Novel bis(phenylselenoalkoxy)calix[4]arene molecular tweezer receptors as sensors for ion-selective electrodes

Four tweezer-like 25,27-dihydroxy-26,28-bis(phenylselenoalkoxy)-5,11,17,23-tetra-tert-butylcalix[4]arenes 5-8 were synthesized for the evaluation of their ion-selectivity in ion-selective electrodes (ISEs). For investigation of the influences of the coordinate atoms on the ion-selectivity, 25,27-dihydroxy-26,28-bis( alkylthiaalkoxy)-5,11,17,23- tetra-tert-butylcalix[4]arenes 9-11 were also prepared and characterized. On the other hand, 1,3-bis(phenylseleno)propane 12 was synthesized for comparison of the influences of coordinate patterns of different ionophores on the ion-selectivity of ISEs. ISEs based on 5-12 as neutral ionophores were prepared, and their selectivity coefficients for Ag+ (log K-Ag,M(pot)) were investigated against alkali metal, alkaline-earth metal, lead, and ammonium ions and some transition metal ions using the fixed interference method (FIM). These ISEs showed excellent Ag+ selectivity over most of the interfering cations examined, except for Hg2+, which had relatively smaller interference (log K-Ag,Hg(pot) less than or equal to -1.6).