The influence of bridge-reduced state levels on the electron transfer within the 2,7-dinitroanthracene radical anion

2015 ◽  
Vol 17 (6) ◽  
pp. 4038-4041 ◽  
Author(s):  
J. P. Telo ◽  
Á. Moneo
Keyword(s):  
Electron Transfer ◽  
Radical Anion ◽  
Redox State ◽  
Electronic Coupling ◽  
Reduced State

The 2,7-dinitroanthracene radical anion has an (apparent) electronic coupling much higher than either itsN,Ndistance or its non-Kekule substitution would suggest. The results can only be explained if a low-lying bridge redox state is influencing the electron transfer.

scholarly journals Effect of Electronic Coupling on Electron Transfer Rates from Photoexcited Naphthalenediimide Radical Anion to Re(bpy)(CO)3X

2019 ◽  
Vol 123 (16) ◽  
pp. 10178-10190 ◽  
Author(s):  
Jose F. Martinez ◽  
Nathan T. La Porte ◽  
Subhajyoti Chaudhuri ◽  
Alessandro Sinopoli ◽  
Youn Jue Bae ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Radical Anion ◽  
Electronic Coupling ◽  
Transfer Rates

Concerted double proton-transfer electron-transfer between catechol and superoxide radical anion

2017 ◽  
Vol 19 (38) ◽  
pp. 26179-26190 ◽  
Author(s):  
Jorge Quintero-Saumeth ◽  
David A. Rincón ◽  
Markus Doerr ◽  
Martha C. Daza
Keyword(s):  
Electron Transfer ◽  
Proton Transfer ◽  
Superoxide Anion ◽  
Radical Anion ◽  
Reaction Rate ◽  
Superoxide Radical ◽  
Superoxide Radical Anion ◽  
Double Proton Transfer

Catechol reacts with a superoxide anion via concerted double proton-transfer electron-transfer with a reaction rate that is dominated by tunneling.

Dual electron transfer pathways from the excited C60 radical anion: enhanced reactivities due to the photoexcitation of reaction intermediates

2015 ◽  
Vol 17 (46) ◽  
pp. 31030-31038 ◽  
Author(s):  
Mamoru Fujitsuka ◽  
Tatsuya Ohsaka ◽  
Tetsuro Majima
Keyword(s):  
Electron Transfer ◽  
Radical Anion ◽  
Reaction Intermediates ◽  
Electron Transfer Pathways

The excited C60 radical anion showed enhanced electron transfer.

Estimation of Electronic Coupling for Intermolecular Electron Transfer from Cross-Reaction Data

2006 ◽  
Vol 110 (41) ◽  
pp. 11665-11676 ◽  
Author(s):  
Stephen F. Nelsen ◽  
Michael N. Weaver ◽  
Yun Luo ◽  
Jack R. Pladziewicz ◽  
Logan K. Ausman ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Cross Reaction ◽  
Electronic Coupling ◽  
Intermolecular Electron Transfer ◽  
Reaction Data

Radical ions in photochemistry. 21. The photosensitized (electron transfer) tautomerization of alkenes; the phenyl alkene system

1989 ◽  
Vol 67 (4) ◽  
pp. 689-698 ◽  
Author(s):  
Donald R. Arnold ◽  
Shelley A. Mines
Keyword(s):  
Hydrogen Bond ◽  
Electron Transfer ◽  
Radical Cation ◽  
Radical Anion ◽  
Phenyl Group ◽  
Oxidation Potential ◽  
Original Position ◽  
Acetonitrile Solution ◽  
Steric Interaction ◽  
Ambident Anion

