Spectroscopic Detection, Reactivity, and Acid− Base Behavior of Ring

Spectroscopic Detection, Reactivity, and Acid− Base Behavior of Ring ...pubs.acs.org/doi/pdfplus/10.1021/jo035492nby M Bietti - ‎2004 - ‎Cited b...
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Spectroscopic Detection, Reactivity, and Acid-Base Behavior of Ring-Dimethoxylated Phenylethanoic Acid Radical Cations and Radical Zwitterions in Aqueous Solution Massimo Bietti* and Alberto Capone Dipartimento di Scienze e Tecnologie Chimiche, Universita` Tor Vergata, Via della Ricerca Scientifica, I-00133 Rome, Italy [email protected] Received October 10, 2003

A product and time-resolved kinetic study of the one-electron oxidation of ring-dimethoxylated phenylethanoic acids has been carried out at different pH values. Oxidation leads to the formation of aromatic radical cations or radical zwitterions depending on pH, and pKa values for the corresponding acid-base equilibria have been measured. The radical cations undergo decarboxylation with first-order rate constants (kdec) ranging from