Picolyl-armed 1,3-alternate calix[4]areneazacrown ethers

A series of novel 1,3-alternate calix[4]arene-azacrown ethers with 2-picoly l, 3-picolyl, and benzyl groups on the nitrogen atom were synthesized by re action of 1,3-alternate calix[4]arene-azacrown ether and aryl halide in the presence of triethylamine as base. Based on two-phase extraction; bulk liq uid membrane, H-1 NMR, and solid-state studies on this ligand-metal complex ation, 2-picolyl-armed calixazacrown ether showed the highest selectivity f or silver ion due to electrostatic interaction through effective:three-dime nsional encapsulation assisted by the nitrogen atom of the 2-picolyl group.