Hyperconjugation in organic chemistry is the stabilizing interaction that results from the interaction of the electrons in a sigma bond (usually C-H or C-C) with an adjacent empty (or partially filled) non-bonding p-orbital or antibonding π orbital to give an extended molecular orbital that increases the stability of the system. Only electrons in bonds that are β to the positively charged carbon can stabilize a carbocation by hyperconjugation. Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting primarily of carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, halogens as well... For other uses, see Electron (disambiguation). ... Electron atomic and molecular orbitals, showing among others the sigma bond of two s-orbitals and a sigma bond of two p-orbitals In chemistry, sigma bonds (σ bonds) are a type of covalent chemical bond. ... Electron configuration is the arrangement of electrons in an atom, molecule or other body. ... Antibonding (or anti-bonding) is a type of chemical bonding. ... Electron atomic and molecular orbitals, showing a Pi-bond at the bottom right of the picture. ... In chemistry, a molecular orbital is a region in which an electron may be found in a molecule. ...

Hyperconjugation can be used for rationalizing a variety of chemical phenomena, including the anomeric effect, the gauche effect, the rotational barrier of ethane, the beta-silicon effect, the vibrational frequency of exocyclic carbonyl groups, and the relative stability of substituted carbocations. Hyperconjugation is proposed by quantum mechanical modeling to be the correct explanation for the preference of the staggered conformation rather than the old textbook notion of steric hindrance. ^{[1] [2]}. In organic chemistry, the anomeric effect is a stereoelectronic effect that describes the tendency of heteroatomic substituents adjacent to a heteroatom within a cyclohexane ring to prefer the axial orientation instead of the less hindered equatorial orientation that would be expected from steric considerations. ... In stereochemistry, gauche interactions hinder bond rotation. ... Alkane stereochemistry concerns the stereochemistry of linear alkanes and the linear alkane conformers. ... This article is about a chemical compound. ... The beta-silicon effect also called silicon hyperconjugation in organosilicon chemistry is a special type of hyperconjugation and describes the stabilizing effect of a silicon atom placed in a position once removed (β) from a carbocation. ... Infrared spectroscopy (IR spectroscopy) is the subset of spectroscopy that deals with the infrared region of the electromagnetic spectrum. ... Cyclopropane is the smallest alicyclic compound. ... Carbonyl group In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom : C=O. The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex (a metal carbonyl, e. ... A carbocation (IPA pronunciation: ) is an ion with a positively-charged carbon atom. ... In chemistry a staggered conformation is a chemical conformation that exists in any open chain single chemical bond connecting two sp3 hybridised atoms as a conformational energy minimum. ... Conformational isomerism is the phenomenon of molecules with the same structural formula but different conformations (conformers) of atoms about a rotating bond. ... Steric effects are the interaction of molecules dictated by their shape and/or spatial relationships. ...

External links

• further reading
• IUPAC definition
• advanced hyperconjugation

References

1. ^ Hyperconjugation not steric repulsion leads to the staggered structure of ethane Pophristic, V. & Goodman, L. Nature 411, 565–568 (2001)Abstract
2. ^ Chemistry: A new twist on molecular shape Frank Weinhold Nature 411, 539-541 (31 May 2001)

Nature is a prominent scientific journal, first published on 4 November 1869. ... Nature is a prominent scientific journal, first published on 4 November 1869. ...

See also

• Conjugated system