Please use this identifier to cite or link to this item:
https://dspace.ffh.bg.ac.rs/handle/123456789/1916
DC Field | Value | Language |
---|---|---|
dc.contributor.author | Marković, R. | en_US |
dc.contributor.author | Baranac, M. | en_US |
dc.contributor.author | Juranić, N. | en_US |
dc.contributor.author | Macura, S. | en_US |
dc.contributor.author | Cekić, I. | en_US |
dc.contributor.author | Minić, Dragica | en_US |
dc.date.accessioned | 2022-12-21T16:59:43Z | - |
dc.date.available | 2022-12-21T16:59:43Z | - |
dc.date.issued | 2006-12-04 | - |
dc.identifier.issn | 0022-2860 | en |
dc.identifier.uri | https://dspace.ffh.bg.ac.rs/handle/123456789/1916 | - |
dc.description.abstract | The rotational barriers between the configurational isomers of two structurally related push-pull 4-oxothiazolidines, differing in the number of exocyclic C{double bond, long}C bonds, have been determined by dynamic 1 H NMR spectroscopy. The equilibrium mixture of (5-ethoxycarbonylmethyl-4-oxothiazolidin-2-ylidene)-1-phenylethanone (1a) in CDCl 3 at room temperature to 333 K consists of the E- and Z-isomers which are separated by an energy barrier ΔG # 98.5 kJ/mol (at 298 K). The variable-temperature 1 H NMR data for the isomerization of ethyl (5-ethoxycarbonylmethylidene-4-oxothiazolidin-2-ylidene)ethanoate (2b) in DMSO-d 6 , possessing the two exocyclic C{double bond, long}C bonds at the C(2)- and C(5)-positions, indicate that the rotational barrier ΔG # separating the (2E,5Z)-2b and (2Z,5Z)-2b isomers is 100.2 kJ/mol (at 298 K). In a polar solvent-dependent equilibrium the major (2Z,5Z)-form (>90%) is stabilized by the intermolecular resonance-assisted hydrogen bonding and strong 1,5-type S · · · O interactions within the S{single bond}C{double bond, long}C{single bond}C{double bond, long}O entity. The 13 C NMR Δδ C(2)C(2′) values, ranging from 58 to 69 ppm in 1a-d and 49-58 ppm in 2a-d, correlate with the degree of the push-pull character of the exocyclic C(2){double bond, long}C(2′) bond, which increases with the electron withdrawing ability of the substituents at the vinylic C(2′) position in the following order: COPh ∼ COEt > CONHPh > CONHCH 2 CH 2 Ph. The decrease of the Δδ C(2)C(2′) values in 2a-d has been discussed for the first time in terms of an estimation of the electron donor capacity of the {single bond}S{single bond} fragment on the polarization of the C{double bond, long}C bonds. © 2006 Elsevier B.V. All rights reserved. | en |
dc.relation.ispartof | Journal of Molecular Structure | en |
dc.subject | 4-Oxothiazolidines | en |
dc.subject | 1 H NMR spectroscopy | en |
dc.subject | Rotational barrier | en |
dc.subject | Z/E-isomerization | en |
dc.title | <sup>1</sup> H NMR Dynamic study of thermal Z/E isomerization of 5-substituted 2-alkylidene-4-oxothiazolidine derivatives: Barriers to rotation about C{double bond, long}C bond | en_US |
dc.type | Article | en_US |
dc.identifier.doi | 10.1016/j.molstruc.2006.03.075 | - |
dc.identifier.scopus | 2-s2.0-33750718764 | - |
dc.identifier.url | https://api.elsevier.com/content/abstract/scopus_id/33750718764 | - |
dc.relation.firstpage | 85 | en |
dc.relation.lastpage | 92 | en |
dc.relation.issue | 1-3 | en |
dc.relation.volume | 800 | en |
item.fulltext | No Fulltext | - |
item.grantfulltext | none | - |
item.cerifentitytype | Publications | - |
item.openairetype | Article | - |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
crisitem.author.orcid | 0000-0001-5055-2039 | - |
Appears in Collections: | Journal Article |
SCOPUSTM
Citations
20
checked on Sep 25, 2024
Page view(s)
9
checked on Oct 1, 2024
Google ScholarTM
Check
Altmetric
Altmetric
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.