纯位移核磁共振氢谱及其应用

J耦合引起的核磁共振(NMR)信号多重裂分的数目和耦合常数反映了磁性原子核之间的化学键数目和空间位置信息,是研究分子结构的重要依据之一.但是当分子中磁性原子核数目增加时,NMR谱图特别是一维核磁共振氢谱(1D ~1H NMR)中,J耦合所致的多重裂分造成谱图重叠,严重干扰结构指认和定量分析.利用纯位移(亦称宽带同核去耦)~1H NMR谱图可以消除J耦合效应(即将相邻质子间耦合所引起的多重裂分融合成一个单峰),得到与去耦碳谱相似的、只含化学位移信息的谱图.该文首先介绍了三种最受关注的获取纯位移核磁共振氢谱技术——BIRD、ZS和PSYCHE的基本原理,随后综述了纯位移~1H NMR谱图的典型应用.

Pure Shift Proton NMR Spectroscopy and Its Applications

Jcoupling gives rise to spectral multiplets (i.e. resonance from one spin is split into a group of equally spaced lines placed symmetrically around the chemical shift). Such spectral splitting contains information on molecular structure, and is therefore useful for structural elucidation. However, when the number of spin increases and many spectral multiplets are present, the spectra, especially proton spectra, could become very crowded, making structural elucidation and quantitative analysis difficult. Using the pure shift (i.e., broadband homonuclear decoupling) proton NMR technique, one could collapse spectral multiplets into singlets, and obtain spectra containing only chemical shift information. In this paper, we give brief introductions to three most widely used pure shift proton NMR techniques, namely BIRD, ZS, and PSYCHE, and describe typical applications of such techniques.