Near-Infrared Luminescence of Supramolecular Species Consisting of Osmium(II)- and/or Ruthenium(II)-Polypyridine Components

Juris, Alberto; Balzani, Vincenzo; Campagna, Sebastiano; Denti, Gianfranco; Serroni, Scolastica; Frei, Gabriela Claudia; Güdel, Hans‐Ulrich

doi:10.1021/ic00085a045

Cited by 76 publications

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“…28,29 Due to enhanced spin-orbit coupling, the formally spin-forbidden 1 A 1 f 3 MLCT transitions can also be easily observed for the Os complexes, at ∼680 nm for 2 and as an extremely broad feature extending past 800 nm for 4. 26,28,30 The corresponding transition in the Ru analogues appears as a weak, lower-energy tail of the main absorption band.…”

Section: A Electronic Absorption Spectra Of Ru and Os Complexes In Smentioning

confidence: 99%

Transient Absorption Spectroscopy of Ruthenium and Osmium Polypyridyl Complexes Adsorbed onto Nanocrystalline TiO₂ Photoelectrodes

et al. 2002

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Transient absorption spectroscopy has been used to probe the electron injection dynamics of transition metal polypyridyl complexes adsorbed onto nanocrystalline TiO 2 photoelectrodes. Experiments were performed on photoelectrodes coated with Ru(H 2 L′) 2 (CN) 2 , Os(H 2 L′) 2 (CN) 2 , Ru(H 2 L′) 2 (NCS) 2 , or Os(H 2 L′) 2 (NCS) 2 , where H 2 L′ is 4,4′-dicarboxylic acid-2,2′-bipyridine, to study how the excited-state energetics and the nature of the metal center affect the injection kinetics. All of these complexes exhibited electron injection dynamics on both the femtosecond and picosecond time scales. The femtosecond components were instrument-limited (<200 fs), whereas the picosecond components ranged from 3.3 ( 0.3 ps to 14 ( 4 ps (electron injection rate constants k 2 ′ ) (7.1-30) × 10 10 s -1). The picosecond decay component became more rapid as the formal excited-state reduction potential of the complex became more negative. Variable excitation wavelength studies suggest that femtosecond injection is characteristic of the nonthermalized singlet metal-to-ligand chargetransfer ( 1 MLCT) excited state, whereas picosecond injection originates from the lowest-energy 3 MLCT excited state. On the basis of these assignments, the smaller relative amplitude of the picosecond component for the Ru sensitizers suggests that electron injection from nonthermalized excited states competes more effectively with 1 MLCT f 3 MLCT conversion for the Ru sensitizers than for the Os sensitizers.

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Section: A Electronic Absorption Spectra Of Ru and Os Complexes In Smentioning

confidence: 99%

Transient Absorption Spectroscopy of Ruthenium and Osmium Polypyridyl Complexes Adsorbed onto Nanocrystalline TiO₂ Photoelectrodes

et al. 2002

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“…Moreover, luminescence and transient absorption spectroscopies have shown that specific subunits have particular characteristics, independent of the other components of the multinuclear assembly. [50,51] Typically, these mixed metal-polypyridine dendrimers absorb light in the UV, the visible, and the near-infrared spectral regions and transfer energy very efficiently to…”

