The Electron Transfer Reaction between Triplet Methylene Blue and Aromatic Compounds

Kikuchi, Kôichi; Tamura, Shin–ichiro; Iwanaga, C.; Kokubun, Hiroshi; Usui, Yoshiharu

doi:10.1524/zpch.1977.106.1_2.017

Cited by 40 publications

(10 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[13,14]. The addition of ferrocene, which itself has negligible absorption at the laser wavelength, leads to a shortening of the triplet decay corresponding to a quenching rate constant of 1.3 × 10 ~° M -l s -1 in good agreement with the value of 1.1 X 10 l° M-1 s-~ reported by Kikuchi et al [10].…”

Section: Transient Absorption Kinetics and Magnetic Field Effectsupporting

confidence: 84%

“…It should be noted that although, according to Eqs. (12,13), the representation of the Kramers doublet components is factorized into a space part and a spin part, giving the a' state a pure character and the fl' state pure fl character, the space parts are partially orthogonal, i.e. we need a two-dimensional basis for the orbital part, the consequence of which will be that the set of radical pair states given in Eqs.…”

Section: Singlet Character Of the Radical Pair's Formal Spin Statesmentioning

confidence: 99%

See 1 more Smart Citation

Magnetic field effect on the photooxidation efficiency of ferrocene

Gilch¹,

Linsenmann²,

Haas³

et al. 1996

Chemical Physics Letters

View full text Add to dashboard Cite

The cage escape efficiency r/ce of radicals in the electron transfer quenching of triplet methylene blue by ferrocene in acetonitrile was found to be sensitive towards an external magnetic field. The field dependence of the effect corresponding to a monotonic decrease of Bee was determined in a field range from 0.0 to 3.2 T, where it reaches a value of -20.7%. The effect is analyzed in terms of a spin chemical model wherein the effective rate of geminate reverse electron transfer, regenerating the singlet ground state of the reactants, becomes magnetic field dependent due to magnetic mixing of non-uniformly reactive spin sublevels by the anisotropic Zeeman interaction. From the analysis, the absolute values of the rate constants of spin-allowed reverse electron transfer (605 ns-~ ), cage escape (15 ns-~ ), and electron spin relaxation in the ferricenium cation (154 ns -1) could be determined.

show abstract

Section: Transient Absorption Kinetics and Magnetic Field Effectsupporting

confidence: 84%

Section: Singlet Character Of the Radical Pair's Formal Spin Statesmentioning

confidence: 99%

Magnetic field effect on the photooxidation efficiency of ferrocene

Gilch¹,

Linsenmann²,

Haas³

et al. 1996

Chemical Physics Letters

View full text Add to dashboard Cite

show abstract

“…Monitoring the radical form of methylene blue MB" is not possible under our experimental conditions, as its maximum absorption in the visible region lies around 430 nm [21] where the samples are opaque due to ferrocene absorption ()tma x = 440 nm).…”

Section: Femtosecond Pump-probe Measurementsmentioning

confidence: 97%

“…Consequently, the spectral changes observed after excitation are essentially due to the various states of methylene blue. We chose three probe wavelengths characterising these different states: 630 nm, absorption of MB +, negative difference absorbance due to ground state depletion; 700 nm, stimulated emission of singlet state 1MB + * ; and 850 nm, red wing of the ~MB + * stimulated emission and absorption of the triplet state 3MB+ * [21].…”

Section: Femtosecond Pump-probe Measurementsmentioning

confidence: 99%

Ultrafast electron transfer, recombination and spin dynamics

Gilch¹,

Pöllinger-Dammer²,

Steiner³

et al. 1997

Chemical Physics Letters

View full text Add to dashboard Cite

The quenching of excited singlet methylene blue (IMB + * ) by N,N-dimethylaminomethylferrocene (FcN) in acetonitrile at room temperature has been studied using femtosecond pump-probe absorption spectroscopy. At high FcN concentration static quenching via an intermolecular electron transfer mechanism constitutes the predominating decay channel for l MB + * The time constants of the large amplitude components for the forward electron transfer from FcN donor to ~ MB ÷ * and the subsequent recombination process recovering the ground states have been determined to be 390 fs and 1 ps, respectively. Thus, the majority of radical pairs has recombined before paramagnetic relaxation induces spin mixing giving rise to triplet-phased radical pairs. These can escape geminate recombination as the system does not offer low-lying local triplet states to be occupied in the recombination process. © 1997 Elsevier Science B.V.

show abstract

“…Using, e.g., ferrous 13, 27). Applying allythiourea (8,28) or Paraions in acid solution, the process can be summar-phenylendiamine (9) concentration of the electron donor can influence k3 = 6 x lo7 dm3 mol-I s-' (25) the yield of semiquinone (12,15,29,30 A direct formation of semiquinone, avoiding all above mentioned factors can be achieved by reaction of thionine with H-atoms. The pulse radiolysis technique offers this possibility.…”

Section: Introductionmentioning

confidence: 99%

Attack of H-atoms on aqueous thionine studied by pulse radiolysis

Solar¹,

Getoff²,

Solar³

et al. 1981

Can. J. Chem.

View full text Add to dashboard Cite

SONIA SOLAR, NIKOLA GETOFF, WOLFGANG SOLAR, and FRANZ MARK. Can. J. Chem. 59,2719Chem. 59, (1981.The reaction mechanism of the H-attack on thionine (TH+) in aqueous solutions (5 X to 2 X mol dm+ TH+; 2 x mol dm-3 r-butanol, pH I and 4) was investigated by pulse radiolysis in combination with simulation by computation. Applying a least-squares fitting procedure it was possible to state that at pH 1,89.5% of the H-atoms react with TH+, k = (8.5 f 0.3) x lo9 dm3 mol-I s-I, to form semiquinone ('TH3Z+, Amax = 390nm, E,,, = 685 f 20 m2 mol-I; &770 = 720 mZ mol-' and Amax = 790nm, E, , , = 775 f 20mZ mol-I), which dismutates to TH+ and leucodye with 2k = (2.4 f 0.1) X lo9 dm3 mol-I s-I. In addition to this a second H-attack (10.5% H) occurs on the ring carbon of the dye with k = (1.0 f 0.1) x lo9 dm3 mol-' s-l, resulting in the production of H-adducts. These results are of interest for photogalvanic cells using thionine as a sensitizer., SONIA SOLAR, NIKOLA GETOFF, WOLFGANG SOLAR et FRANZ MARK. Can. J. Chem. 59,2719Chem. 59, (1981.Utilisant la radiolyse par pulsation combinee avec une simulation obtenue par le calcul, on a ttudie le mecanisme de la reaction 1 d'attaque du H sur la thionine (TH+) dans des solutions aqueuses (5 x a 2 x mol dm-' TH+; 2 x mol d m 3 rerr-butanol,

show abstract

The Electron Transfer Reaction between Triplet Methylene Blue and Aromatic Compounds

Cited by 40 publications

References 12 publications

Magnetic field effect on the photooxidation efficiency of ferrocene

Magnetic field effect on the photooxidation efficiency of ferrocene

Ultrafast electron transfer, recombination and spin dynamics

Attack of H-atoms on aqueous thionine studied by pulse radiolysis

Contact Info

Product

Resources

About