Synthesis of new optically active acridino-18-crown-6 ligands and studies of their potentiometric selectivity toward the enantiomers of protonated 1-phenylethylamine and metal ions

Abstract

Starting from commercially available and relatively inexpensive chemicals, new enantiopure diisobutyl- and dioctyl-substituted acridino-18-crown-6 ether-type ligands [( R,R)- 3] and [( R,R)- 4], respectively were prepared. The two lipophilic isobutyl [( R,R)- 3] and octyl [( R,R)- 4] groups on the stereogenic centers of these macrocycles made it possible to use them as potentiometric sensor molecules when incorporated into plasticized PVC membrane electrodes. Ligand ( R,R)- 3 showed appreciable enantioselectivity toward the enantiomers of 1-phenylethylammonium chloride while macrocycle ( R,R)- 4 exhibited a high selectivity toward the silver ion.