TY - JOUR
T1 - Dioxygen activation by copper complexes. Mechanistic insights into copper monooxygenases and copper oxidases
AU - Itoh, Shinobu
AU - Fukuzumi, Shunichi
PY - 2002/10
Y1 - 2002/10
N2 - Reactions of copper(I) complexes with molecular oxygen have been examined using a series of N-alkyl-bis[2-(2-pyridyl)ethyl]amine tridentate ligands ( R′Py2 R) and N,N-dialkyl-2-(2-pyridyl)ethylamine didentate ligands ( R′Py1 R1.R2) at low temperature. The tridentate ligands predominantly provide (μ-η 2:η 2-peroxo)dicopper(II) complexes (side-on type peroxo complex), while the didentate ligands enhance O-O bond homolysis of the peroxo species to produce bis(μ-oxo)dicopper(III) complexes. With the (μ-η 2:η 2-peroxo)dicopper(II) complexes supported by the tridentate ligand, efficient oxygenation of phenolates to the corresponding catechols has been accomplished to provide a good model reaction of tyrosinase. The bis(μ-oxo)dicopper(III) complexes, on the other hand, undergo aliphatic ligand hydroxylation as well as oxygen atom transfer to sulfides to give the corresponding sulfoxides. In the reaction of bis(μ-oxo)dicopper(III) complex with 10-methyl-9,10-dihydroacridine (AcrH 2) and 1,4-cyclohexadiene (CHD), a new active oxygen intermediate such as a (μ-oxo)(μ-oxyl radical)dicopper(III) or a tetranuclear copper-oxygen complex has been suggested to be involved as the real active oxygen species for the C-H bond activation of the external substrates. A mixed valence bis(μ 3-oxo) trinuclear copper(II,II,III) complex has also been assessed using the didentate ligand with the smallest N-alkyl substituent (methyl). Mechanistic details of the above reactions as well as ligand effects on the copper(I)-dioxygen reactivity are discussed systematically.
AB - Reactions of copper(I) complexes with molecular oxygen have been examined using a series of N-alkyl-bis[2-(2-pyridyl)ethyl]amine tridentate ligands ( R′Py2 R) and N,N-dialkyl-2-(2-pyridyl)ethylamine didentate ligands ( R′Py1 R1.R2) at low temperature. The tridentate ligands predominantly provide (μ-η 2:η 2-peroxo)dicopper(II) complexes (side-on type peroxo complex), while the didentate ligands enhance O-O bond homolysis of the peroxo species to produce bis(μ-oxo)dicopper(III) complexes. With the (μ-η 2:η 2-peroxo)dicopper(II) complexes supported by the tridentate ligand, efficient oxygenation of phenolates to the corresponding catechols has been accomplished to provide a good model reaction of tyrosinase. The bis(μ-oxo)dicopper(III) complexes, on the other hand, undergo aliphatic ligand hydroxylation as well as oxygen atom transfer to sulfides to give the corresponding sulfoxides. In the reaction of bis(μ-oxo)dicopper(III) complex with 10-methyl-9,10-dihydroacridine (AcrH 2) and 1,4-cyclohexadiene (CHD), a new active oxygen intermediate such as a (μ-oxo)(μ-oxyl radical)dicopper(III) or a tetranuclear copper-oxygen complex has been suggested to be involved as the real active oxygen species for the C-H bond activation of the external substrates. A mixed valence bis(μ 3-oxo) trinuclear copper(II,II,III) complex has also been assessed using the didentate ligand with the smallest N-alkyl substituent (methyl). Mechanistic details of the above reactions as well as ligand effects on the copper(I)-dioxygen reactivity are discussed systematically.
UR - http://www.scopus.com/inward/record.url?scp=0036417222&partnerID=8YFLogxK
U2 - 10.1246/bcsj.75.2081
DO - 10.1246/bcsj.75.2081
M3 - Article
AN - SCOPUS:0036417222
SN - 0009-2673
VL - 75
SP - 2081
EP - 2095
JO - Bulletin of the Chemical Society of Japan
JF - Bulletin of the Chemical Society of Japan
IS - 10
ER -