Electron self-exchange kinetics in two average-valence dicopper cryptates

Electron self-exchange rates, reported for two average-valence dicopper cry ptates are, at around 10(5) M-1 s(-1) at the high end of the range for smal l-molecule model compounds. The cross-exchange reaction rate, and those for oxidation with [Co(ox)(3)](3-) . are consistent with an outer-sphere react ion mechanism. Despite the necessity for copper-copper bond making and brea king in the course of redox for one of the cryptates, the self-exchange rat e is not decreased relative to the other cryptate, showing that this step i s not rate limiting.