4981-66-2Relevant articles and documents
DNA-Triggered Enhancement of Singlet Oxygen Production by Pyridinium Alkynylanthracenes
Fudickar, Werner,Bauch, Marcel,Ihmels, Heiko,Linker, Torsten
, p. 13591 - 13604 (2021)
There is an ongoing interest in 1O2 sensitizers, whose activity is selectively controlled by their interaction with DNA. To this end, we synthesized three isomeric pyridinium alkynylanthracenes 2 o–p and a water-soluble trapping reagent for 1O2. In water and in the absence of DNA, these dyes show a poor efficiency to sensitize the photooxygenation of the trapping reagent as they decompose due to electron transfer processes. In contrast, in the presence of DNA 1O2 is generated from the excited DNA-bound ligand. The interactions of 2 o–p with DNA were investigated by thermal DNA melting studies, UV/vis and fluorescence spectroscopy, and linear and circular dichroism spectroscopy. Our studies revealed an intercalative binding with an orientation of the long pyridyl-alkynyl axis parallel to the main axis of the DNA base pairs. In the presence of poly(dA : dT), all three isomers show an enhanced formation of singlet oxygen, as indicated by the reaction of the latter with the trapping reagent. With green light irradiation of isomer 2 o in poly(dA : dT), the conversion rate of the trapping reagent is enhanced by a factor >10. The formation of 1O2 was confirmed by control experiments under anaerobic conditions, in deuterated solvents, or by addition of 1O2 quenchers. When bound to poly(dG : dC), the opposite effect was observed only for isomers 2 o and 2 m, namely the trapping reagent reacted significantly slower. Overall, we showed that pyridinium alkynylanthracenes are very useful intercalators, that exhibit an enhanced photochemical 1O2 generation in the DNA-bound state.
Radical-Pair Dynamics in the Photoreduction of Anthraquinone in Sodium Dodecyl Sulfate Micellar Solution Detected by Pulse-Mode Product-Yield-Detcted Electron Spin Resonance: Temperature and Salt Dependence
Polyakov, Nicolai E.,Okazaki, Masaharu,Konishi, Yoshinari,Toriyama, Kazumi
, p. 15108 - 15113 (1995)
The dynamical behavior of the radical pair (RP) produced in the photoreduction of anthraquinone in sodium dodecyl sulfate (SDS) micellar solutions has been observed at various temperatures and salt concentrations by using the pulse-mode product-yield-detected ESR (PYESR) technique.Trough the numerical calculation of the time-domain PYESR response by the Runge-Kutta method applied to a reaction scheme, dynamical parameters such as the escape rate of the RP (kESC) and the rate of spin trapping directly from the RP (kST) have been obtained.Since these kinetic parameters are very informative for elucidating the micelle dynamics, we may call this method the "spin-pair-probe" technique.
Luminescence of a new Ru(II) polypyridine complex controlled by a redox-responsive protonable anthra[1,10]phenanthrolinequinone
Hartl, Frantisek,Vernier, Sandrine,Belser, Peter
, p. 1891 - 1908 (2005)
Redox-controlled luminescence quenching is presented for a new Ru(II)-bipyridine complex [Ru(bpy)2(1)]2+ where ligand 1 is an anthra[1,10]phenanthrolinequinone. The complex emits from a short-lived metal-to-ligand charge transfer, 3MLCT state (τ = 5.5 ns in deaerated acetonitrile) with a low luminescence quantum yield (5 × 10 -4). The emission intensity becomes significantly enhanced when the switchable anthraquinone unit is reduced to corresponding hydroquinone. On the contrary, chemical one-electron reduction of the anthraquinone moiety to semiquinone in aprotic tetrahydrofuran results in total quenching of the emission.
PHOTOCHEMICAL REACTIONS OF CHLOROANTHRAQUINONES
Hamanoue, Kumao,Yokoyama, Kazuo,Miyake, Takao,Kasuya, Toshihiro,Nakayama, Toshihiro,Teranishi, Hiroshi
, p. 1967 - 1970 (1982)
Irradation of 1,5-dichloroanthraquionone (1,5-DCAQ) with 366 nm light in ethanol gives anthrahydroquinone (AQH2) as a final product.This is interpreted interms of the following cosecutive reactions; 1,5-DCAQ --hν--> 1,5-dichloroanthrahydroquinone --hν--> 1-chloroanthraquinone --hν--> 1-chloroanthrahydroquinone --hν--> anthraquinone --hν--> AQH2.Similar reactions were also observed for other α-chloroanthraquinones.
Th-symmetrical hexakisadducts of C60 with a densely packed π-donor shell can act as energy- or electron-transducing systems
Diekers, Michael,Luo, Chuping,Guldi, Dirk M.,Hirsch, Andreas
, p. 979 - 991 (2002)
For the first time several Th-symmetrical hexakisadducts of C60 bearing up to six electro- and photoactive o-phenylene diamine or 9,10-dialkoxyanthracene moieties were synthesized and subjected to photoinduced electron/energy-transfer studies. Both donors form a densely packed π-donor shell surrounding the fullerene core. In these novel core-shell ensembles (7 and 19), either an efficient energy transfer from the dialkoxyanthracene periphery, or an electron transfer from the o-phenylene diamine periphery transduces the flow of excited-state energy or electrons, respectively, to the fullerene moiety, which resides in the central core. Due to the relatively high reduction potential of the fullerene core, which is anodically shifted by ≈0.7 V, compared with that of pristine C60, the outcome of these intramolecular reactions depends mainly on the donor ability of the peripheral system. Interestingly, the charge-separated state in the o-phenylene diamine heptad (7; τ = 2380 ns in benzonitrile) is stabilized by a factor of 20 relative to the corresponding o-phenylene diamine dyad (6; τ = 120 ns in benzonitrile), an effect that points unequivocally to the optimized storage of charges in this highly functionalized fullerene ensemble.
Bolton et al.
, p. 465,469 (1962)
Intermediates in the cleavage of endoperoxides
Bauch, Marcel,Klaper, Matthias,Linker, Torsten
supporting information, (2017/03/24)
The decomposition of anthracene endoperoxides has been investigated under various conditions. Thermolyses proceed via radical intermediates and afford anthracenes and rearrangement products, depending on the substitution pattern. Interestingly, not only the O–O but also the C–O bond can be cleaved homolytically. Under basic conditions fragmentations take place, affording anthraquinone, and reactive oxygen species. This mechanism explains the often observed decomposition of endoperoxides during work-up. Finally, an acid-catalyzed cleavage has been observed under release of hydrogen peroxide. The results should be interesting for the mechanistic understanding of peroxide decomposition and the endoperoxides might serve as mild sources of reactive oxygen species for future applications. Copyright