Cesium-selective chemically modified field effect transistors with calix[4]arene-crown-6 derivatives

Calix[4]arene-crown-6 derivatives (1–3) in the 1,3-alternate conformation, incorporated in poly(vinylchloride) membranes of CHEMFETs, exhibit good Cs+-selectivity and Nernstian behaviour. The Cs+-selectivity over Na+, i.e., log KpotCs,Na = −3.3, is slightly better than observed for bis(18-crown-6) derivatives (log KpotCs,Na = −3.0). The CHEMFETs respond sub-Nernstian in the presence of NH+4 and K+. Model calculations show that this can be explained by the small difference between the stability constants of the Cs+− and K+-complexes and by the high partition coefficient of NH+4 in favour of the membrane phase, respectively.