A D2 symmetric tetraamide macrocycle based on 1,1′,4,4′-tetrahydro[3,3′(2H,2′H)-spirobiquinoline]-2,2′-dione: synthesis and selectivity for lithium over sodium and alkaline earth ions

Macrocyclic ionophores d,l-3 and d,l-4 with four amide carbonyl ligands were synthesized and investigated in lithium ion-selective electrodes.