Observation of O-O Bond Forming Step of Molecular Co4O4 Cubane Catalyst for Water Oxidation by Rapid-Scan FT-IR Spectroscopy
- Author(s): Liu, H
- Frei, H
- et al.
Published Web Locationhttps://doi.org/10.1021/acscatal.9b03281
Monitoring of water oxidation by the established Co cubane catalyst Co O (OAc) (py) (abbrev. Co O , OAc = acetate, py = pyridine) by time-resolved rapid-scan ATR FT-IR spectroscopy revealed the O-O bond forming intermediate by its O-O stretch mode at 833 cm . The catalysis was either driven in alkaline solution by a visible light sensitizer or in hydroxide (OH ) containing acetonitrile solution using the one-electron oxidized cubane as the sole source of charge. The μ-peroxido structure of the intermediate was established by O isotopic labeling, and its catalytic relevancy and role in the O evolving cycle were revealed by the kinetic relationship with decreasing cubium ([Co O ] ) and recovery of the Co O complex. 4 4 4 4 4 4 2 4 4 4 4 -1 - 18 +