e of the radical pair generated by hydrogen abstraction of triplet xan thone and the yields of the escaped xanthone ketyl and p-aminophenylth iyl radicals increased steeply with increasing magnetic field strength (B) in a low-field region (B less than or equal to 0.05 T) and decrea sed more slightly with increasing B in a high-field region (0.05 T <B less than or equal to 10 T). The observed magnetic field effects can b e interpreted by a combination of the hyperfine coupling and the Delta g mechanisms in the case of a triplet radical pair.