Synthetic Metals 194 (2014) 11–18 Contents lists available at ScienceDirect Synthetic Metals jo ur nal home p age: www.elsevier.com/locate/synmet Synthesis, characterization and morphology of new magnetic fluorochromate hybrid nanomaterials with triethylamine surface modified iron oxide nanoparticles Ali Maleki ∗ , Rahmatollah Rahimi, Saied Maleki Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Iran a r t i c l e i n f o Article history: Received 28 February 2014 Received in revised form 7 April 2014 Accepted 13 April 2014 Keywords: Magnetic nanoparticles Fe3O4 Fluorochromate Immobilization Triethylamine a b s t r a c t Magnetic fluorochromate Fe 3 O 4 @SiO 2 @TEA@[CrO 3 F] was synthesized by ethylene glycol route. The struc- tures, morphologies and properties of the catalyst were characterized by using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), elemental analysis, X-ray fluorescence (XRF), solid state UV–vis, trans- mission electron microscopy (TEM), scanning electron microscope (SEM), N 2 adsorption–desorption (BET and BJH) and vibrating sample magnetometer (VSM). The quantity of chromium is approximately 0.32%, which confirms the immobilization amount of [CrO 3 F] - which is equal with 0.006 mol/100 g. © 2014 Elsevier B.V. All rights reserved. 1. Introduction The selective oxidation of alcohols to the related aldehydes is a commonly used conversion in organic synthesis and therefore types of methods have been developed. A good number of Cr(VI) complexes are being used in the oxidation of organic compounds. Halochro- mates have been used as mild and selective oxidizing reagents in synthetic organic chemistry. The search for new oxidizing agents is of interest to synthetic organic chemists. Many such reagents have been developed in recent years with some success. In recent years, important improvements were achieved by the use of new oxidizing agents such as benzimidazolium fluorochromate, N-methyl benzylam- monium fluorochromate, tributylammonium chlorochromate, pyridinium fluorochromate, imidazolium dichromate and isoquinolinium bromochromate [1–5]. Homogeneous catalysts usually activate at relatively mild states and show high activities and selectivities but have difficult separation and regeneration of the catalyst from the reaction mixture. Covalent grafting of a homogeneous catalyst on solid supports may reduce the active surface area and reactivity of immobilized catalysts. Immobilized homogeneous catalysis has achieved a new impulse with the advent of nanotechnology. Due to the large surface area of nanoparticles, high loadings of catalytically active sites are guaranteed and thus nanoparticles-supported homogeneous catalysts display high catalytic activity and selectivity. In spite of this, nanometer-sized particles are difficult to separate by traditional filtration techniques and expensive ultracentrifugation is often needed to have a good separation of the catalyst from the reaction mixture. This inadequacy could be prevented using magnetic nanoparticle (MNPs) supports. An external magnet could easily separate the immobilized catalysts from the reaction mixture, which results in more successful separation than usual methods [6]. We have focused on using magnetic nanoparticles Fe 3 O 4 (MNPs) for immobilization of fluorochromate as separable oxidant catalyst. In this paper, the magnetically nanoparticles Fe 3 O 4 (MNPs) were synthesized. The external surface of Fe 3 O 4 was coated with silica shell to obtain Fe 3 O 4 @SiO 2 (SCMNPs). Then, Fe 3 O 4 @SiO 2 nanoparticles were functionalized by 3-chloropropyltrimethoxysilane and triethy- lamine to create cationic part as a support (TEASCMNPs). Lastly, anionic fluorochromate was immobilized on TEASCMNPs through ionic interaction and Fe 3 O 4 @SiO 2 @TEA@[CrO 3 F] - (FC-TEASCMNPs) was formed. Because of the presence of magnetite core, the prepared hybrid ∗ Corresponding author. Tel.: +98 21 77240540 50; fax: +98 21 73021584. E-mail addresses: maleki@iust.ac.ir, alimaleki 2003@yahoo.com (A. Maleki). http://dx.doi.org/10.1016/j.synthmet.2014.04.013 0379-6779/© 2014 Elsevier B.V. All rights reserved.