Benzocrown derivatives as ionophores for alkali cations, II. Synthesis and comparison of urethane‐, ether‐, and ester‐linked bis‐crown compounds and several „crown‐ring free” analogues


Nitro derivatives of bis‐crown ethers with urethane (2), ether (10), and ester (9, 16) linkage not being able to form hydrogen bridges were synthesized, and their K+ selectivities were determined. A remarkable effect of the NO2 group on the selectivity was observed when a NO2…NH hydrogen bond could be formed while the others showed only slight improvement in general electroanalytical parameters. Several analogues without the crown ether ring (25, 26) were also prepared, but these compounds lost their alkaline ionophore properties. Copyright © 1988 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim

Publication Title

Liebigs Annalen der Chemie