Valence Localization at a Bio-inspired Mixed-Valent {Cu S} Motif upon Solvation in Acetonitrile: Effect on Nitrous Oxide Reductase (N Or) Activity.

We demonstrate, based on experimental and theoretical evidence, that the isolated [2(CH CN) ] complex prepared in CH CN and containing a mixed-valent {Cu S} core evolves towards a new [2(CH CN) ] species upon solvation in CH CN. Unlike its type III structural analogue [2(H O)(OTf)] active toward N O reduction, this new type I compound is inactive. This outcome opens new perspectives for a rational for N O activation using bio-inspired Cu/S complexes, especially on the role of the valence localization/delocalization and the Cu-Cu bond on the reactivity.