Direct measurements of absolute concentration and lifetime of singlet oxygen in the gas phase by electron paramagnetic resonance

Hasegawa, Keisuke; Yamada, Kenji; Sasase, Ryouji; Miyazaki, Ryoichi; Kikuchi, Azusa; Yagi, Mikio

doi:10.1016/j.cplett.2008.04.031

Cited by 28 publications

(38 citation statements)

References 23 publications

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“…Singlet oxygen ( 1 O 2 )1 is the lowest excited state of oxygen2 and can undergo different reactions, such as Schenck Ene reactions with alkenes3 or [2+2] cycloadditions 4. Besides, it can react with dienes or aromatic systems in a [4+2] manner 5.…”

Section: Introductionmentioning

confidence: 99%

New Singlet Oxygen Donors Based on Naphthalenes: Synthesis, Physical Chemical Data, and Improved Stability

Klaper

Linker

2015

Chemistry A European J

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Singlet oxygen donors are of current interest for medical applications, but suffer from a short half-life leading to low singlet oxygen yields and problems with storage. We have synthesized more than 25 new singlet oxygen donors based on differently substituted naphthalenes in only a few steps. The influence of functional groups on the reaction rate of the photooxygenations, thermolysis, half-life, and singlet oxygen yield has been thoroughly studied. We determined various thermodynamic data and compared them with density functional calculations. Interestingly, remarkable stabilities of functional groups during the photooxygenations and stabilizing effects for some endoperoxides during the thermolysis have been found. Furthermore, we give evidence for a partly concerted and partly stepwise thermolysis mechanism leading to singlet and triplet oxygen, respectively. Our results might be interesting for "dark oxygenations" and future applications in medicine.

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Section: Introductionmentioning

confidence: 99%

New Singlet Oxygen Donors Based on Naphthalenes: Synthesis, Physical Chemical Data, and Improved Stability

Klaper

Linker

2015

Chemistry A European J

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“…17 The reported EPR spectrum of O 2 ( 1 Δ g ) has four components whose origins are well understood on the basis of rotational spectroscopy. 8,14 Thus, the EPR of O 2 ( 1 Δ g ) can serve as a convenient fingerprint of this electronically excited molecule in the gas phase.…”

mentioning

confidence: 99%

“…8−14 EPR of O 2 ( 1 Δ g ) was reported for the first time in 1965. 8 One communication presented data on the kinetics of O 2 ( 1 Δ g ) formation and decay in the gas phase measured by EPR in which its lifetime was τ = 7 s. 14 The contributions of different decay processes in the determined τ 14 remain unknown.…”

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confidence: 99%

Time-Resolved EPR Study of Singlet Oxygen in the Gas Phase

et al. 2013

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“…In the second step, the singlet state underwent an intersystem crossing to an excited triplet state. In the third step, photosensitization,16, 17 the triplet energy in the polymer chain transfered to a π* electron in the ground‐state triplet oxygen molecules, O 2 ( 3 Σ

_{g}^{−}

), dissolved in the n ‐octylbenzene, and the excited‐state singlet oxygen molecules, O 2 ( 1 Δ g ), were generated. In the fourth step, an O 2 ( 1 Δ g ) molecule reacted with an alkene (CC) in the polymer chain by [2 + 2] cycloaddition.…”

Section: Resultsmentioning

confidence: 99%

Single‐molecule imaging of photodegradation reaction in a chiral helical π‐conjugated polymer chain

Shinohara

Kodera

Oohashi

2010

J. Polym. Sci. A Polym. Chem.

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How does the chemical reaction of a single polymer chain progress? This question is not proven, as long as it is studied the data of the ensemble average from the large number of molecules. In this study, we succeeded for the first time in the direct measurement of when, where, and how the chemical reaction of a polymer chain proceeds on a nanometer scale. That is, single-molecule imaging of the photodegradation reaction of a chiral helical p-conjugated polymer following laser irradiation of 405 nm was conducted. Analysis of the chemical kinetics showed that the photodegradation of the single polymer chain proceeded stepwise as a quantum phenomenon. When the motility of the chain-end increased, reactivity of the photodegradation increased. It was also discovered that the photodegradation of the polymer chain proceeded continuously in one direction, like the ''domino effect.'' Our method allowed dynamic imaging of single polymer chains at a solid/ liquid interface, and hence can be applied to the study of many types of polymers. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: [4103][4104][4105][4106][4107] 2010

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Direct measurements of absolute concentration and lifetime of singlet oxygen in the gas phase by electron paramagnetic resonance

Cited by 28 publications

References 23 publications

New Singlet Oxygen Donors Based on Naphthalenes: Synthesis, Physical Chemical Data, and Improved Stability

New Singlet Oxygen Donors Based on Naphthalenes: Synthesis, Physical Chemical Data, and Improved Stability

Time-Resolved EPR Study of Singlet Oxygen in the Gas Phase

Single‐molecule imaging of photodegradation reaction in a chiral helical π‐conjugated polymer chain

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