Transduction of host-guest complexation into electronic signals: Favoured complexation of potassium ions by synthetic macrocyclic polyethers using membrane-modified, ion-sensitive field-effect transistors (ISFETs)
✍ Scribed by Ernst J. R. Sudhölter; Peter D. van der Wal; Maria Skowronska-Ptasinska; Albert van den Berg; David N. Reinhoudt; Piet Bergveld
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 332 KB
- Volume
- 109
- Category
- Article
- ISSN
- 0165-0513
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The selective complexation of K^+^ and Na^+^ salts with a series of synthetic macrocyclic polyethers has been studied on the SiO~2~ gate surface of an Ion‐Sensitive Field‐Effect Transistor (ISFET). The synthetic macrocycles were incorporated in a PVC membrane directly attached to the SiO~2~ gate surface. The selectivities were measured either with tetraethylammonium chloride or lithium chloride as background electrolyte or by direct comparison. The slope of the response curves generally shows near‐Nernstian behaviour (53‐56 mV/pK^+^). Hemispherands 2 and 3, which have molecular cavities composed of 21 ring atoms and 1,3‐dimethyl‐p‐(tert‐butyl)calix[4]arene crown‐5 (11), show high selectivities of K^+^ over Na^+^ (log K(K^+^/Na^+^)= −2.9 to 3.2). The (substituted) benzo‐27‐crown‐9 derivatives (5‐7) show moderate selectivities (log K(K^+^/Na^+^) ≃ −2). The 18‐membered pyrido hemispherand hardly discriminates. Our results correlate well with reported data of picrate extraction experiments and with the relative‐association constants in methanol.