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
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- 作者：Theodore Lazarides ; Timothy L. Easun ; Claire Veyne-Marti ; Wassim Z. Alsindi ; Michael W. George ; Nina Deppermann ; Christopher A. Hunter ; Harry Adams ; Michael D. Ward
- 刊名：Journal of the American Chemical Society
- 出版年：2007
- 出版时间：April 4, 2007
- 年：2007
- 卷：129
- 期：13
- 页码：4014 - 4027
- 全文大小：623K
- 年卷期：v.129,no.13(April 4, 2007)
- ISSN：1520-5126
文摘
We show in this paper how the 3MLCT luminescence of [Ru(bipy)(CN)4]2-, which is known to behighly 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 stateand in solution. A series of crystallographic studies of [Ru(bipy)(CN)4]2- salts with different metal cationsMn+ (Li+, Na+, K+, mixed Li+/K+, Cs+, and Ba2+) shows how the cyanide/Mn+ interaction varies from theconventional "end-on" with the more Lewis-acidic cations (Li+, Ba2+) to the more unusual "side-on" interactionwith the softer metal cations (K+, Cs+). The solid-state luminescence intensity and lifetime of these saltsis highly dependent on the nature of the cation, with Cs+ affording the weakest luminescence and Ba2+ thestrongest. A series of titrations of the more soluble derivative [Ru(tBu2bipy)(CN)4]2- in MeCN with a rangeof metal salts showed how the cyanide/Mn+ association results in a substantial blue-shift of the 1MLCTabsorptions, and 3MLCT energies, intensities, and lifetimes, with the complex varying from essentially non-luminescent in the absence of metal cation to showing strong (
= 0.07), long-lived (1.4 
s), and high-energy (583 nm) luminescence in the presence of Ba2+. This modulation of the 3MLCT energy, over arange of about 6000 cm-1 depending on the added cation, could be used to reverse the direction ofphotoinduced 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 andthereby quenches the [Ru(bipy)3]2+-based luminescence; in the presence of Ba2+ ions, the 3MLCT energyof the [Ru(bipy)(CN)4]2- terminus is raised above that of the [Ru(bipy)3]2+ terminus, resulting in energytransfer to and sensitized emission from the latter.
= 0.07), long-lived (1.4 s), and high-energy (583 nm) luminescence in the presence of Ba2+. This modulation of the 3MLCT energy, over arange of about 6000 cm-1 depending on the added cation, could be used to reverse the direction ofphotoinduced 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 andthereby quenches the [Ru(bipy)3]2+-based luminescence; in the presence of Ba2+ ions, the 3MLCT energyof the [Ru(bipy)(CN)4]2- terminus is raised above that of the [Ru(bipy)3]2+ terminus, resulting in energytransfer to and sensitized emission from the latter.