کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9770140 | 1501940 | 2005 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Conformer dipole moment and syn-1,3-diaxial steric effect on the conformational equilibrium of the cis isomer of some 1,3-disubstituted cyclohexanes
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Conformer dipole moment and syn-1,3-diaxial steric effect on the conformational equilibrium of the cis isomer of some 1,3-disubstituted cyclohexanes Conformer dipole moment and syn-1,3-diaxial steric effect on the conformational equilibrium of the cis isomer of some 1,3-disubstituted cyclohexanes](/preview/png/9770140.png)
چکیده انگلیسی
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 cisâ3-halo-1-methoxycyclohexanes (halo=F, Cl, Br and I). The experimental 3JHH coupling constants are rather large (>10Â 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).
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure - Volume 743, Issues 1â3, 31 May 2005, Pages 69-72
Journal: Journal of Molecular Structure - Volume 743, Issues 1â3, 31 May 2005, Pages 69-72
نویسندگان
Paulo R. de Oliveira, Roberto Rittner,