13C 魔角旋转核磁共振中的增强型三量子激发

Enhanced triple-quantum excitation in 13C magic-angle spinning NMR.

作者信息

Carravetta Marina, Schmedt auf der Günne Jörn, Levitt Malcolm H

机构信息

Physical Chemistry Division, Stockholm University, S-106 91, Sweden.

出版信息

J Magn Reson. 2003 Jun;162(2):443-53. doi: 10.1016/s1090-7807(03)00059-4.

DOI:10.1016/s1090-7807(03)00059-4

PMID:12810030

Abstract

We describe a new method for exciting triple-quantum coherences in 13C-labelled powder samples under MAS. The proposed method combines selective double-quantum excitation with rotational resonance and frequency-selective composite pulses. The spin dynamics of this new method are described theoretically. Numerical calculations of the spin dynamics are compared to experimental results on fully 13C-labelled L-alanine. The observed triple-quantum filtering efficiency is around 10% for the most intense spectral peak. The method is also demonstrated on other fully 13C-labelled compounds, including a uniformly 13C-labelled amino acid.

摘要

我们描述了一种在魔角旋转（MAS）下激发13C标记粉末样品中三量子相干的新方法。所提出的方法将选择性双量子激发与旋转共振和频率选择性复合脉冲相结合。从理论上描述了这种新方法的自旋动力学。将自旋动力学的数值计算结果与全13C标记的L-丙氨酸的实验结果进行了比较。对于最强的光谱峰，观察到的三量子滤波效率约为10%。该方法也在其他全13C标记的化合物上得到了验证，包括一种均匀13C标记的氨基酸。