Probing the Viability of Oxo-Coupling Pathways in Iridium-Catalyzed Oxygen Evolution.

A series of Cp*Ir dimers have been synthesized to elucidate the mechanistic viability of radical oxo-coupling pathways in iridium-catalyzed O evolution. The oxidative stability of the precursors toward nanoparticle formation and their oxygen evolution activity have been investigated and compared to suitable monomeric analogues. We found that precursors bearing monodentate NHC ligands degraded to form nanoparticles (NPs), and accordingly their O evolution rates were not significantly influenced by their nuclearity or distance between the two metals in the dimeric precursors.

Electron-Rich CpIr(biphenyl-2,2'-diyl) Complexes with -Accepting Carbon Donor Ligands.

Cp*Ir and CpIr complexes have attracted interest as catalysts for oxidative transformations, and highly oxidizing iridium species are postulated as key intermediates in both catalytic water and C-H bond oxidation. Strongly electron-donating ligand sets have been shown to stabilize Ir complexes. We describe the synthesis and reactivity of complexes containing the CpIr(biphenyl-2,2'-diyl) moiety stabilized by a series of strong donor carbon-based ligands.