Activation of O2 by a binuclear copper(I) compound. Hydroxylation of a new xylyl-binucleating ligand to produce a phenoxy-bridged binuclear copper(II) complex; X-ray crystal structure of [Cu2{OC6H3[CH2N(CH2CH2py)2]2-2,6}(OMe)](py = 2-pyridyl)

A Minimalist Approach to CH Activation by Copper

“…The CuÀN bond distances of 1.952(4) and 1.951(4) are slightly shorter than the CuÀbenzimidazole distances observed for another square pyramidal copper(II) complex (2.04 [22]), but longer than the bonds to two-coordinate copper(I) in [Cu 2 (1) 2 ] 2+ (1.89 ) [19]. The copper-phenolate distances of 1.974(3) and 2.009(3) are slightly longer than those observed by Karlin et al [4] and Casella et al [8] [19]. The conformation of the ligands is interesting: the phenolate moiety is significantly distorted from planarity, and may be regarded as slightly folded about the axis of the CÀO bond.…”

“…Tyrosinase is structurally similar to the oxygen-carrying protein hemocyanin [3], and both have been the subject of intensive modelling with low-molecular-weight coordination compounds. Hydroxylation of a model complex of Cu I containing a ligand with two tridentate centres separated by a meta-xylyl spacer was reported as long ago as 1981 by Karlin et al [4], and some years later Feringa and co-workers showed a similar effect using a bis-bidentate ligand [5]. Since then, a number of other workers have published similar results using a variety of bis-tridentate ligands [6] [7] and bis-bidentate ligands [8 -10].…”

Modeling tyrosinase activity. Effect of ligand topology on aromatic ring hydroxylation: An overview

“…In 1981 Karlin's group reported the synthesis of a dinucleating ligand (1: R = R 0 = X = H) providing three nitrogen donors to each copper ion, separated by a mxylyl spacer [73]. For this ligand, all of the chelate rings are six-membered, which confer stability not only to copper(I) ions but also allow the copper(II) ions to attain tetragonal geometry without strain.…”

Synthesis of new dinuclear dicopper(II) and dinickel(II) complexes. The kinetics of catechol oxidase and electrochemistry of a dicopper(II) complex

“…The interest in mimicing these metalloenzymes arose when a reaction of dioxygen with the dinuclear copper(I) complex [Cu 2 (XYL-H)] 2+ , wherein a m-xylyl group links two bis[2(2-pyridyl)ethyl]amine units, was successfully accomplished by Karlin et al [6,7]. Based on structural and functional analogy, dinuclear complexes of copper(II) were found to be particularly useful as synthetic oxygen carriers.…”