Efficient conversion of anti-phase spin order of protons into 15N magnetisation using SLIC-SABRE
Efficient conversion of anti-phase spin order of protons into 15N magnetisation using SLIC-SABRE
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DOI：
10.1080/00268976.2018.1515999
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发表时间：
2019-10-02
影响因子：
1.7
通讯作者：
Ivanov, Konstantin L.
中科院分区：
文献类型：
--
作者：
Knecht, Stephan;Kiryutin, Alexey S.;Ivanov, Konstantin L.
SABRE（Signal Amplification By Reversible Exchange）是一种用于增强NMR（核磁共振）信号的技术，其利用仲氢（pH（2），处于其核单重态自旋状态的H-2分子）作为非热自旋序的来源。在SABRE实验中，pH（2）瞬时结合到具有待极化衬底的有机金属络合物;随后，发生自旋序转移，并且衬底获得非热自旋极化，从而导致强NMR信号增强。在这项工作中，我们认为，在SABRE实验中进行的H-2的自旋顺序在高磁场不一定是单态顺序，而是反相极化。虽然SABRE利用pH（2），即H-2的起始自旋顺序被认为是单线态顺序，但在溶液中，一旦pH（2）结合到复合物上，S-T-0转化就变得有效。这种自旋顺序的变化，它成为，有一个重要的后果：用于转移SABRE极化的NMR方法需要修改。在这里，我们证明了为初始单态顺序提出的方法可能不适用于该顺序;然而，一个简单的修改使它们再次有效。[图形]。
SABRE (Signal Amplification By Reversible Exchange) is a technique for enhancement of NMR (Nuclear Magnetic Resonance) signals, which utilises parahydrogen (pH(2), the H-2 molecule in its nuclear singlet spin state) as a source of non-thermal spin order. In SABRE experiments, pH(2) binds transiently to an organometallic complex with a to-be-polarised substrate; subsequently, spin order transfer takes place and the substrate acquires non-thermal spin polarisation resulting in strong NMR signal enhancement. In this work, we argue that the spin order of H-2 in SABRE experiments performed at high magnetic fields is not necessarily the singlet order but rather anti-phase polarisation, . Although SABRE exploits pH(2), i.e. the starting spin order of H-2 is supposed to be the singlet order, in solution, S-T-0 conversion becomes efficient once pH(2) binds to a complex. Such a variation of the spin order, which becomes , has an important consequence: NMR methods used for transferring SABRE polarisation need to be modified. Here we demonstrate that methods proposed for the initial singlet order may not work for the order; however, a simple modification makes them efficient again.[GRAPHICS].