crown ether

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crown ether

[′krau̇n ‚ē·thər]
(organic chemistry)
A macrocyclic polyether whose structure exhibits a conformation with a so-called hole capable of trapping cations by coordination with a lone pair of electrons on the oxygen atoms.
References in periodicals archive ?
Different crown ethers have different binding capacity with the same cation, owing to the size of the cavity.
The dicylcohexano crown has the highest complexation constant of the crown ethers, and this appears to be completely intercalated.
The lower reductions observed for these PS nanocomposites compared to previous work may be due to the poorer nanodispersion with the crown ethers.
Crown ethers have been used to modify both sodium and potassium clays, and the d-spacings of the clays in the presence of the crown ether increases by 0.
6 Table 2 The d-Spacings of Clays Modified With Crown Ethers and Their Blends.
Gokel, Crown Ethers and Cryptands, Royal Society of Chemistry, Cambridge, U.
Another possible modification is to render the alkali metal cation organophiic by complexation with a crown ether.
was dispersed in distilled water (~1 / 100, by weight) by stirring overnight in a beaker; then a 1 ~3 % by volume solution of crown ether in acetone (~150 mmol/ 100 g, crown ether/clay) was added slowly to the suspension.
Cram and his group have concentrated on building rigid molecules that, unlike crown ethers, have a permanent cavity.
Photo: A crown ether unfolds to grab a potassium ion.