Scheme 2. Proposed mechanism for the light-induced CO 2 reduction to CO with UrFe with the species characterized. AngewandteChemie Communications

The covalent insertion of a cobalt heme into the cavity of an artificial protein named alpha Rep (αRep) leads to an artificial cobalt hemoprotein that is active as a catalyst not only for the photo-induced production of H2, but also for the reduction of CO2 in a neutral aqueous solution. This new artificial metalloenzyme has been purified and characterized by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS), circular dichroism, and UltraViolet–Visible spectroscopy. Using theoretical experiments, the structure of this biohybrid and the positioning of the residues near the metal complex were examined, which made it possible to complete the coordination of the cobalt ion by an axial glutamine Gln283 ligand. While the Co(III)–porphyrin catalyst alone showed weak catalytic activity for both reactions, 10 times more H2 and four times more CO2 were produced when the Co(III)–porphyrin complex was buried in the hydrophobic cavity of the protein. This study thus provides a solid basis for further improvement of these biohybrids using well-designed modifications of the second and outer coordination sphere by site-directed mutagenesis of the host protein.

Scheme 2. Proposed mechanism for the light-induced CO 2 reduction to CO with UrFe with the species characterized.

Unravelling the mechanism  of charge accumulation and utilization in the light‐driven carbon dioxide reduction using iron porphyrins bearing hydrogen bonding scaffolds revealed unprecedented puzzle pieces about its rate limiting step. While the formal Fe(0) redox state has been widely accepted as the catalytically active species, Zakaria Halime, Ally Aukauloo et al. show in their Communication (e202117530) that the Fe(I) species is already involved in the substrate activation of the photocatalytic cycle.

Coupling a photoredox module and a bio-inspired non-heme model to activate O2 for oxygen atom transfer (OAT) reaction requires a vigorous investigation to shed light on the multiple competing electron...

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Die Entschlüsselung des Mechanismus der Ladungsakkumulation bei der lichtgetriebenen Kohlendioxidreduktion unter Verwendung von wasserstoffverbrückten Eisenporphyrinen liefert neue Einblicke in den geschwindigkeitsbegrenzenden Schritt. Während der formale Fe(0)‐Redoxzustand weithin als die katalytisch aktive Spezies galt, zeigen Zakaria Halime, Ally Aukauloo et al. in ihrer Zuschrift (e202117530), dass die Fe(I)‐Spezies bereits an der Substrataktivierung des photokatalytischen Zyklus beteiligt ist.