Nanocontact-induced catalytic activation in palladium nanoparticles.

We report the synthesis and catalytic studies of novel palladium nanostructures assembled from small nanoparticles by a surfactant-templated method. These one-dimensional nanomaterials comprise high-density nanocontacts of approximately 1 nm in contact length at the particle-particle interface. In contrast to dispersed Pd nanoparticles ( approximately 5 nm), the polycrystalline palladium nanowires exhibit enhanced ( approximately 200 times) catalytic reactivity towards carbon-carbon cross-couplings under mild conditions. Theoretical modeling studies suggest that the presence of nanocontacts triggers electron transfer and localized charge redistribution in the contact region. The charge redistribution causes the nanocontacts to become highly attractive to charged organic molecules, resulting in the facilitation of organic transformations.