Ionosilica
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Ionosilicas are defined as organosilicas containing chemically bound ionic groups. They represent a class of mesoporous organosilicas.
Mesoporous materials have been defined as porous materials with pore size ranging from 2 nm – 50 nm. Ionosilicas belong to the mesoporous organosilicas materials, but are more specifically constituted by ionic substructures.
Ionosilicas are synthesized by hydrolysis-polycondensation reactions or post synthesis grafting procedures involving ionic precursors.[1] Due to their mixed mineral-ionic nature, ionosilicas are situated at the interface of silica hybrid materials and ionic liquids.[2] Similarly to conventional functional silica based materials, two classes of ionosilicas can be distinguished, depending on the way the ionic group is anchored to the silica support and where it is located. Surface functionalized ionosilicas contain ionic groups located on the materials’ surface and can be obtained either via ‘one-pot’ co-condensation reactions[2] or post grafting procedures.[3][4] On the other side, periodic mesoporous ionosilicas, belonging to the PMO family, are produced starting from oligosilylated ionic precursors.[5][6][7]
Ionosilicas are synthesized via hydrolysis-polycondensation reactions involving ionic precursors. The ionic nature of these compounds has deep influence on the mechanism of the formation of the solid. Ionosilicas with regular architectures are often formed in the presence of anionic surfactants. This behaviour displays the formation of precursor-surfactant ion pairs in the hydrolysis polycondensation mixture.
These hybrid ionosilicas display very specific and unusual surface properties such as high hydrophilicity and high water-affinity. These features can efficiently be varied both via the cation[8] and the anion,[9] resulting in an ability to fine-tune the properties of these materials. Ionosilicas are functional materials for applications in (organo-)catalysis and separation.
References
[edit]- ^ Hesemann, Peter; Nguyen, Thy; Hankari, Samir (11 April 2014). "Precursor Mediated Synthesis of Nanostructured Silicas: From Precursor-Surfactant Ion Pairs to Structured Materials". Materials. 7 (4): 2978–3001. Bibcode:2014Mate....7.2978H. doi:10.3390/ma7042978. PMC 5453373. PMID 28788602.
- ^ a b Gadenne, Benoît; Hesemann, Peter; Moreau, Joël J. E. (2004). "Supported ionic liquids: ordered mesoporous silicas containing covalently linked ionic species". Chemical Communications (15): 1768–1769. doi:10.1039/B405036C. PMID 15278177.
- ^ El Kadib, Abdelkrim; Hesemann, Peter; Molvinger, Karine; Brandner, Jérôme; Biolley, Christine; Gaveau, Philippe; Moreau, Joël J. E.; Brunel, Daniel (4 March 2009). "Hybrid Materials and Periodic Mesoporous Organosilicas Containing Covalently Bonded Organic Anion and Cation Featuring MCM-41 and SBA-15 Structure". Journal of the American Chemical Society. 131 (8): 2882–2892. doi:10.1021/ja807630j. PMID 19193105.
- ^ Motos-Pérez, Blanca; Roeser, Jérôme; Thomas, Arne; Hesemann, Peter (May 2013). "Imidazolium-functionalized SBA-15 type silica: efficient organocatalysts for Henry and cycloaddition reactions". Applied Organometallic Chemistry. 27 (5): 290–299. doi:10.1002/aoc.2974.
- ^ Nguyen, Thy Phuong; Hesemann, Peter; Linh Tran, Thi My; Moreau, Joël J. E. (2010). "Nanostructured polysilsesquioxanes bearing amine and ammonium groups by micelle templating using anionic surfactants". Journal of Materials Chemistry. 20 (19): 3910. doi:10.1039/B925352A.
- ^ Nguyen, Thy Phuong; Hesemann, Peter; Moreau, Joël J.E. (June 2011). "i-Silica: Nanostructured silica hybrid materials containing imidazolium groups by hydrolysis-polycondensation of disilylated bis-N,N′-alkyl-imidazolium halides". Microporous and Mesoporous Materials. 142 (1): 292–300. doi:10.1016/j.micromeso.2010.12.014.
- ^ Hankari, Samir El; Motos-Pérez, Blanca; Hesemann, Peter; Bouhaouss, Ahmed; Moreau, Joël J.E. (2011). "Periodic mesoporous organosilica from zwitterionic precursors". Chemical Communications. 47 (23): 6704–6706. doi:10.1039/C1CC11649E. PMID 21559546.
- ^ Thach, U.D.; Prelot, B.; Hesemann, P. (30 July 2015). "Hybrid Ionosilica containing aromatic groups". The European Physical Journal Special Topics. 224 (9): 1669–1674. Bibcode:2015EPJST.224.1669T. doi:10.1140/epjst/e2015-02489-4. S2CID 98703302.
- ^ Journal of the Taiwan Institute of Chemical Engineers 2014, 45, 2868-2877.