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Conformational analysis. 125. The importance of twofold barriers in saturated molecules 1,2a
Year:
1977
Authors :
הניג, הלמוט
;
.
Volume :
99
Co-Authors:
Allinger, N.L., Department of Chemistry, University of Georgia, Athens, GA 30602, United States
Hindman, D., Department of Chemistry, University of Georgia, Athens, GA 30602, United States
Hönig, H., Lehrkanzel für Organische Chemie, Techn. Univ., Graz, Austria
Facilitators :
From page:
3282
To page:
3284
(
Total pages:
3
)
Abstract:
The use of twofold barriers in force field calculations in molecules of the type XCH2CH2Y can significantly improve the results in many cases as is shown for X, Y = F, OH; F, OAc; and Cl, OH in particular, and these results are applied to 5-substituied-1,3-dioxancs. It is pointed out that for butane (X = Y = methyl) a small twofold term can be used to improve hydrocarbon calculations in at least three of the currently used force fields. With Bartell's 1976 field (MUB2), such a twofold term permits calculation of a more accurate gauche-anti energy difference. With Schleyer's 1973 field (EAS) it will permit a stronger (intuitively desirable) C⋯H repulsion. With our 1973 field (MMI) it will permit smaller hydrogens. It is suggested that this kind of term, which is theoretically fully justifiable, will permit improvement as well as substantial convergence of these three force fields.
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Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
20920
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:40
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Scientific Publication
Conformational analysis. 125. The importance of twofold barriers in saturated molecules 1,2a
99
Allinger, N.L., Department of Chemistry, University of Georgia, Athens, GA 30602, United States
Hindman, D., Department of Chemistry, University of Georgia, Athens, GA 30602, United States
Hönig, H., Lehrkanzel für Organische Chemie, Techn. Univ., Graz, Austria
Conformational analysis. 125. The importance of twofold barriers in saturated molecules 1,2a
The use of twofold barriers in force field calculations in molecules of the type XCH2CH2Y can significantly improve the results in many cases as is shown for X, Y = F, OH; F, OAc; and Cl, OH in particular, and these results are applied to 5-substituied-1,3-dioxancs. It is pointed out that for butane (X = Y = methyl) a small twofold term can be used to improve hydrocarbon calculations in at least three of the currently used force fields. With Bartell's 1976 field (MUB2), such a twofold term permits calculation of a more accurate gauche-anti energy difference. With Schleyer's 1973 field (EAS) it will permit a stronger (intuitively desirable) C⋯H repulsion. With our 1973 field (MMI) it will permit smaller hydrogens. It is suggested that this kind of term, which is theoretically fully justifiable, will permit improvement as well as substantial convergence of these three force fields.
Scientific Publication
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