Ultra-fast MAS NMR probe

超快 MAS NMR 探头

• 批准号: 359075-2008
• 负责人: Wasylishen, Roderick
• 金额: $ 10.11万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments - Category 1 (<$150,000)
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=365917
• 关键词: Ultra; fast; MAS; NMR; probe

This is a request for funds to purchase a double-resonance NMR probe capable of spinning samples of solid materials at frequencies of 60 kHz or greater.  The probe will be designed to operate in an 11.75 T NMR system (500 MHz 1H NMR frequency) and will allow experimentalists at the University of Alberta to spin samples at frequencies approximately double those currently possible.  Ultra-fast spinning of solid samples about an axis inclined at 54.73561 degrees (the "magic-angle") with respect to the applied magnetic field will expand the capabilities of researchers considerably.  First, experiments involving paramagnetic systems will greatly benefit from the rapid sample spinning capabilities because fewer spinning side bands will result in less cluttered spectra.  Furthermore, the signal intensities that are normally distributed in the spinning sidebands will be concentrated in the "isotropic" NMR peak(s).  Second, the small radio-frequency coils used in ultra-fast NMR probes (diameter 1.3 mm) allow for better coupling of the radio-frequency pulses and the nuclear magnetic moments of the sample.  This leads to better 1H-decoupling efficiency and narrowing of "dilute-spin" NMR spectra.  Finally, for abundant spins (e.g., 1H) the resolution achieved via ultra-fast sample spinning is an effective alternative to homonuclear dipolar decoupling via tedious multipulse techniques.  Because of this "line-narrowing", many 2D techniques including indirect 1H-detection experiments become feasible.  The very recent solid-state NMR literature indicates that many new techniques and applications involving ultra-fast MAS are waiting to be discovered.

这是一项资金申请，用于购买能够以 60 kHz 或更高频率旋转固体材料样品的双共振 NMR 探头。  该探针将设计为在 11.75 T NMR 系统（500 MHz 1H NMR 频率）中运行，并允许阿尔伯塔大学的实验人员以大约是目前可能频率的两倍的频率旋转样品。  固体样品围绕与所施加的磁场成 54.73561 度（“魔角”）倾斜的轴进行超快速旋转将大大扩展研究人员的能力。  首先，涉及顺磁系统的实验将极大地受益于快速样品旋转能力，因为旋转边带越少，光谱就越杂乱。  此外，通常分布在旋转边带中的信号强度将集中在“各向同性”NMR 峰中。  其次，超快核磁共振探头（直径 1.3 毫米）中使用的小型射频线圈可以更好地耦合射频脉冲和样品的核磁矩。  这导致更好的 1H 解耦效率和“稀释自旋”NMR 谱的缩小。  最后，对于丰富的自旋（例如 1H），通过超快样品自旋实现的分辨率是通过繁琐的多脉冲技术实现同核偶极去耦的有效替代方案。  由于这种“线窄化”，许多 2D 技术（包括间接 1H 检测实验）变得可行。  最近的固态核磁共振文献表明，许多涉及超快 MAS 的新技术和应用有待发现。