Femtosecond Electron Transfer and Real Time Discrimination of a Disulfide Bond Formation

The aim of this experimental work is to discriminate, in real time, the first steps of a S-S bond formation in solution (figure 1). One electron reduction or oxidation of a simple thioether, the dimethylsulfide (CH3SCH3), has been investigated by femtosecond UV-IR spectroscopy. Indeed, when an electron of excess energy is injected in a liquid organic sulfide characterized by a high electron affinity, an irreversible electron attachment competes with the solvation process. This electron transfer yields a primary anion (RSR-, R = CH3) which exhibits a high reactivity through an ultrafast ion-molecule reaction. This contribution will focus mainly on S-S bridge formation triggered by a primary anion/cation-molecule reaction.