Kinetic salt effects on the reaction between the [1,3,6,8,10,13,16,19-octa-azabicyclo(666)icosane]cobalt(III) ion, Co(sep)3+, and the hexa-aquochromium(II) ion

Abstract

Highly specific effects are shown by different salts on the title reaction. Some salts increase the rate by a factor between ca. two and four, whereas for others the increase is between 30 and over a 1000 times. This is attributed to the formation of highly reactive ion pairs (or triplets), whose formation constants have been evaluated, in some cases, from the kinetic data at constant ionic strength. These ion pairs involve essentially the Cr^II reactant, and their high reactivity is related to the rate of formation of the precursor complex and/or to the rate of electron transfer within the precursor complex.