Dioxygen-copper reactivity: Generation, characterization, and reactivity of a hydroperoxo-dicopper(II) complex

Kenneth D. Karlin, Phalguni Ghosh, Richard W. Cruse, Amjad Farooq, Yilma Gultneh, Richard R. Jacobson, Ninian J. Blackburn, Richard W. Strange, Ninian Blackburn

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Abstract

A hydroperoxo-dicopper(II) species, the protonated form of the peroxo-dicopper(II) complex derived from the reaction of O2 with a dicopper(I) compound, is stable at -80°C in dichloromethane solution and the methods for its generation and its properties are described. This complex, [Cu2(XYL-O-)(OOH)]2+ (3), utilizes a phenolic dinucleating ligand possessing two tridentate PY2 units (PY2 = bis[2-(2-pyridyl)ethyl]amine), XYL-OH. A phenoxo-bridged dicopper(I) complex [Cu2-(XYL-O-))]+ (1) reacts with O2 to form the previously characterized dioxygen (peroxo) adduct [Cu2(XYL-O-)(O2)]+ (2). As shown by a titration followed by UV-vis spectroscopy, one equivalent of H+ can be irreversibly added to -80°C dichloromethane solutions of 2 (isosbestic point observed) to form [Cu2(XYL-O-)(OOH)]2+ (3; λmax = 395 nm, ε = 8000 M-1 cm-1). Complex 3 can also be generated by reaction of the phenoxo- and hydroxo-bridged dicopper(II) complex [Cu2(XYL-O-)(OH)]2+ (4) with hydrogen peroxide, further substantiating its formulation as a peroxidic species. The most convenient method for forming 3 is by the addition of O2 (Cu:O2 = 2:1) to either [Cu2(XYL-OH)]2+ (5) or [Cu2(XYL-OH)(CH3CN)2]2+ (6d); these dicationic dicopper(I) compounds contain an uncoordinated phenol group. While the dioxygen complex [Cu2(XYL-O-)(O2)]+ (2) reacts with triphenylphosphine (PPh3) liberating O2 quantitatively and providing [Cu2(XYL-O-)(PPh3)2]+ (7), the hydroperoxo complex [Cu2(XYL-O-)(OOH)]2+ (3) reacts with PPh3 or sulfides quantitatively to given the monooxygenated substrate (O=PPh3 or RS(O)R) and [Cu2(XYL-O-)(OH)]2+ (4), involving the transfer of a single oxygen atom to the substrate. Similar substrate oxygenation reactions can also be carried out by reacting O2 with compounds [Cu2(XYL-OH)(PPh3)2]2+ (6b) or [Cu2-(XYL-OH)(RSR)2]2+ (6c, RSR = tetramethylene sulfide). Product analyses (4 also produced quantitatively) show that only 1 mol·equiv of substrate is oxygenated, in accord with the manometric dioxygen uptake (Cu:O2 = 2:1); labeling experiments utilizing 18O2 show that the product phosphine oxide or sulfoxide contains a single 18O atom. [Cu2(XYL-O-)(OOH)]2+ (3) is proposed to contain a μ-1,1 -hydroperoxo (-OOH) ligand, based on (i) its structural analogy to [Cu2(XYL-O-)(OH)]2+ (4), deduced from an extended X-ray absorption fine structure (EXAFS) analysis, with four N or O donors at 1.99 Å and Cu⋯Cu = 3.04 Å, and (ii) the chemical and spectroscopic similarities to the recently structurally described acylperoxo complex, [Cu2(XYL-O-)(OOR)]2+ (8, R = m-ClC6H4C(O)-). A crystallographic study of a perchlorate salt of 6b, [Cu2(XYL-OH)(PPh3)2](ClO4) 2·(CD3NO2)2 (C74H76D6Cl2Cu2N 8O13P2), has been carried out; it crystallizes in the triclinic space group P1 with Z = 1 and a = 10.196 (2) Å, b = 11.715 (2) Å, c = 15.506 (3) Å, α = 94.27 (1)°, β = 90.30 (1)°, and γ = 94.53 (1)°. It contains an uncoordinated phenol group with well-separated (Cu⋯Cu = 9.944 (2) Å) tetracoordinate Cu(I) ions ligated to the three N atoms of the PY2 unit and a single triphenylphosphine P atom.

