Efficient Dynamic Nuclear Polarization at 800 MHz/527 GHz with Trityl-Nitroxide Biradicals.
Efficient Dynamic Nuclear Polarization at 800 MHz/527 GHz with Trityl-Nitroxide Biradicals.
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使用三苯甲基氮氧双自由基在 800 MHz/527 GHz 下实现高效动态核极化。
DOI：
10.1002/anie.201504292
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发表时间：
2015-09-28
期刊：
影响因子：
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通讯作者：
Griffin RG
中科院分区：
文献类型：
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作者：
Mathies G;Caporini MA;Michaelis VK;Liu Y;Hu KN;Mance D;Zweier JL;Rosay M;Baldus M;Griffin RG
交叉效应(CE)动态核极化(DNP)是一种快速发展的增强魔角旋转(MAS)核磁共振谱信号强度的技术。我们报道了在211、600和800 MHz的CE DNP实验，使用了一系列被称为TEMTriPol的新的双自由基极化器，其中一个氮氧化物(TEMPO)和一个三丁基自由基被化学拴住。性能最佳的TEMTriPol分子在甘油/水溶剂基质中的浓度为10 mM时，在800 MHz频率下产生创纪录的H 核磁共振信号增强65。对于TEMTriPol双自由基，CE DNP的增强作用并不像通常观察到的双氮氧自由基那样，随着磁场的增加而减小。相反，三苯基和氮氧化物之间相对较强的交换作用决定了观察到最佳增强的磁场。
Cross-effect (CE) dynamic nuclear polarization (DNP) is a rapidly developing technique that enhances the signal intensities in magic-angle spinning (MAS) NMR spectra. We report CE DNP experiments at 211, 600, and 800 MHz using a new series of biradical polarizing agents referred to as TEMTriPols, in which a nitroxide (TEMPO) and a trityl radical are chemically tethered. The TEMTriPol molecule with the optimal performance yields a record (1) H NMR signal enhancement of 65 at 800 MHz at a concentration of 10 mM in a glycerol/water solvent matrix. The CE DNP enhancement for the TEMTriPol biradicals does not decrease as the magnetic field is increased in the manner usually observed for bis-nitroxides. Instead, the relatively strong exchange interaction between the trityl and nitroxide moieties determines the magnetic field at which the optimum enhancement is observed.