674783-97-2Relevant academic research and scientific papers
Photocatalytic electron-transfer oxidation of triphenylphosphine and benzylamine with molecular oxygen via formation of radical cations and superoxide ion
Ohkubo, Kei,Nanjo, Takashi,Fukuzumi, Shunichi
, p. 1489 - 1500 (2006)
Photooxygenation of triphenylphosphine (Ph3P) to triphenylphosphine oxide (Ph3P=O) with molecular oxygen (O 2) occurs under photoirradiation of 9-mesityl-10-methylacridinium perchlorate ([Acr+-Mes]ClO4-) which acts as an efficient electron-transfer photocatalyst. Photooxidation of benzylamine (PhCH2NH2) with O2 also occurs efficiently under photoirradiation of Acr+-Mes to yield PhCH2N=CHPh and hydrogen peroxide (H2O2). Each photocatalytic reaction is initiated by intramolecular photoinduced electron transfer from the Mes moiety to the singlet excited state of the Acr+ moiety to produce the electron-transfer state (Acr?-Mes?+). The Mes?+ moiety oxidizes Ph3P and PhCH 2NH2 to produce the radical cations (Ph3P ?+ and PhCH2NH2?+, respectively), whereas the Acr? moiety reduces O2 to O2?+. The produced Ph3P?+ binds with O2?+ as well as O2, leading to the oxygenated product (Ph3P=O). On the other hand, proton transfer from PhCH2NH2?+ to O2 ?+ occurs, followed by hydrogen transfer, leading to the dehydrogenated dimer product, PhCH2N=CHPh. In each case, the radical intermediates were detected by laser flash photolysis and ESR measurements to clarify the photocatalytic mechanism.
Photoinduced Electron Transfer in 9-Substituted 10-Methylacridinium Ions
Tsudaka, Takeshi,Kotani, Hiroaki,Ohkubo, Kei,Nakagawa, Tatsuo,Tkachenko, Nikolai V.,Lemmetyinen, Helge,Fukuzumi, Shunichi
, p. 1306 - 1317 (2017)
A series of 9-substituted 10-methylacridinium ions (Acr+-R) in which an electron-donor moiety (R) is directly linked with an electron-acceptor moiety (Acr+) at the 9-position was synthesized, and the photodynamics was fully investigated to determine the rate constants of photoinduced electron transfer (ET) and back electron transfer. The driving forces of photoinduced electron transfer and back electron transfer were determined by means of electrochemical and photophysical measurements. The dependence of the ET rate constants on driving force was well analyzed in the light of the Marcus theory of ET. The quantum yields of formation of the triplet ET states vary significantly, depending on the interaction between the donor (R) and acceptor (Acr+) moieties. Among the Acr+-R examined, the 9-mesityl-10-methylacridinium ion (Acr+-Mes) exhibits the best performance in terms of the lifetime of the triplet ET state and the quantum yield. Photoexcitation of Acr+-Mes results in formation of the triplet ET state [3(Acr.-Mes.+)], which has a long lifetime, a high energy (2.37 eV), and a high quantum yield (>75 %) in acetonitrile. The triplet ET state exhibits both the oxidizing and reducing activity of the Mes.+and Acr.moieties, respectively.
Synthesis of dibenzocycloketones by acyl radical cyclization from aromatic carboxylic acids using methylene blue as a photocatalyst
Jiang, Hongshuo,Mao, Guijie,Wu, Hongfeng,An, Qi,Zuo, Minghui,Guo, Weihao,Xu, Chunzhao,Sun, Zhizhong,Chu, Wenyi
supporting information, p. 5368 - 5373 (2019/10/11)
An efficient intramolecular radical cyclization reaction via photoredox catalysis was developed for the synthesis of dibenzocycloketone derivatives using methylene blue as a photosensitizer. This strategy could be widely used to synthesize large heterocycles due to the unique reactivity of phosphoranyl radicals formed by a polar/SET crossover between an aromatic carboxylic acid and a phosphine radical cation. Attractive features of this process include generation of an acyl radical by an inexpensive and metal-free photocatalyst, which effectively undergoes a cyclization process.
Photocatalytic Construction of S-S and C-S Bonds Promoted by Acridinium Salt: An Unexpected Pathway to Synthesize 1,2,4-Dithiazoles
Huang, Xiao-Ying,Ding, Rui,Mo, Zu-Yu,Xu, Yan-Li,Tang, Hai-Tao,Wang, Heng-Shan,Chen, Yan-Yan,Pan, Ying-Ming
supporting information, p. 4819 - 4823 (2018/08/24)
An unexpected cyclization of thioamides with p-quinone methides promoted by acridinium salt under the irradiation of visible light furnished 1,2,4-dithiazoles in moderate to good yields. In addition, the reaction of the obtained 1,2,4-dithiazoles with isocyanides offered a new entry for the synthesis of thiazol-5(4H)-imines in moderate yields.
Synthesis of highly substituted tetrahydrofurans by catalytic polar-radical-crossover cycloadditions of alkenes and alkenols
Grandjean, Jean-Marc M.,Nicewicz, David A.
supporting information, p. 3967 - 3971 (2013/05/09)
Light up my ring: The title reaction is catalyzed by an acridinium/phenylmalononitrile photoredox system. A variety of readily available olefins and unsaturated alcohols can be employed to furnish tetrahydrofuran adducts with complete regiocontrol and up to four contiguous stereogenic centers.
Direct catalytic anti-markovnikov hydroetherification of alkenols
Hamilton, David S.,Nicewicz, David A.
supporting information, p. 18577 - 18580 (2013/01/15)
A direct intramolecular anti-Markovnikov hydroetherification reaction of alkenols is described. By employing catalytic quantities of commercially available 9-mesityl-10-methylacridinium perchlorate and 2-phenylmalononitrile as a redox-cycling source of a
Photocatalytic oxygenation of anthracenes and olefins with dioxygen via selective radical coupling using 9-mesityl-10-methylacridinium ion as an effective electron-transfer photocatalyst
Kotani, Hiroaki,Ohkubo, Kei,Fukuzumi, Shunichi
, p. 15999 - 16006 (2007/10/03)
Visible light irradiation of the absorption band of 9-mesityl-10- methylacridinium ion (Acr+-Mes) in an O2-saturated acetonitrile (MeCN) solution containing 9,10-dimethylanthracene results in formation of oxygenation product, i.e., dimethylepidioxyanthracene (Me 2An-O2). Anthracene and 9-methylanthracene also undergo photocatalytic oxygenation with Acr+-Mes to afford the corresponding epidioxyanthracenes under the photoirradiation. In the case of anthracene, the further photoirradiation results in formation of anthraquinone as the final six-electron oxidation product, via 10-hydroxyanthrone, accompanied by generation of H2O2. When anthracene is replaced by olefins (tetraphenylethylene and tetramethylethylene), the photocatalytic oxygenation of olefins affords the corresponding dioxetane, in which the O-O bond is cleaved to yield the corresponding ketones. The photocatalytic oxygenation of anthracenes and olefins is initiated by photoexcitation of Acr+-Mes, which results in formation of the electron-transfer state: Acr?- Mes?+, followed by electron transfer from anthracenes and olefins to the Mes?+ moiety together with electron transfer from the Acr? moiety to O2. The resulting anthracene and olefin radical cations undergo the radical coupling reactions with O 2?- to produce the epidioxyanthracene (An-O 2) and dioxetane, respectively.
