A phase-sensitive selective j-spectroscopy method for suppressing axial peaks

Abstract

The invention discloses a phase-sensitive selective J spectrum method for suppressing an axial peak, and relates to a nuclear magnetic resonance multidimensional spectrum method. The method comprises:applying a 90-degree hard pulse, rotating a magnetization vector to an XY plane from a Z direction, selecting an S core by using a 180-degree selective pulse and a pair of phase dispersion gradients,other transverse magnetization vectors being subjected to phase dispersion, and applying a perfect echo module; setting parameters, an excitation angle and a corresponding gradient of the PSYCHE module; determining the number ni of indirect dimensional sampling points and the spectral width SW1, and ensuring that the J coupling constant measured by the SW1 is large; setting the cycle index Nt ofthe sampling window; performing direct dimensional Fourier transform on the sampled N-type signal and R-type signal, adding real parts of the N-type signal and R-type signal after Fourier transform toserve as a real part of a composite signal, subtracting the real parts to serve as an imaginary part of the composite signal, and performing indirect dimensional Fourier transform on the composite signal to obtain a phase-sensitive selective J spectrum. The method is more accurate, has high spectrogram resolution, and can be widely used in complex compound structure analysis.

Description

technical field [0001] The invention relates to a nuclear magnetic resonance multidimensional spectrum method, in particular to a phase-sensitive selective J spectrum method for suppressing axial peaks. Background technique [0002] The interaction between spin nuclei and spin nuclei is a main information in the NMR spectrum, which reflects the information of organic structure, especially the information of three-dimensional structure chemistry, which is widely used in the study of molecular conformation. Selective J spectroscopy is a well-established NMR method for measuring J coupling constants. Denis Merlet from the UK proposed a G-SERF method based on the ZS module (Nicolas G, Laetitia B, Jacques C, Denis M. Nuclear Magnetic Resonance Using a Spatial Frequency Encoding: Application to J-Edited Spectroscopy along the Sample.Angew Chem Int Ed Engl.2009 ,55:1090-1093), this method can be used to analyze the J-coupling network of a certain hydrogen atom of interest, and mea...

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Problems solved by technology

Morris then proposed the PSYCHEDELIC method based on the PSYCHE module (A general method for extracting individual coupling constants from crowded 1H NMR spectrum, Angew.Chem.Int.Ed.55(2016) 1090-1093). However, in these conventional selective J spectrum methods Among them, the narrow chemical shift distribution, complex split peak mode and large spectral peak line width make the axial peak intensity of the two-dimensional spectrum too large to cover the response coupling signal, so that the J coupling cannot be identified

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