Unusually large scalar coupling between geminal protons in saturated pyrimidine

Date
2018-04-29
Authors
Mazzola, Eugene P.
Gutierrez, Osvaldo
Fraenkel, Gideon A.
Chow, Albert
Doyle, Michael P.
Mandler, Michael D.
Dykstra, Ryan
Garg, Deeya
Ridge, Clark D.
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
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.

Description
Keywords
1H-1H geminal couplings, spn hybridization, density functional theory calculations, double-bond nodal plan, hybridization, tetrahydropyrimidines
Citation
Department
Chemistry