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A Homoleptic Trisbidentate Ru(II) Complex of a Novel Bidentate Biheteroaromatic Ligand Based on Quinoline and Pyrazole Groups: Structural, Electrochemical, Photophysical, and Computational Characterization.

Jarenmark, Martin LU ; Fredin, Lisa LU ; Hedberg, Joachim H J; Doverbratt, Isa LU ; Persson, Petter LU and Abrahamsson, Maria (2014) In Inorganic Chemistry 53(24). p.12778-12790
Abstract
We synthesized a new homoleptic, tris-bidentate complex [Ru(QPzH)3](2+) based on the novel biheteroaromatic, 8-(3-pyrazolyl)-quinoline ligand QPzH. The QPzH ligand was designed to reduce the distortions typically observed in complexes incorporating the 8-quinolinyl group into the ligand framework. This was indeed observed, and was also, as anticipated, found to facilitate the formation of tris-homoleptic Ru(II) complexes; [Ru(QPzH)3](2+) is the first reported tris-homoleptic complex with ligands based on the 8-quinolinyl group. The synthesis can either result in a statistical 3:1 mer/fac ratio of the complex, or, through controlled exposure to light, be tweaked to allow isolation of the pure mer isomer only. X-ray crystallography reveals... (More)
We synthesized a new homoleptic, tris-bidentate complex [Ru(QPzH)3](2+) based on the novel biheteroaromatic, 8-(3-pyrazolyl)-quinoline ligand QPzH. The QPzH ligand was designed to reduce the distortions typically observed in complexes incorporating the 8-quinolinyl group into the ligand framework. This was indeed observed, and was also, as anticipated, found to facilitate the formation of tris-homoleptic Ru(II) complexes; [Ru(QPzH)3](2+) is the first reported tris-homoleptic complex with ligands based on the 8-quinolinyl group. The synthesis can either result in a statistical 3:1 mer/fac ratio of the complex, or, through controlled exposure to light, be tweaked to allow isolation of the pure mer isomer only. X-ray crystallography reveals three nonequivalent ligands, with significantly less strain than other quinoline-based bidentate ligands. The complex exhibits a nearly octahedral coordination geometry but shows large differences in bond lengths between the Ru core and the quinoline and pyrazoles, respectively. The Ru-N(pyrazole) bond distances are ∼2.04 Å, while the corresponding distances for Ru-N(quinoline) are ∼2.12 Å. Structural, photophysical, electrochemical, and theoretical characterization revealed a mer-Ru(II) complex with a low oxidation potential (0.57 V vs ferrocene(0/+)) attributed to the incorporation of the pyrazolyl group, a ground state absorption that is sensitive to the local environment of the complex, and a short-lived (3)MLCT excited state. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Inorganic Chemistry
volume
53
issue
24
pages
12778 - 12790
publisher
The American Chemical Society
external identifiers
  • wos:000346544100017
  • pmid:25420224
  • scopus:84920181092
ISSN
1520-510X
DOI
10.1021/ic502432c
language
English
LU publication?
yes
id
d6f716c1-28a0-4a1d-b20e-23ccde54af4f (old id 4816214)
date added to LUP
2014-12-12 15:01:30
date last changed
2017-01-01 03:11:50
@article{d6f716c1-28a0-4a1d-b20e-23ccde54af4f,
  abstract     = {We synthesized a new homoleptic, tris-bidentate complex [Ru(QPzH)3](2+) based on the novel biheteroaromatic, 8-(3-pyrazolyl)-quinoline ligand QPzH. The QPzH ligand was designed to reduce the distortions typically observed in complexes incorporating the 8-quinolinyl group into the ligand framework. This was indeed observed, and was also, as anticipated, found to facilitate the formation of tris-homoleptic Ru(II) complexes; [Ru(QPzH)3](2+) is the first reported tris-homoleptic complex with ligands based on the 8-quinolinyl group. The synthesis can either result in a statistical 3:1 mer/fac ratio of the complex, or, through controlled exposure to light, be tweaked to allow isolation of the pure mer isomer only. X-ray crystallography reveals three nonequivalent ligands, with significantly less strain than other quinoline-based bidentate ligands. The complex exhibits a nearly octahedral coordination geometry but shows large differences in bond lengths between the Ru core and the quinoline and pyrazoles, respectively. The Ru-N(pyrazole) bond distances are ∼2.04 Å, while the corresponding distances for Ru-N(quinoline) are ∼2.12 Å. Structural, photophysical, electrochemical, and theoretical characterization revealed a mer-Ru(II) complex with a low oxidation potential (0.57 V vs ferrocene(0/+)) attributed to the incorporation of the pyrazolyl group, a ground state absorption that is sensitive to the local environment of the complex, and a short-lived (3)MLCT excited state.},
  author       = {Jarenmark, Martin and Fredin, Lisa and Hedberg, Joachim H J and Doverbratt, Isa and Persson, Petter and Abrahamsson, Maria},
  issn         = {1520-510X},
  language     = {eng},
  number       = {24},
  pages        = {12778--12790},
  publisher    = {The American Chemical Society},
  series       = {Inorganic Chemistry},
  title        = {A Homoleptic Trisbidentate Ru(II) Complex of a Novel Bidentate Biheteroaromatic Ligand Based on Quinoline and Pyrazole Groups: Structural, Electrochemical, Photophysical, and Computational Characterization.},
  url          = {http://dx.doi.org/10.1021/ic502432c},
  volume       = {53},
  year         = {2014},
}