Synthesis and reactivity of (μ-η22-peroxo)dicopper(II) complexes with dinucleating ligands

Hydroxylation of xylyl linker with a NIH shift

Takahiro Matsumoto, Hideki Furutachi, Shigenori Nagatomo, Takehiko Tosha, Shuhei Fujinami, Teizo Kitagawa, Masatatsu Suzuki

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

New hexadentate dinucleating ligands having a xylyl linker, X-L-R, were synthesized, where X-L-R = 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2,4,6-trimethybenzene (Me2-L-Me) and 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2-fluorobenzene (H-L-F). They form dinuclear copper(I) complexes, [Cu2(X-L-R)]2+ (Me2-L-Me (1) and H-L-F (2)). The copper(I) complexes in acetone at -78 °C react with O2 to produce intra- and intermolecular (μ-η22-peroxo)dicopper(II) species depending on the concentrations of the complexes: both complexes generate intramolecular (μ-η22-peroxo)dicopper(II) species [Cu2(O2)(X-L-R)]2+ (1-O2 and 2-O2) at the concentrations below ∼5 mM, whereas at ∼60 mM, both complexes produce intermolecular (μ-η22-peroxo)dicopper(II) species, which were confirmed by the electronic and resonance Raman spectroscopies. The electronic spectrum of 1-O2 in acetone at concentrations below ∼5 mM showed an absorption band at (λmax = 442 nm, ε = 5600 M-1 cm-1) assignable to the πσ*(O-O)-to-Cu(II) ((d x2 - y2 + d x2 - y2) component) LMCT transition in addition to an intense band attributable to the πσ*(O-O)-to-Cu(II) ((d x2 - y2 - d x2 - y2) component) LMCT transition (λmax = 359 nm, ε = 21000 M-1 cm-1), indicating that the (μ-η22-peroxo)Cu(II)2 core of 1-O2 takes a butterfly structure. Decomposition of 1-O2 resulted in hydroxylation of the 2-position of the xylyl linker with 1,2-methyl migration (NIH shift), suggesting that the hydroxylation reaction proceeds via a cationic intermediate as proposed for closely related (μ-η22-peroxo)Cu(II)2 complexes having a xylyl linker. Kinetic study of the decomposition (hydroxylation of the xylyl linker) of 1-O2 suggests that a stereochemical effect of the methyl group in the 2-position of the xylyl linker has a significant influence on a transition state for decomposition (hydroxylation of the xylyl linker).

Original languageEnglish
Pages (from-to)111-121
Number of pages11
JournalJournal of Organometallic Chemistry
Volume692
Issue number1-3
DOIs
Publication statusPublished - Jan 1 2007
Externally publishedYes

Fingerprint

Hydroxylation
reactivity
Ligands
decomposition
acetone
ligands
shift
synthesis
Acetone
Decomposition
Copper
copper
Fluorobenzenes
electronic spectra
Butterflies
Raman Spectrum Analysis
Raman spectroscopy
absorption spectra
Absorption spectra
kinetics

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

Synthesis and reactivity of (μ-η22-peroxo)dicopper(II) complexes with dinucleating ligands : Hydroxylation of xylyl linker with a NIH shift. / Matsumoto, Takahiro; Furutachi, Hideki; Nagatomo, Shigenori; Tosha, Takehiko; Fujinami, Shuhei; Kitagawa, Teizo; Suzuki, Masatatsu.

In: Journal of Organometallic Chemistry, Vol. 692, No. 1-3, 01.01.2007, p. 111-121.

Research output: Contribution to journalArticle

Matsumoto, Takahiro ; Furutachi, Hideki ; Nagatomo, Shigenori ; Tosha, Takehiko ; Fujinami, Shuhei ; Kitagawa, Teizo ; Suzuki, Masatatsu. / Synthesis and reactivity of (μ-η22-peroxo)dicopper(II) complexes with dinucleating ligands : Hydroxylation of xylyl linker with a NIH shift. In: Journal of Organometallic Chemistry. 2007 ; Vol. 692, No. 1-3. pp. 111-121.
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title = "Synthesis and reactivity of (μ-η2:η2-peroxo)dicopper(II) complexes with dinucleating ligands: Hydroxylation of xylyl linker with a NIH shift",
abstract = "New hexadentate dinucleating ligands having a xylyl linker, X-L-R, were synthesized, where X-L-R = 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2,4,6-trimethybenzene (Me2-L-Me) and 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2-fluorobenzene (H-L-F). They form dinuclear copper(I) complexes, [Cu2(X-L-R)]2+ (Me2-L-Me (1) and H-L-F (2)). The copper(I) complexes in acetone at -78 °C react with O2 to produce intra- and intermolecular (μ-η2:η2-peroxo)dicopper(II) species depending on the concentrations of the complexes: both complexes generate intramolecular (μ-η2:η2-peroxo)dicopper(II) species [Cu2(O2)(X-L-R)]2+ (1-O2 and 2-O2) at the concentrations below ∼5 mM, whereas at ∼60 mM, both complexes produce intermolecular (μ-η2:η2-peroxo)dicopper(II) species, which were confirmed by the electronic and resonance Raman spectroscopies. The electronic spectrum of 1-O2 in acetone at concentrations below ∼5 mM showed an absorption band at (λmax = 442 nm, ε = 5600 M-1 cm-1) assignable to the πσ*(O-O)-to-Cu(II) ((d x2 - y2 + d x2 - y2) component) LMCT transition in addition to an intense band attributable to the πσ*(O-O)-to-Cu(II) ((d x2 - y2 - d x2 - y2) component) LMCT transition (λmax = 359 nm, ε = 21000 M-1 cm-1), indicating that the (μ-η2:η2-peroxo)Cu(II)2 core of 1-O2 takes a butterfly structure. Decomposition of 1-O2 resulted in hydroxylation of the 2-position of the xylyl linker with 1,2-methyl migration (NIH shift), suggesting that the hydroxylation reaction proceeds via a cationic intermediate as proposed for closely related (μ-η2:η2-peroxo)Cu(II)2 complexes having a xylyl linker. Kinetic study of the decomposition (hydroxylation of the xylyl linker) of 1-O2 suggests that a stereochemical effect of the methyl group in the 2-position of the xylyl linker has a significant influence on a transition state for decomposition (hydroxylation of the xylyl linker).",
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AU - Matsumoto, Takahiro

