Reaction behaviour of dinuclear copper(i) complexes with m-xylyl-based ligands towards dioxygen

Abstract

Intramolecular ligand hydroxylation was observed during the reactions of dioxygen with the dicopper(I) complexes of the ligands L(1)(L(1)=alpha,alpha'-bis[(2-pyridylethyl)amino]-m-xylene) and L(3)(L(3)=alpha, alpha'-bis[N-(2-pyridylethyl)-N-(2-pyridylmethyl)amino]-m-xylene). The dinuclear copper(I) complex [Cu(2)L(3)](ClO(4))(2) and the dicopper(II) complex [Cu(2)(L(1)-O)(OH)(ClO(4))]ClO(4) were characterized by single-crystal X-ray structure analysis. Furthermore, phenolate-bridged complexes were synthesized with the ligand L(2)-OH (structurally characterized [Cu(2)(L(2)-O)Cl(3)] with L(2)=alpha, alpha'-bis[N-methyl-N-(2-pyridylethyl)amino]-m-xylene; synthesized from the reaction between [Cu(2)(L(2)-O)(OH)](ClO(4))(2) and Cl(-)) and Me-L(3)-OH: [Cu(2)(Me-L(3)-O)(mu-X)](ClO(4))(2)xnH(2)O (Me-L(3)-OH = 2,6-bis[N-(2-pyridylethyl)-N-(2-pyridylmethyl)amino]-4-methylphenol and X = C(3)H(3)N(2)(-)(prz), MeCO(2)(-) and N(3)(-)). The magnetochemical characteristics of compounds were determined by temperature-dependent magnetic studies, revealing their antiferromagnetic behaviour [-2J(in cm(-1)) values: -92, -86 and -88; -374].

Aromatic Hydroxylation in a Copper Bis(imine) Complex Mediated by a μ‐η2:η2 Peroxo Dicopper Core: A Mechanistic Scenario

“…[8,9,10,11] In the latter case part of the ligand coordinating one or both copper centers is hydroxylated after exposure of the Cu I complex to dioxygen. The relevance of these reactions to tyrosinase has intensively been discussed, and a molecular mechanism of tyrosinase functionality has been suggested based on DFT calculations.…”

Bis‐μ‐pyrazolate‐Bridged Dinickel(II) and Dicopper(II) Complexes: An Example of Stereoelectronic Preference of Metal Ions and Stabilization of Mixed‐Valence NiIIINiII Species

“…[1] As part of our continued involvement in the exploration of interesting coordination chemistry of pyridyl/pyrazole-based chelating ligands, [2] we have investigated the magneto-structural properties of a large variety of dinuclear/trinuclear/polymeric complexes with a varied combinations of endogenous/exogenous and solely exogenous bridging ligands (alkoxo/pyrazolato, [3] acetato/pyrazolato, [4] carbonato, [5] diacetato, [4,6] dichloro, [7] dihydroxo, [4,8] monohydroxo, [9] oxo/bis-acetato, [10,11] phenoxo/chloro, [12] phenoxo/hydroxo, [8,13] diphenoxo [14] ).…”

Copper-mediated intramolecular oxidative N-dealkylation of a bis(ferrocenyl)pyridyl ligand

“…Peptidyl glycine R-amidating monooxygenase (PAM), cleaves glycine-extended peptides in an oxidative N-dealkylation process to yield important hormonal peptides. Some dicopper(I) complexes react with molecular oxygen to form dioxygen adducts, which proceed to yield a mixture of N-oxide and/or N,O-dealkylated products, depending on conditions [4].…”

“…Peptidyl glycine R-amidating monooxygenase (PAM), cleaves glycine-extended peptides in an oxidative N-dealkylation process to yield important hormonal peptides. Some dicopper(I) complexes react with molecular oxygen to form dioxygen adducts, which proceed to yield a mixture of N-oxide and/or N,O-dealkylated products, depending on conditions [4].Ferrocene derivatives have come a long way as a tool in chemistry, with applications in electrochemistry, material science, organic synthesis and asymmetric catalysis [5]. The ferrocenyl ligands represent one of the most important classes among the different types of achiral and chiral ligands used in homogenous catalysis and they have been applied in a variety of transition-metal catalyzed reactions.…”