Spectral Observation of Singlet Molecular Oxygen From Aromatic Endoperoxides in Solution

Wilson, Thérèse; Khan, Ahsan U.; Mehrotra, Mukund M.

doi:10.1111/j.1751-1097.1986.tb05643.x

Cited by 15 publications

(11 citation statements)

References 8 publications

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“…The corresponding possibilities in the case of a "dark" photomedicine would include the use of antibody-dioxetane (--> triplet carbonyls) and antibody-endoperoxide (--> l~g 102) conjugates. Thus appropriate endoperoxides may release 102 at a significant rate even at relatively low temperatures (Wilson et al, 1986), which, incidentally, rises the question as to whether the antitumor properties of the endoperoxide of provitamin D (Matsueda and Katsukura, 1985) and the well-known antihelmintic ~roperties of the a-terpinene-derived ascaridole may be due to release of 02'…”

Section: Discussionmentioning

confidence: 99%

Photobiochemistry without Light: Intracellular Generation and Transfer of Electronic Energy

Cilento

1988

Light in Biology and Medicine

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Section: Discussionmentioning

confidence: 99%

Photobiochemistry without Light: Intracellular Generation and Transfer of Electronic Energy

Cilento

1988

Light in Biology and Medicine

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“…30 Some MOA is unavoidably present during measurements 50 performed at room temperature. 28,30 A lifetime of τ 1/e = 69 min at 325 K for MOA-O 2 has been reported previously.…”

Section: Spin Polarization Of Otempo Under Photolysis Of Moa-omentioning

confidence: 99%

“…It is well-known that photolysis of endoperoxides leads to formation of 1 O 2 28,30 (Scheme 1). In addition, O-O cleavage can occur as side reaction upon photolysis, which forms rearrangement products of endoperoxides (not shown in Scheme 1).…”

Section: Spin Polarization Of Otempo Under Photolysis Of Ma-omentioning

confidence: 99%

“…1 Initial investigations involving 20 radicals interacting in solution with photoexcited organic species [2][3][4] led to the development of the radical-triplet pair mechanism (RTPM) with Shushin making a significant contribution into the theory of RTPM. 16 In general, in non-viscous solvents quenching of excited triplet states (in Boltzmann equilibrium) of organic molecules by a stable radical (nitroxide) leads to net 30 emissive (E) polarization of the ESR signal of the nitroxide, whereas quenching of excited singlet states leads to net absorptive (A) polarization of nitroxide. 16 In general, in non-viscous solvents quenching of excited triplet states (in Boltzmann equilibrium) of organic molecules by a stable radical (nitroxide) leads to net 30 emissive (E) polarization of the ESR signal of the nitroxide, whereas quenching of excited singlet states leads to net absorptive (A) polarization of nitroxide.…”

Section: Introductionmentioning

confidence: 99%

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Photolysis of endoperoxides in the presence of nitroxides: a laser flash photolysis study with optical and ESR detection

Moscatelli

Sartori

Ruzzi

et al. 2014

Photochem Photobiol Sci

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Time-resolved electron paramagnetic resonance spectroscopy, transient absorption, and phosphorescence spectroscopy were used to investigate the spin polarization of a nitroxide free radical induced by interaction with singlet oxygen ((1)O2). The latter was generated by photolysis of endoperoxides of two anthracene derivatives. Although both anthracene endoperoxides are structurally similar, opposite spin polarization of the nitroxide was observed. Photolysis of one endoperoxide leads to absorptive nitroxide spin polarization due to interaction with the generated (1)O2. Photolysis of the other endoperoxide generated emissive nitroxide spin polarization, probably due to interaction of the endoperoxide triplet states with nitroxides.

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“…1,2 The corresponding light-mediated O 2 -adducts of such systems have been utilized for the targeted release of reactive oxygen species such as singlet oxygen. 3,4 Furthermore, the photochemical generation of oxygen-based biradical species from aromatic endoperoxide species has also been investigated in some detail. 5,6 Important biomedical and chemotherapeutic applications of such systems include the delayed triggering of singlet oxygen release, which can induce cellular damage in malignant tissue, 1 and the potential utilization of biomimetic endoperoxide-bond cleavage processes for the controlled deactivation of bacteria, viruses 7 and parasites such as Plasmodium falciparum, which is known to be responsible for the majority of fatal malaria infections.…”

Section: Introductionmentioning

confidence: 99%

Functionalized derivatives of 1,4-dimethylnaphthalene as precursors for biomedical applications: synthesis, structures, spectroscopy and photochemical activation in the presence of dioxygen

et al. 2012

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Decomposition of endoperoxide containing molecules is an attractive approach for the delayed release of singlet oxygen under mild reaction conditions. Here we describe a new method for the adaptation of the corresponding decay times by controlling the supramolecular functional structure of the surrounding matrix in the immediate vicinity of embedded singlet oxygen precursors. Thus, a significant prolongation of the lifetime of the endoperoxide species is possible by raising the energy barrier of the thermal 1 O 2 -releasing step via a restriction of the free volume of the applied carrier material. Enabling such a prolonged decomposition period is crucial for potential biomedical applications of endoperoxide containing molecules, since sufficient time for appropriate cell uptake and transport to the desired target region must be available under physiological conditions before the tissue damaging-power of the reactive oxygen species formed is completely exhausted. Two novel polyaromatic systems for the intermediate storage and transport of endoperoxides and the controlled release of singlet oxygen in the context of anticancer and antibiotic activity have been prepared and characterized. These compounds are based on functionalized derivatives of the 1,4-dimethylnaphthalene family which are readily forming metastable endoperoxide species in the presence of dioxygen, a photosensitizer molecule such as methylene blue and visible light. In contrast to previously known systems of similar photoreactivity, the endoperoxide carrying molecules have been designed with optimized molecular properties in terms of potential chemotherapeutic applications. These include modifications of polarity to improve their incorporation into various biocompatible carrier materials, the introduction of hydrogen bonding motifs to additionally influence the endoperoxide decay kinetics, and the synthesis of bifunctional derivatives to enable synergistic effects of multiple singlet oxygen binding sites with an enhanced local concentration of reactive species. With these compounds, a promising degree of endoperoxide stability adjustment within the carrier matrix has been achieved ( polymer films or nanoparticles), which now opens the stage for appropriate targeting of the corresponding pro-drugs into live cells. First results on cytocidal and cytostatic properties of these compounds embedded in ethylcellulose nanoparticles are presented. Furthermore, an efficient low-cost method for the photochemical production of reactive endoperoxides based on high-power 660 nm LED excitation at room temperature and ambient conditions in ethanol solution is reported.

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Spectral Observation of Singlet Molecular Oxygen From Aromatic Endoperoxides in Solution

Abstract: Abstract— The characteristic near‐infrared emission band of O2 (1Δg) at 1.28 μm has been recorded from carbon tetrachloride solutions of the 1, 4‐endoperoxides of 1,4‐dimethyInaphthalene and 1, 4‐dimethoxy‐9.10‐diphenylanthracene undergoing thermal decomposition.

Cited by 15 publications

References 8 publications

Photobiochemistry without Light: Intracellular Generation and Transfer of Electronic Energy

Photobiochemistry without Light: Intracellular Generation and Transfer of Electronic Energy

Photolysis of endoperoxides in the presence of nitroxides: a laser flash photolysis study with optical and ESR detection

Functionalized derivatives of 1,4-dimethylnaphthalene as precursors for biomedical applications: synthesis, structures, spectroscopy and photochemical activation in the presence of dioxygen

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