Schneider Denis, Toufar Helge, Samoson Ago, Freude Dieter
Bruker BioSpin GmbH, Silberstreifen, 76287 Rheinstetten, Germany.
Solid State Nucl Magn Reson. 2009 Apr;35(2):87-92. doi: 10.1016/j.ssnmr.2009.02.003. Epub 2009 Feb 26.
We demonstrate complementary (1)H, (17)O, (27)Al and (29)Si measurements for basic low-silica-X zeolites, which were unloaded and pyrrole and formic acid-loaded. It was found that the acid-base-system is not stabile, if the loading exceeds one pyrrole molecule or two formic acid molecules per supercage.(17)O DOR NMR spectra exhibit at least four lines, which are broadened by a distribution of chemical shifts in a similar extend as the (29)Si MAS NMR spectra are broadened by distribution of Si-O-Al angles. A strong cation influence upon (17)O shifts was observed. But there was no strong influence of the acid molecules on the mean value of the (17)O shift of the spectra.
我们展示了对未负载以及负载吡咯和甲酸的碱性低硅X型沸石进行的互补性氢-1、氧-17、铝-27和硅-29测量。结果发现，如果每个超笼的负载超过一个吡咯分子或两个甲酸分子，酸碱体系就不稳定。氧-17双旋转核磁共振光谱显示至少有四条谱线，其化学位移分布使其变宽，变宽程度与硅-29魔角旋转核磁共振光谱因硅-氧-铝角分布而变宽的程度相似。观察到阳离子对氧-17位移有强烈影响。但酸分子对光谱中氧-17位移的平均值没有强烈影响。
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