English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/169298
Share/Impact:
Statistics
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Title

Computational reexamination of the eclipsed conformation in cis-2-tert-butyl-5-(tert-butylsulfonyl)-1,3-dioxane

AuthorsJuaristi, E.; Notario, Rafael
Issue Date2013
PublisherKluwer Academic/Plenum Publishers
CitationStructural Chemistry 24: 1855- 1862 (2013)
AbstractThe conformational free energy differences, ΔG values, for the methyl sulfide, methyl sulfoxide, methyl sulfone, tert-butyl sulfide, tert-butyl sulfoxide, and tert-butyl sulfone groups at C(5) in the 1,3-dioxane ring have been calculated at two different levels, B3LYP/6-31G(d) and B3LYP/6-311++G(d,p). There is good agreement between experimental and calculated values, particularly in the case of data obtained at the lower level of theory, B3LYP/6-31G(d). In order to get information that could help understand the nature of the effects present in the molecules of interest, the charge distribution in representative compounds was analyzed by means of the natural bond orbital (NBO) analysis. NBO calculations indicate the existence of substantial negative charges at oxygen and significant positive charge at sulfur. This observation seems to support the argument the existence of electrostatic, attractive interactions between the endocyclic oxygens and the axial sulfonyl group. From the second order perturbation theory analysis of Fock matrix, two σ C-C → σ*S-O delocalizing interactions are observed in the methyl-inside conformer of cis-2-tert-butyl-5-(methylsulfonyl)-1,3-dioxane derivative cis-7. These results are in line with anti-periplanar σ C-C → σ*S-O hyperconjugative interactions that help stabilize the methyl-inside conformation of cis-7, as previously found by 1H NMR analysis. By contrast, NBO analysis does not provide evidence for the existence of σ C-C → σ*S-O hyperconjugative interactions that might help stabilize the eclipsed tert-butyl - outside conformation previously found in the solid-state crystallographic structure of analog cis-1. Because of the threshold value of the NBO calculations, if present such syn-periplanar stereoelectronic interaction should be less than 0.5 kcal mol-1. This observation suggests that an anti-periplanar orientation of the interacting orbitals is more effective relatively to the corresponding syn-periplanar orientation. © 2013 Springer Science+Business Media New York.
URIhttp://hdl.handle.net/10261/169298
Identifiersdoi: 10.1007/s11224-013-0236-y
issn: 1040-0400
Appears in Collections:(IQFR) Artículos
Files in This Item:
File Description SizeFormat 
accesoRestringido.pdf15,38 kBAdobe PDFThumbnail
View/Open
Show full item record
Review this work
 

Related articles:


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.