title: Synthesis and solid-state NMR characterization of cubic mesoporous silica SBA-1 functionalized with sulfonic acid groups.
abstract: Well-ordered cubic mesoporous silicas SBA-1 functionalized with sulfonic acid groups have been synthesized through in situ oxidation of mercaptopropyl groups with H(2)O(2) via co-condensation of tetraethoxysilane (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) templated by cetyltriethylammonium bromide (CTEABr) under strong acidic conditions. Various synthesis parameters such as the amounts of H(2)O(2) and MPTMS on the structural ordering of the resultant materials were systematically investigated. The materials thus obtained were characterized by a variety of techniques including powder X-ray diffraction (XRD), multinuclear solid-state Nuclear Magnetic Resonance (NMR) spectroscopy, (29)Si{(1)H} 2D HETCOR (heteronuclear correlation) NMR spectroscopy, thermogravimetric analysis (TGA), and nitrogen sorption measurements. By using (13)C CPMAS NMR technique, the status of the incorporated thiol groups and their transformation to sulfonic acid groups can be monitored and, as an extension, to define the optimum conditions to be used for the oxidation reaction to be quantitative. In particular, (29)Si{(1)H} 2D HETCOR NMR revealed that the protons in sulfonic acid groups are in close proximity to the silanol Q(3) species, but not close enough to form a hydrogen bond.
authors.affiliation: Department of Chemistry, National Central University, Chung-Li 32054, Taiwan, ROC.
authors.forename: Hui-Hsu Gavin
authors.initials: HH
authors.lastname: Tsai
authors.forename: Po-Jui
authors.initials: PJ
authors.lastname: Chiu
authors.forename: Guang-Liang
authors.initials: GL
authors.lastname: Jheng
authors.forename: Chun-Chiang
authors.initials: CC
authors.lastname: Ting
authors.forename: Yu-Chi
authors.initials: YC
authors.lastname: Pan
authors.forename: Hsien-Ming
authors.initials: HM
authors.lastname: Kao
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D010316:Particle Size; D016062:Porosity; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D013451:Sulfonic Acids; D012822:Silicon Dioxide