Ketoterminated

Ketoterminated, also written ketone-terminated, is a descriptor used in organic and polymer chemistry to indicate that a molecule or polymer chain ends with a ketone functional group (a carbonyl attached to two carbon substituents). This terminal carbonyl can influence the chemical reactivity, polarity, and stability of the molecule and provides a specific handle for further functionalization.

In polymers, ketone termination refers to chains whose ends carry a ketone group, enabling post-polymerization modification or targeted conjugation. Ketone ends can arise when a terminal functional group is oxidized to a carbonyl, or when synthesis or termination steps are designed to cap the chain with a ketone rather than with alcohols, halides, or inert hydrogens. The presence of a ketone end can affect strategies for end-group analysis, purification, and downstream chemistry, including potential reactivity under nucleophilic or acidic conditions.

Synthesis and formation methods commonly involve selective oxidation of a terminal alcohol or alkene, or deliberate post-polymerization modification to install a carbonyl end group. In small-molecule synthesis, ketone termination can result from oxidative workups or strategic coupling that yields a terminal carbonyl.

Characterization of ketoterminated compounds typically relies on infrared spectroscopy to detect the characteristic C=O stretch around 1650–1750 cm−1 and on nuclear magnetic resonance to observe signals adjacent to the carbonyl. Mass spectrometry and end-group analysis are also used to confirm the presence and position of the terminal ketone.

Applications of ketone-terminated species include chemoselective ligations (such as oxime or hydrazone formation), further carbon–carbon or carbon–nitrogen bond-forming reactions, and use as reactive handles for surface modification or bioconjugation.