One-Electron Reduction of 3,3,6,6-Tetramethyl-3,4,6,7,9,10-hexahydro-(1,8)-(2H,5H)-acridinedione: A Pulse Radiolysis Study

Abstract

The radical anion formed on reaction of e aq ¯ with acridinedione dye (ADH) exhibits transient optical absorption bands at λ max = 315, 460, and >780 nm. The bimolecular rate constant for the reaction of e aq ¯ with the dye was determined to be 2.7 × 10 10 dm 3 mol -1 s -1 . It is converted to (ADH 2 • ) on protonation and showed an absorption band at 310 nm. At pH = 1, acetone ketyl radicals are observed to react with the dye with a bimolecular rate constant of 2.3 × 10 8 dm 3 mol -1 s -1 , and the transient optical absorption bands ( λ max = 315, 540 nm) are assigned to (ADH 3 ) •+ . The radical anion (ADH •- ) is a strong reducing agent, with reduction potential = -1.37 V vs NHE, and is able to undergo electron-transfer reactions with methyl viologen (MV 2+ ) and p-nitroacetophenone (p-NAP) with bimolecular rate constants of 4.9 × 10 9 and 6.1 × 10 9 dm 3 mol -1 s -1 , respectively.