Journal ArticleDOI
Photoreduction of anthraquinone by triethylamine in ethanol and toluene studied by steady-state photolysis and laser photolysis.
Kumao Hamanoue,Toshihiro Nakayama,Yoshiaki Yamamoto,Kazuhide Sawada,Yoshihito Yuhara,Hiroshi Teranishi +5 more
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In this article, the authors studied the photoreduction of anthraquinone (AQ) by triethylamine (TEA) in toluene and ethanol by means of steady-state photolysis and laser photolysis.Abstract:
Photoreduction of anthraquinone (AQ) by triethylamine (TEA) in toluene and ethanol was studied by means of steady-state photolysis and laser photolysis. In toluene, addition of TEA enhanced the quantum yield of photoreduction of AQ, and the reaction was found to originate via the formation of an exciplex between ground-state TEA and the lowest triplet state of AQ: This exciplex changed to a contact ion pair followed by proton transfer, generating anthrasemiquinone radical and triethylamine radical, and 9,10-anthracenediol was obtained as the final photoproduct. Although the mechanism of the photoreduction of AQ in ethanol/TEA was essentially the same as that in toluene/TEA and the final products in ethanol/TEA were 9,10-anthracenediol and its anion, the quantum yield of photoreduction decreased with increase in TEA concentration. It was proposed that the exciplex in ethanol was quenched by ground-state TEA via the formation of a triplex of a radical anion of AQ and a radical cation of TEA dimer bonded by ...read more
Citations
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Laser flash photolysis studies on hydrogen atom abstraction from phenol by triplet naphthoquinones in acetonitrile
TL;DR: In this article, the absorption spectra and molar absorption coefficients of the 1,4naphthosemiquinone radical (NQH˙) and 2,3-dimethyl-1,4-naphinone (DMNQ) from phenol (PhOH) in MeCN were determined by ns laser flash photolysis.
Journal ArticleDOI
Photoreduction of 9,10-anthraquinone by triethylamine: a Fourier-transform EPR study
TL;DR: In this article, the photoreduction of anthraquinone by triethylamine in 2-propanol solution was investigated using time resolved Fourier-transform EPR spectroscopy.
Journal ArticleDOI
Hydrogen atom transfer and electron transfer reactions in the triplet π,π* state of 1,4-anthraquinone studied by CIDEP techniques and laser flash photolysis
Toshitada Yoshihara,Minoru Yamaji,Takao Itoh,Haruo Shizuka,Takuji Shimokage,Shozo Tero-Kubota +5 more
TL;DR: In this paper, it was shown on the basis of CIDEP measurements that both hydrogen atom transfer (HT) and electron transfer (ET) reactions in the excited state of 1,4-AQ originated from the triplet state.
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Flash CIDNP investigation of a cyclic photoreaction
TL;DR: In this paper, the cyclic photoreaction between 9,10-anthraquinone and N,N-dimethylaniline (DMA) in acetonitrile- d 3 has been studied between 237 and 296 K by time resolved measurements of chemically induced dynamic nuclear polarization (CIDNP).
Journal ArticleDOI
Pulse radiolyses of anthraquinone and anthraquinone-triethylamine in acetonitrile and toluene at room temperature
TL;DR: In this paper, the authors performed nanosecond pulse radiolysis of anthraquinone (AQ) in several solvents at room temperature, and the following results were obtained: (1) in acetonitrile (CH3CN), the formation of triplet AQ and a free-radical anion of AQ is observed.
References
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