二氧化硅表面硅官能团分布的高分辨率29Si固体核磁共振研究
High-resolution 29Si solid-state NMR study of silicon functionality distribution on the surface of silicas.
作者信息
Luhmer M, d'Espinose J B, Hommel H, Legrand A P
机构信息
Laboratoire de Physique Quantique, URA CNRS 1428 ESPCI, Paris, France.
出版信息
Magn Reson Imaging. 1996;14(7-8):911-3. doi: 10.1016/s0730-725x(96)00180-4.
29Si solid-state NMR allows us to distinguish silicon atoms involved in siloxane bridges (Q4), single silanol (Q3) and geminal silanol groups (Q2) on the surface of silica. The relative proportions of each species can be obtained by Magic Angle Spinning (MAS) associated with 1H-->29Si crosspolarization (CP/MAS). This preliminary study deals with the silicon functionality of MCM-41, a purely siliceous, amorphous and mesoporous silica. From the 29Si spectra the relative proportions are estimated to be 3.7% Q2 27.3% Q3 and 69.0% Q4, while the ratio Q2/Q2 + Q3) is 0.12. These results are found to be in perfect agreement with a binomial probability distribution of sites.
29Si 固体核磁共振使我们能够区分二氧化硅表面参与硅氧烷桥（Q4）、单硅醇（Q3）和连位硅醇基团（Q2）的硅原子。每种物种的相对比例可以通过与 1H→29Si 交叉极化（CP/MAS）相关的魔角旋转（MAS）获得。这项初步研究涉及 MCM-41 的硅官能团，MCM-41 是一种纯硅质、无定形的介孔二氧化硅。从 29Si 光谱估计，相对比例为 3.7% Q2、27.3% Q3 和 69.0% Q4，而 Q2/（Q2 + Q3）的比率为 0.12。发现这些结果与位点的二项式概率分布完全一致。
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