Dynamic nuclear polarization experiments at 14.1 T for solid-state NMR
Dynamic nuclear polarization experiments at 14.1 T for solid-state NMR
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DOI：
10.1039/c002268c
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发表时间：
2010-01-01
影响因子：
3.3
通讯作者：
Fujiwara, Toshimichi
中科院分区：
文献类型：
--
作者：
Matsuki, Yoh;Takahashi, Hiroki;Fujiwara, Toshimichi
开发了 14.1 T 高场动态核极化 (DNP) 仪器，以增强固体 NMR 的核极化。陀螺仪在二次谐波 TE(0,6) 模式下产生 394.5 GHz 亚毫米 (sub-mm) 波，功率为 40 W。功率为 0.5-3 W 的亚毫米波通过具有光滑壁圆形波导系统的低温 DNP-NMR 探头传输到样品。对于具有硝酰基双自由基 TOTAPOL 的 (13)C 标记化合物，观察到高达约 10 的 (1)H 偏振增强因子。 DNP 增强通过 90 K NMR 信号振幅的静磁场依赖性得到证实。讨论了高场 DNP 实验的改进。
Instrumentation for high-field dynamic nuclear polarization (DNP) at 14.1 T was developed to enhance the nuclear polarization for NMR of solids. The gyrotron generated 394.5 GHz submillimeter (sub-mm) wave with a power of 40 W in the second harmonic TE(0,6) mode. The sub-mm wave with a power of 0.5- 3 W was transmitted to the sample in a low-temperature DNP-NMR probe with a smooth-wall circular waveguide system. The (1)H polarization enhancement factor of up to about 10 was observed for a (13)C-labeled compound with nitroxyl biradical TOTAPOL. The DNP enhancement was confirmed by the static magnetic field dependence of the NMR signal amplitude at 90 K. Improvements of the high-field DNP experiments are discussed.