Critical Effects of Ligand Integration in Creating Palladium-Incorporated Porous Polymer Composites

This Article reports on the ligand integration effect of poly(amidoamine) (PAMAM) dendrimers working in the solid composite systems, which is significant for stabilizing Pd nanoparticles (PdNPs). To carry forward this research, the fourth generation of PAMAM dendrimer (G4) was modified with polymerizable functions and tied to polymer networks constituting porous composites through the polymerization-induced phase separation (PIPS) strategy. The obtained results indicate that creation of PdNPs is strongly affected by the G4 template, and, consequently, unforeseen critical control of their sizes was definitely performed. Also, the crucial importance from perspective of catalytic applications is strong suppression of Pd leaching for the G4-utilized porous polymer composites (G4-p). This fact means that the catalytic event of G4-p entirely occurs on the polymer support. All of these characteristics are in marked contrast to those of the composite that was fabricated with a nonintegrated, small molecule ligand system. On the basis of the present study, a primary mechanism that describes how Pd and ligand associate mutually during PIPS is proposed, where the Pd reduction and polymer propagation concurrently occurred.