Sudhakara, Pamidighantam V and Chandrasekhar, Jayaraman (1989) Geometry changes induced by negative hyperconjugative interactions involving carbonyl and thiocarbonyl groups. In: Journal of Molecular Structure, 194 . pp. 135-147.
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MNDO geometry optimizations have been carried out on a series of acyclic and cyclic unsymmetrically disubstituted carbonyl and thiocarbonyl compounds. The C=X unit shows a consistent and often sizeable tilt towards one of the substituents, following the order O > Snot, vert, similarN > C > B. Reference ab initio calculations and available experimental results support the MNDO results. The effect, which is particularly dramatic in small rings, is attributed primarily to favorable negative hyperconjugative interaction between the lone pair on X and a low lying adjacent σ* orbital. Such an interaction can lead to highly distorted structures, including perhaps to a planar molecule with an inverted sp2 carbon center.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier Science.|
|Department/Centre:||Division of Chemical Sciences > Organic Chemistry|
|Date Deposited:||19 Aug 2010 12:39|
|Last Modified:||19 Sep 2010 06:14|
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