Efficient NMR pulse sequences to transfer the parahydrogen-induced polarization to hetero nuclei
Efficient NMR pulse sequences to transfer the parahydrogen-induced polarization to hetero nuclei
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DOI：
10.1021/ja960067f
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发表时间：
1996-09-11
影响因子：
15
通讯作者：
Bargon, J
中科院分区：
文献类型：
--
作者：
Haake, M;Natterer, J;Bargon, J
PASADENA或PHIP效应源于氢化后发现两个质子处于磁性不相等位置时仲氢对称性的破坏。结果，可以观察到质子NMR谱中高达10（4）的信号增强。本文介绍了三种高效记录仲氢标记化合物原位杂原子NMR谱的极化转移技术，即PH-INEPT、PH-INEPT+和INEPT（+pi/4）。给出了C-13和Si-29的完整乘积算符处理和实验结果。用这些序列，我们得到了500的信号增强，这使得在原位NMR调查的异核系统在自然丰度。
The PASADENA or PHIP effect originates from the breakdown of the parahydrogen symmetry when the two protons are found in magnetically inequivalent positions after hydrogenation. As a result, a signal enhancement of up to 10(4) in the proton NMR spectra can be observed. We introduce three polarization transfer techniques, namely PH-INEPT, PH-INEPT+, and INEPT(+pi/4), that are highly effective to record in situ hetero NMR spectra of parahydrogen-labeled compounds. A complete product operator treatment as well as experimental results for C-13 and Si-29 have been given. With these sequences we obtained a signal enhancement of 500 which allows in situ NMR investigations of hetero nuclear systems at natural abundance.