Clarke, CJ, Hayama, S, Hawes, A et al. (4 more authors) (2019) Zinc 1s Valence-to-Core X-ray Emission Spectroscopy of Halozincate Complexes. The Journal of Physical Chemistry A, 123 (44). pp. 9552-9559. ISSN 1089-5639
Abstract
The Zn 1s valence-to-core (VtC) X-ray emission spectra of six ionic liquids have been measured experimentally and simulated based upon time-dependent density-functional theory (TDDFT) calculations. The seven ionic liquids were made by mixing [C₈C₁Im]X and Zn(II)X₂ at three different ZnX₂ mole fractions (0.33, 0.50 or 0.67) for X=Cl or Br, and a further ionic liquid was made by mixing [P₆,₆,₆,₁₄]Cl and a mole fraction of ZnCl₂ of 0.33. Calculations were performed for the [ZnX₄]²‾, [Zn₂X₆]²‾ and [Zn₄X₁₀]²‾ ions to capture the expected metal complex speciation. The VtC emission spectra showed three bands arising from single electron processes that can be assigned to emission from ligand p-type orbitals, zinc d orbitals and ligand s-type orbitals. For all seven ionic liquids, the highest occupied molecular orbital arises from the ligand p orbitals, and the spectra for the different size metal complexes for the same X were found to be very similar, in terms of both relative peak intensities and peak energies. For both experiments and TDDFT calculations, there was an energy difference of 0.5 eV between the Cl-based and Br-based metal complexes for the ligand s and p orbitals, while the Zn 3d orbital energies were relatively unaffected by the identity of the ligand. The TDDFT calculations find that for the ions with symmetrically equivalent zinc atoms ([Zn₂X₆]²‾ and [Zn₄X₁₀]²‾), the most appropriate core-ionised reference state has a core-hole that is localised on a single zinc atom. In this framework, the spectra for the larger ions can be viewed as a sum of spectra for the tetrahedral complex with a single zinc atom with small variations in the structure of the coordinating ligands. Since the spectra are relatively insensitive to small changes in the geometry of the ligands, this is consistent with the small variation in the spectra measured in experiment.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2019, American Chemical Society. This is an author produced version of a paper published in The Journal of Physical Chemistry A. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Inorganic Chemistry (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 28 Oct 2019 10:19 |
Last Modified: | 14 Oct 2020 00:38 |
Status: | Published |
Publisher: | American Chemical Society (ACS) |
Identification Number: | 10.1021/acs.jpca.9b08037 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:152683 |