Isolation and Crystallographic Characterization of an Octavalent Co2O2 Diamond Core

High-valent cobalt-oxides play a pivotal role in alternative energy technology as catalysts for water splitting and as cath-odes in lithium-ion batteries. Despite this importance, the properties governing the stability of high-valent cobalt-oxides, and specifically possible oxygen evolution pathways, are not clear. One root of this limited understanding is the scarcity of high-valent, Co(IV)-containing model complexes; there are no reports of stable, well-defined complexes with multiple Co(IV) centers. Here, an oxidatively robust fluorinated ligand scaffold enables the isolation and crystallographic charac-terization of a Co(IV)2-bis-μ-oxo complex. This complex is remarkably stable, in stark contrast with previously reported Co(IV)2 species which are highly reactive, which demonstrates that oxy-Co(IV)2 species are not necessarily unstable with respect to oxygen evolution. This example underscores a new design strategy for highly oxidizing transition metal frag-ments and provides detailed data on a previously inaccessible chemical unit of relevance to O–O bond formation and oxygen evolution.