Eugene P. Mazzola, Osvaldo Gutierrez, Gideon A. Fraenkel, Albert Chow, Michael P. Doyle, Michael D. Mandler, Ryan Dykstra, Deeya Garg, Clark D. Ridge
{"title":"Unusually large scalar coupling between geminal protons in a saturated pyrimidine","authors":"Eugene P. Mazzola, Osvaldo Gutierrez, Gideon A. Fraenkel, Albert Chow, Michael P. Doyle, Michael D. Mandler, Ryan Dykstra, Deeya Garg, Clark D. Ridge","doi":"10.1002/cmr.a.21424","DOIUrl":null,"url":null,"abstract":"<p>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 <i>symmetrical</i> bonding orbitals results in more slightly positive geminal coupling constants while that from <i>antisymmetrical</i> bonding orbitals produces more negative coupling constants, which has been found to be very large in certain rigid systems.</p>","PeriodicalId":55216,"journal":{"name":"Concepts in Magnetic Resonance Part A","volume":"45A 6","pages":""},"PeriodicalIF":0.4000,"publicationDate":"2018-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/cmr.a.21424","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Concepts in Magnetic Resonance Part A","FirstCategoryId":"92","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/cmr.a.21424","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
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.
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
京公网安备 11010802042870号
京ICP备2023020795号-1
分享
求助内容：
应助结果提醒方式：
扫码关注我们
