Model System for Solid-State NMR Study on Co-condensation Behavior of Silicon Precursors in Periodic Mesoporous Organosilicas

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/28312

Title:	Model System for Solid-State NMR Study on Co-condensation Behavior of Silicon Precursors in Periodic Mesoporous Organosilicas
Authors:	Pan,YC;Wu,HY;Kao,CC;Kao,HM;Shieh,YN;Fey,GTK;Chang,JH;Tsai,HHG
Contributors:	中央大學
Keywords:	MOLECULAR-SCALE PERIODICITY;CHANNEL WALLS;PORE WALLS;BRIDGING GROUPS;ORGANIC GROUPS;SURFACTANT;SBA-1;CRYSTAL;ORGANIZATION;MORPHOLOGY
Date:	2009
Issue Date:	2010-06-29 19:45:56 (UTC+8)
Publisher:	化學研究所
Abstract:	Ordered periodle mesoporous organosilloas containing diffeerent fractions of benzene groups in the sillen framework based on the cubic SBA-1 mesostructure (Pm3n mesophase), were synthesized with teh direct. synthesis route via co-condensation of tetraethoxysilane (TEOS) and 1,4 bis(triethoxysilyl)benzene (BTEB) under acidic conditions using cetyltriethylammonium bromide as a structure-directing agent. A significantly large amount of TEOS, up to 70 mol % based on silica, can be incorporated into the silica wall without degrading the structural integrity of the materials. By optimization of the synthesis compositions, the resulting materials exhibited much higher surface areas (up to 1210 m(2)/g) and larger pore volumes (up to 0.64 cm(2)/g) as compared to the previous analogue, which only exhibited a surface area of 381 m(2)/g and a pore volume of 0.11 cm(3)/g. Two-dimensional (2D) Si-29 {H-1} heteronuclear correlation (HETCOR) NMR spectra, acquired as a function of contact time, provided direct spectroscopic evidence that a single mesophase with various Q (from TEOS) and T silicon species (from BTEB) located randomly within the pore walls via co-condensation of BTEB and TEOS at a molecular level. Such information is often not achievable by other characterization techniques, The H-1-Si-29 distance information between phenylene protons and nearby V silicon atoms obtained from density functional theory calculations is also in good agreement with the observations of 2D Si-29(H-1) HETCOR NMR experiments.
Relation:	JOURNAL OF PHYSICAL CHEMISTRY C
Appears in Collections:	[Graduate Institute of Chemistry] journal & Dissertation

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