16651-76-6Relevant academic research and scientific papers
Radical Cations of some Low-potential Viologen Compounds; Reduction Potentials and Electron-transfer Reactions
Anderson, Robert F.,Patel, Kantilal B.
, p. 2693 - 2702 (2007/10/02)
The one-electron reduction potentials (E1) of certain pyrazinediium, diazepinediium and diazocinediium viologen compounds substituted with methyl groups, V(2+), have been determined from the position of the one-electron transfer equilibria with reference compounds using pulse radiolysis.E1 ranges from -491 +/- 6 mV (vs NHE) for 6,7-dihydro-2,11-dimethyldipyridopyrazinediium dibromide (V21(2+)) to -832 +/- 11 mV for 6,7,8,9-tetrahydro-2,3,12,13-tetramethyldipyridodiazocinediium dibromide (V42(2+)).The rates of reduction by e(1-)aq were found to be independent of E1 whereas the rates of electron transfer from CO2(1-). and (CH3)2C.OH species do show a dependence on E1 for V(2+) compounds of lowest E1.Marcus-type treatment of the rate-constant data yields a rate constant of electron exchange between propan-2-oxyl radicals and acetone in the range (2-6)E6 dm3mol-1s-1 and between the radical cation of 6,7-dihydro-2,3,10,11-tetramethyldipyridopyrazinediium dibromide (V22.(1+)) and its unreduced form (V22(2+)) of 5E7 dm3mol-1s-1.
