Mass spectrometric behavior of functionalized calix[4]arenes: the screening ability of host–guest complex formation with amino acid methyl esters

Extraction and complexation of alkali and alkaline earth metal cations by lower-rim calix[4]arene diethylene glycol amide derivatives

The metal-ion extraction abilities of calix[4]arene derivatives1and2are largely dependent on the type of the amide group forming the cation-binding site. Tertiary-amide derivative2was shown to be an excellent extractant for most alkali and alkaline earth cations.