Cu(I) Complexes of Pincer Pyridine-Based N‑Heterocyclic Carbenes with Small Wingtip Substituents: Synthesis and Structural and Spectroscopic Studies
Inorg. Chem. (2016) 55, 11685
Six new Cu(I) complexes with bis(NHC) ligands bearing pyridyl or methylpyridyl linkers were synthesized and characterized. In solution, the pyridyl-linked complexes undergo multiple and are oxidized by one-electron. However, the methylpyridyl-linked complexes present a reversible Cu(II)/Cu(I) couple at very close potentials to that of ferrocene and the Cu(I) with tripodal NHC systems.
Sonogashira-type cross-coupling reactions catalyzed by copper complexes of pincer N-heterocyclic carbenes
J. Organomet. Chem. (2018) 860, 98
A new protocol for efficient cross-coupling of aryl- and heterocyclic iodides and aryl alkynes is developed in air using Cu-pincer bis(NHC) complexes with alkyl wingtips. The reaction involves oxidation of initial Cu(I)-NHC complexes, leading to a more active catalyst through generation of a high-valent Cu-oxygen intermediate.
Factors That Control Catalytic Two- versus Four-Electron Reduction of Dioxygen by Copper Complexes
J. Am. Chem. Soc. (2012) 134, 7025
The selective 2e- reduction of O2 by 1e- reductants such as Me8Fc and Me10Fc is efficiently catalyzed by a binuclear Cu(II) complex in the presence of an acid in acetone.