There seems to be an effect of the bpy ligand itself that is not accounted for by the N(c 3 ) minimal models. For Reaction 1, comparing the 75 • P(c 4 ) model with the bpy complex (i.e. the zero line in Figure ) suggests that using N(c 3 ) linkers should decrease the favorability, contrary to the difference seen for the 75 • N(c 3 ) minimal model. To narrow down the possible causes, we constructed an intermediate model, depicted in Figure , where the N(c 3 ) linkers are connected by a C --C bridge, creating a bis(methyleneamino) ethene (mae) ligand. This mimics the extended conjugation and closed ring structure of the bpy complex, while neglecting any effects of aromaticity within the pyridine rings. As shown in mae is more favorable than ∆∆E R1 P(c 4 ) , which again differs from the full bpy complex. Both the rhodium and nitrogen atomic charges are nearly identical to those in the bpy complex, see Figure and Figure in the SI. It would seem that the aromaticity of the bpy ligand has a significant effect on reactivity beyond the effect of mere conjugation between the linker atoms. This is presumably an electronic effect that is not detected by our simple chargebased metric. That the effect is largest for the Rh(I) species makes sense, as the Rh has no additional attached ligands that can compete with or counteract the effect of the bpy.