Temporal Chemical Shift Correlations in Reactions Studied by Hyperpolarized Nuclear Magnetic Resonance
Temporal Chemical Shift Correlations in Reactions Studied by Hyperpolarized Nuclear Magnetic Resonance
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DOI：
10.1021/ac900456q
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发表时间：
2009-06-01
影响因子：
7.4
通讯作者：
Hilty, Christian
中科院分区：
文献类型：
--
作者：
Bowen, Sean;Hilty, Christian
高分辨率核磁共振波谱（NMR）具有提供分子结构和动力学方面无与伦比的细节的能力。通过超极化，可以实现信号强度的决定性增益，从而扩大了核磁共振的适用性，以研究远离平衡的快速过程。不可逆化学和生化反应的进展可以用超极化核磁共振相对容易地跟踪，在一个可观察的窗口内，包括亚秒到秒的时间尺度。在这里，我们提出了一种方案，该方案使用实时、超极化增强核磁共振，除了简单地监测反应过程外，还可以获得时间相关性。由于即使携带自旋的原子直接参与反应，核自旋状态也能保持，因此随着时间的推移，将这些原子在反应物和生成物之间的位置联系起来成为可能。我们演示了该技术在3-甲基二苯甲酮甲基溴化镁格氏加成反应中的应用。同样的实验也可用于确定有机化学、酶学或蛋白质折叠等领域非平衡过程的机制和中间状态。
High-resolution nuclear magnetic resonance spectroscopy (NMR) has the capability of providing often unrivaled detail on molecular structure and dynamics. Through hyperpolarization, a decisive gain in signal strength can be realized, which extends the applicability of NMR to the investigation of rapid processes far from equilibrium. The progress of irreversible chemical and biochemical reactions can be followed by hyperpolarized NMR with relative ease, within an observable window encompassing the subsecond to second time scales. Here, we present a scheme that uses real-time, hyperpolarization enhanced NMR to make temporal correlations accessible in addition to simply monitoring reaction progress. Since nuclear spin states can be preserved even if the spin carrying atoms directly participate in a reaction, it becomes possible to correlate the positions of these atoms between the reactant and the product species, over time. We demonstrate the application of this technique to the Grignard addition of methylmagnesium bromide to 3-methylbenzophenone. The same experiment may be used for the determination of mechanisms and intermediate states in non-equilibrium processes in fields as varied as organic chemistry, enzymology, or protein folding.