通过17O固态NMR光谱在19.6 T的模型Gly-Gly-Gly中进行离子结合研究
Eduard Y Chekmenev1, Kevin W Waddell, Jun Hu
1NMR Program, National High Magnetic Field Laboratory (NHMFL), Tallahassee, Florida 32310, USA.
Journal of the American Chemical Society
|July 27, 2006
概括
(Li(+)) 和 (Ca(2+)) 离子与基氧基的结合显著改变了 (17) O NMR 特性. 离子结合效应在这个模型系统中远大于结合的效应.
科学领域:
- 固态NMR光谱学 固态NMR光谱学
- 计算化学计算化学
- 生物物理学的生物物理.
背景情况:
- 的结构和功能受到离子相互作用的影响.
- 了解离子结合机制需要详细的分子见解.
- 固态NMR光谱学提供了关于分子结构和动态的原子级信息.
研究的目的:
- 为了研究Li(+) 和Ca(2+) 对基基氧原子的结合的影响.
- 为了比较离子结合与结合对17O NMR参数的影响.
- 阐明模型系统中金属离子协调引起的特定扰动.
主要方法:
- 使用了高磁场 (19.6 T) 的固态NMR光谱 (17) O.
- 采用静止和快速魔法角旋转 (MAS) 技术来获得光谱.
- 增强实验数据与密度函数理论 (DFT) 对分子的计算.
主要成果:
- 在四个Gly- ((Gly- ((17) O) -Gly多态中确定了 (17) O化学转移 (CS) 和四极合 (QC) 张量.
- 在离子结合时,观察到 (17) O CS张力元件 (delta(11),delta(22) 的显著下降.
- 据报道,由于离子协调,四极合常数减少了高达1MHz.
- 量化离子结合效应大约大约一个数量级大于结合效应.
结论:
- (((+) 和Ca (((2+) 结合诱导了17O核糖氧基的NMR参数的实质性变化.
- 离子协调显著扰乱了碳酸氧原子的电子环境.
- 固态NMR和DFT计算提供了对离子-相互作用的补充见解.
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