Naphthidine di(radical cation)s-stabilized palladium nanoparticles for efficient catalytic Suzuki–Miyaura cross-coupling reactions

Stable Pd(0) nanoparticles were prepared at room temperature in 1,4-dioxane from PdCl2 using N,N′-bis(4-methoxyphenyl)-(1,1′-binaphthyl)-4,4′-diamine (naphthidine) as reducing and stabilizing agent. This procedure resulted in Pd(0) particles possessing an average diameter of ca. 25 nm stabilized against aggregation due to a barrier of the naphthidine di(radical cation) Napht2.2+. These particles were evaluated for their capability to act as catalysts in Suzuki–Miyaura coupling reactions. The Pd(0)/Napht2.2+ provides a general and convenient method to prepare biaryls from aryl bromides or iodides and boronic acids with a broad range of functional groups in 1,4-dioxane at 80 °C and under aerobic conditions.