Bakhmutov Vladimir I, Shpeizer Boris G, Clearfield Abraham
Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, USA.
Magn Reson Chem. 2006 Sep;44(9):861-7. doi: 10.1002/mrc.1866.
Some silica-based solids, prepared by the sol/gel method in the presence of high Mn2+ concentrations, have been characterized by the 29Si, 27Al MAS NMR spectra and 29Si T1 measurements. The single-pulse 29Si and 27Al MAS NMR spectra have shown broad spinning sideband patterns that are interpreted in terms of anisotropic bulky magnetic susceptibility (BMS) and dipole-field effects. In the absence of paramagnetic isotropic shifts, the 29Si and 27Al nuclei observed in the single-pulse NMR spectra have been assigned to nuclei remote from paramagnetic centers. It has been demonstrated that the 29Si and 27Al nuclei, which are in the vicinity of the manganese ions, can be detected by the Hahn-echo MAS NMR experiments at different carrier frequencies.
通过溶胶/凝胶法在高浓度Mn2+存在下制备的一些硅基固体，已通过29Si、27Al MAS NMR光谱和29Si T1测量进行了表征。单脉冲29Si和27Al MAS NMR光谱显示出宽的旋转边带模式，这些模式根据各向异性体积磁化率（BMS）和偶极场效应进行了解释。在不存在顺磁各向同性位移的情况下，单脉冲NMR光谱中观察到的29Si和27Al核已被归属于远离顺磁中心的核。已经证明，在锰离子附近的29Si和27Al核可以通过不同载频的Hahn回波MAS NMR实验检测到。
