Synthesis and Properties of 1,3,5-Tris(phenoxymethyl)-2,4,6-triethylbenzenes as NH 4 + Ionophores

The synthesis, spectroscopic characterization, and potentiometricmeasurements of new 1,3,5-trisphenoxy-2,4,6-triethylbenzenesare described. The cation binding abilities oftrisphenoxy-2,4,6-triethylbenzenes were strongly dependenton the substituents introduced on the phenoxy units: thereceptors with electron-donating alkoxy groups (–OCH₃and –OCH₂C₆H₅) provided similar potentiometricperformance to that of nonactin in PVC-based, ion-selectivemembrane electrodes. The trisphenoxy-2,4,6-triethylbenzenereceptors with ether groups on ortho and meta positions ofphenoxy units exhibit almost identical cation recognitionproperties in the PVC membranes. It is postulated that theelectron-donating nature of the alkoxy substituents increases theelectron density in the phenoxy units, resulting in increasedcation- interactions.