三自旋体系核自旋单重态的制备与单重态二维谱的实现
Preparing Nuclear Spin Singlet State in a Three-spin System and Its Application in 2D Spectrum
Received date: 2021-04-16
Online published: 2021-06-02
核自旋单重态是一种特殊的自旋状态，其寿命远长于相应自旋的横向和纵向弛豫时间，能够被用于研究分子的慢扩散、慢运动、特征信号选择等过程.目前单重态的研究主要集中于孤立的两自旋体系.而本文以N-乙酰基天冬氨酸（NAA）分子中由亚甲基和次甲基的三个氢原子核构成的三自旋体系为研究对象，将亚甲基中的两个氢核制备成单重态.利用优化控制和数值计算方法，分别设计了包含和不包含次甲基氢核耦合的单重态制备脉冲，结果发现，不考虑次甲基氢耦合设计的优化脉冲，其在实际三自旋体系中的单重态制备效率会显著下降.另外，我们以单重态为起点，实现了针对次甲基和亚甲基的信号选择COSY谱和NOESY谱，结果表明基于单重态的二维谱能够有效避免谱峰重叠现象，提高谱图分辨率，并有助于提高分子结构解析的准确性.
胡凯瑞 , 杨雪 , 黄志明 , 辛家祥 , 魏达秀 , 姚叶锋 . 三自旋体系核自旋单重态的制备与单重态二维谱的实现[J]. 波谱学杂志, 2022 , 39(1) : 96 -107 . DOI: 10.11938/cjmr20212910
Nuclear spin singlet state is a special spin state, whose main characteristic is that its lift-time can be much longer than the corresponding longitudinal/transverse relaxation time. It can be used to study molecular slow diffusion, slow motion, special signal selection or other molecular motion. In the literature, singlet states are mainly studied in an isolated two-spin system. Here we discuss the nuclear spin singlet state preparation in a three-spin system. The system consisting of three protons in the molecule N-acetyl aspartic acid (NAA) was used as an example. Specifically, we used optimal control theory and numerical calculation method to design the pulse sequence and to transfer the two spins in methylene group into singlet state. The shaped pulses including and not including the proton in the methyne group were designed respectively. Our simulation results indicate that to ensure a high efficiency for the singlet state preparation, the coupling of the proton in the methyne group should be included in the pulse calculation. Furthermore, the singlet state can be combined with two-dimensional pulse sequences such as COSY and NOESY. The experimental results show that some correlation peaks could be selectively observed in the two-dimensional spectrum based on singlet state. It will be useful for the spectral peak assignment especially in the case of serious spectral overlap.
| 1 | CARRAVETTA M , JOHANNESSEN O G , LEVITT M H . Beyond the T1 limit: singlet nuclear spin states in low magnetic fields[J]. Phys Rev Lett, 2004, 92 (15): 153003. |
| 2 | CARRAVETTA M , LEVITT M H . Long-lived nuclear spin states in high-field solution NMR[J]. J Am Chem Soc, 2004, 126 (20): 6228- 6229. |
| 3 | PILEIO G , LEVITT M H . Theory of long-lived nuclear spin states in solution nuclear magnetic resonance. Ⅱ. Singlet spin locking[J]. J Chem Phys, 2009, 130 (21): 214501. |
| 4 | DUMEZ J N , HAKANSSON P , MAMONE S , et al. Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation[J]. J Chem Phys, 2015, 142 (4): 044506. |
| 5 | STEVANATO G , ROY S S , HILL-COUSINS J , et al. Long-lived nuclear spin states far from magnetic equivalence[J]. Phys Chem Chem Phys, 2015, 17 (8): 5913- 5922. |
| 6 | LEVITT M H . Singlet nuclear magnetic resonance[J]. Annu Rev Phys Chem, 2012, 63, 89- 105. |
| 7 | TAYLER M C D , LEVITT M H . Singlet nuclear magnetic resonance of nearly-equivalent spins[J]. Phys Chem Chem Phys, 2011, 13 (13): 5556- 5560. |
| 8 | DEVIENCE S J , WALSWORTH R L , ROSEN M S . Preparation of nuclear spin singlet states using spin-lock induced crossing[J]. Phys Rev Lett, 2013, 111 (17): 173002. |
| 9 | CARRAVETTA M , LEVITT M H . Theory of long-lived nuclear spin states in solution nuclear magnetic resonance. I. Singlet states in low magnetic field[J]. J Chem Phys, 2005, 122 (21): 214505. |
