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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Transfer of parahydrogen-induced hyperpolarization to F-19
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Transfer of parahydrogen-induced hyperpolarization to F-19

机译：对氢诱导的超极化转移至F-19

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摘要

Homogeneous hydrogenations of unsaturated substrates with parahydrogen yield strong NMR signal enhancements of the transferred H-1 nuclei if the symmetry of H-2 is broken in the resulting hydrogenated products. This chemically induced hyperpolarization known as Parahydrogen-induced polarization (PHIP) is also transferred to other protons and heteronuclei (H-2, C-13, Si-29, P-31) when the hydrogenation is initiated at low magnetic fields. Hydrogenating various fluorinated styrenes and phenylacetylenes, we show that PHIP-derived hyperpolarization is transferred to F-19 not only in the Earth's magnetic field (ALTADENA condition) but also in a strong magnetic field, e.g., when carrying out the reaction in the NMR spectrometer (PASADENA condition). Upon conducting a systematic analysis of the observed PHIP transfer to H-1, C-13, and F-19 in the hydrogenation products to elucidate the mechanisms that govern this parahydrogen-aided resonance transfer (PART), we conclude that high- and low-field PHIP transfer mechanisms differ in detail depending on either through-bond or through-space interactions. Substrates with high hydrogenation rates and long spin-lattice relaxation times (T-1) yield the highest degree of heteronuclear hyperpolarization. Possible medical applications for hyperpolarized F-19-containing molecules as "active" contrast agents for magnetic resonance imaging (MRI) are outlined.
机译：如果在生成的氢化产物中破坏了H-2的对称性，则具有对氢的不饱和底物的均相氢化将使转移的H-1原子核产生强烈的NMR信号增强。当在低磁场下引发氢化反应时，这种化学诱导的超极化现象也称为对氢诱导极化（PHIP），它也会转移到其他质子和杂核（H-2，C-13，Si-29，P-31）。氢化各种氟化苯乙烯和苯乙炔，我们证明，例如，在NMR光谱仪中进行反应时，PHIP衍生的超极化不仅会在地球磁场（ALTADENA条件）中而且还会在强磁场中转移至F-19。 （PASADENA条件）。对观察到的加氢产物中H-1，C-13和F-19的PHIP转移进行系统分析以阐明控制该副氢辅助共振转移（PART）的机制后，我们得出结论，高和低场PHIP传输机制在细节上会有所不同，具体取决于通过键绑定或通过空间交互。具有高氢化率和长自旋晶格弛豫时间（T-1）的基板产生最高程度的异核超极化。概述了超极化的含F-19分子作为磁共振成像（MRI）的“活性”造影剂的可能医学应用。

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