Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot (Israel) http://www.weizmann.ac.il/chemphys/Frydman_group/home.html; Current address: Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 150 Albany St, NW14, Cambridge, MA 02139 (USA).
Angew Chem Int Ed Engl. 2015 Jan 7;54(2):594-8. doi: 10.1002/anie.201407869. Epub 2014 Sep 26.
Samples prepared following dissolution dynamic nuclear polarization (DNP) enable the detection of NMR spectra from low-γ nuclei with outstanding sensitivity, yet have limited use for the enhancement of abundant species like (1)H nuclei. Small- and intermediate-sized molecules, however, show strong heteronuclear cross-relaxation effects: spontaneous processes with an inherent isotopic selectivity, whereby only the (13)C-bonded protons receive a polarization enhancement. These effects are here combined with a recently developed method that delivers homonuclear-decoupled (1)H spectra in natural abundance samples based on heteronuclear couplings to these same, (13)C-bonded nuclei. This results in the HyperBIRD methodology; a single-shot combination of these two effects that can simultaneously simplify and resolve complex, congested (1)H NMR spectra with many overlapping spin multiplets, while achieving 50-100 times sensitivity enhancements over conventional thermal counterparts.
采用溶解动态核极化（DNP）技术制备的样品可实现低γ核 NMR 谱的高灵敏度检测，但对于（1）H 等丰核的增强作用有限。然而，小分子和中等大小的分子表现出强烈的异核交叉弛豫效应：这是一种具有固有同位素选择性的自发过程，只有（13）C 键合的质子会受到极化增强。这些效应与最近开发的方法相结合，该方法基于与这些相同的（13）C 键合核的异核偶合，在自然丰度样品中提供同核去耦（1）H 谱。这导致了 HyperBIRD 方法的出现；这两种效应的单次组合可以同时简化和分辨复杂、拥挤的（1）H NMR 谱，其中包含许多重叠的自旋多重峰，同时相对于常规热对应物实现 50-100 倍的灵敏度增强。
