Pathways of 1O2, transfer in the oxidation of anthracenes with the H2O2/VV/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 transfer 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)) molecule is practically inactive toward anthracene in the AcOH solution. The vanadium(V) complex with the singlet dioxygen ligand was suggested to be the 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) dissolved in AcOH solution is similar to 15 at the same 2-ethylanthracene concentration. (C) 2000 Elsevier Science B.V. All rights reserved.