Calix[4]arene-based ion or ion-pair receptors

Calix[4]arene derivatives are one of the most important supramolecular scaffolds. They have been extensively exploited to build more elaborate systems. Calix[4]arene derivatives can stabilize host-guest complexes with various ions and neutral molecular guests through non-covalent interactions (e.g., hydrogen bonding, electrostatic interactions and cation-π interactions). This dissertation describes efforts to develop more efficient calix[4]arene-based ion and ion-pair receptors. Chapter 1 describes an overview of sensitive ion selective chromogenic and fluoregenic sensors based on calix[4]arene derivatives. Chapter 2 details a chromogenic calix[4]arene-calix[4]pyrrole sensor system formed by appending an indane substituent to the β-pyrrole position of the calix[4]pyrrole portion of the hybrid and its use in detecting cesium salts. The indane substituted calix[4]arene-calix[4]pyrrole system gives rise to a colorimetric response when only exposed to simple ion pairs containing the cesium cation. Chapter 3 describes amido-indole incorporated calix[4]arene anion receptors. An amido-indole moieties appended calix[4]arene provides multiple hydrogen bond donors for the interaction with anions. In Chapter 4, graphene field-effect transistors (GFETs) are introduced for cesium ion sensing based on electrostatic measurements. In this work, a crown-6-ether strapped calix[4]arene derivative that adopts a cesium ion selective conformation was prepared. Then, it was attached to various graphene field-effect transistors (GFETs) via π−π interactions. The co-complexation of Cs⁺ ion and calix[4]arene receptor on the GFETs alters the electronic behavior of the system in an ion and concentration dependent manner. This work serves to extend the fundamental chemistry of calix[4]arene-based cesium ion recognition to new research areas. Lastly, an experimental section and characterization data are provided in Chapter 5.