CO and O2 binding studies of new model complexes for CcO

A very efficient, simple synthesis of a porphyrin mimic for cytochrome c oxidase is presented. This complex contains a covalently attached copper binding site and a phenyl ring that mimics the Tyr part of the enzyme. Structural studies revealed that the copper binding tridentate ligand is situated on top of the porphyrin plane and the hydroxyl of the phenyl ring is oriented towards the center of the molecule. Moreover, Fe at the reduced form of the model is capable of binding CO, as confirmed by FT-IR and upon photolysis CO is bound to Cu site. Finally, electrochemical studies using rotating ring-disk electrode showed that the complexes reduce oxygen via two mechanisms (2e− and 4e−) and have low stability.

Graphical abstractNew CcO model derivative has been synthesized and fully characterized in various coordination and oxidation states.Figure optionsDownload full-size imageDownload as PowerPoint slide