Photophysical properties of an assembly containing a [Ru(bpy)3]2+ chromophore and a [Ru(bpy)(CN)4]2- quencher unit linked by a hydrogen-bonded interface based on the [Ru(bpy)(CN)4]2-/aza-crwn association (Articolo in rivista)

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  • Photophysical properties of an assembly containing a [Ru(bpy)3]2+ chromophore and a [Ru(bpy)(CN)4]2- quencher unit linked by a hydrogen-bonded interface based on the [Ru(bpy)(CN)4]2-/aza-crwn association (Articolo in rivista) (literal)
Anno
  • 2002-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1039/b202067j (literal)
Alternative label
  • Simpson N.R.M.; Ward M.D.; Farran Morales A.; Ventura B.; Barigelletti F. (2002)
    Photophysical properties of an assembly containing a [Ru(bpy)3]2+ chromophore and a [Ru(bpy)(CN)4]2- quencher unit linked by a hydrogen-bonded interface based on the [Ru(bpy)(CN)4]2-/aza-crwn association
    in Journal of the Chemical Society. Dalton transactions (Online)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Simpson N.R.M.; Ward M.D.; Farran Morales A.; Ventura B.; Barigelletti F. (literal)
Pagina inizio
  • 2455 (literal)
Pagina fine
  • 2461 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • - (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • a School of Chemistry, University of Bristol, Cantock's Close, Bristol, UK BS8 ITS b Istituto ISOF-CNR, Via P. Gobetti 101, 40129 Bologna, Italy (literal)
Titolo
  • Photophysical properties of an assembly containing a [Ru(bpy)3]2+ chromophore and a [Ru(bpy)(CN)4]2- quencher unit linked by a hydrogen-bonded interface based on the [Ru(bpy)(CN)4]2-/aza-crwn association (literal)
Abstract
  • The two complexes [(bpy)(2)Ru(bpy-cyclamH(2))](4+) (Ru-cy; bpy = 2,2'-bipyridine; bpy-cyclam = 1-(2,2'-bipyridin-5-yl-methyl)-1,4,8,11-tetraazacyclotetradecane) and [Ru(bpy)(CN)(4)](2-) (Ru-CN) associate in MeCN solution via a hydrogen-bonding interaction between the externally-directed lone pairs of the cyanide ligands on the Ru-CN unit, and the protonated amine sites of the cyclam macrocycle which is pendant from the [Ru(bpy)(3)](2+) core of the Ru-cy unit. Due to the sensitivity of the Ru-CN chromophore to interactions of the cyanide lone pairs, this association results in characteristic changes in its absorption and emission properties; viz. the (MLCT)-M-1 absorption is blue-shifted, from 535 to 480 nm, and the (MLCT)-M-3 emission is also blue-shifted, from 790 nm to 680 nm. In addition, the association between the components results in quenching of the characteristic (MLCT)-M-3 luminescence of the Ru-cy unit. Analysis of the absorption and emission properties of mixtures of the two components in varying proportions indicates that a 2 : 1 associate Ru-cy:Ru-CN:Ru-cy forms, in which two of the cyanide ligands of Ru-CN interact with each of the Ru-cy units. The overall association constant for formation of this is K-ass = 2.6 x 10(11) M-2; under the dilute conditions necessary for luminescence experiments the association is not complete however and some free Ru-CN and Ru-cy are also present in the equilibrium mixture. Within the hydrogen-bonded associate, quenching of the (MLCT)-M-3 luminescence of the Ru-cy unit occurs, most likely by a Forster energy transfer mechanism, with ca. 88% efficiency and a rate constant of k(q) = 3.8 x 10(7) s(-1), corresponding to an inter-chromophore separation of ca. 11.5 Angstrom. (literal)
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