Lesage A, Emsley L
Laboratoire de Stéréochimie et des Interactions Moléculaires, UMR-117 CNRS/ENS, Ecole Normale Supérieure de Lyon, 69364 Lyon, France.
J Magn Reson. 2001 Feb;148(2):449-54. doi: 10.1006/jmre.2000.2249.
A new through-bond carbon-proton correlation technique, the MAS-J-HSQC experiment, is described for solid-state NMR. This new pulse scheme is compared experimentally with the previously proposed MAS-J-HMQC experiment in terms of proton resolution on a model sample of powdered L-alanine. We show that for natural abundance compounds, the MAS-J-HMQC and MAS-J-HSQC experiments give about the same proton resolution, whereas, for (13)C-labeled materials, narrower proton linewidths are obtained with the MAS-J-HSQC experiment. In addition we show that in scalar as well as in dipolar heteronuclear shift correlation experiments, when the proton chemical shift is encoded by the evolution of a single-quantum coherence, the proton resolution can be enhanced by simply adding a 180 degrees carbon pulse in the middle of the t(1) evolution time.
本文描述了一种用于固态核磁共振的新的直接键连碳-质子相关技术——MAS-J-HSQC实验。在粉末状L-丙氨酸模型样品上,就质子分辨率而言,将这种新的脉冲序列与先前提出的MAS-J-HMQC实验进行了实验比较。我们表明,对于天然丰度的化合物,MAS-J-HMQC和MAS-J-HSQC实验给出的质子分辨率大致相同,而对于(13)C标记的材料,MAS-J-HSQC实验可获得更窄的质子线宽。此外,我们还表明,在标量以及偶极异核位移相关实验中,当质子化学位移由单量子相干的演化编码时,通过在t(1)演化时间中间简单添加一个180°碳脉冲,可以提高质子分辨率。