1. In Search of Aryloxenium Ions
Michael Novak
Department of Chemistry and Biochemistry
Miami University
Laser flash photolysis of 4-acetoxy-4-(4´-methylpheny)-2,5-cyclohexadienone generates two transient absorbance bands. The one with λmax 460 nm decays in a first-order manner with a rate constant that is independent of O2, but depends on [N3-]. The azide/solvent selectivity, kaz/ks, is identical to that obtained by N3--trapping of the hydrolysis reaction of the same quinol ester. The intermediate is identified as the 4´-methylbiphenylyloxenium ion. The band with λmax 360 nm decays more slowly in a biphasic manner with rate constants that are independent of both O2 and N3-. This intermediate has not yet been identified.