Delivered by Publishing Technology to: Deakin University Library IP: 40.130.45.22 On: Mon, 04 Jan 2016 04:13:48 Copyright: American Scientific Publishers Copyright © 2015 American Scientific Publishers All rights reserved Printed in the United States of America Article Journal of Nanoscience and Nanotechnology Vol. 15, 9358–9368, 2015 www.aspbs.com/jnn Recyclable Mesoporous Ceria Supported Gold Nanoparticles Based Catalyst for O-Arylation of Phenols P. Emayavaramban 1 * , S. Ganesh Babu 2 3 , R. Karvembu 3 , and N. Dharmaraj 1 * 1 Inorganic and Nanomaterials Research Laboratory, Department of Chemistry, Bharathiar University, Coimbatore 641046, India 2 SRM Research Institute, SRM University, Kattankulathur 603203, India 3 Department of Chemistry, National Institute of Technology, Tiruchirappalli 620015, India Ceria supported gold nanoparticles (Au-CeO 2 NPs) were prepared by a simple deposition- precipitation method. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and Raman analysis indicated the formation of gold nanoparticles over phase pure cerianite ceria sup- port. The presence of gold nanoparticles was well identified by UV-DRS study. In addition, the field emission scanning electron microscope (FESEM) and high resolution transmission electron micro- scope (HR-TEM) images revealed that the maximum number of particles having spherical shape were approximately 10 nm size. Subsequently, surface area of the catalyst determined from BET, Langmuir and DFT methods were found to be 83.1, 134 and 85.2 m 2 g −1 respectively. N 2 absorption- desorption measurement revealed that Au–CeO 2 NPs was mesoporous in nature. Au–CeO 2 NPs proved to be an efficient catalyst for the O-arylation reactions. The reaction conditions were opti- mized using 2,6-dimethoxyphenol and 1-chloro-4-nitrobenzene as a model substrate by changing the solvent, base, quantity of catalyst, and temperature. The scope of the work was extended to various substituted phenols and aryl halides (F, Cl and Br) and reusabilityof catalyst was tested for four cycles which showed no loss in its activity. Keywords: Gold Nanoparticles, Ceria Support, Mesoporous Materials, Catalysts, Phenols, O-Arylation. 1. INTRODUCTION Diaryl ether synthesis is an important strategy in organic chemistry. Many of the naturally occurring compounds consists of basic structural units are diaryl ethers, which are highly active drug for several human diseases. Among them, gerfelin is the human inhibitor geranylgeranyl diphosphate (GGPP) isolated from beauveria felina and thyroxin which is the major hormone secreted by the fol- licular cells of the thyroid gland and was among the first diaryl ethers detected in nature and prepared in the laboratory (Fig. 1). Furthermore, pulcherosine and van- comycin are powerful antibiotics clinically used to combat methicillin-resistant Staphylococcus aureus (MRSA). 1 In general, diaryl ethers are synthesized on transi- tion metal-catalyzed systems, as it was introduced by Hartwig. 2 3 Later, developments were made by Buchwald, * Authors to whom correspondence should be addressed. who developed a library of substituted phenolic nucle- ophiles and aromatic electrophiles as reagents for the syn- thesis of diaryl ethers. 4 5 The extensive, usage of Cu, Pd and Ni complexes have reported for the syntheses of diaryl ethers using aryl halides. 6–9 However, this method was limited by harsh reaction conditions, such as high tem- perature, excess amount of catalysts and reagents, use of highly expensive ligands. 10 Recently CuO nanoparticles were found to be an efficient heterogeneous catalyst for O-arylation reaction. 11 Moreover noble metal nanoparti- cles has loss or decreases in its catalytic activity because of change of oxidation state ranging from Pd(0) to Pd(IV) and for Cu(0) to Cu(II). 12 Inorder to overcome these limita- tions, much attention has been recently focused to develop catalytic systems to the environmental impact (E-factor) of the processes. 13 14 Gold nanoparticles (AuNPs) are of immense interest in the catalysis owing to small size, high surface area 9358 J. Nanosci. Nanotechnol. 2015, Vol. 15, No. 12 1533-4880/2015/15/9358/011 doi:10.1166/jnn.2015.10354