Function Provision to Fe-Porphyrin Complexes for CO Reduction.

CO reduction has recently attracted attention to address environmental and energy issues owing to its ability to convert greenhouse gases into valuable chemical fuels. Fe-porphyrin complexes ([Fe-(P)]-s) have been widely studied as catalysts for CO reduction owing to their high activity, selectivity, and robustness. In this perspective, [Fe-(P)]-s are classified in terms of our original concept, function provision, which serves to provide the function to approach key elements of the reaction. First, we introduce complexes with four functions (A) electron-accepting ability, (B) CO accumulation, (C) intermediate stabilization, and (D) proton supply. Next, we focus on complexes with multiple functions. Finally, a strategy for developing highly efficient CO reduction catalysts by multifunctional provision is presented. The concept of function provision is expected to serve as a strategy for developing efficient CO reduction catalysts.