Original languageEnglish (US)
Pages (from-to)6769-6780
Number of pages12
JournalJournal of the American Chemical Society
Volume110
Issue number20
StatePublished - 1988

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Copper
Oxygen
Atoms
phosphine
sulfoxide
Methylene Chloride
Dichloromethane
Sulfides
Substrates
Phenol
Phenols
Ligands
Oxygenation
X ray absorption
Ultraviolet spectroscopy
Titration
Hydrogen peroxide
Oxides
Labeling
Hydrogen Peroxide

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Karlin, K. D., Ghosh, P., Cruse, R. W., Farooq, A., Gultneh, Y., Jacobson, R. R., ... Blackburn, N. (1988). Dioxygen-copper reactivity: Generation, characterization, and reactivity of a hydroperoxo-dicopper(II) complex. Journal of the American Chemical Society, 110(20), 6769-6780.

Dioxygen-copper reactivity : Generation, characterization, and reactivity of a hydroperoxo-dicopper(II) complex. / Karlin, Kenneth D.; Ghosh, Phalguni; Cruse, Richard W.; Farooq, Amjad; Gultneh, Yilma; Jacobson, Richard R.; Blackburn, Ninian J.; Strange, Richard W.; Blackburn, Ninian.

In: Journal of the American Chemical Society, Vol. 110, No. 20, 1988, p. 6769-6780.

