Dual-host salt extraction

The anion- and cation-binding portions of an ion pair binding system do not necessarily have to be covalently linked together and indeed it is synthetically usually much more straightforward and cheaper 

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Dual host salt extraction involves the simultaneous extraction of a cation and anion by two separate receptors, one complementary to each ion. 

Table 5.1 Extraction constants (JQJ of K+ salts of various anions either by dicyclohexano [18] crown-6 (5.30) alone or by the dual-host system dicyclohexano [18] crown-6/A/)A/i -diphenylthiourea.

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