Inhibition of acid‐induced decomposition of diphenyltriazenes by complexation with cyclodextrins |
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Authors: | Tingting Xu Atefeh Vaez‐Zadeh Asadi Mónica Barra |
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Affiliation: | Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 |
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Abstract: | Acid‐promoted N? N bond cleavage in 1,3‐diphenyltriazenes (X‐Ph‐N=N‐NH‐Ph‐X; X = H, 4‐OCH3), leading to formation of diazonium ions and anilines, is strongly inhibited in aqueous solutions in the presence of cyclodextrins (CDs). The inhibition is ascribed to the formation of inclusion complexes that render the guest diphenyltriazene significantly less basic as a result of the less polar nature of the CD cavity (a microsolvent effect). Association equilibrium constants for 1:1 host–guest complexes increase in the order α‐CD <β‐CD ~ permethyl‐β‐CD < hydroxypropyl‐β‐CD, with values for X = 4‐OCH3 being larger than those for X = H. In the case of α‐CD, formation of 2:1 host–guest complexes is also involved. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 567–574, 2010 |
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