Combination of Organic Dye and Iron for CO Reduction with Pentanuclear FeNa Purpurin Photocatalysts.

Molecular photocatalysts designed with earth-abundant elements are rare and challenging in artificial photosynthesis study. Herein, we report a multimetallic FeNa purpurin () complex for the reduction of CO in DMF under visible-light irradiation. The photocatalytic system achieves 91% selectivity and 2625 ± 334 turnovers of CO in 120 h, which is among the highest reported for a noble-metal-free catalyst without an additional photosensitizer. UV-vis and electrochemical studies suggest that the mechanism involves subsequent reductions and protonations of to generate [FeNa(PP)] and [FeNa(PP)] as the active photocatalysts in CO reduction.