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 PdCl(2) using N,N'-bis(4-methoxyphenyl)-(1,1'-bi-naphthyl)-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) Napht(2.2+). These particles were evaluated for their capability to act as catalysts in Suzuki - Miyaura coupling reactions. The Pd(0)/Napht(2.2+) 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 degrees C and under aerobic conditions. (c) 2007 Elsevier Ltd. All rights reserved.