Single Electron
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Synthesis ◽  
2021 ◽  
Cuiwen Kuang ◽  
Chuanfa Ni ◽  
Yucheng Gu ◽  
Jinbo Hu

A novel nucleophilic reaction between cyclic ethers and benzyl bromides is achieved under photoredox catalysis. The reaction proceeds through a single electron transfer (SET) pathway rather than a common SN2 mechanism. By two steps of reduction and oxidation, a benzyl bromide heterolyzes to give a carbocation and bromide ion under mild conditions, and then a cyclic ether captures both the carbocation and bromide ion to afford the addition product.

Navyasree Venugopal ◽  
Johannnes Moser ◽  
Margareta Vojtickova ◽  
Ivana Cisařová ◽  
Burkhard Koenig ◽  

N. R. Beysengulov ◽  
J. R. Lane ◽  
J. M. Kitzman ◽  
K. Nasyedkin ◽  
D. G. Rees ◽  

2021 ◽  
Vol 119 (15) ◽  
pp. 153102
H. Howe ◽  
M. Blumenthal ◽  
H. E. Beere ◽  
T. Mitchell ◽  
D. A. Ritchie ◽  

Nano Letters ◽  
2021 ◽  
Mahdi Asgari ◽  
Dominique Coquillat ◽  
Guido Menichetti ◽  
Valentina Zannier ◽  
Nina Diakonova ◽  

Yao Zhou ◽  
Hangya Lv ◽  
Haoxiang Li ◽  
Jingyi Li ◽  
Yunfeng Yan ◽  

Nitroreductases (NTRs) catalyze the reduction of a wide range of nitro-compounds and quinones using NAD(P)H. Although the physiological functions of these enzymes remain obscure, a tentative function of resistance to reactive oxygen species (ROS) via the detoxification of menadione has been proposed. This suggestion is based primarily on the transcriptional or translational induction of an NTR response to menadione, rather than on convincing experimental evidence. We investigated the performance of a fungal NTR from Aspergillus nidulans (AnNTR) exposed to menadione, to address the question of whether NTR is really a ROS defense enzyme. We confirmed that AnNTR was transcriptionally induced by external menadione. We observed that menadione treatment generated cytotoxic levels of O 2 •− , which requires well-known antioxidant enzymes such as superoxide dismutase, catalase, and peroxiredoxin, to protect A. nidulans against menadione-derived ROS stress. However, AnNTR was counterproductive for ROS defense, since knocking out AnNTR decreased the intracellular O 2 •− levels, resulting in fungal viability higher than that of the wild type. This observation implies that AnNTR may accelerate the generation of O 2 •− from menadione. Our in vitro experiments indicated that AnNTR uses NADPH to reduce menadione in a single-electron reaction, and the subsequent semiquinone-quinone redox cycling resulted in O 2 •− generation. We demonstrated that A. nidulans nitroreductase should be a ROS generator, but not a ROS scavenger, in the presence of menadione. Our results clarified the relationship between nitroreductase and menadione-derived ROS stress, which has long been ambiguous. Importance Menadione is commonly used as an O 2 •− generator in studies into oxidative stress responses. However, the precise mechanism through which menadione mediates cellular O 2 •− generation, and the way in which cells respond, remains unclear. Elucidating these events will have important implications for the use of menadione in biological and medical studies. Our results show that the production of Aspergillus nidulans nitroreductase (AnNTR) was induced by menadione. However, the accumulated AnNTR did not protect cells, but instead increased the cytotoxic effect of menadione, through a single-electron reduction reaction. Our finding that nitroreductase is involved in the menadione-mediated O 2 •− generation pathway has clarified the relationship between nitroreductase and menadione-derived ROS stress, which has long been ambiguous.

SynOpen ◽  
2021 ◽  
Addison M Duda ◽  
Michael T Giurini ◽  
Jason G Gillmore ◽  
Thomas F Guarr

Synthetic preparation of carbazoles can be challenging, requiring ring building strategies and/or precious metal catalysts. Presented herein is a method for preparation of carbazoles with the use of inexpensive and reliable hypervalent iodine chemistry. An oxidative single electron transfer (SET) event initiates cyclization for preparation of our trifluoromethyl carbazoles. This method has been shown to be useful for a variety of bis(trifluoromethyl)carbazole isomers that are of primary interest for use as battery materials.

2021 ◽  
Vol 104 (4) ◽  
pp. 33-48
Katsuhiko Nishiguchi ◽  
Kensaku Chida ◽  
Akira Fujiwara

2021 ◽  
Mikhail Ivantsov

Abstract The present work as part of a known task of single-electron atom has been carried out, wherein one mathematical theorem is proved. Herewith an orbital electron was modeled, for which a certain parallelism exists between the highlighted ground state of the atom and special transition states in subatomic structure. Moreover, the ground state in unambiguous solution of fine-structure constant is obtained, where first transition state at the exceptional accordance with proton nucleus can be founded. For here, it is possible to relate the hyper-fine nuclear structure like the Lamb shift of hydrogen atom. In this substantiation of the task, multiply charged states were predicted for a hypothetical nucleus, as in the higher order of meson-boson transitions. The specified approach, in the terms of electric interaction, may be beyond a scope of the existing boson classification, supposedly for the carriers of electroweak interaction.

Qingbao Gong ◽  
Kai Cheng ◽  
Qinghua Wu ◽  
Wanwan Li ◽  
Changjiang Yu ◽  

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