Linear scaling relationships in homogeneous photoredox catalysis†

Abstract

This work investigates two competing pathways for the terphenyl radical anion in the photoredox catalytic cycle for CO₂ reduction – the desired electron transfer to CO₂ and the undesired carboxylation and deactivation of the terphenyl catalyst. A linear relationship is identified between the energetics of the two pathways when trends are examined via p-substitutions to the three isomeric forms of terphenyl. Analogous to linear scaling relationships in heterogeneous catalysis and electrocatalysis, this correlation highlights intrinsic bounds on catalyst performance towards photoredox CO₂ reduction.