Research output: Contribution to journalArticle

Karlin, KD, Ghosh, P, Cruse, RW, Farooq, A, Gultneh, Y, Jacobson, RR, Blackburn, NJ, Strange, RW & Blackburn, N 1988, 'Dioxygen-copper reactivity: Generation, characterization, and reactivity of a hydroperoxo-dicopper(II) complex', Journal of the American Chemical Society, vol. 110, no. 20, pp. 6769-6780.
Karlin, Kenneth D. ; Ghosh, Phalguni ; Cruse, Richard W. ; Farooq, Amjad ; Gultneh, Yilma ; Jacobson, Richard R. ; Blackburn, Ninian J. ; Strange, Richard W. ; Blackburn, Ninian. / Dioxygen-copper reactivity : Generation, characterization, and reactivity of a hydroperoxo-dicopper(II) complex. In: Journal of the American Chemical Society. 1988 ; Vol. 110, No. 20. pp. 6769-6780.
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title = "Dioxygen-copper reactivity: Generation, characterization, and reactivity of a hydroperoxo-dicopper(II) complex",
abstract = "A hydroperoxo-dicopper(II) species, the protonated form of the peroxo-dicopper(II) complex derived from the reaction of O2 with a dicopper(I) compound, is stable at -80°C in dichloromethane solution and the methods for its generation and its properties are described. This complex, [Cu2(XYL-O-)(OOH)]2+ (3), utilizes a phenolic dinucleating ligand possessing two tridentate PY2 units (PY2 = bis[2-(2-pyridyl)ethyl]amine), XYL-OH. A phenoxo-bridged dicopper(I) complex [Cu2-(XYL-O-))]+ (1) reacts with O2 to form the previously characterized dioxygen (peroxo) adduct [Cu2(XYL-O-)(O2)]+ (2). As shown by a titration followed by UV-vis spectroscopy, one equivalent of H+ can be irreversibly added to -80°C dichloromethane solutions of 2 (isosbestic point observed) to form [Cu2(XYL-O-)(OOH)]2+ (3; λmax = 395 nm, ε = 8000 M-1 cm-1). Complex 3 can also be generated by reaction of the phenoxo- and hydroxo-bridged dicopper(II) complex [Cu2(XYL-O-)(OH)]2+ (4) with hydrogen peroxide, further substantiating its formulation as a peroxidic species. The most convenient method for forming 3 is by the addition of O2 (Cu:O2 = 2:1) to either [Cu2(XYL-OH)]2+ (5) or [Cu2(XYL-OH)(CH3CN)2]2+ (6d); these dicationic dicopper(I) compounds contain an uncoordinated phenol group. While the dioxygen complex [Cu2(XYL-O-)(O2)]+ (2) reacts with triphenylphosphine (PPh3) liberating O2 quantitatively and providing [Cu2(XYL-O-)(PPh3)2]+ (7), the hydroperoxo complex [Cu2(XYL-O-)(OOH)]2+ (3) reacts with PPh3 or sulfides quantitatively to given the monooxygenated substrate (O=PPh3 or RS(O)R) and [Cu2(XYL-O-)(OH)]2+ (4), involving the transfer of a single oxygen atom to the substrate. Similar substrate oxygenation reactions can also be carried out by reacting O2 with compounds [Cu2(XYL-OH)(PPh3)2]2+ (6b) or [Cu2-(XYL-OH)(RSR)2]2+ (6c, RSR = tetramethylene sulfide). Product analyses (4 also produced quantitatively) show that only 1 mol·equiv of substrate is oxygenated, in accord with the manometric dioxygen uptake (Cu:O2 = 2:1); labeling experiments utilizing 18O2 show that the product phosphine oxide or sulfoxide contains a single 18O atom. [Cu2(XYL-O-)(OOH)]2+ (3) is proposed to contain a μ-1,1 -hydroperoxo (-OOH) ligand, based on (i) its structural analogy to [Cu2(XYL-O-)(OH)]2+ (4), deduced from an extended X-ray absorption fine structure (EXAFS) analysis, with four N or O donors at 1.99 {\AA} and Cu⋯Cu = 3.04 {\AA}, and (ii) the chemical and spectroscopic similarities to the recently structurally described acylperoxo complex, [Cu2(XYL-O-)(OOR)]2+ (8, R = m-ClC6H4C(O)-). A crystallographic study of a perchlorate salt of 6b, [Cu2(XYL-OH)(PPh3)2](ClO4) 2·(CD3NO2)2 (C74H76D6Cl2Cu2N 8O13P2), has been carried out; it crystallizes in the triclinic space group P1 with Z = 1 and a = 10.196 (2) {\AA}, b = 11.715 (2) {\AA}, c = 15.506 (3) {\AA}, α = 94.27 (1)°, β = 90.30 (1)°, and γ = 94.53 (1)°. It contains an uncoordinated phenol group with well-separated (Cu⋯Cu = 9.944 (2) {\AA}) tetracoordinate Cu(I) ions ligated to the three N atoms of the PY2 unit and a single triphenylphosphine P atom.",
author = "Karlin, {Kenneth D.} and Phalguni Ghosh and Cruse, {Richard W.} and Amjad Farooq and Yilma Gultneh and Jacobson, {Richard R.} and Blackburn, {Ninian J.} and Strange, {Richard W.} and Ninian Blackburn",
year = "1988",
language = "English (US)",
volume = "110",
pages = "6769--6780",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
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TY - JOUR

T1 - Dioxygen-copper reactivity

T2 - Generation, characterization, and reactivity of a hydroperoxo-dicopper(II) complex

AU - Karlin, Kenneth D.

AU - Ghosh, Phalguni

AU - Cruse, Richard W.

AU - Farooq, Amjad

AU - Gultneh, Yilma

AU - Jacobson, Richard R.

AU - Blackburn, Ninian J.

AU - Strange, Richard W.

