Revisiting Formal Copper(III) Complexes: Bridging Perspectives with - Configurations.

The formal Cu(III) complex [Cu(CF)] has often served as a paradigmatic example of challenging oxidation state assignment - with many reports proposing conflicting descriptions. Here we report a computational analysis of this compound, employing Energy Decomposition Analysis and Intrinsic Bond Orbital Analysis. We present a perspective of the metal centre, resulting from ambiguities in electron counting. The implications for describing reactions which undergo oxidation state changes, such as the formal reductive elimination from the analogous [Cu(CF)(CHPh)] complex (Paeth . , 141, 3153), are probed. Electron flow analysis finds that the changes in electronic structure may be understood as a to transition at the metal centre, rendering this process essentially redox neutral. This is reminiscent of a previously studied formal Ni(IV) complex (Steen ., . , , 13133-13139), and indicates that our description of electronic structure has implications for the understanding of elementary organometallic reaction steps.