Pathways of O-1(2), transfer in the oxidation of anthracenes with the H2O2/V-V/AcOH system

Anthracene and its alkyl derivatives were found to undergo oxidation by the V-V/H2O2/AcOH catalytic system via a polar mechanism involving the transfe r of singlet dioxygen from the vanadium(V)/O-I(2) exniplex to the molecule of unsaturated substrate. The free singlet dioxygen O-1(2)((1)Delta (g)) mo lecule is practically inactive toward anthracene in the AcOH solution. The vanadium(V) complex with the singlet dioxygen ligand was suggested to be th e only oxidant species active in the reaction. The deactivation rate of the complex is similar to 1.5 times less than the rate of its reaction with 2- ethylanthracene (10(-2) M). Meantime, the analogous ratio of the O-1(2) dis solved in AcOH solution is similar to 15 at the same 2-ethylanthracene conc entration. (C) 2000 Elsevier Science B.V. All rights reserved.