AU - Blackburn, Ninian

PY - 1988

Y1 - 1988

N2 - A hydroperoxo-dicopper(II) species, the protonated form of the peroxo-dicopper(II) complex derived from the reaction of O2 with a dicopper(I) compound, is stable at -80°C in dichloromethane solution and the methods for its generation and its properties are described. This complex, [Cu2(XYL-O-)(OOH)]2+ (3), utilizes a phenolic dinucleating ligand possessing two tridentate PY2 units (PY2 = bis[2-(2-pyridyl)ethyl]amine), XYL-OH. A phenoxo-bridged dicopper(I) complex [Cu2-(XYL-O-))]+ (1) reacts with O2 to form the previously characterized dioxygen (peroxo) adduct [Cu2(XYL-O-)(O2)]+ (2). As shown by a titration followed by UV-vis spectroscopy, one equivalent of H+ can be irreversibly added to -80°C dichloromethane solutions of 2 (isosbestic point observed) to form [Cu2(XYL-O-)(OOH)]2+ (3; λmax = 395 nm, ε = 8000 M-1 cm-1). Complex 3 can also be generated by reaction of the phenoxo- and hydroxo-bridged dicopper(II) complex [Cu2(XYL-O-)(OH)]2+ (4) with hydrogen peroxide, further substantiating its formulation as a peroxidic species. The most convenient method for forming 3 is by the addition of O2 (Cu:O2 = 2:1) to either [Cu2(XYL-OH)]2+ (5) or [Cu2(XYL-OH)(CH3CN)2]2+ (6d); these dicationic dicopper(I) compounds contain an uncoordinated phenol group. While the dioxygen complex [Cu2(XYL-O-)(O2)]+ (2) reacts with triphenylphosphine (PPh3) liberating O2 quantitatively and providing [Cu2(XYL-O-)(PPh3)2]+ (7), the hydroperoxo complex [Cu2(XYL-O-)(OOH)]2+ (3) reacts with PPh3 or sulfides quantitatively to given the monooxygenated substrate (O=PPh3 or RS(O)R) and [Cu2(XYL-O-)(OH)]2+ (4), involving the transfer of a single oxygen atom to the substrate. Similar substrate oxygenation reactions can also be carried out by reacting O2 with compounds [Cu2(XYL-OH)(PPh3)2]2+ (6b) or [Cu2-(XYL-OH)(RSR)2]2+ (6c, RSR = tetramethylene sulfide). Product analyses (4 also produced quantitatively) show that only 1 mol·equiv of substrate is oxygenated, in accord with the manometric dioxygen uptake (Cu:O2 = 2:1); labeling experiments utilizing 18O2 show that the product phosphine oxide or sulfoxide contains a single 18O atom. [Cu2(XYL-O-)(OOH)]2+ (3) is proposed to contain a μ-1,1 -hydroperoxo (-OOH) ligand, based on (i) its structural analogy to [Cu2(XYL-O-)(OH)]2+ (4), deduced from an extended X-ray absorption fine structure (EXAFS) analysis, with four N or O donors at 1.99 Å and Cu⋯Cu = 3.04 Å, and (ii) the chemical and spectroscopic similarities to the recently structurally described acylperoxo complex, [Cu2(XYL-O-)(OOR)]2+ (8, R = m-ClC6H4C(O)-). A crystallographic study of a perchlorate salt of 6b, [Cu2(XYL-OH)(PPh3)2](ClO4) 2·(CD3NO2)2 (C74H76D6Cl2Cu2N 8O13P2), has been carried out; it crystallizes in the triclinic space group P1 with Z = 1 and a = 10.196 (2) Å, b = 11.715 (2) Å, c = 15.506 (3) Å, α = 94.27 (1)°, β = 90.30 (1)°, and γ = 94.53 (1)°. It contains an uncoordinated phenol group with well-separated (Cu⋯Cu = 9.944 (2) Å) tetracoordinate Cu(I) ions ligated to the three N atoms of the PY2 unit and a single triphenylphosphine P atom.

