ELECTROCHEMISTRY IN LIQUID SULFUR-DIOXIDE .1. OXIDATION OF THIANTHRENE, PHENOTHIAZINE, AND 9,10-DIPHENYLANTHRACENE

Electrochemical investigations of liquid sulfur dioxide solutions at -40 °C are reported. Cyclic voltammetric and coulometric studies of the oxidations of thianthrene (TH), phenothiazine (PH), and 9, 10-diphenylanthracene (DPA) in SO2containing 0.15 M tetra-n-butylammonium perchlorate show that all three compounds are oxidized in two reversible one-electron steps to their respective radical cations and dications. Controlled potential coulometric studies with reversal show that both the radical cations and dications of TH and PH arestable on the coulometric time scale (~2 h), but DPA dication is not. © 1979, American Chemical Society. All rights reserved.