Accessibility of Amino Groups in Postsynthetically Modified Mesoporous Silica
Accessibility of Amino Groups in Postsynthetically Modified Mesoporous Silica
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DOI：
10.1021/jp901983j
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发表时间：
2009-05
影响因子：
3.7
通讯作者：
H. Ritter;D. Brühwiler
中科院分区：
文献类型：
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作者：
H. Ritter;D. Brühwiler
通过与异硫氰酸荧光素（FITC）反应，研究了合成后功能化介孔分子筛MCM-41、MCM-48和SBA-15中氨基的可及性。定量分析的表面接枝的氨基基团的量耦合的FITC在很宽的负载范围内提供有关潜在的孔阻塞的信息。在3 - 4 nm的孔径范围内，具有一维通道系统（MCM-41）的材料的实际孔径强烈影响FITC偶联产率和锚定荧光素部分的分布。在SBA-15（7.6 nm孔径）的情况下，接枝氨基的可及性类似于具有完全开放表面的材料的预期可及性。然而，在SBA-15的壁内微孔中接枝导致相当大部分的不可接近的氨基。作为短通道长度和大的外表面积的直接后果，也观察到纳米尺寸的M…
The accessibility of amino groups in postsynthetically functionalized mesoporous silica MCM-41, MCM-48, and SBA-15 is investigated by reaction with fluorescein isothiocyanate (FITC). The quantitative analysis of the surface-grafted amino groups in relation to the amount of coupled FITC over a wide range of loadings affords information about potential pore blocking. In the pore diameter domain of 3−4 nm, the actual pore size of materials with a one-dimensional channel system (MCM-41) strongly affects the FITC coupling yield and the distribution of the anchored fluorescein moieties. In the case of SBA-15 (7.6 nm pore diameter), the accessibility of the grafted amino groups is similar to what is expected for a material with a completely open surface. However, grafting in the intrawall micropores of SBA-15 leads to a substantial fraction of inaccessible amino groups. As a direct consequence of short channel lengths and large external surface area, excellent accessibility is also observed for nanometer-sized M...