Dual Role of Zirconium Oxoclusters in Hybrid Nanoparticles: Cross-Linkers and Catalytic Sites.
Organic-inorganic hybrid nanoparticles are prepared by free-radical copolymerization of methyl methacrylate (MMA) with the structurally well-defined methacrylate-functionalized zirconium oxocluster Zr4O2(methacrylate)12. The polymerization process occurs in the confined space of miniemulsion droplets. The formation of covalent chemical bonds between the organic and the inorganic counterparts improves the distribution of the guest species (oxoclusters) in the polymer particles, overcoming problems related to migration, leaching, and stability. Because of the presence of a high number of double bonds (12 per oxocluster), the oxoclusters act as efficient cross-linking units for the resulting polymer matrix, thus ruling its swelling behavior in organic solvents. The synthesized hybrid nanostructures are applied as heterogeneous systems in the catalytic oxidation of an organic sulfide to the corresponding sulfoxide and sulfone by hydrogen peroxide, displaying quantitative sulfide conversion in 4-24 h, with overall turnover numbers (TON) up to 8000 after 4 cycles.
Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
Cesare
C
Benedetti
Dipartimento di Scienze Chimiche, Università degli Studi di Padova , Via Marzolo 1, 35131 Padova, Italy.
Alessandro
A
Cazzolaro
Dipartimento di Scienze Chimiche, Università degli Studi di Padova , Via Marzolo 1, 35131 Padova, Italy.
Mauro
M
Carraro
Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
Robert
R
Graf
Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
Katharina
K
Landfester
Dipartimento di Scienze Chimiche, Università degli Studi di Padova , Via Marzolo 1, 35131 Padova, Italy.|ICMATE-CNR , Via Marzolo 1, 35131 Padova, Italy.
Silvia
S
Gross
Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.|Institut de Ciència dels Materials (ICMUV), Universitat de València , C/Catedràtic José Beltrán 2, 46980 Paterna, Spain.
Rafael
R
Muñoz-Espí
hybrid; miniemulsion; nanoparticles; oxocluster; polymer