Electrochemical monitoring of compartmentalization effects in the stability of meisenheimer anions supported in hydrotalcite and X and y zeolites

Meisenheimer anions (MS-) derived from 2,4-dinitroaniline are stabilized into Li+- and Na+-exchanged zeolites X and Y forming alkali ion-MS ion pairs. Upon attachment of the zeolites to polymer film electrodes immersed into Et4N+/MeCN and Li +/MeCN electrolytes, boundary-associated MS- ions display two oxidation processes at +0.40 and +0.65 V vs. AgCl/Ag. This response sharply contrasts with that recorded for MS- in solution and incorporated within hydrotalcite, for which a unique oxidation peak at +0.35 V is recorded. The electrochemistry of zeolite-associated MS- can be described in terms of an unusual electron-transfer/ chemical reaction/electron-transfer/comproportionation competitive mechanism involving an intermediate deprotonation reaction. Compartmentalization of Meisenheimer ions into zeolite frameworks increases notably the thermodynamic stability of the intermediate species and produces a significant lowering of the rate at which the intermediate deprotonation process occurs with respect to the observed behavior in solution. © 2005 The Electrochemical Society. All rights reserved.