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HERFD-XANES probes of electronic structures of ironII/IIIcarbene complexes

Guo, Meiyuan LU ; Prakash, Om LU ; Fan, Hao LU ; de Groot, Lisa H.M. LU ; Hlynsson, Valtýr Freyr LU ; Kaufhold, Simon LU ; Gordivska, Olga LU ; Velásquez, Nicolás LU ; Chabera, Pavel LU and Glatzel, Pieter , et al. (2020) In Physical Chemistry Chemical Physics 22(16). p.9067-9073
Abstract

Iron centeredN-heterocyclic carbene (Fe-NHC) complexes have shown long-lived excited states with charge transfer character useful for light harvesting applications. Understanding the nature of the metal-ligand bond is of fundamental importance to rationally tailor the properties of transition metal complexes. The high-energy-resolution fluorescence detected X-ray absorption near edge structure (HERFD-XANES) has been used to probe the valence orbitals of three carbene complexes, [FeII(bpy)(btz)2](PF6)2(bpy = 2,2′-bipyridine, btz = 3,3′-dimethyl-1,1′-bis(p-tolyl)-4,4′-bis(1,2,3-triazol-5-ylidene)), [FeIII(btz)3](PF6)3, and... (More)

Iron centeredN-heterocyclic carbene (Fe-NHC) complexes have shown long-lived excited states with charge transfer character useful for light harvesting applications. Understanding the nature of the metal-ligand bond is of fundamental importance to rationally tailor the properties of transition metal complexes. The high-energy-resolution fluorescence detected X-ray absorption near edge structure (HERFD-XANES) has been used to probe the valence orbitals of three carbene complexes, [FeII(bpy)(btz)2](PF6)2(bpy = 2,2′-bipyridine, btz = 3,3′-dimethyl-1,1′-bis(p-tolyl)-4,4′-bis(1,2,3-triazol-5-ylidene)), [FeIII(btz)3](PF6)3, and [FeIII(phtmeimb)2]PF6(phtmeimb = [phenyl(tris(3-methylimidazol-2-ylidene))borate]). The multiconfigurational restrict active space (RAS) approach has been used to simulate the metal K pre-edge X-ray absorption spectroscopy of these carbene complexes, and have reproduced the metal K pre-edge spectral features in terms of relative intensity and peak positions. The evident intensity difference between the FeIIand the other two FeIIIcomplexes has been elucidated with different intensity mechanisms in the transition. The smaller splitting between the t2gand egcharacter peak for [FeIII(btz)3](PF6)3has been observed in the experimental measurements and been reproduced in the RAS calculations. The results show how the combination of experimental HERFD-XANES measurements andab initioRAS simulations can give quantitative evaluation of the orbital interactions between metal and ligands for such large and strongly interacting systems and thus allow to understand and predict properties of novel complexes.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Chemistry Chemical Physics
volume
22
issue
16
pages
7 pages
publisher
Royal Society of Chemistry
external identifiers
  • pmid:32297625
  • scopus:85084167963
ISSN
1463-9076
DOI
10.1039/c9cp06309a
language
English
LU publication?
yes
id
d3b9e264-355c-4a0f-add5-74e50714d313
date added to LUP
2021-01-14 15:33:33
date last changed
2021-04-06 02:01:29
@article{d3b9e264-355c-4a0f-add5-74e50714d313,
  abstract     = {<p>Iron centeredN-heterocyclic carbene (Fe-NHC) complexes have shown long-lived excited states with charge transfer character useful for light harvesting applications. Understanding the nature of the metal-ligand bond is of fundamental importance to rationally tailor the properties of transition metal complexes. The high-energy-resolution fluorescence detected X-ray absorption near edge structure (HERFD-XANES) has been used to probe the valence orbitals of three carbene complexes, [Fe<sup>II</sup>(bpy)(btz)<sub>2</sub>](PF<sub>6</sub>)<sub>2</sub>(bpy = 2,2′-bipyridine, btz = 3,3′-dimethyl-1,1′-bis(p-tolyl)-4,4′-bis(1,2,3-triazol-5-ylidene)), [Fe<sup>III</sup>(btz)<sub>3</sub>](PF<sub>6</sub>)<sub>3</sub>, and [Fe<sup>III</sup>(phtmeimb)<sub>2</sub>]PF<sub>6</sub>(phtmeimb = [phenyl(tris(3-methylimidazol-2-ylidene))borate]<sup>−</sup>). The multiconfigurational restrict active space (RAS) approach has been used to simulate the metal K pre-edge X-ray absorption spectroscopy of these carbene complexes, and have reproduced the metal K pre-edge spectral features in terms of relative intensity and peak positions. The evident intensity difference between the Fe<sup>II</sup>and the other two Fe<sup>III</sup>complexes has been elucidated with different intensity mechanisms in the transition. The smaller splitting between the t<sub>2g</sub>and e<sub>g</sub>character peak for [Fe<sup>III</sup>(btz)<sub>3</sub>](PF<sub>6</sub>)<sub>3</sub>has been observed in the experimental measurements and been reproduced in the RAS calculations. The results show how the combination of experimental HERFD-XANES measurements andab initioRAS simulations can give quantitative evaluation of the orbital interactions between metal and ligands for such large and strongly interacting systems and thus allow to understand and predict properties of novel complexes.</p>},
  author       = {Guo, Meiyuan and Prakash, Om and Fan, Hao and de Groot, Lisa H.M. and Hlynsson, Valtýr Freyr and Kaufhold, Simon and Gordivska, Olga and Velásquez, Nicolás and Chabera, Pavel and Glatzel, Pieter and Wärnmark, Kenneth and Persson, Petter and Uhlig, Jens},
  issn         = {1463-9076},
  language     = {eng},
  month        = {04},
  number       = {16},
  pages        = {9067--9073},
  publisher    = {Royal Society of Chemistry},
  series       = {Physical Chemistry Chemical Physics},
  title        = {HERFD-XANES probes of electronic structures of iron<sup>II/III</sup>carbene complexes},
  url          = {http://dx.doi.org/10.1039/c9cp06309a},
  doi          = {10.1039/c9cp06309a},
  volume       = {22},
  year         = {2020},
}