Homonuclear J-Coupling Spectroscopy at Low Magnetic Fields using Spin-Lock Induced Crossing**
Homonuclear J-Coupling Spectroscopy at Low Magnetic Fields using Spin-Lock Induced Crossing**
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DOI：
10.1002/cphc.202100162
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发表时间：
2021-08-23
期刊：
影响因子：
2.9
通讯作者：
Rosen, Matthew S.
中科院分区：
文献类型：
--
作者：
DeVience, Stephen J.;Greer, Mason;Rosen, Matthew S.
核磁共振光谱学通常需要很高的磁场才能在不同的质子物种之间产生光谱分辨率。虽然质子信号也可以在低场下探测到，但如果J耦合比化学位移色散强，则光谱表现为单线。在这项工作中，我们证明了在这种强耦合状态下，仍然可以使用一种称为自旋锁定诱导交叉(SLIC)的新型脉冲序列来获得光谱。这项技术探测由微弱的自旋锁定脉冲引起的能级交叉，并为大多数有机分子产生独特的J耦合光谱。与其他形式的低场J耦合光谱不同，我们的技术不需要异核的存在，并且可以用于大多数处于自然状态的化合物。我们对一些小分子在276 kHz和20.8 MHz进行了SLIC光谱，结果表明模拟的SLIC光谱与测量结果吻合得很好。
Nuclear magnetic resonance (NMR) spectroscopy usually requires high magnetic fields to create spectral resolution among different proton species. Although proton signals can also be detected at low fields the spectrum exhibits a single line if J-coupling is stronger than chemical shift dispersion. In this work, we demonstrate that the spectra can nevertheless be acquired in this strong-coupling regime using a novel pulse sequence called spin-lock induced crossing (SLIC). This techniques probes energy level crossings induced by a weak spin-locking pulse and produces a unique J-coupling spectrum for most organic molecules. Unlike other forms of low-field J-coupling spectroscopy, our technique does not require the presence of heteronuclei and can be used for most compounds in their native state. We performed SLIC spectroscopy on a number of small molecules at 276 kHz and 20.8 MHZ and show that the simulated SLIC spectra agree well with measurements.