The time-resolved absorption-detected magnetic resonance spectrum of the polymethylene linked biradical: effect of the exchange integral

Maeda, Kiminori; Araki, Yasuyuki; Kamata, Yoshiyuki; Enjo, Kentaro; Murai, Hisao; Azumi, Tohru

doi:10.1016/0009-2614(96)01047-0

Cited by 29 publications

(25 citation statements)

References 17 publications

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“…The signal of the transient absorption stored in an 8 bit digital oscilloscope (LeCroy 9350) was processed similarly to that of PCDMR. The microwave pulse fxom a TWT amplifier (Applied System 127X, maximum output power of 2 kW) was attenuated to 30 W for this observation [10]. The laser excitation and the transient absorption measurement were carried out during the microwave pulse (4 ixs).…”

Section: Admr Observationmentioning

confidence: 99%

“…The microwave B 1 fŸ less than 1.0 mT in the present setup, was estimated from the independent measurement of the nutation frequency of the DFDMR signal observed in the system of TMPD in 2-propanol (Iwasaki Y., Mural H., Maeda K., Azumi T., unpubl.) and/or from the method reported in our previous paper [10]. A proton-resonance type Gaussmeter was used to measure the accurate magnetic field.…”

Section: Admr Observationmentioning

confidence: 99%

“…The data of the microwave effect were expressed by the ratio of the signal change with and without the microwave radiation under the external magnetic field. The detailed experimental setup has already been reported recently [ 10,11].…”

Section: Admr Observationmentioning

confidence: 99%

“…We do not know a clear picture of this particular RIP composed of the cation radical and the solvated electron, but the present data suggest a dynamic model tbat makes the linewidth large. The dynamic modulation of the exchange interaction [10,13] of this system may provide the broad spectrum probably because of the mobility of the solvated electron. The clear spectrum of the solvated electron may also not appear due to either the broadening by the B 1 field or by the dynamic modulation.…”

Section: Transient Admr Observation Of the Rip Formed From Tmpdmentioning

confidence: 99%

“…In this report, three different RYDMR observations, photoconductivity detected magnetic resonance (PCDMR), transient-absorption detected magnetic resonance (ADMR) [10], and delayed fluorescence detected magnetic resonance (DFDMR), of the transient RIP formed in the photolysis of TMPD in alcohol solution are presented. The first method was newly developed to study the RIP in photochemistry [11].…”

Section: Introductionmentioning

confidence: 99%

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Several RYDMR studies on the radical-ion pair formed in the photolysis of TMPD: Photoconductivity, transient-absorption and fluorescence detection methods

et al. 1997

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Three different RYDMR (reaction-yield detected magnetic resonance) techniques, photoconductivity detected magnetic resonance (PCDMR), transient-absorption detected magnetic resonance (ADMR) and detayed fluorescente detected magnetic resonance (DFDMR), are applied to the investigation of the radical-ion pair formed in the photolysis of TMPD in mixed alcohol solution. Here, PCDMR is a newly developed RYDMR method to study the radical-ion pair. PCDMR and ADMR methods show the acceleration of the quenching reaction from the triplet manifold of the radical-ion pair by microwave radiation under electron spin resonance conditions. These spectra of the radicalion pair are significantly broadened probably because of the dynamic behavior of the radical-ion pair interacting strongly. The long lifetime of the radical-ion pair is due to the Coulomb interaction and the special role of the mixed solvent containing 2-propanol that stabilizes the radical-ion pair. Furthermore, the simultaneous observation of the PCDMR and the DFDMR shows different spectra. This indicates that the spectrum observed by the DFDMR is due to the wealdy interacting RIP formed through the pathway different from those observed by the other two methods.

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Section: Admr Observationmentioning

confidence: 99%

Section: Admr Observationmentioning

confidence: 99%

Section: Admr Observationmentioning

confidence: 99%

Section: Transient Admr Observation Of the Rip Formed From Tmpdmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Several RYDMR studies on the radical-ion pair formed in the photolysis of TMPD: Photoconductivity, transient-absorption and fluorescence detection methods

et al. 1997

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Reaction-yield-detected magnetic resonance in the intra-and intermolecular electron transfer reactions

et al. 1997

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The spin dynamics of the intermediate radical ion pairs formed in the intra-and intermolecular electron transfer reactions between N,N-dimethylaniline and phenanthrene is studied by employing the polymethylene-linked and nonlinked systems. Reaetion-yield-detected magnetic resonance (RYDMR) expe¡ are performed by monitoring the exciplex fluorescente. From the theoretical consideration of the data, we conelude that the lifetime of the radical ion pair in the linked system is shorter than that in the nonlinked system. This tendency is opposite to what is generally observed in linked and nonlinked neutral biradical.

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The time-resolved ADMR in the photolysis of the polymethylene-linked system of xanthone and xanthene: Power dependence

Maeda¹,

Araki²,

Enjo³

et al. 1997

Appl. Magn. Reson.

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Abstraet. The time-resolved ADMR (absorption-detected magnetic resonance) spectrum of the polymethylene linked biradical generated in the photolysis of ct-(xanthene-2-carbony!oxy)-co-(xanthene-2-carbonyloxy) dodecane is observed at various microwave power. When the lower microwave power is low, the ADMR spectrum is totally negative (the absorbance of xanthyl radical decreases by the microwave irradiation) and is interpreted in terms of the hyperfine strueture of the terminal radieals. In contrast with this, the ADMR spectrum obtained at high microwave field consists of two eomponents: central component and wing component. The central component is positive and is interpreted in terms of the deceleration of the intersystem crossing by microwave, which is known as the spin locking. The wing component is negative and the linewidth is much larger than that of the central one. Ir is ascribed to the transitions from ]T+~) and IT 1) states to singlet state having a slight IT0) character. It is proposed that the width of the time resolved spectrum is due to the fluctuation of the exchange integral (modulated exehange integral) by the motion of the polymethylene chain. The time dependence of the central and wing components and the conditions for observation of them are discussed.

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The time-resolved absorption-detected magnetic resonance spectrum of the polymethylene linked biradical: effect of the exchange integral

Cited by 29 publications

References 17 publications

Several RYDMR studies on the radical-ion pair formed in the photolysis of TMPD: Photoconductivity, transient-absorption and fluorescence detection methods

Several RYDMR studies on the radical-ion pair formed in the photolysis of TMPD: Photoconductivity, transient-absorption and fluorescence detection methods

Reaction-yield-detected magnetic resonance in the intra-and intermolecular electron transfer reactions

The time-resolved ADMR in the photolysis of the polymethylene-linked system of xanthone and xanthene: Power dependence

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