Shao Limin, Crockford Charles, Geen Helen, Grasso Giuseppe, Titman Jeremy J
School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
J Magn Reson. 2004 Mar;167(1):75-86. doi: 10.1016/j.jmr.2003.11.005.
A new NMR experiment which allows a measurement of the chemical shift anisotropy (CSA) tensor under magic angle spinning (MAS) is described. This correlates a fast MAS spectrum in the omega2 dimension with a sideband pattern in omega1 in which the intensities mimic those for a sample spinning at a fraction of the rate omega r/N, and these sidebands result from an amplification by a factor N of the modulation caused by the CSA. Standard methods can be used to extract the principal tensor components from the omega1 sideband patterns, and the nature of the experiment is such that the use of a large number of t1 increments can be avoided without compromising the resolution of different chemical sites. The new experiment is useful for accurately measuring narrow shift anisotropies.
本文描述了一种新的核磁共振实验，该实验能够在魔角旋转（MAS）条件下测量化学位移各向异性（CSA）张量。此实验将ω2维度中的快速MAS谱与ω1中的边带模式相关联，其中边带强度模拟了以ωr/N的分数速率旋转的样品的边带强度，这些边带是由CSA引起的调制放大N倍所致。可使用标准方法从ω1边带模式中提取主张量分量，并且该实验的特性在于，无需牺牲不同化学位点的分辨率，就能避免使用大量的t1增量。这种新实验对于精确测量窄位移各向异性很有用。
