SABRE enhancement with oscillating pulse sequences
SABRE enhancement with oscillating pulse sequences
复制标题
通过振荡脉冲序列增强 SABRE
DOI：
10.1039/d2cp00899h
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发表时间：
2022
影响因子：
3.3
通讯作者：
Warren, Warren S.
中科院分区：
文献类型：
--
作者：
Li, Xiaoqing;Lindale, Jacob R.;Eriksson, Shannon L.;Warren, Warren S.
SABRE（可逆交换信号放大）方法提供了一种简单、快速且经济高效的方法来超极化溶液中的各种分子，并已通过质子以及最近的异核 (X-SABRE) 得到证实。在这里，我们提出了几种振荡脉冲序列，它们使用远离连续激励谐振条件的磁场，并且通常可以使极化增加三倍。平均哈密顿理论的分析表明，振荡脉冲实际上调整了氢化物和目标核之间的 J 耦合，并且较弱的耦合产生最大极化。这种理论处理与模拟和实验相结合，显示出相对于传统 X-SABRE 方法的磁化强度的显着改进。它还表明，与大多数脉冲序列应用相比，切换帧中时间对称性降低的波形使磁化生成对实验缺陷更加稳健。
SABRE (Signal Amplification by Reversible Exchange) methods provide a simple, fast, and cost-effective method to hyperpolarize a wide variety of molecules in solution, and have been demonstrated with protons and, more recently, with heteronuclei (X-SABRE). Here, we present several oscillating pulse sequences that use magnetic fields far away from the resonance condition of continuous excitation and can commonly triple the polarization. An analysis with average Hamiltonian theory indicates that the oscillating pulse, in effect, adjusts the J-couplings between hydrides and target nuclei and that a much weaker coupling produces maximum polarization. This theoretical treatment, combined with simulations and experiment, shows substantial magnetization improvements relative to traditional X-SABRE methods. It also shows that, in contrast to most pulse sequence applications, waveforms with reduced time symmetry in the toggling frame make magnetization generation more robust to experimental imperfections.