Therefore, dicationic derivatives of bipyridinium (DMDQ, OH-Vi, and Me-Vi) have a more favorable reduction reaction. A similar effect could also be triggered in dBR5 and 2HNQ by protonation. Marcus theory shows that it is possible for a reaction with a larger negative free energy (∆A 0 IJ ) to proceed more slowly than one with a less negative free energy. The region in which this occurs is called "inverted region" (See Fig. ). Characteristic of this region is that the vertical gaps between the states of the reaction, I and J, have opposite signs.