Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
J Am Chem Soc. 2012 Sep 5;134(35):14287-90. doi: 10.1021/ja304918g. Epub 2012 Aug 23.
The synthesis of air-stable, highly water-soluble organic radicals containing a 1,3-bis(diphenylene)-2-phenylallyl (BDPA) core is reported. A sulfonated derivative, SA-BDPA, retains the narrow electron paramagnetic resonance linewidth (<30 MHz at 5 T) of the parent BDPA in highly concentrated glycerol/water solutions (40 mM), which enables its use as polarizing agent for solid effect dynamic nuclear polarization (SE DNP). A sensitivity enhancement of 110 was obtained in high-field magic-angle-spinning (MAS) NMR experiments. The ease of synthesis and high maximum enhancements obtained with the BDPA-based radicals constitute a major advance over the trityl-type narrow-line polarization agents.
本文报道了一种空气稳定的、高度水溶性的有机自由基的合成方法，该自由基含有 1,3-双（二苯基）-2-苯丙基（BDPA）核心。磺化衍生物 SA-BDPA 在高浓度甘油/水溶液（40 mM）中保留了母体 BDPA 的窄电子顺磁共振线宽（5 T 时小于 30 MHz），这使其可用作固态效应动态核极化（SE DNP）的极化剂。在高场魔角旋转（MAS）NMR 实验中获得了 110 的灵敏度增强。与三苯基型窄线极化剂相比，基于 BDPA 的自由基的合成容易和高的最大增强是一个重大进展。
