Jameson Cynthia J
Contribution from the Department of Chemistry, M/C-111, University of Illinois at Chicago, 845 West Taylor, Chicago, IL 60607-7061, USA.
J Am Chem Soc. 2004 Aug 25;126(33):10450-6. doi: 10.1021/ja040012a.
We report, for the first time, a theoretical prediction of the (129)Xe nuclear magnetic resonance chemical shift tensor of xenon atom in a single crystal of silicalite at near-zero occupancy and the temperature dependence of the Xe NMR chemical shift tensor for the polycrystalline silicalite at maximum occupancy. The former is a measure of the sensitivity of the Xe tensor components to the local structure of the channels without Xe-Xe contributions. The latter is a measure of the sensitivity of the Xe-Xe tensor components to the Xe-Xe distributions, as determined by the Xe-Xe potential function in competition with the Xe-silicalite potential function. Both theoretical predictions can be compared against Xe NMR experiments: the first against the Xe spectra collected as a function of rotation of the single crystal about the three crystalline axes in a magnetic field, and the second against variable temperature Xe NMR studies (below room temperature) of polycrystalline silicalite at maximum Xe occupancy. With the same parameter set (Xe-O potential and shielding functions), we predict the line shapes of Xe in SSZ-24 zeolite under various conditions of occupancy and temperature.
我们首次报道了在接近零占有率的硅铝酸盐单晶中氙原子的（129）Xe核磁共振化学位移张量的理论预测，以及在最大占有率下多晶硅铝酸盐中Xe NMR化学位移张量的温度依赖性。前者衡量了Xe张量分量对通道局部结构的敏感性，且无Xe-Xe贡献。后者衡量了Xe-Xe张量分量对Xe-Xe分布的敏感性，这是由与Xe-硅铝酸盐势函数竞争的Xe-Xe势函数决定的。这两个理论预测都可以与Xe NMR实验进行比较：第一个与在磁场中围绕单晶的三个晶轴旋转收集的Xe光谱进行比较，第二个与在最大Xe占有率下多晶硅铝酸盐的变温Xe NMR研究（低于室温）进行比较。使用相同的参数集（Xe-O势和屏蔽函数），我们预测了在各种占有率和温度条件下SSZ-24沸石中Xe的线形。
