ELECTROCHEMICAL AND SPECTROELECTROCHEMICAL STUDIES OF DIHYDRO-TETRA-AZAPENTACENE AS A MODEL OF POLYAZAACENE

5,14-dihydro-5,7,12, 14-tetraazapentacene (5, 14-dihydro-quinoxalino[2 , 3-b]phenazine) has been synthesized and studied as a model for polya zaacene with respect to the electrochemical reduction and oxidation in an aprotic electrolyte. While reduction consists of two separate one- electron steps, the oxidation is a single two-electron step. Both proc esses are irreversible due to chemical follow-up reactions and may be classified as ECE and EC mechanism, respectively. The reduction is fol lowed by a self-protonation reaction. The oxidation is accompanied by proton loss. Using in situ uv/vis spectroscopy it has been proved that the intermediate products reform the pristine compound in the reverse potential scan. The influence of the self-protonation reaction on the reduction process can be restricted by lowering the concentration of the substance in solution as well as by increasing the scan rate. It c an be excluded completely by addition of proton donors. In the presenc e of trifluoroacetic acid a complex is formed, the reduction of which is reversible. The oxidation of that complex remains irreversible at t hese conditions.