Crown ethers

1,4-Dioxane () is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers (1,2- and 1,3-) are rarely encountered.

family of chemical compounds

18-Crown-6 is an organic compound with the formula [C2H4O]6 and the IUPAC name of 1,4,7,10,13,16-hexaoxacyclooctadecane. It is a white, hygroscopic crystalline solid with a low melting point. Like other crown ethers, 18-crown-6 functions as a ligand for some metal cations with a particular affinity for potassium cations (binding constant in methanol: 106 M−1). The point group of 18-crown-6 is S6. The dipole moment of 18-crown-6 is solvent- and temperature-dependent. Below 25 °C, the dipole moment of 18-crown-6 is in cyclohexane and in benzene. The synthesis of the crown ethers led to

12-Crown-4, also called 1,4,7,10-tetraoxacyclododecane and lithium ionophore V, is a crown ether with the formula C8H16O4. It is a cyclic tetramer of ethylene oxide which is specific for the lithium cation.

15-Crown-5 is a crown ether with the formula (C2H4O)5. It is a cyclic pentamer of ethylene oxide that forms a complex with various cations, including sodium (Na+)

Dibenzo-18-crown-6 is the organic compound with the formula [OC6H4OCH2CH2OCH2CH2]2. It is a white solid that is soluble in organic solvents. As one of the most popular crown ethers, it facilitates the dissolution of many salts in organic solvents. It is related to the non-benzannulated 18-crown-6.

21-Crown-7 is an organic compound with the formula (C2H4O)7. Similar to other crown ethers, 21-crown-7 functions as a ligand for certain metal cations, with a specific affinity for caesium cations. The dipole moment of 21-crown-7 varies depending on the solvent and temperatures.

9-Crown-3, also called 1,4,7-trioxonane or 1,4,7-trioxacyclononane, is a crown ether with the formula (C2H4O)3. A colorless liquid, it is obtained in low yield by the acid-catalyzed oligomerization of ethylene oxide.