饱和嘧啶中双质子之间异常大的标量耦合

IF 0.4 4区化学 Q4 CHEMISTRY, PHYSICAL

Concepts in Magnetic Resonance Part A Pub Date : 2018-04-29 DOI:10.1002/cmr.a.21424

Eugene P. Mazzola, Osvaldo Gutierrez, Gideon A. Fraenkel, Albert Chow, Michael P. Doyle, Michael D. Mandler, Ryan Dykstra, Deeya Garg, Clark D. Ridge

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引用次数: 0

摘要

在立体化学刚性体系中观察到异常大的双偶联，使得亚甲基质子和相邻的碳-碳双键之间具有良好的偶联排列。已经发现这种耦合依赖于连接双氢和相邻双键节点平面的线的排列，以及相邻杂原子上的孤对电子的取向。对称成键轨道上的电子退出导致了更轻微的正耦合常数，而非对称成键轨道上的电子退出则产生了更多的负耦合常数，在某些刚性体系中发现了很大的负耦合常数。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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Unusually large scalar coupling between geminal protons in a saturated pyrimidine

An unusually large geminal coupling has been observed in a stereochemically rigid system that permits a favorable coupling alignment between the methylene protons and an adjacent carbon-carbon double bond. Such couplings have been found to depend on both the alignment of a line connecting the geminal hydrogens and the nodal plane of the adjacent double bond, and the orientation of lone-pair electrons on adjacent heteroatoms. Electron withdrawal from symmetrical bonding orbitals results in more slightly positive geminal coupling constants while that from antisymmetrical bonding orbitals produces more negative coupling constants, which has been found to be very large in certain rigid systems.

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来源期刊

Concepts in Magnetic Resonance Part A 物理-光谱学

CiteScore

0.90

自引率

0.00%

发文量

审稿时长

>12 weeks

期刊介绍： Concepts in Magnetic Resonance Part A brings together clinicians, chemists, and physicists involved in the application of magnetic resonance techniques. The journal welcomes contributions predominantly from the fields of magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR), and electron paramagnetic resonance (EPR), but also encourages submissions relating to less common magnetic resonance imaging and analytical methods. Contributors come from academic, governmental, and clinical communities, to disseminate the latest important experimental results from medical, non-medical, and analytical magnetic resonance methods, as well as related computational and theoretical advances. Subject areas include (but are by no means limited to): -Fundamental advances in the understanding of magnetic resonance -Experimental results from magnetic resonance imaging (including MRI and its specialized applications) -Experimental results from magnetic resonance spectroscopy (including NMR, EPR, and their specialized applications) -Computational and theoretical support and prediction for experimental results -Focused reviews providing commentary and discussion on recent results and developments in topical areas of investigation -Reviews of magnetic resonance approaches with a tutorial or educational approach