J. Andraos, Y. Chiang, A. Kresge
Sep 10, 1997
Citations
0
Influential Citations
16
Citations
Journal
Journal of the American Chemical Society
Abstract
Flash photolysis of 10-diazo-9(10H)-phenanthrenone in aqueous solution was found to give two successively formed transient species and to produce fluorene-9-carboxylic acid as the major reaction product. These transients were identified, through solvent isotope effects and the form of acid−base catalysis, as fluorenylideneketene, formed by photo-Wolff reaction of the diazophenanthrenone, and fluorene-9-carboxylic acid enol, formed by hydration of this ketene. Analysis of the rate profile of the enol ketonization reaction produced the first and second ionization constants for the enol ionizing as an oxygen acid, = 2.01 and = 9.61, respectively. The rate of enolization of fluorene-9-carboxylic acid was also determined, by bromine scavenging, and that, coupled with a literature value of the acidity constant of this acid, allowed evaluation of the two keto−enol equilibrium constants (pKE = 9.67 for interconverting un-ionized carboxylic acid and enol and pK‘E = 8.24 for interconverting singly ionized acid and ...