C-nitroso compounds. Part I. The formation of nitroxides by photolysis of nitroso compounds as studied by electron spin resonance.

Mackor, A.; Wajer, Th. A. J. W.; Boer, Th. J. de; Voorst, J.D.W. van

doi:10.1016/s0040-4039(00)72808-5

Cited by 86 publications

(18 citation statements)

References 9 publications

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“…Photochromic molecules that show homolysis generate open-shell radical pairs (or biradicals) upon light irradiation. For example, hexaarylbiimidazole (HABI) is a well-known photochromic compound which generates a pair of triphenylimidazolyl radicals upon UV light irradiation. − 2,3,4,4-Tetrachloro-l-oxo-l,4-dihydronaphthalene (β-TKN) and dimeric nitroso compounds , also show the photoinduced homolysis and generate radical pairs upon light irradiation. Because radical species generated by the photoinduced homolysis have relatively high reactivities, these photochromic materials can be applied to the initiator for radical polymerizations and rate-tunable photoswitching materials …”

Section: Introductionmentioning

confidence: 99%

Photochromic Radical Complexes That Show Heterolytic Bond Dissociation

et al. 2020

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Photochromic materials have been widely used in various research fields because of their variety of photoswitching properties based on various molecular frameworks and bond breaking processes, such as homolysis and heterolysis. However, while a number of photochromic molecular frameworks have been reported so far, there are few reports on photochromic molecular frameworks that show both homolysis and heterolysis depending on the substituents with high durability. The biradicals and zwitterions generated by homolysis and heterolysis have different physical and chemical properties and different potential applications. Therefore, the rational photochromic molecular design to control the bond dissociation in the excited state on demand expands the versatility for photoswitch materials beyond the conventional photochromic molecular frameworks. In this study, we synthesized novel photochromic molecules based on the framework of a radical-dissociationtype photochromic molecule: phenoxyl-imidazolyl radical complex (PIC). While the conventional PIC shows the photoinduced homolysis, the substitution of a strong electron-donating moiety to the phenoxyl moiety enables the bond dissociation process to be switched from homolysis to heterolysis. This study gives a strategy for controlling the bond dissociation process of the excited state of photochromic systems, and the strategy enables us to develop further novel radical and zwitterionic photoswitches.

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Section: Introductionmentioning

confidence: 99%

Photochromic Radical Complexes That Show Heterolytic Bond Dissociation

et al. 2020

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“…It was over 50 years ago that free radical addition to nitrosoalkanes and nitrones was shown to produce nitroxide radicals, which are relatively stable due to resonance delocalisation along the N-O bond; see Figure 3 [22][23][24][25][26]. Figure 4 shows how the addition of a free radical, X • , produces nitroxyl radicals from nitrones and nitrosoalkanes.…”

Section: Electron Paramagnetic Resonance (Epr) and Spin Trappingmentioning

confidence: 99%

Section: Electron Paramagnetic Resonance (Epr) and Spin Trappingmentioning

confidence: 99%

“…Overall, while BR shows no fluorescence itself, three photochemical reactions of bilirubin occur: photooxidation, configurational isomerization, and structural isomerization [57]. The configurational isomerization leads to the production of Z,E iso-BM-DBM + 1 O 2 (22) Clearly, to overcome this problem, other (anti-oxidant) molecules which can efficiently remove (quench) the triplet states are worthwhile. Many combinations of sunscreensusually mixing UVB absorbers with BM-DBM-have been considered [72,75] to improve photostability.…”

Section: Neonatal Jaundicementioning

confidence: 99%

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The Reactive Oxygen Species Singlet Oxygen, Hydroxy Radicals, and the Superoxide Radical Anion—Examples of Their Roles in Biology and Medicine

Edge

Truscott

2021

Oxygen

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Reactive oxygen species comprise oxygen-based free radicals and non-radical species such as peroxynitrite and electronically excited (singlet) oxygen. These reactive species often have short lifetimes, and much of our understanding of their formation and reactivity in biological and especially medical environments has come from complimentary fast reaction methods involving pulsed lasers and high-energy radiation techniques. These and related methods, such as EPR, are discussed with particular reference to singlet oxygen, hydroxy radicals, the superoxide radical anion, and their roles in medical aspects, such as cancer, vision and skin disorders, and especially pro- and anti-oxidative processes.

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“…Nevertheless, free radicals usually have too short life‐times for detection by EPR spectroscopy. In that case, spin trapping molecules can be used to react covalently with free radicals and form more stable adducts detectable by EPR spectroscopy, which then gives rise to the spin trapping detection method . Wu et al successfully applied the spin trapping technique to dose the reactive oxygen species in a non‐thermal plasma jet.…”

Section: Introductionmentioning

confidence: 99%

A plasma/liquid microreactor for radical reaction chemistry: An experimental and numerical investigation by EPR spin trapping

Zhang

Ognier

Touati

et al. 2017

Plasma Processes & Polymers

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In this paper, a novel plasma/liquid microreactor has been developed to generate and inject radical species with the aim to perform chemical synthesis reactions in liquid phase. Plasma has always been considered as a source of reactive species, such as radicals, atoms, electrons, etc., with applications mostly dedicated to surface modifications of materials. By injecting reactive species created by the plasma to the liquid phase, it is possible to initiate liquid phase synthesis reactions. In addition, gas/liquid interactions can be enhanced with a high surface‐area‐to‐volume ratio by confining the plasma and the liquid in diphasic micro‐structured systems. Herein is reported a novel plasma/liquid microreactor for liquid phase radical reactions. Radicals are generated in the gas phase in a steady flow microreactor and then transported to the liquid phase. The spin trapping reaction and the electron paramagnetic resonance (EPR) spectroscopy have been used to identify and quantify the radical species generated in the microreactor. Hydroxyl radicals and hydrogen atoms have been detected and measured in the liquid phase, indicating the huge potential of the microreactor as a handful tool for chemical synthesis.

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C-nitroso compounds. Part I. The formation of nitroxides by photolysis of nitroso compounds as studied by electron spin resonance.

Cited by 86 publications

References 9 publications

Photochromic Radical Complexes That Show Heterolytic Bond Dissociation

Photochromic Radical Complexes That Show Heterolytic Bond Dissociation

The Reactive Oxygen Species Singlet Oxygen, Hydroxy Radicals, and the Superoxide Radical Anion—Examples of Their Roles in Biology and Medicine

A plasma/liquid microreactor for radical reaction chemistry: An experimental and numerical investigation by EPR spin trapping

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