Study by solid-state NMR of /sup 133/Cs and /sup 1/H of a hydrated and dehydrated cesium mordenite
Study by solid-state NMR of /sup 133/Cs and /sup 1/H of a hydrated and dehydrated cesium mordenite
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通过固态NMR研究水合和脱水铯丝光沸石的/sup 133/Cs和/sup 1/H
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
K. Klier
中科院分区：
文献类型：
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作者：
P. Chu;B. C. Gerstein;J. Nunan;K. Klier
测定了碳交换丝光沸石中/sup 133/Cs和/sup 1/H的固态核磁共振，并将其作为沸石脱水的函数。在完全水合的丝光沸石中，/sup 133/Cs（I=7/2）的单线比饱和CsCl高64 ppm。在魔角纺丝下，Cs在-57 ppm和-190 ppm处，无水样品呈现出两条强度为3:1的主谱线。主要的强度是在水合样品中观察到的线的前场。无水样品的电场梯度参数为e/sup 2/qQ = 3.1 MHz, eta = 0.65，水合样品的电场梯度参数降为e/sup 2/qQ = 210 kHz, eta = 0。Cs在无水样品中占据的三个位点的分配和相应的化学位移为位点II， -157 ppm；site IV, -186 ppm；而站点VI在二阶四极移校正后为-24 ppm。在完全水合和无水样品之间，静态质子光谱的强度下降了35倍。当质子谱线宽度保持在6.6 kHz时，其形状随脱水而变化，且在无水样品中表现出各向异性。
The solid-state NMR of /sup 133/Cs and /sup 1/H in Cs-exchanged mordenite has been monitored as a function of dehydration of the zeolite. In the fully hydrated mordenite, /sup 133/Cs(I=7/2) exhibits a single line 64 ppm upfield of aqueous saturated CsCl. The anhydrous sample exhibits two major lines of intensities 3:1 with center of mass at -57 and -190 ppm, respectively, for Cs under magic-angle spinning. The major intensity is upfield of the line observed in the hydrated sample. The electric field gradient parameters for Cs of the anhydrous sample are e/sup 2/qQ = 3.1 MHz and eta = 0.65, which reduced to e/sup 2/qQ = 210 kHz and eta = 0 for the hydrated sample. Assignment for the three sites occupied by Cs in the anhydrous sample and the corresponding chemical shifts are site II, -157 ppm; site IV, -186 ppm; and site VI, -24 ppm after correction for the second-order quadrupolar shift. The static proton spectra decrease in intensity by a factor of 35 between the fully hydrated and anhydrous sample. While maintaining a roughly constant width of 6.6 kHz, the shape of the proton line changes with dehydration and exhibits an anisotropy in the anhydrous sample.