Synthesis, Catalytic GPx-like Activity, and SET Reactions of Conformationally Constrained 2,7-Dialkoxy-Substituted Naphthalene-1,8-diselenides.

Several 2,7-dialkoxy-substituted naphthalene-1,8-diselenides were prepared and tested for catalytic antioxidant activity in an NMR-based assay employing the reduction of hydrogen peroxide with stoichiometric amounts of benzyl thiol. Acidic conditions enhanced their catalytic activity, whereas basic conditions suppressed it. The highest activity was observed with a 2,7-bis(triethyleneglycol) derivative.

Acid-Catalyzed Electron Transfer Processes in Naphthalene peri-Dichalcogenides.

1,8-Naphthalene peri-dichalcogenides undergo protonation by Bronsted acids to produce electrophilic cations. Single electron transfer (SET) from the remaining unprotonated electron-rich peri-dichalcogenide to the cation then generates a radical cation and a radical. Thus, the formation of radical species results in severe peak broadening and coalescence of NMR signals when trifluoroacetic acid or other strong acids are added to the peri-dichalcogenide, and the process can be reversed by treatment with base.