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Oxygen Transfer from Trimethylamine N-Oxide to CuI Complexes Supported by Pentanitrogen Ligands

Ramírez, Erick ; Hossain, Md Kamal LU ; Flores-Alamo, Marcos ; Haukka, Matti ; Nordlander, Ebbe LU and Castillo, Ivan (2020) In European Journal of Inorganic Chemistry
Abstract

[N,N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L1) and [N,N-bis(2-quinolylmethyl)-N-bis(2-pyridyl)methylamine] (L2) were employed to prepare CuII and CuI complexes for spectroscopic and structural characterization. [L1CuII(H2O)](NO3)2 and [L2CuII(NO3)]NO3 have Jahn–Teller distorted octahedral geometries and give rise to isotropic EPR spectra in frozen solution. [L1CuI(CH3CN)]OTf and [L2CuI(CH3CN)]OTf have distorted trigonal bipyramidal and tetrahedral solid-state structures, respectively. The N-donors... (More)

[N,N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L1) and [N,N-bis(2-quinolylmethyl)-N-bis(2-pyridyl)methylamine] (L2) were employed to prepare CuII and CuI complexes for spectroscopic and structural characterization. [L1CuII(H2O)](NO3)2 and [L2CuII(NO3)]NO3 have Jahn–Teller distorted octahedral geometries and give rise to isotropic EPR spectra in frozen solution. [L1CuI(CH3CN)]OTf and [L2CuI(CH3CN)]OTf have distorted trigonal bipyramidal and tetrahedral solid-state structures, respectively. The N-donors display labile behavior in solution, based on variable-temperature 1H NMR studies. Addition of trimethylamine N-oxide (Me3NO) to solutions of [L1CuI(CH3CN)]OTf and [L2CuI(CH3CN)]OTf resulted in diamagnetic species tentatively assigned as the corresponding adducts upon replacement of coordinated acetonitrile, based on 1H NMR spectroscopy. Heating [L1CuI(CH3CN)]OTf to 50–60 °C in the presence of Me3NO resulted in its cupric analogue [L1CuII(CH3CN)]2+, as well as a small amount of 2-dipyridylketone, along with other oxidation by-products. In the case of [L2CuI(CH3CN)]OTf, the reaction with Me3NO resulted in the cupric complex bis(2-quinolinecarboxamidato)copper(II), along with 2-dipyridylketone as oxidation products.

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organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Copper, C–H activation, N ligands, Oxidation, Oxido transfer
in
European Journal of Inorganic Chemistry
publisher
John Wiley and Sons Inc.
external identifiers
  • scopus:85087684555
ISSN
1434-1948
DOI
10.1002/ejic.202000488
language
English
LU publication?
yes
id
b2ee10a6-5f5d-4449-9c35-36ccbff97845
date added to LUP
2020-07-23 11:32:55
date last changed
2020-07-29 06:16:59
@article{b2ee10a6-5f5d-4449-9c35-36ccbff97845,
  abstract     = {<p>[N,N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L<sup>1</sup>) and [N,N-bis(2-quinolylmethyl)-N-bis(2-pyridyl)methylamine] (L<sup>2</sup>) were employed to prepare Cu<sup>II</sup> and Cu<sup>I</sup> complexes for spectroscopic and structural characterization. [L<sup>1</sup>Cu<sup>II</sup>(H<sub>2</sub>O)](NO<sub>3</sub>)<sub>2</sub> and [L<sup>2</sup>Cu<sup>II</sup>(NO<sub>3</sub>)]NO<sub>3</sub> have Jahn–Teller distorted octahedral geometries and give rise to isotropic EPR spectra in frozen solution. [L<sup>1</sup>Cu<sup>I</sup>(CH<sub>3</sub>CN)]OTf and [L<sup>2</sup>Cu<sup>I</sup>(CH<sub>3</sub>CN)]OTf have distorted trigonal bipyramidal and tetrahedral solid-state structures, respectively. The N-donors display labile behavior in solution, based on variable-temperature <sup>1</sup>H NMR studies. Addition of trimethylamine N-oxide (Me<sub>3</sub>NO) to solutions of [L<sup>1</sup>Cu<sup>I</sup>(CH<sub>3</sub>CN)]OTf and [L<sup>2</sup>Cu<sup>I</sup>(CH<sub>3</sub>CN)]OTf resulted in diamagnetic species tentatively assigned as the corresponding adducts upon replacement of coordinated acetonitrile, based on <sup>1</sup>H NMR spectroscopy. Heating [L<sup>1</sup>Cu<sup>I</sup>(CH<sub>3</sub>CN)]OTf to 50–60 °C in the presence of Me<sub>3</sub>NO resulted in its cupric analogue [L<sup>1</sup>Cu<sup>II</sup>(CH<sub>3</sub>CN)]<sup>2+</sup>, as well as a small amount of 2-dipyridylketone, along with other oxidation by-products. In the case of [L<sup>2</sup>Cu<sup>I</sup>(CH<sub>3</sub>CN)]OTf, the reaction with Me<sub>3</sub>NO resulted in the cupric complex bis(2-quinolinecarboxamidato)copper(II), along with 2-dipyridylketone as oxidation products.</p>},
  author       = {Ramírez, Erick and Hossain, Md Kamal and Flores-Alamo, Marcos and Haukka, Matti and Nordlander, Ebbe and Castillo, Ivan},
  issn         = {1434-1948},
  language     = {eng},
  month        = {06},
  publisher    = {John Wiley and Sons Inc.},
  series       = {European Journal of Inorganic Chemistry},
  title        = {Oxygen Transfer from Trimethylamine N-Oxide to Cu<sup>I</sup> Complexes Supported by Pentanitrogen Ligands},
  url          = {http://dx.doi.org/10.1002/ejic.202000488},
  doi          = {10.1002/ejic.202000488},
  year         = {2020},
}