Localized Cation Unlocks Unique Activity-Selectivity Trends in Molecular Oxygen Reduction Catalysis

Integrating electrostatic and Lewis acid effects within a single molecular framework is a critically designed consideration central to the rational design of functional catalysts. Here, we report modular crown–porphyrin architectures that incorporate redox-inactive cations into programmable secondary coordination environments. This design enables systematic modulation of local electric fields, revealing charge-dependent perturbations across mono-, di-, and tri-valent cations through spectroscopic and electrochemical analyses. In oxygen reduction catalysis, the corresponding iron complexes (FeL1–Cl) display tunable reactivity landscapes arising from the interplay of electrostatic and Lewis acid effects. These results provide a framework for the design of cation-responsive molecular architectures in which cooperative noncovalent interactions can be leveraged to influence catalytic outcomes, as illustrated here for oxygen reduction reaction.