A Versatile and Convenient Method for the Functionalization of Porphyrins

Through-Space Electrostatic Interactions Surpass Classical Through-Bond Electronic Effects in Enhancing CO2 Reduction Performance of Iron Porphyrins

In his pioneering work to unravel the catalytic power of enzymes, Warshel has pertinently validated that electrostatic interactions play a major role in the activation of substrates. Implementing such chemical artifice in molecular catalysts may help improve their catalytic properties. In this study, a series of tetra-, di-, and mono-substituted iron porphyrins with cationic imidazolium groups were designed. Their presence in the second coordination sphere helped stabilize the [Fe-CO₂ ] intermediate through electrostatic interactions. It was found herein that the electrocatalytic overpotential is a function of the number of embarked imidazolium. Importantly, a gain of six orders of magnitude in turnover frequencies was observed going from a tetra- to a mono-substituted catalyst. Furthermore, the comparative study showed that catalytic performances trend of through-space electrostatic interaction, a first topological effect reported for iron porphyrins, outperforms the classical through-structure electronic effect.

The ligand influence in stereoselective carbene transfer reactions promoted by chiral metal porphyrin catalysts

This Perspective illustrates the state-of-the-art of stereoselective carbene transfer reactions catalysed by chiral metal porphyrin complexes. A particular attention is focused on the active role of the porphyrin ligand to drive the carbene insertion into the target organic skeleton.