Two-dimensional solid-state proton NMR and proton exchange
Two-dimensional solid-state proton NMR and proton exchange
复制标题
二维固态质子核磁共振和质子交换
DOI：
10.1021/ja00067a045
复制
发表时间：
1993
影响因子：
15
通讯作者：
J. Herzfeld
中科院分区：
文献类型：
--
作者：
Ling Zheng;K. Fishbein;R. Griffin;J. Herzfeld
采用氘自旋稀释和高速魔角自旋（MAS）相结合的方法获得了高分辨率的固态1h核磁共振谱。质子与氘核的反向交叉极化（RCP）降低了质子的有效弛豫时间t1。利用RCP获得的二维1 H NOESY光谱研究了固体中的质子交换，这种方法观察到的快速质子交换与氢键有关。定量分析了二维光谱强度随混合时间（温度）的变化规律，确定了草酸二水合物中草酸部分羧基与水合水之间质子/氘核交换的速率和活化能
High-resolution solid-state 1 H NMR spectra were obtained by combining deuterium spin-dilution and high-speed magic-angle spinning (MAS). The effective proton relaxation time T 1 , which is long in these magnetically dilute samples, was reduced by reverse cross-polarization (RCP) of protons from deuterons. Two-dimensional 1 H NOESY spectra obtained with RCP were used to investigate proton exchange in solids, and the rapid proton exchange observed in this way was linked to hydrogen bonds. A quantitative analysis of the dependence of the 2D spectral intensities on mixing time, as a function of temperature, was employed to determine the rates, and activation energies, for proton/deuteron exchange between the carboxyl groups of the oxalate moiety and the water of hydration in oxalic acid dihydrate