Studies on the complexation between generation-4.5 methyl ester-terminated poly(amidoamine) dendrimer and Pd²⁺ ions in methanol

Poly(amidoamine) (PAMAM) dendrimers have attracted attention because of their well-defined molecule structures and chemical versatility, which also complicate the mechanism of interactions between metal ions and PAMAM dendrimers. To further understand the complexation of dendrimers with metal ions, the interactions between Pd²⁺ ions and G4.5-COOCH₃ PAMAM dendrimers were investigated by UV-vis and FTIR spectrophotometric method. The results show that the addition of K₂PdCl₄ results in covalent attachment of the PdCl^-₃ akoholysis product of this complex to tertiary amines within the dendrimers under the appropriate conditions. This process was also supported by X-ray photoelectron spectroscopy data of the new complex which indicated a 1: 3 Pd/Cl ratio. The maximum loading of 80 Pd²⁺ ions within the G4.5-COOCH₃ dendrimers and the best pH value of 8.3 for complexation system are also obtained. Details regarding the Pd species present in solution of different chemical environments are reported