https://doi.org/10.15255/KUI.2004.010
Published: Kem. Ind. 54 (2) (2005) 57–63
Paper reference number: KUI-10/2004
Paper type: Original scientific paper
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Sensing and Fixation of NO2 by Calixarenes

D. M. Rudkevich

Abstract

In this short review, an approach towards visual detection, conversion and use of NO2 is described, which applies methods and techniques of supramolecular chemistry and employs calix[ 4]arenes. Exposure of alkylated calix[4]arenes to NO2 / N2O4, both in chlorinated solvents and in the solid state, results in deeply colored calixarene-nitrosonium (NO+) complexes. NO+ were found encapsulated within the calixarene cavities, and stable charge-transfer complexes resulted with Kassoc> 106 dm3 mol–1 (CDCl3). The complexation process is reversible, and the complexes dissociate upon addition of water and alcohol, recovering the parent calixarenes. Attachment of calix[4]arenes to silica gel was demonstrated, which afforded a solid material for visual detection and entrapment of NO2 / N2O4. Design and synthesis of calixarene-based nanotubes for trapping NO2 / N2O4 was proposed. Chemical utilization of NO2 / N2O4 was demonstrated through the transformation into calixarene-NO+ complexes and their use as nitrosonium storing and transferring reagents for organic synthesis. These findings open wider perspectives towards NO2 / NOX sensing, storing and converting materials.

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Keywords

calixarenes, nitrogen oxides, polymers, sensors, supramolecular chemistry