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.
Предметные области OECD FOS+WOS
- 1.03 ФИЗИЧЕСКИЕ НАУКИ И АСТРОНОМИЯ