Tungstate Supported on Periodic Mesoporous Organosilica with Imidazolium Framework as an Efficient and Recyclable Catalyst for the Selective Oxidation of Sulfides Babak Karimi,* [a] Mojtaba Khorasani, [a] Fatemeh Bakhshandeh Rostami, [a] Dawood Elhamifar, [b] and Hojatollah Vali [c] Introduction Since the discovery of ordered mesoporous silica (OMS), [1] a va- riety of organic–inorganic hybrid mesoporous materials with high specific surface area, available pore volume, and tunable pore size have been developed extensively in view of their po- tential applications in various fields from catalysis [2] and ad- sorption [3] to nanoelectronics [4] and controlled drug delivery. [5] These surfactant-derived organo-functionalized ordered meso- porous materials are typically synthesized either by terminally bonded siliceous organic groups [(R’O) 3 Si R] through co-con- densation or post-grafting of surface silanol groups in the parent OMS. [2d, 6] Moreover, these materials have attracted great interest from the viewpoints of academia and industry, be- cause many of their characteristics, such as hydrophilicity/hy- drophobicity, mechanical/hydrothermal stability, and other chemical or physical properties, can be adjusted intelligently and simply by varying the nature of the immobilized organic group (R). [7] In this way, a large number of successful incorpora- tions of various sophisticated organosilanes into the nano- space of OMS have been reported by applying post-grafting and/or co-condensation, but it has been proven that this ap- proach could potentially lead to a dramatic pore-blocking effect and inhomogeneous distribution of organic functional groups throughout the surface of these materials. [8] In addition, in many circumstances, the long-range order of the resulting material could be reduced dramatically if an organic content (organosilane precursors) greater than 25 % was employed during the co-condensation methods. [9] To overcome these limitations, periodic mesoporous organo- silicas (PMOs), which were built by the self-assembly of bridged organosilane precursors [(R’O) 3 SiRSi(OR’) 3 ] in the pres- ence of surfactants as structure-directing agents (SDAs), were developed. [10] Because PMOs often exhibit large internal sur- face areas and open pore structures, the organic bridging groups inside the pore wall of mesochannels are readily acces- sible to molecules diffusing through the porous matrix, [11] a fea- ture that makes these materials a unique platform in preparing advanced functionalized catalysts for important liquid-phase organic transformation. [12] Compared with functionalized OMSs, the PMO surface reactivity, hydrophilicity/hydrophobicity bal- ance, structural rigidity, and mass-transfer rate as well as its surface, optical, electronic, magnetic, and charge-transport properties, can be readily tuned for specific applications in a more sophisticated way. [13] In recent years, many catalytic systems based on PMOs com- prising simple groups, such as sulfonic acids, Brønsted or Lewis bases, and phenylene, as well as bulky organic functional groups, such as phosphine complex, 1,1’-bi-2-naphthol (BINOL), 2,2’-bis(diphenylphosphino)-1,1’-binaphthyl (BINAP), A catalyst based on immobilization of tungstate ions (WO 4 2 ) inside the mesochannels of periodic mesoporous organosilica comprising bridged ionic liquid (1,3-bis(3-trimethoxysilylprop- yl)imidazolium chloride) has been synthesized and character- ized. This catalyst was then employed for the selective oxida- tion of organic sulfides to the corresponding sulfoxides or sul- fones. The final synthesized catalyst was characterized by vari- ous techniques such as nitrogen sorption analysis, transmission electron microscopy, and thermogravimetric analysis. The cata- lyst was also applied to the selective oxidation of sulfides con- taining readily oxidizable functional groups such as hydroxyl, allylic, and even challenging aliphatic sulfides. Interestingly, it was found that on changing the reaction medium from aque- ous methanol to aqueous acetonitrile, the product selectivity was changed successfully from sulfoxide to sulfone with good to excellent yields. Moreover, the catalyst can also be recov- ered and reused efficiently in nine subsequent reaction cycles without any remarkable decrease in the catalyst activity and selectivity. [a] Prof. Dr. B. Karimi, Dr. M. Khorasani, F. Bakhshandeh Rostami Department of Chemistry Institute for Advanced Studies in Basic Science (IASBS) P.O. Box 45195-159, Gava Zang, Zanjan 45195 (Iran) Fax: (+ 98) 241-4153232 E-mail : karimi@iasbs.ac.ir [b] Dr. D. Elhamifar Department of Chemistry Yasouj University, Yasouj 75918-74831 (Iran) [c] Prof. H. Vali Department of Anatomy and Cell Biology and Facility for Electron Microscopy Research McGill University, 3450 University St., Montreal, QC H3A 2A7 (Canada) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/cplu.201500010. ChemPlusChem 0000, 00,0–0  0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 1 & These are not the final page numbers! ÞÞ These are not the final page numbers! ÞÞ Full Papers DOI: 10.1002/cplu.201500010