1 2 Original article 3 Synthesis and characterization of a new magnetic bromochromate 4 hybrid nanomaterial with triethylamine surface modiﬁed iron oxide 5 nanoparticles 6 Rahmatollah Rahimi Q1 , Ali Maleki *, Saied Maleki 7 Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Iran 8 9 1. Introduction 10 A series of compounds containing chromium (VI) has been 11 examined as versatile reagents capable of oxidizing almost 12 every oxidiasable functional group. New chromium (VI) 13 reagents were also tested for the effective and selective 14 oxidation of organic substrates, speciﬁcally alcohols, under mild 15 conditions. In recent years, considerable progress was achieved 16 by the application of these new oxidizing agents. Quaternary 17 ions, such as ammonium and phosphonium, are often used as 18 phase transfer catalysts. This could make triphenylpropylpho- 19 sphonium bromochromate (VI) a more useful and strong 20 oxidizing agent. This compound was used for quantitative 21 oxidation of many organic substrates [1,2]. 22 Over the last decade, magnetic organic–inorganic nanocompo- 23 sites have become of considerable interest as magnetic catalysts in 24 both academic and industrial ﬁelds. The use of these magnetic 25 nanoparticle catalysts can address the isolation and recycling 26 problem encountered in many heterogeneous and homogenous 27 catalytic reactions, since they can also be recovered with an 28 external magnetic ﬁeld and their catalytic efﬁciency remains after 29 many repeated reaction cycles [3]. Most importantly, the 30 magnetic-supported catalysts show not only high catalytic 31 activity, but also high degree of chemical stability and they do 32 not swell in organic solvents. 33 The Fe 3 O 4 nanoparticles are easily prepared and surface 34 functionalized and can be isolated and recycled from the 35 solution by an external magnetic ﬁeld. Thus, the catalyst 36 supported on Fe 3 O 4 nanoparticles can be easily separated from 37 the reaction system and reused. At present, much attention is 38 focused on the synthesis of magnetic core –shell structures by 39 coating a SiO 2 shell around a preformed nanoparticle. Silica 40 coatings can not only keep the magnetic cores from erosion in 41 acidic solutions, but also effectively screen from intersystem 42 dipolar interactions, and provide a platform for easy surface 43 modiﬁcation by silanol groups that are useful for practical 44 applications. As a result, the silica-coated, magnetic nanopar- 45 ticles have received more and more attention as promising 46 candidates for wide applications. 47 Homogeneous catalysts show higher catalytic activities than 48 their heterogeneous counter parts because of their solubility in 49 reaction media, which increases catalytic site accessibility for the 50 substrate. But, the recycling of homogeneous catalysts is often 51 tedious and time consuming and there is also product contamina- 52 tion observed when these catalysts are reused. Transition metals 53 have been considerably studied because of their ability for use as 54 catalysts in a wide range of reactions. However, homogenous metal 55 catalysts are easily deactivated through the formation of dimeric 56 peroxo and m-oxo species. To overcome the aforementioned 57 drawbacks, the recent applications of complex of metal ions 58 supported on superparamagnetic Fe 3 O 4 @SiO 2 nanoparticles were 59 reported as an efﬁcient, selective and recyclable catalyst for 60 reactions [4–8]. Chinese Chemical Letters xxx (2014) xxx–xxx A R T I C L E I N F O Article history: Received 7 February 2014 Received in revised form 13 April 2014 Accepted 28 April 2014 Available online xxx Keywords: Magnetic nanoparticles Fe 3 O 4 Bromochromate A B S T R A C T We describe a novel method for the synthesis a new magnetic bromochromate hybrid nanomaterial, Fe 3 O 4 @SiO 2 @TEA@[CrO 3 Br], as a catalyst. The physical properties, morphology and magnetic investigations of magnetic bromochromate hybrid nanomaterials are identiﬁed by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) techniques. Fourier transform infrared (FT-IR), elemental analysis, X-ray ﬂuorescence (XRF), X-ray diffraction (XRD) were also used for structural identiﬁcation. The quantity of chromium is approximately 0.38%, which conﬁrms to the immobilization amount of [CrO 3 Br]  and is equal to 0.007 mol/100 g. ß 2014 Ali Maleki. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. * Corresponding author. E-mail address: maleki@iust.ac.ir (A. Maleki). G Model CCLET 2984 1–4 Please cite this article in press as: R. Rahimi, et al., Synthesis and characterization of a new magnetic bromochromate hybrid nanomaterial with triethylamine surface modiﬁed iron oxide nanoparticles, Chin. Chem. Lett. (2014), http://dx.doi.org/10.1016/ j.cclet.2014.05.006 Contents lists available at ScienceDirect Chinese Chemical Letters jo u rn al h om epag e: ww w.els evier.c o m/lo cat e/cc let http://dx.doi.org/10.1016/j.cclet.2014.05.006 1001-8417/ß 2014 Ali Maleki. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.