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The binding and subsequent reactivity of dioxygen (O 2 ) upon binding to copper ion centers is of fundamental interest in chemical and biological processes. We provide here a detailed account of the reaction of O 2 with dicopper(I) complexes, involving O 2 -reversible binding, followed by the stoichiometric aromatic hydroxylation of the ligand. Thus, tricoordinated dicopper(I) complexes [Cu 2 (R-XYL)] 2+ (R=H, MeO, t-Bu, F, CN, NO 2 ; 1a-f possess dinucleating meta-substituted xylylene ligands with two chelating tridentate bis[2-(2-pyridyl)ethyl]amine (PY2) moieties and a 5-R substituent

The binding of O 2 to copper(I) and its subsequent reactivity is important in a variety of chemical and biological processes. We previously studied functional models of hemocyanins (arthropodal and molluscan O 2 carriers) involving a class of O 2 adducts [Cu 2 (Nn)(O 2 )] 2+ , where Nn are dinucleating ligands which employ two tridentate bis(2-pyridylethyl)amine (PY2) moieties, connected by a variable alkyl chain.

The mechanism of aromatic hydroxylation for 2-methyl substituted analogues of copper complexes studied previously, namely [Cu{sub 2}(Me{sub 2}XYL-CH{sub 3})]{sup 2+} (4) and [Cu{sub 2}(XYL-CH{sub 3})]{sup 2+} (5) are described in detail. Manometric O{sub 2} uptake experiments and labeling studies were used to unravel the reaction pathway. The NIH shift mechanism is said to be operative in a copper monooxygenase model system involving dicopper ion complex mediated O{sub 2} hydroxylation of an arene substrate. Manometric O{sub 2} uptake experiments and labeling studies were used to unravel the reaction pathway. 66 refs., 7 figs.

We report a novel case of a metal ion induced oxidative dehalogenation ,the first copper mediated hydroxylation induced dechlorination of an aromatic substrate.