Reversible Dioxygen Binding and Aromatic Hydroxylation in O2-Reactions with Substituted Xylyl Dinuclear Copper(I) Complexes: Syntheses and Low-Temperature Kinetic/Thermodynamic and Spectroscopic Investigations of a Copper Monooxygenase Model System

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