Synergistic activities of magnetic iron-oxide nanoparticles and stabilizing ligands containing ferrocene moieties in selective oxidation of benzyl alcohol

Abstract

Magnetic iron-oxide nanoparticles stabilized by imine or amine ligands containing ferrocene moieties were synthesized and characterized by FTIR, XRD, AAS, TEM, vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. The oxidation of benzyl alcohol was carried out in the presence of the synthesized magnetic nanoparticles with or without ferrocene moieties as nanocatalysts and H 2 O 2 as oxidant. The synergistic activities between magnetic nanoparticles and ferrocene moieties in the stabilizing ligands were observed in this nanocatalysis. It turned out that the conversions of benzyl alcohol and the selectivities of benzaldehyde in the nanocatalytic systems with magnetic iron-oxide nanoparticles stabilizing by ligands containing ferrocene moieties were enhanced significantly than the ferrocene-free nanocatalytic systems. The nanocatalysis was proposed to be proceeded via first adsorption of benzyl alcohol on the surface of nanoparticles and then Fenton-typed reactions operating at both magnetic iron-oxide nanoparticles and ferrocene moieties. Ferrocene moieties play an important role in the nanocatalysis for the enhanced selectivity of benzaldehyde by their synergistic interactions to magnetic iron-oxide nanoparticles. Accordingly, the enhanced catalytic activity of nanocatalysts can be achieved by tuning the structure of stabilizing ligands surrounding to nanoparticles. © 2012 Elsevier B.V. All rights reserved.