Controlled O2 reduction at a mixed-valent (II,I) Cu2S core.

Inspection of Oxygen Reduction Reactions (ORRs) using a mixed-valent Cu2S complex as a pre-catalyst revealed a tuneable H2O2vs. H2O production under mild conditions by controlling the amount of sacrificial reducer. The fully reduced bisCuI state is the main active species in solution, with fast kinetics. This new catalytic system is robust for H2O2 production with several cycles achieved and opens up perspectives for integration into devices.

Valence Localization at a Bio-inspired Mixed-Valent {Cu2 S}2+ Motif upon Solvation in Acetonitrile: Effect on Nitrous Oxide Reductase (N2 Or) Activity.

We demonstrate, based on experimental and theoretical evidence, that the isolated [2(CH3 CN)2 ]2+ complex prepared in CH3 CN and containing a mixed-valent {Cu2II,I S} core evolves towards a new [2(CH3 CN)3 ]2+ species upon solvation in CH3 CN. Unlike its type III structural analogue [2(H2 O)(OTf)]+ active toward N2 O reduction, this new type I compound is inactive. This outcome opens new perspectives for a rational for N2 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.