Fig. 7. Previously reported high-spin heme–peroxo–copper complexes and their O–O vibrational frequencies as detected by rR spectroscopy. Incorporation of the phenol-imidazole moiety (vs. the parent TMPA complex) showed a similar ν(O–O) stretch, suggesting the phenol is too far away to directly interact with the peroxo core (similar to what is observed in CcO), providing indirect evidence for an interstitial water.