Différences entre les versions de « VBFile 4-4 »

De Workshops
Aller à la navigation Aller à la recherche
Ligne 77 : Ligne 77 :
 
</pre></html>
 
</pre></html>
 
|}
 
|}
In the BLW part we localize px-like pi orbitals of atoms C2 and C6 and  py-like orbitals for C1 C5 to avoid hyperconjugaison.
+
In the BLW part we localize px-like pi orbitals of atoms C1=C2 and  py-like orbitals for C3=C4 to avoid hyperconjugaison.
 
{| class="collapsible collapsed wikitable"
 
{| class="collapsible collapsed wikitable"
 
|-
 
|-

Version du 11 juillet 2012 à 16:54

return to Tutorial n°4 Two geometries are provided the planar and the twisted where a vinyl part C1 C5 has been twisted by 90°. this second moieties has its pi orbitals along the y direction.

Evaluation of the conjugaison

Localization of px-like pi orbitals to deconjugate keeping planar

Evaluation of the hyperconjugaison in the twisted form

In the BLW part we localize px-like pi orbitals of atoms C1=C2 and py-like orbitals for C3=C4 to avoid hyperconjugaison.

We find
delocalized planar -155.8824504889
localized planar -155.8603462862 (13.9 kcal/mol)
Twisted -155.8695790387 ( 8.1 kcal/mol)
Twisted but local -155.8537320442 (18.0 kcal/mol)

Hence conjugaison is 13.9 kcal/mol, and the hyper conjugaison in the twisted form is as large as 9.9 kcal/mol