固体核磁共振魔角旋转条件下的定量交叉极化技术（英文）

Quantitative Cross Polarization Magic-Angle Spinning NMR Spectroscopy in Solids

交叉极化与魔角旋转结合(CP/MAS)的方法已经成为增强固体核磁共振(NMR)检测灵敏度最重要的技术之一.CP/MAS技术的应用大大提高了固体NMR谱图的采集效率.然而,I-S偶极耦合作用、旋转坐标系下的自旋-晶格弛豫、分子运动,以及样品中丰核的分布情况等因素,通常会导致CP/MAS谱图失去定量作用.近年来,多个研究组通过改进或者设计新型固体NMR脉冲序列,获得了基于CP的可用于定量分析的固体NMR谱图.本综述首先简要介绍了CP及CP动力学,随后介绍了一系列基于CP的定量固体NMR信号增强技术,具体包括ramped-amplitude CP(RAMP-CP)、multiple-contact CP、quantification of CP(QCP)、Lee-Goldburg frequency modulated CP(LG-FMCP)和quantitative CP(QUCP).

The combination of cross polarization and magic-angle spinning(CP/MAS),is a routine technique for signal enhancement in solid-state nuclear magnetic resonance(NMR)spectrum.With CP/MAS,the acquisition efficiency of solid-state NMR experiments can be improved greatly.However,the enhanced signal is not quantitative according to the different CP dynamics dominated by several factors including heteronuclear dipolar couplings,spin-lattice relaxation times in the rotating frame,molecular motions,number of around abundant spins,and so on.Over the years,numerous efforts have been made to obtain quantitative CP/MAS spectroscopy.This review firstly briefly illustrated the introduction of CP and CP dynamics,and then a series of quantitative NMR methods based on CP were introduced,including ramped-amplitude CP(RAMP-CP),multiplecontact CP,quantification of CP(QCP),Lee-Goldburg frequency modulated CP(LG-FMCP)and quantitative CP(QUCP).