Lazarides, Theodore, Easun, Timothy ORCID: https://orcid.org/0000-0002-0713-2642, Veyne-Marti, Claire, Alsindi, Wassim Z., George, Michael W., Deppermann, Nina, Hunter, Christopher A., Adams, Harry and Ward, Michael D. 2007. Structural and photophysical properties of adducts of [Ru(bipy)(CN)(4)](2-) with different metal cations: Metallochromism and its use in switching photoinduced energy transfer. Journal of the American Chemical Society 129 (13) , pp. 4014-4027. 10.1021/ja068436n |
Abstract
We show in this paper how the 3MLCT luminescence of [Ru(bipy)(CN)4]2-, which is known to be highly solvent-dependent, may be varied over a much wider range than can be achieved by solvent effects, by interaction of the externally directed cyanide ligands with additional metal cations both in the solid state and in solution. A series of crystallographic studies of [Ru(bipy)(CN)4]2- salts with different metal cations Mn+ (Li+, Na+, K+, mixed Li+/K+, Cs+, and Ba2+) shows how the cyanide/Mn+ interaction varies from the conventional “end-on” with the more Lewis-acidic cations (Li+, Ba2+) to the more unusual “side-on” interaction with the softer metal cations (K+, Cs+). The solid-state luminescence intensity and lifetime of these salts is highly dependent on the nature of the cation, with Cs+ affording the weakest luminescence and Ba2+ the strongest. A series of titrations of the more soluble derivative [Ru(tBu2bipy)(CN)4]2- in MeCN with a range of metal salts showed how the cyanide/Mn+ association results in a substantial blue-shift of the 1MLCT absorptions, and 3MLCT energies, intensities, and lifetimes, with the complex varying from essentially non-luminescent in the absence of metal cation to showing strong (φ = 0.07), long-lived (1.4 μs), and high-energy (583 nm) luminescence in the presence of Ba2+. This modulation of the 3MLCT energy, over a range of about 6000 cm-1 depending on the added cation, could be used to reverse the direction of photoinduced energy transfer in a dyad containing covalently linked [Ru(bipy)3]2+ and [Ru(bipy)(CN)4]2- termini. In the absence of a metal cation, the [Ru(bipy)(CN)4]2- terminus has the lower 3MLCT energy and thereby quenches the [Ru(bipy)3]2+-based luminescence; in the presence of Ba2+ ions, the 3MLCT energy of the [Ru(bipy)(CN)4]2- terminus is raised above that of the [Ru(bipy)3]2+ terminus, resulting in energy transfer to and sensitized emission from the latter.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Chemistry |
Subjects: | Q Science > QD Chemistry |
Publisher: | American Chemical Society |
ISSN: | 0002-7863 |
Last Modified: | 28 Oct 2022 08:30 |
URI: | https://orca.cardiff.ac.uk/id/eprint/71028 |
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