Metal nanoparticles stabilized by cubic silsesquioxanes for catalytic hydrogenations

Octa(diacetic aminophenyl) silsesquioxanes (OAAPS) were synthesized and used as stabilizers for preparing metal (Pt, Pd and Ru) nanoparticles using NaBH4 as a reducing agent. The synthesized catalysts were characterized by UV-vis, XRD, and TEM. The average diameters of Pt (0), Pd (0) and Ru (0) nanoparticles are 1.6 +/- 0.3, 1.4 +/- 0.2 and 1.3 +/- 0.2 nm, respectively. The metal colloids show excellent stability since OAAPS offer stronger bonding of the cubic linker to the metal nanoparticles through the chelating effect. All colloids prepared are stable and show no precipitation at room temperature for several months. The catalytic hydrogenations of phenyl aldehydes using the metal colloids as catalysts demonstrate that catalytic activities depend on the variety of the metal colloids and the substrates. The colloidal catalysts stabilized by OAAPS can be recycled by simply adjusting the pH of the solution.