Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/56541
Type: Artigo de periódico
Title: Conformer dipole moment and syn-1,3-diaxial steric effect on the conformational equilibrium of the cis isomer of some 1,3-disubstituted cyclohexanes
Author: de Oliveira, PR
Rittner, R
Abstract: The theoretical values of the dipole moment for the diaxial (ax-ax) conformer are larger than for the eq-eq conformer of some cis-3-halocyclohexanols (halo=Cl, Br and I) and c, S-3-halo-1-methoxycyclohexanes (halo=F, Cl, Brand 1). The experimental (3)J(HH) Coupling constants are rather large (> 10 Hz) indicating that the diequatorial (eq-eq) conformer is predominant for all compounds in the solvents studied. Dipole moments and NMR data lead to the conclusion that the conformational. equilibra of these 1,3-derivatives are not controlled by the solvent polarity, as is observed for the 1,2-disubstituted cyclohexanes, but are dictated by the syn-1,3-diaxial steric effect, which predominates over stabilization of the ax-ax conformer by an intramolecular hydrogen bond (IAHB). © 2005 Elsevier B.V. All rights reserved.
Subject: conformational analysis
theoretical calculations
solvent effects
1,3-disubstituted cyclohexanes
dipole moments
H-1 NMR coupling constants
Country: Holanda
Editor: Elsevier Science Bv
Rights: fechado
Identifier DOI: 10.1016/j.molstruc.2005.02.028
Date Issue: 2005
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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