探测通过质子检测到的O-H键1H-17O双共振固态NMR光谱
Scott L Carnahan1,2, Bryan J Lampkin1, Pranjali Naik1,2
1Department of Chemistry , Iowa State University , Ames , Iowa 50011 , United States.
Journal of the American Chemical Society
|December 12, 2018
概括
这项研究通过使用快速魔角旋转和质子检测来增强氧-17固态NMR,提高分子结构分析的灵敏度和分辨率.
科学领域:
- 固态核磁共振光谱
- 材料科学
- 化学物理
背景情况:
- 氧-17 (17O) 固态NMR对于研究分子结构和动力学至关重要.
- 传统的17O核磁共振实验具有低灵敏度和广泛的信号,限制了它们的应用.
- 开发先进的核磁共振技术对于克服这些局限性至关重要.
研究的目的:
- 展示一种提高170个固态NMR实验灵敏度和分辨率的一般方法.
- 能够准确地确定各种化学系统中相对于氧原子的质子位置.
- 扩大17ONMR在探测氧相互作用中的实用性.
主要方法:
- 使用D-RINEPT脉冲序列与质子检测相结合的快速魔法角度旋转 (MAS) 的应用.
- 获得2D 17O → 1H D-RINEPT相关性NMR光谱.
- 纳入J分辨或分离的局部场块 (SLF) 用于测量标尺和二极合.
- 使用平面波密度函数理论 (DFT) 进行计算分析.
主要成果:
- 使用最小的物质 (< 10 mg) 和低的17O丰富度 (< 20%) 在不到10小时内获得完整的2D1H-17O相关谱.
- 使用质子化学转移和变化的磁化转移时间来证明重叠的氧气位点的分辨率.
- 成功测量了1H-17O单键标量 (1JOH) 和双极 (DOH) 合,使得可以推断键长度.
- DFT的计算显示出与实验合常数的良好一致.
结论:
- 开发的2D 1H-17O相关性NMR方法显著提高了17O固态NMR的灵敏度和分辨率.
- 这种技术可以精确地确定与氧原子相对的质子位置.
- 这种方法为研究不同化学环境中的氧-相互作用提供了新的途径.
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