Metal catalysis in oxidation by peroxides. 31. The hydroxylation of benzene by VO(O2)(PIC)(H2O)2: mechanistic and synthetic aspects

摘要: The oxidation of benzene to phenol by the vanadium(V) peroxo complex VO(O{sub 2})(PIC)(H{sub 2}O){sub 2} (1) has been investigated in various solvents and presence both one-electron donors radical traps. hypothesis is advanced that active oxidizing species a vanadium resulting from monoreduction 1, i.e., formally radical-anion derivative. Such process readily occurs noncoordinating (CH{sub 3}NO{sub 2}, C{sub 6}H{sub 6}, also CH{sub 3}CN) whereas it almost suppressed coordinating ones 3}OH DMF). PIC ligand plays role, likely stabilizing species, which, however, may be formed simple complexes such as 2})(OR). As far synthetic applications 1 are concerned, preliminary data indicate running two-phase system main drawback process, fast decomposition oxidant, be, at least part, overcome.