The Energetics of Halogenated Ethylenes (Ethynes) and 1,3-Butadienes (Butadiynes): A Computational and Conceptual Study of Substituent Effects and “Dimerization”

The energetics of ethylenes and 1,3-butadienes may be interrelated by the reaction: RHC=CH2 + H2C=CHR' → RHC=CH−CH=CHR' + H2. Shown earlier to be nearly enthalpically thermoneutral for a variety of hydrocarbon cases, we are now interested in the related energetics of halogenated alkenes an...

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Bibliographic Details
Published in:Croatica Chemica Acta 2009-06, Vol.82 (1), p.165
Main Authors: Deakyne, Carol A, Warfel IV, Lawrence H, Thomas, Haunani M, Nauduri, Dhananjaya, Ajibowo, Toyosi Esther A, Carbonaro, Nicole J, Simpson, Alec G, Liebman, Joel F
Format: Article
Language:English
Subjects:
ab initio calculations
dienes
diynes
halogenated compounds
isodesmic reactions
resonance (conjugation) energy
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Summary:The energetics of ethylenes and 1,3-butadienes may be interrelated by the reaction: RHC=CH2 + H2C=CHR' → RHC=CH−CH=CHR' + H2. Shown earlier to be nearly enthalpically thermoneutral for a variety of hydrocarbon cases, we are now interested in the related energetics of halogenated alkenes and alkynes. Using quantum chemical calculations, we have studied this as recast as the isodesmic reactions: 2(H2C=CHX) + H2C=CH−CH=CH2 → p,q-di-X-1,3-butadiene + 2H2C=CH2 2(HC≡CX) + HC≡C−C≡CH → di-X-butadiyne + 2HC≡CH. Here p,q- = 1,3-; 1,4- and 2,3- with X = F, Cl, Br, and I. The halogen and location-dependent deviations from near enthalpic thermoneutrality are discussed.
ISSN:0011-1643
1334-417X