Electronic effect

An electronic effect influences the structure, reactivity, or properties of molecule but is neither a traditional bond nor a steric effect. In organic chemistry, the term stereoelectronic effect is also used to emphasize the relation between the electronic structure and the geometry (stereochemistry) of a molecule.

Induction is the redistribution of electron density through a traditional sigma bonded structure according to the electronegativity of the atoms involved. The inductive effect drops across every sigma bond involved limiting its effect to only a few bonds.

Conjugation is a redistribution of electron density similar to induction but transmitted through interconnected pi-bonds. Conjugation is not only affected by electronegativity of the connected atoms but also affected by the position of electron lone pairs with respect to the pi-system. Electronic effects can be transmitted throughout a pi-system allowing their influence to extend further than induction.

Hyperconjugation 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 or an antibonding sigma orbital to give an extended molecular orbital that increases the stability of the system. Hyperconjugation can be used to explain phenomena such as the gauche effect and anomeric effect.

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