imino group
Very lowTechnical/Scientific
Definition
Meaning
A chemical functional group with the structure =NH, derived from ammonia by removal of two hydrogen atoms.
In biochemistry, the imino group is found in molecules like proline (where it forms part of a cyclic structure) and in various intermediates of metabolic pathways. It can also refer to the =NH moiety in organic compounds like imines.
Linguistics
Semantic Notes
The term is almost exclusively used in chemistry and biochemistry. It is not a standalone word in general language but a compound noun specifying a precise chemical structure. The 'group' part is essential; 'imino' alone typically functions as a prefix or adjective (e.g., imino acid).
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Spelling conventions for related chemical terms (e.g., 'sulphur' vs. 'sulfur') do not directly apply to this specific term.
Connotations
None beyond its strict scientific definition.
Frequency
Equally rare and specialised in both varieties.
Vocabulary
Collocations
Grammar
Valency Patterns
The [compound] contains an imino group.The imino group in [molecule] is [property/action].Vocabulary
Synonyms
Neutral
Weak
Usage
Context Usage
Business
Not used.
Academic
Used in advanced chemistry and biochemistry textbooks, research papers, and lectures.
Everyday
Never used.
Technical
Core term in organic chemistry and biochemistry for describing molecular structure and reaction mechanisms.
Examples
By Part of Speech
adjective
British English
- The imino nitrogen is highly reactive.
- Proline is an imino acid.
American English
- The imino nitrogen is highly reactive.
- Proline is an imino acid.
Examples
By CEFR Level
- The structure of proline is unique because it contains an imino group.
- In this diagram, the imino group is highlighted in blue.
- The enzyme catalyses the transfer of the imino group from the substrate to the cofactor.
- Tautomerisation can convert the ketone into an enol, which subsequently forms an imino group.
Learning
Memory Aids
Mnemonic
Imagine 'I'M In NO' hurry to lose two hydrogens – an ammonia (NH3) molecule loses two 'H's to become an imino (=NH) group.
Conceptual Metaphor
A hook or connection point: The imino group is often conceptualised as a reactive site or a connecting bridge within a larger molecule.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid translating 'group' as 'группировка' (which implies a gathering). The correct term is 'группа' as in 'химическая группа'.
- Do not confuse with 'amino group' (NH2), which is more common.
Common Mistakes
- Using 'imino' as a standalone noun (e.g., 'an imino') instead of 'an imino group'.
- Confusing the imino group (=NH) with the more common amino group (NH2).
Practice
Quiz
What is the chemical structure of an imino group?
FAQ
Frequently Asked Questions
No. An amino group is -NH2 (a primary amine), while an imino group is =NH (derived from a secondary amine or imine).
In proline. Its side chain forms a five-membered ring with the backbone nitrogen, making it a secondary amine and creating an imino group in the cyclic structure.
Rarely and only in highly technical shorthand within a clear context. It is almost always used as part of the compound noun 'imino group' or as an adjective (e.g., imino compound).
No, it is a strictly technical term with no application in everyday language, business, or non-scientific academic fields.