Laser photoionization of phenothiazine in alcoholic and aqueous micellar solution. Electron transfer from triplet states to metal ion acceptors

Alkaitis, S. A.; Beck, G.; Gräetzel, Michael

doi:10.1021/ja00853a015

Cited by 213 publications

(127 citation statements)

References 1 publication

(1 reference statement)

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“…2b. It was the characteristic absorption of PTH +• produced by photoionization of PTH (19). As TiO 2 colloids were added to the solution without irradiation, no new band was observed at the same conditions, as shown in Fig.…”

Section: Absorption Spectramentioning

confidence: 76%

Intermediates Produced in the Electron-Transfer Processes of Phenothiazine/Semiconductor Systems

Jian

Xiang

Sun

et al. 2000

Journal of Colloid and Interface Science

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Section: Absorption Spectramentioning

confidence: 76%

Intermediates Produced in the Electron-Transfer Processes of Phenothiazine/Semiconductor Systems

Jian

Xiang

Sun

et al. 2000

Journal of Colloid and Interface Science

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“…Since ionization occurs during the laser pulse (~ 10 ns), relaxation of the triplet spin system may be minor so that the doublet radicals can be strongly polarized. With signal intensity given by the product of radical concentration and spin polarization, the biphotonic channel can be responsible fox the observed resonances even though it is known that the singlet channel is much more efficient in producing e~ [7]. We note that this mechanism has been invoked as well by Ishiwata et al [4] and Forbes et al [2] to account for CIDEP generated by photoionization of aromatics in homogeneous as well as micellar solutions.…”

Section: Cidep Of Photoionization Productsmentioning

confidence: 64%

“…Signal decay was examined in the hope that it would exhibit distinct components due to spin-lattice relaxation (T1) and chemical decay since this would give quantitative information on the magnitude of spin polarization. According to the literature, the T 1 of the hydrated electron should be around 8 ~ts [3] and its chemical lifetime might be of similar magnitude in the absence of electron acceptors [7]. Therefore, signal decay could reflect both spin and chernical dynamics.…”

Section: Cidep Of Photoionization Productsmentioning

confidence: 97%

FT-EPR study of photoionization in micellar solutions

et al. 1997

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AbstracL Fourier Transform EPR (FT-EPR) was used to study the formation and decay of free radicals produced by photoionization of phenothiazine (PTH) solubilized in aqueous SDS and Triton X-100 micellar solutions in the absence and presente of electron aeceptors. C1DEP spectra produced by PTH photoionization in micellar solution differ from those found in homogeneous solution. The effect is attributed to changes in relative importante of single-photon, singlet excited state, and biphotonic, triplet exeited state, photoionization. With quinone acceptors present in the bulk aqueous phase, photoionization of PTH in SDS, results in instantaneous formation of quinone anion radicals that carry the spin polarization of the precursor hydrated electrons. Ir the acceptor is anchored in the micelle, electron capture carmot compete with electron escape hato the aqueous phase. Instead, anion radicals are formed primarily by reductive quenching of 3pTH*. This process gives rise to a spectrum that is attributed to long-lived spin-correlated radical pairs, [PTH+...Q-].

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“…[40] The difference spectra thus obtained clearly show the signatures of the Q À and PTZ + radicals around 440 and 510 nm, respectively. [41][42][43][44] and ground-state recovery/growth of PTZ + (510 nm) of 1 a and 3 a are shown in Figure 5. The concomitant growth of the Q À and PTZ + signatures and decay of the [RuA C H T U N G T R E N N U N G (dqp) 2 ] 2 + * excited state was fitted to rate constants of k CS A C H T U N G T R E N N U N G (1 a) = 1.0 10 9 and k CS A C H T U N G T R E N N U N G (3 a) = 5.2 10 8 s À1 , respectively, in global fits at five to ten wavelengths.…”

Section: Electrochemistrymentioning

confidence: 99%

Vectorial Electron Transfer in Donor–Photosensitizer–Acceptor Triads Based on Novel Bis‐tridentate Ruthenium Polypyridyl Complexes

Kumar

Karlsson

Streich

et al. 2010

Chemistry A European J

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The first examples of rodlike donor-photosensitizer-acceptor arrays based on bis-2,6-di(quinolin-8-yl)pyridine Ru(II) complexes 1a and 3a for photoinduced electron transfer have been synthesized and investigated. The complexes are synthesized in a convergent manner and are isolated as linear, single isomers. Time-resolved absorption spectroscopy reveals long-lived, photoinduced charge-separated states (tau(CSS) (1a)=140 ns, tau(CSS) (3a)=200 ns) formed by stepwise electron transfer. The overall yields of charge separation (> or = 50% for complex 1a and > or = 95% for complex 3a) are unprecedented for bis-tridentate Ru(II) polypyridyl complexes. This is attributed to the long-lived excited state of the [Ru(dqp)(2)](2+) complex combined with fast electron transfer from the donor moiety following the initial charge separation. The rodlike arrangement of donor and acceptor gives controlled, vectorial electron transfer, free from the complications of stereoisomeric diversity. Thus, such arrays provide an excellent system for the study of photoinduced electron transfer and, ultimately, the harvesting of solar energy.

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Laser photoionization of phenothiazine in alcoholic and aqueous micellar solution. Electron transfer from triplet states to metal ion acceptors

Cited by 213 publications

References 1 publication

Intermediates Produced in the Electron-Transfer Processes of Phenothiazine/Semiconductor Systems

Intermediates Produced in the Electron-Transfer Processes of Phenothiazine/Semiconductor Systems

FT-EPR study of photoionization in micellar solutions

Vectorial Electron Transfer in Donor–Photosensitizer–Acceptor Triads Based on Novel Bis‐tridentate Ruthenium Polypyridyl Complexes

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