Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Am Chem Soc. 2013 Feb 27;135(8):2935-8. doi: 10.1021/ja312265x. Epub 2013 Feb 13.
We report direct (13)C dynamic nuclear polarization at 5 T under magic-angle spinning (MAS) at 82 K using a mixture of monoradicals with narrow EPR linewidths. We show the importance of optimizing both EPR linewidth and electron relaxation times by studying direct DNP of (13)C using SA-BDPA and trityl radical, and achieve (13)C enhancements above 600. This new approach may be best suited for dissolution DNP and for studies of (1)H depleted biological and other nonprotonated solids.
我们报告了在 5 T 下使用具有较窄 EPR 线宽的单自由基混合物在 MAS 下进行的直接(13)C 动态核极化,在 82 K 下进行。通过研究使用 SA-BDPA 和三苯基自由基的(13)C 直接 DNP,我们展示了优化 EPR 线宽和电子弛豫时间的重要性,并实现了超过 600 的(13)C 增强。这种新方法可能最适合溶解 DNP 和研究(1)H 耗尽的生物和其他非质子化的固体。