AU - Furutachi, Hideki

AU - Nagatomo, Shigenori

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AU - Fujinami, Shuhei

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N2 - New hexadentate dinucleating ligands having a xylyl linker, X-L-R, were synthesized, where X-L-R = 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2,4,6-trimethybenzene (Me2-L-Me) and 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2-fluorobenzene (H-L-F). They form dinuclear copper(I) complexes, [Cu2(X-L-R)]2+ (Me2-L-Me (1) and H-L-F (2)). The copper(I) complexes in acetone at -78 °C react with O2 to produce intra- and intermolecular (μ-η2:η2-peroxo)dicopper(II) species depending on the concentrations of the complexes: both complexes generate intramolecular (μ-η2:η2-peroxo)dicopper(II) species [Cu2(O2)(X-L-R)]2+ (1-O2 and 2-O2) at the concentrations below ∼5 mM, whereas at ∼60 mM, both complexes produce intermolecular (μ-η2:η2-peroxo)dicopper(II) species, which were confirmed by the electronic and resonance Raman spectroscopies. The electronic spectrum of 1-O2 in acetone at concentrations below ∼5 mM showed an absorption band at (λmax = 442 nm, ε = 5600 M-1 cm-1) assignable to the πσ*(O-O)-to-Cu(II) ((d x2 - y2 + d x2 - y2) component) LMCT transition in addition to an intense band attributable to the πσ*(O-O)-to-Cu(II) ((d x2 - y2 - d x2 - y2) component) LMCT transition (λmax = 359 nm, ε = 21000 M-1 cm-1), indicating that the (μ-η2:η2-peroxo)Cu(II)2 core of 1-O2 takes a butterfly structure. Decomposition of 1-O2 resulted in hydroxylation of the 2-position of the xylyl linker with 1,2-methyl migration (NIH shift), suggesting that the hydroxylation reaction proceeds via a cationic intermediate as proposed for closely related (μ-η2:η2-peroxo)Cu(II)2 complexes having a xylyl linker. Kinetic study of the decomposition (hydroxylation of the xylyl linker) of 1-O2 suggests that a stereochemical effect of the methyl group in the 2-position of the xylyl linker has a significant influence on a transition state for decomposition (hydroxylation of the xylyl linker).

AB - New hexadentate dinucleating ligands having a xylyl linker, X-L-R, were synthesized, where X-L-R = 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2,4,6-trimethybenzene (Me2-L-Me) and 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2-fluorobenzene (H-L-F). They form dinuclear copper(I) complexes, [Cu2(X-L-R)]2+ (Me2-L-Me (1) and H-L-F (2)). The copper(I) complexes in acetone at -78 °C react with O2 to produce intra- and intermolecular (μ-η2:η2-peroxo)dicopper(II) species depending on the concentrations of the complexes: both complexes generate intramolecular (μ-η2:η2-peroxo)dicopper(II) species [Cu2(O2)(X-L-R)]2+ (1-O2 and 2-O2) at the concentrations below ∼5 mM, whereas at ∼60 mM, both complexes produce intermolecular (μ-η2:η2-peroxo)dicopper(II) species, which were confirmed by the electronic and resonance Raman spectroscopies. The electronic spectrum of 1-O2 in acetone at concentrations below ∼5 mM showed an absorption band at (λmax = 442 nm, ε = 5600 M-1 cm-1) assignable to the πσ*(O-O)-to-Cu(II) ((d x2 - y2 + d x2 - y2) component) LMCT transition in addition to an intense band attributable to the πσ*(O-O)-to-Cu(II) ((d x2 - y2 - d x2 - y2) component) LMCT transition (λmax = 359 nm, ε = 21000 M-1 cm-1), indicating that the (μ-η2:η2-peroxo)Cu(II)2 core of 1-O2 takes a butterfly structure. Decomposition of 1-O2 resulted in hydroxylation of the 2-position of the xylyl linker with 1,2-methyl migration (NIH shift), suggesting that the hydroxylation reaction proceeds via a cationic intermediate as proposed for closely related (μ-η2:η2-peroxo)Cu(II)2 complexes having a xylyl linker. Kinetic study of the decomposition (hydroxylation of the xylyl linker) of 1-O2 suggests that a stereochemical effect of the methyl group in the 2-position of the xylyl linker has a significant influence on a transition state for decomposition (hydroxylation of the xylyl linker).

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