Substituent stabilisation energies in α-substituted carbocations CH2Z+, CH3CHZ+ and (CH3)2CZ+ where Z is NH2, PH2, AsH2, OH, SH and SeH
In: Journal of Molecular Structure: THEOCHEM, Jg. 152 (1987-06-01), S. 55-68
Online
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Zugriff:
Ab initio molecular orbital calculations at the MINI 1 and 3–21G levels of theory have been used to optimise structures for α-substituted carbocations CH 2 Z + , CH 3 CHZ + , and (CH 3 ) 2 CZ + , and for the hydrocarbons CH 3 Z, CH 3 CH 2 Z and (CH 3 ) 2 CHZ where Z is NH 2 , PH 2 , AsH 2 , OH, SH and SeH. Energy differences between conformers as calculated by theory are compared with experimental results. Substituent stabilisation energies, calculated by using isodesmic reactions, are largest in primary ions and smallest in tertiary ions. For elements from Group V the stabilising effect of an α-substituent is NH 2 > PH 2 > AsH 2 and for Group VI OH > SeH > SH. There is a good correlation between experimental and calculated values for the effect of methyl substitution on the hydride affinities of substituted methyl cations.
Titel: |
Substituent stabilisation energies in α-substituted carbocations CH2Z+, CH3CHZ+ and (CH3)2CZ+ where Z is NH2, PH2, AsH2, OH, SH and SeH
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Autor/in / Beteiligte Person: | Rodriquez, C.F. ; Hopkinson, A.C. |
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Zeitschrift: | Journal of Molecular Structure: THEOCHEM, Jg. 152 (1987-06-01), S. 55-68 |
Veröffentlichung: | Elsevier BV, 1987 |
Medientyp: | unknown |
ISSN: | 0166-1280 (print) |
DOI: | 10.1016/0166-1280(87)87005-7 |
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