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.
Photochemical Reactions of Bromoanthraquinones in Ethanol at Room Temperature Studied by Steady-State Photolysis and Laser Photolysis
Hamanoue, Kumao,Nakayama, Toshihiro,Sawada, Kazuhide,Yamamoto, Yoshiaki,Hirase, Susumu,Teranishi, Hiroshi
, p. 2735 - 2742 (1986)
Photolyses of α-bromoanthraquinones (1-bromo-, 1,5-dibromo- and 1,8-dibromoanthraquinones) with 366 nm light in ethanol at room temperature gave rise to the formation of debrominated 9,10-anthracenediol as a final product.This was interpreted in terms of the sequence of the formation of α-bromo-9,10-anthracenediols followed by the photochemical dehydrobromination yielding the corresponding anthraquinones with one less bromine atom than original ones.Photolysis of 2-bromoanthraquinone gave rise to the formation of 2-bromo-9,10-anthracenediol, and no dehydrobromination was observed.Combined with the values of the quantum yields of photoreduction, the results of the laser photolyses revealed that the rate constant for the hydrogen-atom abstraction from ethanol decreased as an increase of the ??* character of the lowest triplet states of a α-bromoanthraquinones.
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.
Formation of Anthrahydroquinones (XAQH2) via Excited Singlet Charge-transfer Complexes (or Singlet Ion Pairs) of Anthraquinones with 2,5-Dimethylhexa-2,4-diene (DMHD), and Photochemical Reaction of XAQH2 with DMHD
Nakayama, Toshihiro,Nakamura, Noriyasu,Miki, Sadao,Hamanoue, Kumao
, p. 607 - 614 (1995)
Upon picosecond excitation of a ground-state complex formed between anthraquinone (AQ, a typical planar molecule) and 2,5-dimethylhexa-2,4-diene (DMHD), an excited singlet charge-transfer complex 1(AQδ--DMHDδ+)*> or a singlet ion pair 1(AQ.--DMHD.+)> is produced within the duration of the excitation light pulse.This transient complex decays following a single-expotential function with a lifetime of 90 ps and the decay process is ascribed to the intracomplex proton transfer, yielding the semiquinone radical of AQ and the 2,5-dimethylhexa-2,4-dienyl radical.A similar result has been obtained for non-planar 1,8-dichloroanthraquinone (cf.Hamanoue et al., J.Photochem.Photobiol.A: Chem., 1993, 76, 7), and so nanosecond laser photolysis of XAQ (anthraquinone or 1,8-dichloroanthraquinone) has also been performed and the second-order decay rate constant of the semiquinone radical (XAQH(1.) of XAQ generated in DMHD-toluene is found to be one order of magnitude greater than that generated in ethanol without DMHD.Hence, it is concluded that XAQH(1.) abstracts a hydrogen atom from the 2,5-dimethylhexa-2,4-dienyl radical yielding a photoreduced product (XAQH2, i.e. anthrahydroquinone or 1,8-dichloroanthrahydroquinone) and a biradical of DMHD; probably the reactions of this biradical yield the dimeric and oligomeric compounds of DMHD.Although steady-state photolysis of XAQ in neat DMHD causes the disappearance of the reactant absorption without the accompanying formation of XAQH2, examination of the effect of DMHD concentration on the formation of XAQH2 upon steady-state photolysis of XAQ in DMHD-toluene (or benzene) reveals that XAQH2 disappears by its photochemical reaction with ground-state DMHD.For anthrahydroquinone, the formation of 4',4'-dimethyl-3'-(2-methylprop-1-en-1-yl)spiro-9(10H)-one is confirmed.
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.
Solvent Effects on the Formation and Decay of Ionic Intermediates for the Photoreduction of Anthraquinone by Triethylamine in Ethanol, Toluene, and Acetonitrile at Room Temperature
Hamanoue, Kumao,Nakayama, Toshihiro,Sasaki, Hideyuki,Ikenaga, Koichiro,Ibuki, Kazuyasu
, p. 3141 - 3148 (1992)
In toluene and ethanol containing triethylamine (TEA), a reaction of the lowest excited triplet state 3AQ(T1)> of anthraquinone (AQ) with ground-state TEA gave rise to the formation of an exciplex 3(AQ-TEA)*> which converted into a contact ion pair between the AQ radical anion (AQ-.) and the TEA radical cation (TEA+.).By an intramolecular proton transfer, this contact ion pair yielded anthrasemiquinone radical followed by the formation of 9,10-anthracenediol (AQH2); in ethanol, the monoanion (AQH-) of AQH2 was also produced.In ethanol TEA, moreover, not only the decay rate constant of 3(AQ-TEA)* but also the quantum yield for the photoreduction of AQ were affected by the change of TEA concentration.This was interpreted in terms of the existence of a rapid interconversion between 3(AQ-TEA)* and a triplex 3(AQ-TEA2)*> of 3AQ(T1) with ground-state TEA.In contrast to the exciplex formation in ethanol and toluene, free AQ-anion radical (and TEA-cation radical) and 3(AQ-TEA)* 3(AQ-TEA)* or the contact (or solvent-separated) ion pair dissocited into the radical ions (AQ-anion radical and TEA-cation radical) followed by their second-order reaction yielding finally AQH2 and AQH-.
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.
Mechanism of С-Н cyclization of alkynylanthraquinones into thienoanthraquinones with the participation of sodium sulfide
Fedenok, Lidiya,Dultsev, Fedor,Barabanov, Igor,Polyakov, Nikolay
, p. 6334 - 6340 (2017)
The CH-cyclization of alkynyl-9,10-anthraquinones 1 into thienoanthraquinones 2 is shown to be initiated by the neutral S2 molecule and not by the sulfide anion as it is assumed in the existing model of CH-cyclization with the nucleophiolic substitution of H. The formation of S2 takes place in the reaction medium due to the partial reduction of the substrate 1 by Na2S into the corresponding anthrahydroquinone, which is inactive in the main reaction. We present a new cyclization mechanism with the key stage involving the electrophilic displacement of H, which results in the formation of the reaction product 2 and elimination of S. In the reaction medium atomic sulfur is transformed into S2, which initiates the next cyclization act. This determines the chain nature of cyclization with the participation of S2. Within this model, the route to increase the yield of target thienoanthraquinones is proposed through the introduction of a neutral quinone able to generate S2 by means of easy reduction.
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.
Anthraquinone thin-film electrodes for reversible CO2 capture and release
Wielend, Dominik,Apaydin, Dogukan Hazar,Sariciftci, Niyazi Serdar
, p. 15095 - 15101 (2018)
We report reversible electrochemical capture and release of carbon dioxide using the well-known dye precursor and industrial catalyst anthraquinone. Although quinones are well-studied for electrochemical capture and release of CO2 in solution, we have discovered that a 100 nm film of anthraquinone can realize this in a heterogeneous fashion. In-depth spectroelectrochemical studies were performed in order to study the mechanism of this CO2 capture and release. Anthraquinone films reached an uptake capacity of 5.9 mmolCO2 gAQ-1.
