Dynamic Nuclear Polarization with Vanadium(IV) Metal Centers
Dynamic Nuclear Polarization with Vanadium(IV) Metal Centers
复制标题
钒（IV）金属中心的动态核极化
DOI：
10.1016/j.chempr.2020.10.021
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发表时间：
2021-02-11
期刊：
影响因子：
23.5
通讯作者：
Han, Songi
中科院分区：
文献类型：
--
作者：
Jain, Sheetal Kumar;Yu, Chung-Jui;Han, Songi
动态核极化(DNP)利用电子自旋的大极化来显著提高核磁共振(核磁共振)的灵敏度。这项研究扩大了DNP的范围，使其超越了传统的关注使用外源极化剂(PA)超极化溶剂网络的范围。我们引入了具有内源V4+中心的H-1DNP，它位于一组具有可调的V4+-H-1距离的钒基配合物中。我们跟踪了从V4+到H-1自旋的极化转移，特别是区分了直接的V4+-(1)HS极化转移和H-1自旋扩散介导的主体溶剂H-1极化建立，并说明了V4+-H-1距离对这些过程的影响。这些结果加深了我们对极化途径的理解，并将光谱分析的范围扩展到宽线过渡金属。这项研究建立了关键的第一步，为DNP使用战略定位的内源顺磁金属中心和超精细DNP光谱的概念框架奠定了基础，该概念框架融合了对目标核自旋的空间和化学诊断。
Dynamic nuclear polarization (DNP) harnesses the large polarization of electron spins to dramatically increase nuclear magnetic resonance (NMR) sensitivity. This study expands the scope of DNP beyond its traditional focus on hyperpolarizing the solvent network using exogenous polarizing agents (PAs). We introduce H-1 DNP with endogenous V4+ centers positioned in a set of vanadyl complexes with tunable V4+-H-1 distances. We traced the polarization transfer from V4+ to H-1 spins, specifically differentiating between direct V4+-(1)Hs polarization transfer and the H-1 spin-diffusion-mediated bulk solvent H-1 polarization buildup and illuminated the effect of the V4+-H-1 distance on these processes. These results deepen our understanding of polarization pathways and expand the catalog of PAs to broad-line transition metals. This study establishes crucial first steps toward employing strategically positioned endogenous paramagnetic metal centers for DNP and the conceptual framework of hyperfine DNP spectroscopy that merges both spatial and chemical diagnosis of target nuclear spins.