Title: heteroconjugation
Long Title: IUPAC Gold Book - heteroconjugation
DOI: 10.1351/goldbook.H02796
Status: current

Definition
[obsolete] Association between a base and the conjugate acid of a different base through a hydrogen bond ($\ce{B'\bond{...}HB^{+}}$ or $\ce{A'H\bond{...}A^{-}}$). The term has its origin in the conjugate acid–base pair and is in no way related to conjugated systems of orbitals. Heteroassociation is a more appropriate term.
[obsolete] Some authors refer to conjugated systems containing a heteroatom, e.g. pyridine, as 'heteroconjugated systems'. This usage is discouraged since it inappropriately suggests an analogy to homoconjugation, and conflicts with the currently accepted definition of that term.


Related Terms
- Association: https://goldbook.iupac.org/terms/view/A00472
- conjugate acid–base pair: https://goldbook.iupac.org/terms/view/C01266
- conjugated systems: https://goldbook.iupac.org/terms/view/C01267
- homoconjugation: https://goldbook.iupac.org/terms/view/H02842
- hydrogen bond: https://goldbook.iupac.org/terms/view/H02899
- orbitals: https://goldbook.iupac.org/terms/view/O04317

Source
- PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1120 (https://doi.org/10.1351/pac199466051077)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/H02796/html
- json: https://goldbook.iupac.org/terms/view/H02796/json
- xml: https://goldbook.iupac.org/terms/view/H02796/xml

Citation: Citation: 'heteroconjugation' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.H02796
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Accessed: 2026-07-24T01:50:57+00:00