Quantum yields of 3MLCT excited state formation and triplet—triplet absorption spectra of ruthenium(II) tris-chelate complexes containing five- and six-membered heterocyclic moieties

Orellana, Guillermo; Braun, André M.

doi:10.1016/1010-6030(89)87009-1

Cited by 22 publications

(4 citation statements)

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“…Parameter φ is the quantum efficiency for the formation of the triplet Ru(bipy) 3 2+ * species, for which a value of 1.07 has been obtained by transient spectroscopic methods . This allows calculation of φ CE = 0.12 (Figure data) and 0.076 (Figure data), average = 0.099, a value that compares well with that of φ CE = 0.11 for the Ru(bipy) 3 2+ /1,1‘-dimethyl-4,4‘-bipyridinium (MV 2+ ) system 35 as measured by pulse laser spectrochemical means.…”

Section: Resultsmentioning

confidence: 68%

“…Good linearity is observed, giving k 1 / k 0 = K SV = 2.05 m 3 mol -1 , which is in good agreement with a literature values of 0.9−1.6 m 3 mol -1 32 derived by spectrofluorimetric measurements. Such measurements give a lifetime of the emitting state of Ru(bipy) 3 2+ * of 610 ns, , allowing derivation of a value of k 0 = 1.64 × 10 6 s -1 and, from K SV = 2.05 m 3 mol -1 , k 1 = 3.36 × 10 6 m 3 mol -1 s -1 . This compares well with a literature k 1 of 2.6 × 10 6 m 3 mol -1 s -1 …”

Section: Resultsmentioning

confidence: 99%

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The Micro-Optical Ring Electrode. 3: Transient Photocurrent Studies of Photophysical−Electrochemical and Photophysical−Chemical−Electrochemical Systems

2006

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The micro-optical ring electrode (MORE) is a photoelectrochemical device based on a ring microelectrode that uses the insulating material interior to the ring electrode as a light guide. In this paper, we describe the preparation and characterization of very thin ring MOREs with (ring inner radius)/(ring outer radius) > 0.99. Theoretically, we derive asymptotic analytical expressions for the time dependence of the diffusion-limited transient light-on photocurrent generated by two general types of photoelectrochemical systems: (a) the PE (photophysical-electrochemical) system, wherein the photoexcited species itself is directly detected on the ring; (b) the PCE (photophysical-chemical-electrochemical) system, wherein the photoexcited species undergoes a homogeneous electron transfer reaction prior to electrochemical detection. Experimentally, we establish that it is possible to use such MOREs to study the wavelength dependence of photocurrents derived from photoelectrochemically active systems, such as the Ru(bipy)3 2+/Fe3+ PCE system, demonstrating the potential utility of the MORE as a selective electroanalytical probe. We also use our expressions for the time dependence of photocurrents at the MORE to derive values for the photoelectrochemical kinetic parameters of this system, including the rate coefficient for the back reaction of photogenerated Ru(bipy)3 3+ (0.115 s(-1)) and the quantum efficiency for the primary redox products, Ru(bipy)3 3+ and Fe2+, escaping cage recombination, phi(CE) = 0.099.

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Section: Resultsmentioning

confidence: 68%

Section: Resultsmentioning

confidence: 99%

The Micro-Optical Ring Electrode. 3: Transient Photocurrent Studies of Photophysical−Electrochemical and Photophysical−Chemical−Electrochemical Systems

2006

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“…The quantum yield of triplet formation of most [RuL 3 ] in solution is known to be close to unity. ,− The quantum yields of singlet oxygen production (Φ Δ ) and were experimentally determined (eqs 3 and 13, respectively), then could be calculated using eq 12. The values of these parameters in air-equilibrated media are listed in Table and shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

Singlet Oxygen (¹Δ_g) Production by Ruthenium(II) Complexes in Microheterogeneous Systems

et al. 2003

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Singlet oxygen (O 2 ( 1 ∆ g )) production and quenching in homogeneous and microheterogeneous media are reported for two anionic ruthenium(II) complexes ([RuL 2 L′] 2-(where L stands for (1,10-phenanthroline-4,7-diyl)bis-(benzenesulfonate) (pbbs) and L′ stands for N- (1,10-phenanthrolin-5-yl)acetamide (paa) or N-(1,10phenanthrolin-5-yl)tetradecanamide (pta)) and for the cationic complex [Ru(bpy) 3 ] 2+ (bpy: 2,2′-bipyridine). Comparative results of photosensitized 1 O 2 generation in micelles, reverse micelles, and microemulsions reveal that the nature of the ligands and the size and charge of the [RuL 3 ] complexes are important factors affecting their effective location and 1 O 2 production in these media. The rate constants of quenching of the excited state [RuL 3 ]* by molecular oxygen (k q ) are in the range of (1-3) × 10 9 M -1 s -1 . The emission lifetimes of [RuL 3 ]* and k q values depend on the nature of the ligand and on the medium. The complexes are stable singlet oxygen sensitizers, with quantum yields of singlet oxygen production (Φ ∆ ) in air-equilibrated solutions between 0.30 and 0.75. The efficiency of 1 O 2 formation (i.e., the fraction of triplet excited states quenched by oxygen yielding 1 O 2 , f ∆ T ) is a valuable probe of the interactions of the [RuL 3 ] complexes with micelles and microemulsions. The highest f ∆ T values (g0.90) were observed in micellar media based on surfactants bearing a charge opposite to that of the [RuL 3 ] complex. In the microheterogeneous systems investigated, the most probable location of the [RuL 3 ] sensitizers is the micellar interfacial region.

