Surfactant-free single-nano-sized colloidal Cu nanoparticles for use as an active catalyst in Ullmann-coupling reaction.

Surfactant-free, single-nano-sized copper nanoparticles (Cu NPs) (size: about 2 nm) were prepared by the DMF reduction method. The Cu NPs showed high catalytic activity (with a turnover number (TON) of up to 2.2 × 10(4)) in Ullmann-type cross-coupling of aryl halides with phenols under ligand-free conditions. This journal is © The Royal Society of Chemistry 2012