Macrocyclic Ligands with Partially Fluorinated Sidearms: Synthesis and Metal Ion Complexation

Derivatives of aza-12-crown-4, aza-15-crown-5, aza-18-crown-6, 1,10-diaza-18-crown-6 and 1,4,8,12-tetraazacyclopentadecane with partially fluorinated substituents attached to nitrogen are prepared. Their efficiencies and selectivities in alkali metal and silver picrate extractions from aqueous solutions into chloroform are determined and compared with those of appropriate model compounds. Ionophores with longer spacers of –CH2OCH2CH2– and –CH2CH2OCH2CH2– between the nitrogen atom(s) of the macroring and the perfluoroalkyl group(s) exhibit greater extraction efficiencies than do analogues with shorter spacers consisting of one or two methylene groups.