Singlet oxygen is quenched by a series of 4-substituted thioanisoles (methoxy to nitro), with rate constant kt= 7× 104 to 7× 106 M-1 s-1, close to the value observed for the myoglobin- catalyzed sulfoxidation of the same sulfides. Correlations with σ (ρ=-1.97) and with E ox (slope-3.9 V-1) are evidence for an electrophilic mechanism. In methanol sulfoxides are formed (85%) via an intermediate quenched by diphenyl sulfoxide; competing minor paths ...
