Applicability of the Marcus relationship to copper(II/I) electron transfer. Comparison of NMR self-exchange relaxation and reduction and oxidation cross-reaction kinetics for a macrocyclic amino tetrathiaether-copper(II/I) complex in aqueous solution

The value of the electron self-exchange rate constant for Cu II/I ([15]aneNS 4 ) {[15]aneNS 4 =1,4,7,10-tetrathia- 13-azacyclopentadecane, a quinquedentate macrocycle} has been determined directly by NMR line-broadening measurements in D 2 O over the temperature range 5-45 o C at pD values ranging from 5.3 to 8.5.