Photoreduction of benzophenone in benzene. II. Flash photolysis study of primary photochemical reactions

Buettner, A. V.; Dedinas, Jonas

doi:10.1021/j100672a003

Cited by 48 publications

(21 citation statements)

References 2 publications

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“…Triplet states of aromatic carbonyls have attracted considerable experimental interest due to their photoreducing activity in the presence of hydrogen atom donors, 1 and their capacity to transfer the excitation energy in the presence of triplet quenchers. 2 In both cases, the nature of the lowest-lying excited triplet states determines mainly the photophysical activity of the molecule.…”

Section: Introductionmentioning

confidence: 99%

“…In the seminal work of Fang and Phillips, it has been found that acetophenone has an exotic three-state intersection between the 3 (np*), 3 (pp*) and 1 (np*) states. 9,11 The three-state crossing involves first an efficient intersystem crossing between 3 (pp*) and 1 (np*) states and second an internal conversion between the 3 (pp*) and the 3 (np*) states, which would explain the rapid population of the triplet manifold after S 1 absorption. 9 Based on these results, Cui et al have studied the photocleavage reaction occurring at the lowest triplet state, postulating the photochemical pathway starting from the S 2 absorption.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical study of the photochemical generation of triplet acetophenone

Huix‐Rotllant

Siri

Ferré

2013

Phys. Chem. Chem. Phys.

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Acetophenone has a rich photochemistry, which strongly depends on the absorbing state. For example, the excitation to the lowest singlet excited state (S1) leads to a triplet population with a phosphorescence quantum yield of one, while the excitation to S2 leads to photocleavage reactions. Here, we rationalize the photochemistry of acetophenone after being absorbed into the S1, S2 and S3 states by performing a systematic study of all the singlet and triplet minimum energy structures and state crossings between the relevant electronic states. We calculate these structures at the complete-active space self-consistent field (CASSCF) level of theory and at the correlated extended second-order quasi-degenerate multi-reference perturbation theory (XMCQDPT2), emphasizing the importance of correlation effects in the determination of structures.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical study of the photochemical generation of triplet acetophenone

Huix‐Rotllant

Siri

Ferré

2013

Phys. Chem. Chem. Phys.

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“…The quantum yield in vacuum is also 0.14, showing that the reaction occurs from the singlet excited state of M(DZDA/o-EA). For the reaction of the hydrogen abstraction of benzophenone, deactivation by aromatic solvents was observed [20], but the quantum yield for the decomposition of M(DZDA/ o-EA) in CHzC12 solution is the same as that in ethylbenzene solution, showing that the rate constant of the reaction is much larger than that for deactivation by the solvent. Table 2 summarizes the quantum yields of the model compounds prepared from aliphatic and aromatic amines, as well as the quantum yields for the photodecomposition Photoirradiation Time (min)…”

Section: Photoreaction Of Diazo-containing Model Compoundsmentioning

confidence: 98%

Synthesis of a photosensitive polyimide containing a diazo group and its photocrosslinking reactions via a long‐lived active intermediate

et al. 1995

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Anovel intrinsic photosensitive polyimide containing a diazo group in the main chain was prepared,and the quantum yield for the photocrosslinking reaction was determined to be 0.13 under air at room temperature by GPC measurement. The quantum yield for the photo-decomposition reaction of the diazo group was also determined to be 0.06. These values are higher by about two orders of magnitude than those for the photocrosslinking reaction of a benzophenone-containing polyimide, which is prepared from benzophenonetetracarboxylic dianhydride (BTDA) and methylene bis(2-ethylaniline) (DEDPM).The reaction was found to proceed via its singlet excited state to give a long-lived active intermediate,a carbene, which plays a great role in the increase in the photoreactivity. Characteristics of the photoreaction and the fluorescence behavior of a series of imide-substituted diphenyldiazomethanes were also investigated, showing that the reactivity of the diazo groups is not affected by the existence of charge transfer structures of the imide groups.

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“…The value of k. for benzene agrees well with that reported (1.6 x 10 2 M-1 s-1 ). 24 For cases of non-diffusioncontrolled reactions, the rates for reactions between a polymer and a small molecule are usually considered to be equal to the rate for corresponding model reaction between small molecules. 8 • 23 • 25 But for the hydrogen abstractions of tert-butoxy radical from polystyrene and polypropyrene, 26 • 27 the molecular weight 892 effects have been reported.…”

Section: Rate Constants For Hydrogen Abstraction and Quenchingmentioning

confidence: 99%

Rates of Quenching and Hydrogen Abstraction of Benzophenone Triplet with Cumene and Oligostyrenes

Horie

Takagi

Mita

et al. 1984

Polym J

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ABSTRACT:Rate constants of quenching, kq, and hydrogen abstraction, k., of benzophenone triplet with oligostyrenes from dimer to hexamer as well as with cumene were determined in acetonitrile at 30oC from transient phosphorescence decay and· quantum yield for benzophenone reduction measurements. The values of kq =(4.0± 1.0) x 10 6 unit-M-1 s-1 and k. =(1.3 ±0.3) x 10 5 unit-M-1 s-1 for oligostyrenes are independent of the number of monomer unit, n. The kq for oligostyrene is three times larger than kq for cumene, its monomer model, supposingly due to a: sandwich-type encounter of benzophenone with two adjacent phenyl groups, but k. for oligostyrene is equal to k. for cumene. The chemical reaction (hydrogen abstraction) contributes in only to total deactivation of benzophenone triplet by oligostyrenes.

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Photoreduction of benzophenone in benzene. II. Flash photolysis study of primary photochemical reactions

Cited by 48 publications

References 2 publications

Theoretical study of the photochemical generation of triplet acetophenone

Theoretical study of the photochemical generation of triplet acetophenone

Synthesis of a photosensitive polyimide containing a diazo group and its photocrosslinking reactions via a long‐lived active intermediate

Rates of Quenching and Hydrogen Abstraction of Benzophenone Triplet with Cumene and Oligostyrenes

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