High-resolution nuclear magnetic resonance spectroscopy for measuring hydrogen-hydrogen J coupling constant

Abstract

The invention provides a high-resolution nuclear magnetic resonance spectroscopy for measuring a hydrogen-hydrogen J coupling constant. The method comprises the following steps: after a 90-degree excitation pulse is applied, applying a monochromatic selective 180-degree pulse to a to-be-detected proton, delaying for t1/2 time, applying a dichromatic selective 180-degree pulse to the to-be-detectedproton and another proton coupled with the to-be-detected proton, and delaying for t1/2 time; carrying out sampling after an evolution period; after the experiment is finished, extracting starting delta time length data from each group of data, and sequentially splicing the data into new one-dimensional data; and carrying out Fourier transform, so as to obtain a new one-dimensional spectrum required by a user, wherein only a signal for detecting the proton selected by the user is maintained, and only J coupling cracking between the proton and another selected proton is maintained. Therefore,the J coupling constant between the two protons can be accurately measured.

Description

technical field [0001] The invention relates to a nuclear magnetic resonance method, in particular to a high-resolution nuclear magnetic resonance spectrum method for measuring hydrogen-hydrogen scalar coupling constants. Background technique [0002] Scalar coupling (also called J coupling) is an important property in NMR spectroscopy, which can provide important information about molecular structure. Hydrogen-hydrogen J-couplings play an important role in molecular structure identification, especially hydrogen-hydrogen triple bond J-couplings, which can provide dihedral angle information between two carbon-hydrogen bonds. Therefore, the study and measurement of the hydrogen-hydrogen J coupling constant has become an important topic in NMR spectroscopy. The hydrogen-hydrogen J coupling constant can be measured from the distance between the corresponding split peaks in the one-dimensional hydrogen spectrum. However, in conventional one-dimensional proton NMR spectroscopy, ...

AI Technical Summary

Problems solved by technology

However, in conventional NMR one-dimensional hydrogen spectroscopy, due to the small range of chemical shift distribution and complex splitting modes, it is often not easy to measure the J coupling constant.

Conventional J-decomposition two-dimensional spectroscopy reduces signal crowding and improves measurement accuracy by separating chemical shift and J-coupling into two dimensions, but is still limited by complex J-coupling splitting

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