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H-1 NMR Chemical Shifts of Cyclopropane and Cyclobutane: A Theoretical Study
dc.creator | Baranac-Stojanović, Marija | |
dc.creator | Stojanović, Milovan | |
dc.date.accessioned | 2019-01-30T17:36:25Z | |
dc.date.available | 2019-01-30T17:36:25Z | |
dc.date.issued | 2013 | |
dc.identifier.issn | 0022-3263 | |
dc.identifier.uri | https://cer.ihtm.bg.ac.rs/handle/123456789/1284 | |
dc.description.abstract | This study was undertaken in order to rationalize the peculiar H-1 NMR chemical shifts of cyclopropane (delta 0.22) and cyclobutane (delta 1.98) which are shifted upfield and downfield with respect to larger cycloalkanes (delta 1.44-1.54). This is conventionally accounted for by shielding contributions arising from an aromatic-like ring current in cyclopropane, involving six electrons in the three C-C bonds, and deshielding coming from the sigma antiaromatic CC framework of cyclobutane. The shielding pattern arising from the cyclopropane and cyclobutane CC framework response to a perpendicular magnetic field was visualized as two-dimensional grid distribution of NICS values. Further insight into the origin of chemical shift values was obtained by the NCS-NBO analysis of proton shielding tensor. In the case of cyclopropane, the CC framework shielding pattern implies the existence of both delocalized and localized currents that have a dominant shielding effect on protons. The magnitude of C-H bonds shielding effect is significant, too. Unlike the conventional interpretation, the CC framework shields cyclobutane hydrogens, and its response to a perpendicular magnetic field is quite similar to responses of other planar sigma CC frameworks. | en |
dc.publisher | American Chemical Society (ACS) | |
dc.relation | info:eu-repo/grantAgreement/MESTD/Basic Research (BR or ON)/172020/RS// | |
dc.rights | restrictedAccess | |
dc.source | Journal of Organic Chemistry | |
dc.title | H-1 NMR Chemical Shifts of Cyclopropane and Cyclobutane: A Theoretical Study | en |
dc.type | article | |
dc.rights.license | ARR | |
dcterms.abstract | Баранац-Стојановиц, Марија; Стојановић, Милован; | |
dc.citation.volume | 78 | |
dc.citation.issue | 4 | |
dc.citation.spage | 1504 | |
dc.citation.epage | 1507 | |
dc.citation.other | 78(4): 1504-1507 | |
dc.citation.rank | M21 | |
dc.identifier.pmid | 23330566 | |
dc.identifier.doi | 10.1021/jo3025863 | |
dc.identifier.scopus | 2-s2.0-84873955750 | |
dc.identifier.wos | 000315254100019 | |
dc.type.version | publishedVersion |