Lin Yanqin, Chen Zhong, Cai Shuhui, Zhong Jianhui
Department of Physics, State Key Laboratory for Physical Chemistry of Solid Surface, Xiamen University, Xiamen, Fujian, PR China.
J Magn Reson. 2008 Feb;190(2):298-306. doi: 10.1016/j.jmr.2007.11.010. Epub 2007 Nov 22.
Two new NMR pulse sequences, based on intermolecular multiple-quantum coherences (iMQCs), were developed to obtain apparent J coupling constants with a scaling factor from one to infinity relative to the conventional J coupling constants. Here the apparent J coupling constants were defined as apparent peak separations in unit of Hz in a reconstructed spectrum for a coupled spin system. Except for the adjustable scaling factor for apparent J coupling constants, the sequences hold the advantage of high acquisition efficiency, and retain the spectral information such as chemical shifts, multiplet patterns, and relative peak areas under inhomogeneous fields. For spin systems with small scalar coupling constants, well-resolved J-spectra can be achieved by selecting a proper scaling factor. Theoretical predictions are in good agreement with simulation results and experimental observations.
基于分子间多量子相干（iMQCs）开发了两种新的核磁共振脉冲序列，以获得相对于传统J耦合常数具有从1到无穷大缩放因子的表观J耦合常数。这里，表观J耦合常数被定义为耦合自旋系统在重建谱中以Hz为单位的表观峰间距。除了表观J耦合常数的可调缩放因子外，这些序列具有采集效率高的优点，并在非均匀场下保留了化学位移、多重峰模式和相对峰面积等光谱信息。对于具有小标量耦合常数的自旋系统，通过选择合适的缩放因子可以实现分辨率良好的J谱。理论预测与模拟结果和实验观察结果吻合良好。