| 10 | PILEIO G , CARRAVETTA M , HUGHES E , et al. The long-lived nuclear singlet state of 15N-nitrous oxide in solution[J]. J Am Chem Soc, 2008, 130 (38): 12582- 12583. |
| 11 | SARKAR R , VASOS P , BODENHAUSEN G . Singlet-state exchange NMR spectroscopy for the study of very slow dynamic processes[J]. J Am Chem Soc, 2007, 129 (2): 328- 334. |
| 12 | PILEIO G , OSTROWSKA S . Accessing the long-time limit in diffusion NMR: The case of singlet assisted diffusive diffraction q-space[J]. J Magn Reson, 2017, 285, 1- 7. |
| 13 | CAVADINI S , DITTMER J , ANTONIJEVIC S , et al. Slow diffusion by singlet state NMR spectroscopy[J]. J Am Chem Soc, 2005, 127 (45): 15744- 15748. |
| 14 | PILEIO G , BOWEN S , LAUSTSEN C , et al. Recycling and imaging of nuclear singlet hyperpolarization[J]. J Am Chem Soc, 2013, 135 (13): 5084- 5088. |
| 15 | KOVTUNOV K V , TRUONG M L , BARSKIY D A , et al. Long-lived spin States for low-field hyperpolarized gas MRI[J]. Chemistry, 2014, 20 (45): 14629- 14632. |
| 16 | SINGH M , SONI V K , MISHRA R , et al. Relaxation editing using long-lived states and coherences for analysis of mixtures[J]. Anal Chem, 2016, 88 (6): 3004- 3008. |
| 17 | PILEIO G , CARRAVETTA M , LEVITT M H . Storage of nuclear magnetization as long-lived singlet order in low magnetic field[J]. Proc Natl Acad Sci U S A, 2010, 107 (40): 17135- 17139. |
| 18 | BENGS C , SABBA M , JERSCHOW A , et al. Generalised magnetisation-to-singlet-order transfer in nuclear magnetic resonance[J]. Phys Chem Chem Phys, 2020, 22 (17): 9703- 9712. |
| 19 | PILEIO G . Singlet NMR methodology in two-spin-1/2 systems[J]. Prog Nucl Magn Reson Spectrosc, 2017, 98-99, 1- 19. |
| 20 | DEVIENCE S J , WALSWORTH R L , ROSEN M S . Nuclear spin singlet states as a contrast mechanism for NMR spectroscopy[J]. NMR Biomed, 2013, 26 (10): 1204- 1212. |
| 21 | GUO H Q , XIN J X , LIU H X , et al. Preparation of long-lived nuclear singlet states in three-spin systems[J]. Chinese J Magn Reson, 2018, 35 (3): 345- 352. |
| 21 | 郭海清, 辛家祥, 刘慧霞, 等. 三自旋体系长寿命核自旋单重态的制备[J]. 波谱学杂志, 2018, 35 (3): 345- 352. |
| 22 | KHANEJA N , REISS T , KEHLET C , et al. Optimal control of coupled spin dynamics: design of NMR pulse sequences by gradient ascent algorithms[J]. J Magn Reson, 2005, 172 (2): 296- 305. |
| 23 | LI Y , XIN J X , WANG J C , et al. Comparison of preparation efficiencies of nuclear spin singlet state based on three pulse sequences[J]. Chinese J Magn Reson, 2021, 38 (2): 227- 238. |
| 23 | 李毅, 辛家祥, 王嘉琛, 等. 三种脉冲序列制备核自旋单重态效率的比较[J]. 波谱学杂志, 2021, 38 (2): 227- 238. |
| 24 | LIU H X , XIN J X , WEI D X , et al. Preparation of nuclear spin singlet states and analysis of influencing factors on their conversion efficiency and lifetime[J]. Chinese J Magn Reson, 2020, 37 (2): 182- 192. |
| 24 | 刘慧霞, 辛家祥, 魏达秀, 等. 核自旋单重态的制备及其转化效率和寿命的影响因素分析[J]. 波谱学杂志, 2020, 37 (2): 182- 192. |
| 25 | WEI D X , XIN J X , HU K R , et al. Preparation of long-lived states in a multi-spin system by using an optimal control method[J]. Chemphyschem, 2020, 21 (12): 1326- 1330. |
| 26 | TO?NER Z , VOSEGAARD T , KEHLET C , et al. Optimal control in NMR spectroscopy: Numerical implementation in SIMPSON[J]. J Magn Reson, 2009, 197 (2): 120- 134. |
| 27 | В. И. 阿诺尔德著. 齐民友译. 经典力学中的数学方法(第4版)[M]. 北京: 高等教育出版社. 2006. |
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