OBSERVATIONS OF C‐S AND S‐S BOND CLEAVAGE IN THE PHOTOLYSIS OF DISULFIDES IN SOLUTION

Abstract

Abstract— A comparison of the transient absorption spectra from the photolysis of disulfides in solution suggests that C‐S bond breakage is a common primary photolytic process. This process becomes more important as the resulting carbon centered radical is stabilized by increasing alkyl substitution or resonance interaction with an aromatic system. The perthiyl radical product is characterized by λ max ?380 nm,ε 380 ?1700 M −1 cm −1 and decays by second order kinetics with k 2 ?3.7×10 8 M −1 s −1 in water. In the presence of O 2 , the photolysis of disulfides which produce the thiyl radical give transient absorptions in the 500–600 nm region. Possible identities of these transients are discussed.