Zubaidi, Z.N., Metherell, A.J., Baggaley, E. et al. (1 more author) (2017) Ir(III) and Ir(III)/Re(I) complexes of a new bis(pyrazolyl-pyridine) bridging ligand containing a naphthalene-2,7-diyl spacer: Structural and photophysical properties. Polyhedron, 133. pp. 68-74. ISSN 0277-5387
Abstract
A new bridging ligand has been prepared in which two chelating bidentate pyrazolyl-pyridine termini are connected to a central naphthalene-2,7-diyl core via methylene spacer units. This ligand has been used to prepared mononuclear and dinuclear Ir(III) complexes in which {Ir(F2ppy)2} [F2ppy = cyclometallating anion of 2-(3,5-difluorophenyl)-pyridine] complex fragments are coordinated to one or both of the pyrazolyl-pyridine termini; in addition a heterodinuclear complex has been prepared containing one {Ir(F2ppy)2} unit and one {Re(CO)3Cl} unit in the two binding sites. X-ray crystallographic studies show that the bridging naphthyl group lies stacked with a coordinated F2ppy ligand from a terminal {Ir(F2ppy)2} unit in every case. Luminescence measurements show that the usual strong Ir(III)-centred blue luminescence is substantially quenched by the presence of a low-lying triplet state on the naphthyl group; in the Ir(III)/Re(I) dyad we observe both weak Ir(III)-based emission as well as lower-energy Re(I)-based emission which overlap; Ir(III) → Re(I) energy-transfer occurs on a timescale of <1 ns as no rise-time for sensitised Re(I)-based emission could be detected, in contrast to other Ir(III)/Re(I) dyads in which the Ir(III) → Re(I) energy-transfer is slower (10–100 ns timescale). We ascribe this to the spatial and energetic intermediacy of the naphthyl group whose triplet energy lies between that of the Ir(III) and Re(I) termini, providing an effective conduit for energy-transfer to occur.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 Elsevier. This is an author produced version of a paper subsequently published in Polyhedron. Uploaded in accordance with the publisher's self-archiving policy. Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/). |
Keywords: | Iridium(III) complex; Rhenium(I) complex; Luminescence; Bridging ligand; Crystal structures |
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 ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL (EPSRC) EP/N031555/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 22 Jun 2017 15:20 |
Last Modified: | 18 May 2018 00:39 |
Published Version: | https://doi.org/10.1016/j.poly.2017.05.017 |
Status: | Published |
Publisher: | Elsevier |
Refereed: | Yes |
Identification Number: | 10.1016/j.poly.2017.05.017 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:117596 |