13C n.m.r. in organic solids: limits to spectral resolution and to determination of molecular motion
13C n.m.r. in organic solids: limits to spectral resolution and to determination of molecular motion
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13C 核磁共振
DOI：
10.1098/rsta.1981.0038
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
W. Earl
中科院分区：
文献类型：
--
作者：
A. N. Garroway;D. Vanderhart;W. Earl
高分辨率核磁共振成像的历史。在固体中，阿利亚是对窄谱线的追求。然而，除了少数例外，固态共振还没有被锐化到液体共振的程度。帮助评估n.m.r.的状况。在固体中，我们确定并总结了13 C n.m.r.的特殊情况。在有机固体中，这些影响会降低分辨率。其中一些机制是在实验者的控制之下;例如，某些在高磁场下会加剧。然而，其他的，代表由标本施加的基本限制，是有效的反射的复杂性的固体相比，液体。在固体中，磁偶极自旋-自旋耦合不仅会降低分辨率，而且会使自旋-晶格弛豫速率的测定复杂化，在某些情况下，这是毫无希望的，人们可以从中寻找分子运动的信息。这种自旋自旋和自旋晶格效应之间的竞争的后果进行检查，以及标准和策略，以隔离的运动的贡献弛豫率。
The history of high-resolution n.m.r. in solids has been, inter alia, a quest for narrow spectral lines. Yet, with few exceptions, solid state resonances have not been sharpened to the degree of liquid resonances. To aid in the appraisal of the status of n.m.r. in solids, we identify and summarize, for the particular case of 13C n.m.r. in organic solids, those effects that can degrade resolution. Some of these mechanisms are under the experimenter’s control; for example, certain are exacerbated at high magnetic field. Others, however, represent fundamental limitations imposed by the specimen and are valid reflections of the complexity of a solid as contrasted to a liquid. In solids, magnetic dipolar spin-spin couplings can not only degrade resolution but also complicate, hopelessly in some cases, the determination of spin-lattice relaxation rates from which one seeks information about molecular motions. The consequences of this competition between spin-spin and spin-lattice effects are examined, as well as criteria and strategies to isolate the motional contributions to relaxation rates.