Luminescent Pt(Ii)(Bipyridyl)(Diacetylide) Chromophores with Pendant Binding Sites As Energy Donors for Sensitised Near-infrared Emission from Lanthanides: Structures and Photophysics of Pt(Ii)/Ln(Iii) Assemblies.
From: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
Chemistry (Weinheim an der Bergstrasse, Germany)
- Publish Date: Dec 2006
- ISSN: 0947-6539
- Volume: 12
- Issue: 36
- Pages: 9299-313
- Medium: Print
- Language: English
- Citation (JAMA): Ronson Tanya K, Lazarides Theodore, Adams Harry, et al. Luminescent Pt(Ii)(Bipyridyl)(Diacetylide) Chromophores with Pendant Binding Sites As Energy Donors for Sensitised Near-infrared Emission from Lanthanides: Structures and Photophysics of Pt(Ii)/Ln(Iii) Assemblies.. Dec 2006;12:9299-313
Abstract
The complexes [Pt(bipy){CC-(4-pyridyl)}(2)] (1) and [Pt(tBu(2)bipy){CC-(4-pyridyl)}(2)] (2) and [Pt(tBu(2)-bipy)(CC-phen)(2)] (3) all contain a Pt(bipy)(diacetylide) core with pendant 4-pyridyl (1 and 2) or phenanthroline (3) units which can be coordinated to {Ln(diketonate)(3)} fragments (Ln = a lanthanide) to make covalently-linked Pt(II)/Ln(III) polynuclear assemblies in which the Pt(II) chromophore, absorbing in the visible region, can be used to sensitise near-infrared luminescence from the Ln(III) centres. For 1 and 2 one-dimensional coordination polymers [1Ln(tta)(3)](infinity) and [2Ln(hfac)(3)](infinity) are formed, whereas 3 forms trinuclear adducts [3{Ln(hfac)(3)}(2)] (tta=anion of thenoyl-trifluoroacetone; hfac=anion of hexafluoroacetylacetone). Complexes 1-3 show typical Pt(II)-based (3)MLCT luminescence in solution at approximately 510 nm, but in the coordination polymers [1Ln(tta)(3)](infinity) and [2Ln(hfac)(3)](infinity) the presence of stacked pairs of Pt(II) units with short PtPt distances means that the chromophores have (3)MMLCT character and emit at lower energy ( approximately 630 nm). Photophysical studies in solution and in the solid state show that the (3)MMLCT luminescence in [1Ln(tta)(3)](infinity) and [2Ln(hfac)(3)](infinity) in the solid state, and the (3)MLCT emission of [3{Ln(hfac)(3)}(2)] in solution and the solid state, is quenched by Pt — >Ln energy transfer when the lanthanide has low-energy f-f excited states which can act as energy acceptors (Ln=Yb, Nd, Er, Pr). This results in sensitised near-infrared luminescence from the Ln(III) units. The extent of quenching of the Pt(II)-based emission, and the Pt — >Ln energy-transfer rates, can vary over a wide range according to how effective each Ln(III) ion is at acting as an energy acceptor, with Yb(III) usually providing the least quenching (slowest Pt — >Ln energy transfer) and either Nd(III) or Er(III) providing the most (fastest Pt — >Ln energy transfer) according to which one has the best overlap of its f-f absorption manifold with the Pt(II)-based luminescence.
Mesh Headings (Keywords): Binding Sites, Lanthanoid Series Elements, Luminescence, Models, Molecular, Molecular Structure, Platinum Compounds, Spectroscopy, Near-Infrared
Check for Full Text / PubMed Unique Identifier (PMID): 16991190
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.