The syntheses of phenol-containing azamacrocycles and liquid membrane transports of alkali cations

Two new tetra-N-substituted tetraazacrown ether derivatives, 4,7,13,16-tetra(2-hydroxy-3,4-dimethylbenzyl)-1,10-dioxa-4,7,13,16-tetraazacyclooctadecane (1) and 4,7,13,16-tetra(5-t-butyl-2-hydroxybenzyl)-1,10-dioxa-4,7,13,16-tetraazacyclooctadecane (2), have been synthesized via one-pot Mannich reaction. The compound 2 was structurally characterized. The liquid membrane transports of alkali metal cations using these two new macrocycles and the other two bisphenol-containing diaza-18-crown-6 ligands as ion-carriers were also studied. The results show that the rates of cation transport are closely related to the number of nitrogen donors and the steric effect of the substituted groups. Compared with some macrocyclic ligands, the two newly synthesized tetraazamacrocycles showed a good selectivity for Li+, and the two diazamacrocycles showed a good selectivity for Na+. (C) 2004 Elsevier B.V. All rights reserved.