From the various model comparisons, we now have a fairly clear picture of what ligand features most affect the reaction thermodynamics. Obviously, kinetics effects can also significantly affect the outcomes of reactivity in complexes supported by different ligands. For instance, the inclusion of electron-directing groups may affect barrier heights in the same or in the opposite direction in terms of reaction favorability for a specific step compared to the corresponding effect on the reaction thermodynamics. Another example is that the formation of transition state structures may be hindered by more bulky substituents. Therefore, thermodynamic and kinetic effects should in principle be considered together to obtain a complete picture of the ligand effect on this reaction. However, for clarity's sake in this work we have focused on the detailed analysis of thermodynamic effects, and we leave the corresponding kinetics study of all relevant species to a complementary work. Nonetheless, the work completed so far enabled us to suggest some preliminary guidelines for the targeted functionalization of the ligands in order to tune the reactivity of potential catalysts. In general, the ∆∆E R X for an effective catalyst should not differ much from ∆∆E R bpy since the bpy complex is known to be catalytically active. The condition in Eq. 4 ensures that one reaction becoming more favorable will be compensated by one or both of the other reactions becoming less favorable, so significant deviation from the bpy complex would likely prevent some steps from proceeding. With this in mind, N(c 4 ) or P(c 3 ) linkers seem unable to produce a viable catalyst; while each model has a reaction that is highly favorable, they also have at least one step that is 15 kcal/mol less favorable than the bpy complex and likely to be inactive. For this reason, we mainly consider the P(c 4 ) or N(c 3 ) models going forward.