Stabilization of cation-anion pairs by crown ethers liquid clathrates

2 Stabilization of Cation-Anion Pairs by Crown Ethers Liquid Clathrates 

Liquid clathrates, analogues of the gas clathrates but present in the liquid phase, are unusual two phase systems in which an upper layer of solvent lies above a denser layer of solvent saturated with ionic species. Some interesting examples are found in Atwood s work. Initially a salt, such as sodium chloride, is added to an aromatic solvent in which it is insoluble. Another reagent, an aluminium alkyl in one example, is added and the salt is solublized to form a dense phase [1] which may be interpreted as  

It was later discovered that addition of a stoichiometric quantity of an appropriate crown ether aided the formation of the complex salts [2,3] through 

In an extension to this work it was found that simple metal halides (and some carbonyls) could also form liquid clathrates with [18] crown-6 in toluene or benzene when HC1 was bubbled through the mixture, but only in the presence of trace water (or fortuitous water , as it became known within the group) [4]. These systems also generated hydronium ions that were stabilized by the crown ether and crystallized from solution. 

Potassium chloride Distilled water Deuterochloroform (CDC13) 

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STABILIZATION OF CATION-ANION PAIRS BY CROWN ETHERS LIQUID CLATHRATES... 

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