的共同结构动机中的相互作用张量和局部动力学:固态14NNMR和DFT研究
Luke A O'Dell1, Robert W Schurko, Kristopher J Harris
1Steacie Institute for Molecular Sciences, National Research Council, 100 Sussex Drive, Ottawa, K1A 0R6 Ontario, Canada. luke.odell@nrc-cnrc.gc.ca
Journal of the American Chemical Society
|December 25, 2010
概括
超宽线 (14) N固态NMR成功探测了分子结构和动态. 这种方法准确地确定电场梯度张量参数,并揭示了各种系统中的动态过程的洞察力.
科学领域:
- 固态核磁共振 (NMR) 光谱学. 固态核磁共振 (NMR) 光谱学.
- 材料科学和计算化学.
背景情况:
- 固态核磁共振对于描述分子结构和动态至关重要.
- -14 ((14) N) NMR对其本地电子环境敏感,但获得详细信息可能具有挑战性.
研究的目的:
- 开发和验证一种先进的 (14) N固态核磁共振方法,用于精确确定电场梯度 (EFG) 张量参数.
- 研究有机和无机系统中的分子动力学和结构性质.
主要方法:
- 在高磁场 (21.1 T) 采用宽带,频率扫描脉冲和分片采集方法获取 (14) N 固态NMR粉末图案.
- 使用四极卡尔-普尔塞尔梅布姆-吉尔 (QCPMG) 协议,根据T(2) 放松差异选择性增强环境.
- 执行广泛的密度函数理论 (DFT) 计算,以比较和解释实验结果.
主要成果:
- 成功获得了对具有不对称环境 (C(Q) 的系统的EFG张量参数,直至大约. 4 MHz) 的频率.
- 观察到 (14) N T(2) 放松异质性,提供了关于运动几何和跳跃速度的见解.
- 证明分子动力学可以调节EFG张量或异核二极合,影响 (14) N光谱.
- DFT的计算与实验数据有很好的一致性,可以预测张量定向和地点分配.
结论:
- 超宽线 (14) N 固态核磁共振是一种强大而简单的探测分子结构和动态的技术.
- 开发的方法准确地描述了EFG张量,并提供了关于分子运动的有价值信息.
- 结合先进的NMR技术和DFT计算,提供了一种全面的方法来理解复杂的环境.
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