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Gas-Phase NMR of Hyperpolarized Propane with 1H-to-13C Polarization Transfer by PH-INEPT
Applied Magnetic Resonance ( IF 1.1 ) Pub Date : 2021-07-14 , DOI: 10.1007/s00723-021-01377-4
Dudari B. Burueva 1, 2 , Vitaly P. Kozinenko 1, 2 , Sergey V. Sviyazov 1, 2 , Larisa M. Kovtunova 1, 3 , Oleg G. Salnikov 1, 2, 3 , Kirill V. Kovtunov 1, 2 , Igor V. Koptyug 1 , Valerii I. Bukhtiyarov 2, 3 , Eduard Y. Chekmenev 4, 5
Affiliation  

In this work we demonstrate the possibility to transfer parahydrogen-derived 1H polarization to 13C nuclei in the gas phase using PH-INEPT-based pulse sequences. The propane with hyperpolarized 1H nuclei was produced via hydrogenation of propylene (at natural 13C abundance) with parahydrogen over the heterogeneous 1 wt% Rh/TiO2 catalyst at 7.05 T magnetic field of a NMR spectrometer. The apparent proton polarization was estimated as 1.8 ± 0.4%, taking into account the polarization losses caused by spin relaxation. The optimal inter-pulse delays for both the PH-INEPT and the PH-INEPT + sequences were determined via the numerical calculations considering the full spin system of propane which includes eight protons and one 13C nucleus. The application of the optimized PH-INEPT polarization transfer sequence resulted in the 13C polarization values of 0.07 ± 0.01% and 0.030 ± 0.006% for the methyl group of [1-13C]propane and the methylene group of [2-13C]propane, respectively. The experimental dependence of the 13C polarization values for [1-13C]propane and [2-13C]propane on the inter-pulse delay τ1 of the PH-INEPT sequence is in a good agreement with the simulation. The resulting 13C polarization using PH-INEPT + sequence is ~ 2.5 times lower than that via PH-INEPT, which is also consistent with the numerical calculations.



中文翻译:

通过 PH-INEPT 进行 1H 到 13C 极化转移的超极化丙烷的气相 NMR

在这项工作中,我们证明了使用基于 PH-INEPT 的脉冲序列将副氢衍生的1 H 极化转移到气相中的13 C 核的可能性。具有超极化1 H 核的丙烷是通过丙烯(在天然13 C 丰度下)与仲氢在异质 1 wt% Rh/TiO 2上氢化生产的核磁共振波谱仪在 7.05 T 磁场下的催化剂。考虑到自旋弛豫引起的极化损失,表观质子极化估计为 1.8 ± 0.4%。PH-INEPT 和 PH-INEPT + 序列的最佳脉冲间延迟是通过数值计算确定的,考虑到丙烷的完整自旋系统,包括八个质子和一个13 C 核。优化的PH-INEPT极化转移序列的应用导致[1- 13 C]丙烷的甲基和[2- 13 C的亚甲基的13 C极化值分别为0.07±0.01%和0.030±0.006% ]丙烷,分别。13的实验依赖性[1- 13 C]丙烷和[2- 13 C]丙烷在PH-INEPT序列的脉冲间延迟τ 1上的C极化值与模拟非常一致。使用 PH-INEPT + 序列产生的13 C 极化比通过 PH-INEPT产生的13 C 极化低约 2.5 倍,这也与数值计算一致。

更新日期:2021-07-14
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