Uleanya, Kelechi O., Wilson, Sarah A. orcid.org/0000-0002-6897-6224 and Dessent, Caroline E.H. orcid.org/0000-0003-4944-0413 (2024) N-Aromatic Complexation in Tetraphenyl Porphyrin Iron (III)-Pyridine:Evidence of Spin-Flip via Gas-Phase Electronic Spectroscopy. ChemPhysChem. e202400669. ISSN 1439-4235
Abstract
There is growing interest in the electronic properties of metalloporphyrins especially in relation to their interactions with other molecular species in their local environment. Here, UV-VIS laser photodissociation spectroscopy in vacuo has been applied to an iron-centred metalloporphyrin (FeTPP+) and its N-aromatic adduct with pyridine (py) to determine the electronic effect of complexation. Both the metalloporphyrin (FeTPP+) and pyridine adduct (FeTPP+⋅py) absorb strongly across the spectral region studied (652–302 nm: 1.91–4.10 eV). Notably, a large blue shift was observed for the dominant Soret band (41 nm) upon complexation (0.47±0.02 eV), indicative of strong pyridine binding. Significant differences in the profiles (i. e. number and position of bands) of the electronic spectra are evident comparing FeTPP+ and FeTPP+⋅py. Time-dependent density functional theory calculations were used to assign the spectra, revealing that the FeIII spin-state flips from S=3/2 to S=5/2 upon complexation with pyridine. For FeTPP+, all bright spectral transitions are found to be π-π* in character, with electron density variously distributed across the porphyrin and/or its phenyl substituents. Similar electronic excitations are observed for FeTPP+⋅py, with an additional bright transition which involves charge transfer from the porphyrin to the pyridine moiety.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2024 The Authors. ChemPhysChem published by Wiley-VCH GmbH |
Keywords: | Density functional theory,Excited states,Mass spectrometry,Metalloporphyrin,Molecular orbitals |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Chemistry (York) The University of York > Faculty of Social Sciences (York) > The York Law School |
Depositing User: | Pure (York) |
Date Deposited: | 25 Nov 2024 09:30 |
Last Modified: | 25 Nov 2024 09:30 |
Published Version: | https://doi.org/10.1002/cphc.202400669 |
Status: | Published online |
Refereed: | Yes |
Identification Number: | 10.1002/cphc.202400669 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:220044 |
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Description: ChemPhysChem - 2024 - Uleanya - N‐Aromatic Complexation in Tetraphenyl Porphyrin Iron III ‐Pyridine Evidence of Spin‐Flip
Licence: CC-BY 2.5