Heterocycles, cation recognition

Crown ethers are heterocycles consisting of oxyethylene units, and their size depends on the number of these repeating units. They are known to capture cations into their cavities selectively. Specific cation recognitions of the crown ethers led to the development of various applications such as metal cation sensors and phase transfer cata-lysts.2 Since the hydrophilicities of the crown ethers increase through complexation with cations, introducing crown ether units into thermosensitive polymers should control their solubilities and LCST behaviors in the presence of cations as stimuli. 

Of the acyl hydrazones formed in this case, active lead compounds containing two terminal cationic heterocyclic recognition groups separated by a spacer of appropriate structure could be rapidly identified using a dynamic deconvolution procedure. 

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