AB - A hydroperoxo-dicopper(II) species, the protonated form of the peroxo-dicopper(II) complex derived from the reaction of O2 with a dicopper(I) compound, is stable at -80°C in dichloromethane solution and the methods for its generation and its properties are described. This complex, [Cu2(XYL-O-)(OOH)]2+ (3), utilizes a phenolic dinucleating ligand possessing two tridentate PY2 units (PY2 = bis[2-(2-pyridyl)ethyl]amine), XYL-OH. A phenoxo-bridged dicopper(I) complex [Cu2-(XYL-O-))]+ (1) reacts with O2 to form the previously characterized dioxygen (peroxo) adduct [Cu2(XYL-O-)(O2)]+ (2). As shown by a titration followed by UV-vis spectroscopy, one equivalent of H+ can be irreversibly added to -80°C dichloromethane solutions of 2 (isosbestic point observed) to form [Cu2(XYL-O-)(OOH)]2+ (3; λmax = 395 nm, ε = 8000 M-1 cm-1). Complex 3 can also be generated by reaction of the phenoxo- and hydroxo-bridged dicopper(II) complex [Cu2(XYL-O-)(OH)]2+ (4) with hydrogen peroxide, further substantiating its formulation as a peroxidic species. The most convenient method for forming 3 is by the addition of O2 (Cu:O2 = 2:1) to either [Cu2(XYL-OH)]2+ (5) or [Cu2(XYL-OH)(CH3CN)2]2+ (6d); these dicationic dicopper(I) compounds contain an uncoordinated phenol group. While the dioxygen complex [Cu2(XYL-O-)(O2)]+ (2) reacts with triphenylphosphine (PPh3) liberating O2 quantitatively and providing [Cu2(XYL-O-)(PPh3)2]+ (7), the hydroperoxo complex [Cu2(XYL-O-)(OOH)]2+ (3) reacts with PPh3 or sulfides quantitatively to given the monooxygenated substrate (O=PPh3 or RS(O)R) and [Cu2(XYL-O-)(OH)]2+ (4), involving the transfer of a single oxygen atom to the substrate. Similar substrate oxygenation reactions can also be carried out by reacting O2 with compounds [Cu2(XYL-OH)(PPh3)2]2+ (6b) or [Cu2-(XYL-OH)(RSR)2]2+ (6c, RSR = tetramethylene sulfide). Product analyses (4 also produced quantitatively) show that only 1 mol·equiv of substrate is oxygenated, in accord with the manometric dioxygen uptake (Cu:O2 = 2:1); labeling experiments utilizing 18O2 show that the product phosphine oxide or sulfoxide contains a single 18O atom. [Cu2(XYL-O-)(OOH)]2+ (3) is proposed to contain a μ-1,1 -hydroperoxo (-OOH) ligand, based on (i) its structural analogy to [Cu2(XYL-O-)(OH)]2+ (4), deduced from an extended X-ray absorption fine structure (EXAFS) analysis, with four N or O donors at 1.99 Å and Cu⋯Cu = 3.04 Å, and (ii) the chemical and spectroscopic similarities to the recently structurally described acylperoxo complex, [Cu2(XYL-O-)(OOR)]2+ (8, R = m-ClC6H4C(O)-). A crystallographic study of a perchlorate salt of 6b, [Cu2(XYL-OH)(PPh3)2](ClO4) 2·(CD3NO2)2 (C74H76D6Cl2Cu2N 8O13P2), has been carried out; it crystallizes in the triclinic space group P1 with Z = 1 and a = 10.196 (2) Å, b = 11.715 (2) Å, c = 15.506 (3) Å, α = 94.27 (1)°, β = 90.30 (1)°, and γ = 94.53 (1)°. It contains an uncoordinated phenol group with well-separated (Cu⋯Cu = 9.944 (2) Å) tetracoordinate Cu(I) ions ligated to the three N atoms of the PY2 unit and a single triphenylphosphine P atom.

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