Role of (μ-oxo)dicopper(III) complexes in oxidative polymerization of phenol.: A DFT study

A detailed quantum mechanical study of the generation of "controlled" radical species participating in regioselective polymerization of phenol has been carried out at the GGAII/LACVP* level of theory. There are two pathways of "controlled" radicals generation which represent phenol radicals stabilized by Cu(I)-amine complexes, postulated as active species in regioselective polymerization of phenol. One of them is the proton abstraction from phenol-Cu(II)-amine complexes by organic base available in the reaction mixture while the other is the hydrogen abstraction by (mu-oxo)dicopper(III) complexes from Cu(I)-phenol complexes. According to calculations mu-eta(2):eta(2)-peroxodicopper(II) complexes originally postulated as precursors for generating of "controlled" radicals are incapable of their generation. it seems it is (mu-oxo)dicopper(III) complexes that are responsible for "radical controlled" oxidative polymerization of phenol.