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“…detecting the generated MV +. absorption at 600 nm as a function of the laser energy and extrapolating to saturation (LJA~a~~ra'ion) [18]. Magnetic fields up to 3.2 T were generated using a Bruker B-E15 magnet.…”

Section: Methodsmentioning

confidence: 99%

Aspects of Ligand and Electron-Acceptor Dependence of Magnetic Field Effects on Net Electron Transfer Efficiencies in Photooxidation of Ru(II)-trisbipyridyl Type Complexes

Wolff¹,

Steiner²

1990

Zeitschrift Für Physikalische Chemie

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Photo electron transfer / Magnetic field effects / Spin-orbit couplingThe heteroleptic series of Ru(bpY)n(dce)~:::n,with bpy = 2,2'-bipyridine, and dce = 4,4'-diethoxycarbonyl-2,2'-bipyridine, has been investigated for the kinetic parameters of photo electron transfer, and for the magnetic field dependence of the net electron transfer efficiency (rIce) in photooxidations with methylviologen and propylviologen sulfonate (the latter only in the case n = 3) using ns-laser-flash spectroscopy and stationary illumination methods. Whereas the electric charge of the electron acceptor had no influence on the magnetic field effect on !Jceo the variation of ligands was found to result in a strictly linear (with n) increase of the magnetic field effect on k bet , the effective rate constant of backward electron transfer in the primary redox pair. The physical implications of these observations with respect to a previously developed magnetokinetic model are discussed.Die heteroleptische Reihe der Komplexe Ru(bpY)n(dceH:::n mit bpy = 2,2'-bipyridin. und dce = 4,4'-diethoxycarbonyl-2.2'-bipyridin, wurde im Hinblick auf die kinetischen Parameter der photochemischen Elektroneniibertragung und auf die Magnetfeldabhiingigkeit der Nettoausbeute der Elektroneniibertragung (tTce) fUr die Photoreaktion mit Methylviologen und Propylviologensulfonat (letzteres nur fUr n = 3) mittels ns-Laserblitzspektroskopie und kontinuierlicher Belichtungsmethoden untersucht. Wiihrend die Ladung des Elektronenakzeptors keinen EinfluJ3 auf den Magnetfeldeffekt auf !Jce hatte. bewirkte die Variation der Liganden eine streng lineare Zunahme (beziiglich n) des Magnetfeldeffektes auf k belo die effektive Geschwindigkeitskonstante der Elektronen-Riickiibertragung im primiiren Redox-Paar. Die physikalische Bedeutung dieser Beobachtungen wird im Rahmen eines kiirzlich entwickelten magnetokinetischen Modells diskutiert.

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Quantum yields of 3MLCT excited state formation and triplet—triplet absorption spectra of ruthenium(II) tris-chelate complexes containing five- and six-membered heterocyclic moieties

Cited by 22 publications

References 40 publications

The Micro-Optical Ring Electrode. 3: Transient Photocurrent Studies of Photophysical−Electrochemical and Photophysical−Chemical−Electrochemical Systems

The Micro-Optical Ring Electrode. 3: Transient Photocurrent Studies of Photophysical−Electrochemical and Photophysical−Chemical−Electrochemical Systems

Singlet Oxygen (¹Δ_g) Production by Ruthenium(II) Complexes in Microheterogeneous Systems

Aspects of Ligand and Electron-Acceptor Dependence of Magnetic Field Effects on Net Electron Transfer Efficiencies in Photooxidation of Ru(II)-trisbipyridyl Type Complexes

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Quantum yields of 3MLCT excited state formation and triplet—triplet absorption spectra of ruthenium(II) tris-chelate complexes containing five- and six-membered heterocyclic moieties

Cited by 22 publications

References 40 publications

The Micro-Optical Ring Electrode. 3: Transient Photocurrent Studies of Photophysical−Electrochemical and Photophysical−Chemical−Electrochemical Systems

The Micro-Optical Ring Electrode. 3: Transient Photocurrent Studies of Photophysical−Electrochemical and Photophysical−Chemical−Electrochemical Systems

Singlet Oxygen (1Δg) Production by Ruthenium(II) Complexes in Microheterogeneous Systems

Aspects of Ligand and Electron-Acceptor Dependence of Magnetic Field Effects on Net Electron Transfer Efficiencies in Photooxidation of Ru(II)-trisbipyridyl Type Complexes

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Singlet Oxygen (¹Δ_g) Production by Ruthenium(II) Complexes in Microheterogeneous Systems