Investigations of the vinyl iodides 5 and 40 revealed that while direct reduction does not occur, significant differences in behavior exist between these two model vinyl iodides when NiCl2(bpy) and RAE are present (Figure -IV). When RDE voltammetry was conducted using NiCl2(bpy) and 40, a catalytic current response was observed at the Ni(0)/Ni(II) redox couple (resulting from the oxidative addition of the vinyl iodide) consistent with ECcat kinetics and the previously mentioned electrode passivation. Furthermore, in the presence of RAE 7, this passivation behavior disappeared when using the methyl ester vinyl iodide 40. Interestingly, use of halo-acid 5 in these measurements generated a catalytic current without significant electrode passivation even in the absence of RAE. Surprisingly, after addition of RAE 7 to halo-acid 5 and NiCl2(bpy), the second reduction wave was still observed at -1.48 V vs Ag/AgCl potential. We propose this wave is the electrochemical reduction of a nickel (II/III) alkenyl to a nickel (I) alkenyl intermediate. This profound difference in behavior when using halo-acid 5 instead of methyl ester 40 has significant implications on the detrimental behavior of carboxylic acids on reaction yield in the absence of AgNO3. Recent evidence has emerged suggesting the deactivation of nickel (I) intermediates through dimerization or aggregation. One can also imagine how this reduced species could accelerate the consumption of RAE in the homogeneous environment. Comparing the onset of these two reduction waves to the cell potential of the reaction without AgNO3 (Ecell = -1.66 V vs. Ag/AgCl) and with AgNO3 (Ecell = -1.15 V vs. Ag/AgCl) is particularly informative. This finding implied that the Ag-NP layer decreases overpotential to the point immediately prior to the second reduction wave whereas with the use of bare glassy carbon electrodes, more reducing potentials beyond the second wave under standard reaction conditions (constant current) are applied.