Structural insights into [Co4O4(C5H5N)4(CH3CO2)4]+, a rare Co(IV)-containing cuboidal complex

We report high-frequency (up to 219GHz) and correspondingly high-field electron paramagnetic resonance spectra and X-ray crystal structure of [Co4O4(pyridine)4(acetate)4]+ ([Co4O4(py)4(OAc)4]+) that serves as a structural and spectroscopic model of cobalt-oxide films that are capable of oxidizing water. These results are, in large part, consistent with those from our earlier, lower-frequency study and serve to benchmark future high-field studies on paramagnetic states of the catalyst film.