The second-order rate constants are reported for reduction of 11 cobalt (II1) complexes by viologen radicals, derived from diquaternary salts of 4, 4'-bipyridine and 2, 2'-bipyridine. Rate constants vary from 1.5 X lo2 to 6.0 X lo8 MI sI, a nd an excellent correlation with the Marcus expression for 14 redox reactions is observed. These data conform, on the basis of a unity transmission coefficient, to a self-exchange rate constant for the viologens (X2+/+ ...
