6533b85afe1ef96bd12b8a36

RESEARCH PRODUCT

Electrochemical Monitoring of Compartmentalization Effects in the Stability of Meisenheimer Anions Supported in Hydrotalcite and X and Y Zeolites

subject

description

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 immersedinto Et 4 N + /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.