tautomerism

A molecule exhibits tautomerism by shifting a hydrogen atom between two structural forms.

Definition

1. Noun (Chemistry):
   • Dynamic equilibrium of structural isomers: "Tautomerism" refers to a phenomenon in which a chemical compound exists as a mixture of two or more structural isomers that readily interconvert by the migration of a proton (hydrogen atom) and a shift of bonding electrons. The individual isomers are called tautomers.

Usage Examples

• (The compound can switch between ketone and enol forms.)
• (Structural rearrangements occur in nitrogen-containing rings.)

Advanced Usage

• "Prototropic tautomerism": a specific type involving the movement of a proton.

  • Prototropic tautomerism is responsible for the acidity of carbonyl compounds. (Proton transfer occurs between atoms.)

• "Valence tautomerism": a form of tautomerism involving the rearrangement of electrons and bonds without proton transfer.

  • Valence tautomerism is observed in some organic radicals. (Electron redistribution leads to structural changes.)

Variants and Related Words

• Tautomer (n): one of the individual isomers in a tautomeric equilibrium.

  • The enol tautomer of acetone is less stable than the keto form. (A specific structural version of the compound.)

• Tautomeric (adj): relating to or exhibiting tautomerism.

  • The tautomeric forms of guanine affect its base-pairing properties. (Describes the property of having interconvertible structures.)

Synonyms

• Isomerization: the process of converting one isomer into another.
• Structural rearrangement: a change in the arrangement of atoms within a molecule.

Related Idioms

Phrasal Verbs