Section: Introductionmentioning

confidence: 99%

Extending the Light‐Harvesting Properties of Transition‐Metal Dendrimers

et al. 2007

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We report a study of the electronic energy-transfer dynamics within the transition-metal polypyridine complex OsRu3pyr6 (Os[(dpp)Ru(bpy{pyrene})2]3(8+), where dpp=2,3-bis(2'-pyridyl)pyrazine and bpy=2,2'-bipyridine) after excitation with UV light. By using a broadband visible femtosecond probe, we are able to simultaneously detect both the energy transfer from the peripheral aromatic ligands to the Os center and the sub-picosecond energy transfer from the initially excited Ru-bpy ligand-centered state to the Os triplet metal-to-ligand charge-transfer (MLCT) state. Pyrene energy transfer occurs from both the nonrelaxed and the relaxed S(1) states on timescales of 6 and 45 ps, respectively. In both cases, the energy transfer is described by means of Förster energy transfer theory. Sub-picosecond energy transfer within the OsRu3 metal-ligand core most likely includes a direct energy transfer between the higher-lying ligand-centered states on Ru and Os, in addition to the transfer between the MLCT states. The absorption cross-sections in both the UV and the visible spectral regions are enhanced by attaching the aromatic pyrene ligands. Furthermore, energy transfer is directed only towards the Os core, which ultimately leads to an exclusive population of the Os-based triplet MLCT state, thus making the OsRu3pyr6 transition metal-polypyridine dendrimer an obvious candidate for artificial light-harvesting systems.

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“…An interesting series of polynuclear species of large nuclearity, which because of their shape can be called "dendrimers" or "arborols", has been obtained using Ru(II) and/or Os(II) as metal centers, bis-bipyridine-type ligands as bridging groups, and bipyridine-type terminal ligands [36][37][38] . Following a modular synthetic strategy known as "complexes-as-metals/complexes-as- ligands", such polynuclear species can be obtained with a high degree of synthetic control, in terms of the nature and position of metal centers, bridging ligands, and terminal ligands.…”

Section: Artificial Antenna Systemsmentioning

confidence: 99%

“…via efficient intercomponent energy-transfer processes, from the center to the periphery of the complex, where it is re-emitted by the Os(II)-containing units as near-infrared luminescence 37 . Several other energy migration patterns can be obtained in similar decanuclear species, simply by using different combination of metals and ligands 36 .…”

Section: Figure 9 Decanuclear Complex ("Dendrimer") Based On Ru and mentioning

confidence: 99%

Chemistry and light - part 2: light and energy

1997

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Recebido em 19/8/96The conversion of solar energy into more useful forms of energy, such as chemical fuels or electricity, is one of the central problems facing modern science. Progress in photochemistry and chemical synthesis has led to a point where light energy conversion by means of artificial molecular devices can be rationally attempted. In this article, a general approach towards this challenging goal is presented. Thomas, Leipzig (1911)

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Near-Infrared Luminescence of Supramolecular Species Consisting of Osmium(II)- and/or Ruthenium(II)-Polypyridine Components

Cited by 76 publications

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Transient Absorption Spectroscopy of Ruthenium and Osmium Polypyridyl Complexes Adsorbed onto Nanocrystalline TiO₂ Photoelectrodes

Transient Absorption Spectroscopy of Ruthenium and Osmium Polypyridyl Complexes Adsorbed onto Nanocrystalline TiO₂ Photoelectrodes

Extending the Light‐Harvesting Properties of Transition‐Metal Dendrimers

Chemistry and light - part 2: light and energy

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Near-Infrared Luminescence of Supramolecular Species Consisting of Osmium(II)- and/or Ruthenium(II)-Polypyridine Components

Cited by 76 publications

References 0 publications

Transient Absorption Spectroscopy of Ruthenium and Osmium Polypyridyl Complexes Adsorbed onto Nanocrystalline TiO2 Photoelectrodes

Transient Absorption Spectroscopy of Ruthenium and Osmium Polypyridyl Complexes Adsorbed onto Nanocrystalline TiO2 Photoelectrodes

Extending the Light‐Harvesting Properties of Transition‐Metal Dendrimers

Chemistry and light - part 2: light and energy

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Transient Absorption Spectroscopy of Ruthenium and Osmium Polypyridyl Complexes Adsorbed onto Nanocrystalline TiO₂ Photoelectrodes

Transient Absorption Spectroscopy of Ruthenium and Osmium Polypyridyl Complexes Adsorbed onto Nanocrystalline TiO₂ Photoelectrodes