• Carbocation lifetimes and entropy of water addition to carbocations dependent on their stability

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    • Keywords


      Nucleophilic solvation; carbocation lifetimes; entropy of water addition; α-azidobenzyl carbocations

    • Abstract


      Iminodiazonium ions (α-azidobenzyl carbocations) were produced in aqueous solution by chemical initiation (solvolysis) of benzyl-gem-diazides. Solvolysis reactions of benzyl-gem-diazides in water proceed by a stepwise mechanism through a-azidobenzyl carbocation intermediates, which are captured by water to give the corresponding carbonyl compounds as the sole detectable products. Rate constant ratiokaz/ks (M-1) for partitioning of the carbocation between reaction with azide ion and reaction with water was determined by analysis of azide common ion inhibition of the solvolysis reaction. Rate constantsks (s-1) for the reaction of the cation with solvent water were determined from the experimental values ofkaz/ks andksolv, for the solvolysis of the benzyl-gem-diazides, usingkaz = 5 X 109 M-1 s-1 for diffusion-limited reactions of azide ion with a-azidobenzyl carbocations. Values of1/ks were thus the lifetimes of the a-azidobenzyl carbocations. From the study of effect of temperature onksolv andks the activation parameters are determined and discussed.

    • Author Affiliations


      V Jagannadham1

      1. Department of Chemistry, Osmania University, Hyderabad - 500 007, India
    • Dates

  • Journal of Chemical Sciences | News

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