Deibel, N, Schweinfurth, D, Hohloch, S et al. (5 more authors) (2014) Electrochemistry, Chemical Reactivity, and Time-Resolved Infrared Spectroscopy of Donor-Acceptor Systems [(Q(x))Pt(pap(y))) (Q = Substituted o-Quinone or o-Iminoquinone; pap = Phenylazopyridine). Inorganic Chemistry, 53 (2). 1021 - 1031. ISSN 0020-1669
Abstract
The donor−acceptor complex [(O,NQ2−)Pt- (pap0)] (1; pap = phenylazopyridine, O,NQ0 = 4,6-di-tertbutyl- N-phenyl-o-iminobenzoquinone), which displays strong π-bonding interactions and shows strong absorption in the near-IR region, has been investigated with respect to its redoxinduced reactivity and electrochemical and excited-state properties. The one-electron-oxidized product [(O,NQ•−)Pt- (pap0)](BF4) ([1]BF4) was chemically isolated. Single-crystal X-ray diffraction studies establish the iminosemiquinone form of O,NQ in [1]+. Simulation of the cyclic voltammograms of 1 recorded in the presence of PPh3 elucidates the mechanism and delivers relevant thermodynamic and kinetic parameters for the redox-induced reaction with PPh3. The thermodynamically stable product of this reaction, complex [(O,NQ•−) Pt(PPh3)2](PF6) ([2]PF6), was isolated and characterized by X-ray crystallography, electrochemistry, and electron paramagnetic resonance spectroscopy. Picosecond time-resolved infrared spectroscopic studies on complex 1b (one of the positional isomers of 1) and its analogue [(O,OQ2−)Pt(pap0)] (3; O,OQ = 3,5-di-tert-butyl-o-benzoquinone) provided insight into the excited-state dynamics and revealed that the nature of the lowest excited state in the amidophenolate complex 1b is primarily diimine-ligandbased, while it is predominantly an interligand charge-transfer state in the case of 3. Density functional theory calculations on [1]n+ provided further insight into the nature of the frontier orbitals of various redox forms and vibrational mode assignments. We discuss the mechanistic details of the newly established redox-induced reactivity of 1 with electron donors and propose a mechanism for this process.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2014 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Chemistry (Sheffield) |
Funding Information: | Funder Grant number EPSRC GR/T03355 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 08 May 2014 14:33 |
Last Modified: | 08 May 2014 14:33 |
Published Version: | http://dx.doi.org/10.1021/ic4024713 |
Status: | Published |
Publisher: | American Chemical Society |
Refereed: | Yes |
Identification Number: | 10.1021/ic4024713 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:78875 |