Preparation and characterization of Pd nanoclusters templated by PAMAM dendrimers

Pd nanoclusters templated by methoxycarbonyl-terminated poly (amidoamine) (PAMAM) dendri-mers were successfully prepared in methanol. The complexation between Pd²⁺ ions and dendrimers was investigated by UV-Vis and FTIR spectophotometric method. These results show that Pd²⁺ ions are coordinated with the interior amine groups of PAMAM dendrimers. As shown in HRTEM images, reduction with NaBH₄ resulted in well-dispersed and nearly size monodisperse Pd nanoclusters (2 nm, FCC) encapsulated in dendrimers. The investigation of UV-Vis data indicates that the size of particle increases with the metal-to-dendrimer molar ratio. Besides, due to the close-packed spherical periphery and rich ligands in interior cavities, dendrimers of higher generation are more effective for preparing Pd DENs with smaller size and better dispersion.