Experimental validation of Marcus theory for outer-sphere heterogeneous electron-transfer reactions: the oxidation of substituted 1,4-phenylenediamines.

Rate constants depend on molecular size: Results are presented to validate the relationship between molecular size and the standard electrochemical rate constant predicted by Marcus theory (see graphic). Measurement of hydrodynamic radii and electron-transfer rates for substituted 1,4-phenylenediamines have been made under steady-state conditions using both hydrodynamic and stationary electrodes.