Alkenes, conjugated with a phenyl group, can be converted to nonconjugated tautomers by sensitized (electron transfer) irradiation. For example, irradiation of an acetonitrile solution of the conjugated alkene 1-phenylpropene, the electron accepting photosensitizer 1,4-dicyanobenzene, the cosensitizer biphenyl, and the base 2,4,6-trimethylpyridine gave the nonconjugated tautomer 3-phenylpropene in good yield. Similarly, 2-methyl-1-phenylpropene gave 2-methyl-3-phenylpropene, and 1-phenyl-1-butene gaveE- and Z-1-phenyl-2-butene. The reaction also works well with cyclic alkenes. For example, 1-phenylcyclohexene gave 3-phenylcyclohexene, and 1-(phenylmethylene)cyclohexane gave 1-(phenylmethyl)cyclohexene. The proposed mechanism involves the initial formation of the alkene radical cation and the sensitizer radical anion, induced by irradiation of the sensitizer and mediated by the cosensitizer. Deprotonation of the radical cation assisted by the base gives the ambident radical, which is then reduced to the anion by the sensitizer radical anion. Protonation of the ambident anion at the benzylic position completes the sequence. Reprotonation at the original position is an energy wasting step. Tautomerization is driven toward the isomer with the higher oxidation potential, which is, in the cases studied, the less thermodynamically stable isomer. The regioselectivity of the deprotonation step is dependent upon the conformation of the allylic carbon–hydrogen bond. The tautomerization of 2-methyl- 1-phenylbutene gave both 2-phenylmethyl-1-butène and 2-methyl-1-phenyl-2-butene (E and Z isomers), while 2,3-dimethyl- 1-phenylbutene gave only 3-methyl-2-phenylmethyl-1 -butene. In the latter case, steric interaction of the methyls on the isopropyl group prevents effective overlap of the tertiary carbon–hydrogen bond with the singly occupied molecular orbital, thus inhibiting deprotonation from this site. Keywords: photosensitized, electron transfer, alkene, tautomerization, radical cation.

Elektronentransfer und Ionenpaare, 15 [ 1– 3] Radikalanion und Radikal-Kontakt-Ionenpaare von Dimesityl-tetraketon / Electron Transfer and Ion Pairing, 15 [1-3] Radical Anion and Radical Ion Pairs of Dimesityl Tetraketone

1990 ◽  
Vol 45 (8) ◽  
pp. 1197-1204 ◽  
Author(s):  
H. Bock ◽  
P. Hänel ◽  
H.-F. Herrmann
Keyword(s):  
Electron Transfer ◽  
Radical Anion ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Temperature Dependent ◽  
Contact Ion Pairs

The radical anion of dimesityltetraketone (ERed, I = -0.40 V) is easily generated in THF by potassium mirror/[2.2.2]-cryptand reduction. Its contact ion pairs with Na⊕, Cs⊕ and Ba⊕⊕ counter cations, prepared in THF solution by single electron transfer from the respective metals, are characterized by their ESR/ENDOR spectra, which exhibit temperature-dependent metal couplings of aNa⊕ = 0.061 mT (190 K), aCs⊕ = 0.021 mT (190 K), and aBa⊕⊕ = 0.145 mT (295 K).

scholarly journals Controlling Electron Transfer between the Two Cofactor Chains of Photosystem I by the Redox State of One of Their Components

2015 ◽  
Vol 108 (6) ◽  
pp. 1537-1547 ◽  
Author(s):  
Stefano Santabarbara ◽  
Bradford Bullock ◽  
Fabrice Rappaport ◽  
Kevin E. Redding
Keyword(s):  
Electron Transfer ◽  
Photosystem I ◽  
Redox State

scholarly journals IMAGING REDOX STATE HETEROGENEITY WITHIN INDIVIDUAL EMBRYONIC STEM CELL COLONIES

2011 ◽  
Vol 04 (03) ◽  
pp. 279-288 ◽  
Author(s):  
HE N. XU ◽  
RUSSELL C. ADDIS ◽  
DAVIDA F. GOINGS ◽  
SHOKO NIOKA ◽  
BRITTON CHANCE ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Redox State ◽  
Embryonic Stem ◽  
Reduced Form ◽  
Significant Heterogeneity ◽  
Imaging Data ◽  
Mitochondrial Redox State ◽  
Reduced State

Redox state mediates embryonic stem cell (ESC) differentiation and thus offers an important complementary approach to understanding the pluripotency of stem cells. NADH redox ratio (NADH/(Fp + NADH)), where NADH is the reduced form of nicotinamide adenine dinucleotide and Fp is the oxidized flavoproteins, has been established as a sensitive indicator of mitochondrial redox state. In this paper, we report our redox imaging data on the mitochondrial redox state of mouse ESC (mESC) colonies and the implications thereof. The low-temperature NADH/Fp redox scanner was employed to image mESC colonies grown on a feeder layer of gamma-irradiated mouse embryonic fibroblasts (MEFs) on glass cover slips. The result showed significant heterogeneity in the mitochondrial redox state within individual mESC colonies (size: ~200–440 μm), exhibiting a core with a more reduced state than the periphery. This more reduced state positively correlates with the expression pattern of Oct4, a well-established marker of pluripotency. Our observation is the first to show the heterogeneity in the mitochondrial redox state within a mESC colony, suggesting that mitochondrial redox state should be further investigated as a potential new biomarker for the stemness of embryonic stem cells.

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