Electron transfer versus hydrogen abstraction in photoreduction of quinones. An application of chemically induced dynamic electron polarization

Wong, S. K.

doi:10.1021/ja00485a036

Cited by 28 publications

(17 citation statements)

References 3 publications

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“…Photophysics and photochemistry of 1,4-naphthoquinones have been a subject of study for a long time . Studies by emission and absorption spectroscopies made a fundamental contribution to our understanding of the electronic structure of their excited states. − The primary photochemical processes have been also investigated very actively by CIDEP , and laser flash photolysis spectroscopies. − However, little is known of the ZFS parameters of the T 1 states of 1,4-naphthoquinone (NQ) and its derivatives. Using a time-resolved EPR (TREPR) technique, a very large zero-field splitting (ZFS) constant of | D | = 0.33 cm -1 was determined for the T 1 state of NQ in polar solvents .…”

Section: Introductionmentioning

confidence: 99%

Substituent and Matrix Effects on the Excited Triplet States of 1,4-Naphthoquinones

Shimokage¹,

Ikoma²,

Akiyama³

et al. 1997

J. Phys. Chem. A

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Phosphorescence and TREPR spectra have been measured for 2-methyl-1,4-naphthoquinone (MNQ), 2,3-dimethyl-1,4-naphthoquinone (DMNQ), and 2-methoxynaphthoquinone (MeONQ) in several matrices at low temperatures. The |D| value of ZFS parameter decreases with increasing the electron-donating character of the substituent group. For MNQ, the T1 state is clearly assigned to be 3nπ* in character. The broad phosphorescence spectra and minor effects of the matrix polarity on the ZFS parameters lead to the conclusion that the character of the T1 states are mainly 3ππ* in DMNQ and MeONQ. The T1 states of the present naphthoquinone derivatives have more or less mixed character of the 3nπ* and 3ππ* states.

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Section: Introductionmentioning

confidence: 99%

Substituent and Matrix Effects on the Excited Triplet States of 1,4-Naphthoquinones

Shimokage¹,

Ikoma²,

Akiyama³

et al. 1997

J. Phys. Chem. A

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“…+ E$lx (2) The superscript CP marks the contributions to which a correction term has been added. These corrections are expressed in the following form = + (3) where X denotes one of the components of (1) (X = EX, CT, MIX). The total CP correction, applied to £ , is given by (45) (a) Jorgensen, W. L.; Gao, J.…”

Section: Outlines Of the Methodsmentioning

confidence: 99%

Effect of counterpoise corrections on the components of the interaction energy in the formate-, acetate-, and phosphate-water dimers: a study of basis set effects

Alagona¹,

Ghio²,

Tomasi³

1989

J. Phys. Chem.

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Several variants of the counterpoise procedure for the correction of the basis set superposition error in the interaction energy and in its separate components are examined for a set of six dimers formed between the formate, acetate, and phosphate anions and water along two different approaching paths, namely those giving linear and bifurcated dimers. The analysis is performed over a representative set of intermonomeric distances, using six basis sets. The counterpoise correction has a beneficial effect on the prediction of /?^) and R^: sizable changes in these two quantities are accompanied by a noticeable reduction of the spread due to the basis set. Only the STO-3G basis set shows evident phenomena of overcorrection, whereas the smallest corrections are found for the 3-21G+ one. The most convenient basis sets for calculations on similar dimers are identified. The comparison with corresponding analyses for neutral electron donor-water dimers permits a quantitative interpretation of the nature of the interaction, giving also some suggestions on simplified computational procedures to be

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“…Laser photolysis (4)(5)(6). CIDEP (7,8), and CIDNP (9) are currently employed to clarify these mechanisms. The CHDEP (CF3'2C=0 and CIDNP applications to photochemistry have been reviewed recently (10).…”

Section: IImentioning

confidence: 99%

“…The dissociation process, similar to reaction [8], must be very inefficient in the system of decafluorobenzophensne. The protonated species was the sole esr signal observed when THF solutions of decafluorobenzophenone and various tetraphenylborates, even in the presence of crown ethers, was imadiated.…”

Section: Photolysis Ofthfsolutions Containing Fluoroketones and Teframentioning

confidence: 99%

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Photochemical reactions of fluoro-substituted ketones with amines, tetraphenylborates, and organometals: an electron spin resonance study

Chen¹,

Foster²,

Wan³

1980

Can. J. Chem.

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Ammonium ion-pairs, solvent-separated alkaii-metal ion-pairs, and Group IVB organometallic adducts of fluoro-substituted ketones were generaied photochemically. The structure and the controlling factors for the formation of contact ammonium ion-pair were deduced from the effects of solvent. amine. and fluorine substitution. The effect of fluorine on the formation of the alkali-metal ion-pairs and organometallic adducts was discussed. KUANG S. CHES. TERRY FOSTER^^ JEFFREY M. S. W A~. Can. J. Chem. 98,591 (1980). On a produit phoiochimiquement des paires d'ions ammonium. des paires d'ions de metaux alcalins separes par un solvant et des adduits organometalliques du groupe IVB de fluorocetones. On a deduit la structure et les facteurs contralant la formation de la paire d'ions ammonium de contact, a partir des effetets de solvant et de la substitution par une amine ou un fluor. On discute de l'effet du fluor sur la formation des paires d'ions de metaux alcalins et des adduits organometalliques.[Traduit par le journal]

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Electron transfer versus hydrogen abstraction in photoreduction of quinones. An application of chemically induced dynamic electron polarization

Cited by 28 publications

References 3 publications

Substituent and Matrix Effects on the Excited Triplet States of 1,4-Naphthoquinones

Substituent and Matrix Effects on the Excited Triplet States of 1,4-Naphthoquinones

Effect of counterpoise corrections on the components of the interaction energy in the formate-, acetate-, and phosphate-water dimers: a study of basis set effects

Photochemical reactions of fluoro-substituted ketones with amines, tetraphenylborates, and organometals: an electron spin resonance study

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