scholarly journals Excited States in Electron-Transfer Reaction Products: Ultrafast Relaxation Dynamics of an Isolated Acceptor Radical Anion

2011 ◽  
Vol 115 (30) ◽  
pp. 8369-8374 ◽  
Author(s):  
Daniel A. Horke ◽  
Gareth M. Roberts ◽  
Jan R. R. Verlet
Keyword(s):  
Electron Transfer ◽  
Excited States ◽  
Radical Anion ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Relaxation Dynamics ◽  
Reaction Products ◽  
Ultrafast Relaxation

Elektronentransfer und Ionenpaar-Bildung, 48 [1] Titrationen von Tetraphenyl-p-benzochinon mit Natrium- und Kaliummetall in aprotischen Lösungen / Electron Transfer and Ion Pair Formation, 48 [ 1 ] Titrations of Tetraphenyl-p-benzoquinone with Sodium and Potassium Metals in Aprotic Solutions

1996 ◽  
Vol 51 (9) ◽  
pp. 1222-1228 ◽  
Author(s):  
Hans Bock ◽  
Markus Kleine
Keyword(s):  
Electron Transfer ◽  
Radical Anion ◽  
Esr Spectra ◽  
Electron Transfer Reaction ◽  
Ion Pair ◽  
Pair Formation ◽  
Reaction Products ◽  
Ion Pair Formation ◽  
Electron Reduction ◽  
Sodium And Potassium

UV/VIS and ESR spectra of electron transfer reaction products in aprotic (cH⊕ < 0,1 ppm) solution can be measured in an especially designed and sealed glass apparatus and provide information on unknown facets of the microscopic pathway through the network of interdependent equilibria. For tetraphenyl-p-benzoquinone in tetrahydrofuran, single-electron reduction by a sodium metal mirror produces a red solution and, unexpectedly, after addition of 2.2.2. cryptand, contact with a potassium metal mirror generates a green (!) one. For both, ESR/ENDOR spectra prove the presence of tetraphenyl-p-benzoquinone radical anion. UV/VIS measurements provide the clue: In the equilibrium revealed by repetetive spectra recording, M·⊖solv + Me⊕solv ⇄ [M·⊖···Me⊖]solv, the radical anion is green (vm = 16900 cm-1) and the contact ion pair red (vm=18900 cm-1 ). On ion pair formation, therefore, the excitation energy of the radical anion increases by 0.25 eV.

Regioselective Dye-Induced Photocleavage of Epoxides as an Alternative Mild Synthetic Route to a Targeted Alcohol Functionality

2015 ◽  
Vol 68 (3) ◽  
pp. 500 ◽  
Author(s):  
Anthony A. Provatas ◽  
Gary A. Epling ◽  
James D. Stuart ◽  
Aliaksandr Yeudakimau
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Ring Opening ◽  
Radical Anion ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Hydroxyl Group ◽  
Synthetic Approach ◽  
Synthetic Route ◽  
Toxic Dyes

The regioselective cleavage of epoxides using visible light and a catalytic dye is reported in this study as an alternative mild synthetic approach. The epoxide radical anion is generated via visible light in an electron transfer reaction, induced by non-toxic dyes, leading to ring opening and formation of the corresponding alcohol with the hydroxyl group on the less substituted carbon in excellent yields.

scholarly journals Kinetics and Mechanism of Oxidation of L-Ascorbic Acid by Pt(IV)(aq) in Aqueous Hydrochloric Acid Medium

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Sadhana Senapati ◽  
S. P. Das ◽  
A. K. Patnaik
Keyword(s):  
Electron Transfer ◽  
Ascorbic Acid ◽  
Acid Medium ◽  
Redox Reaction ◽  
Transfer Reaction ◽  
Total Concentration ◽  
Activation Parameters ◽  
Order Rate Constant ◽  
Electron Transfer Reaction ◽  
Reaction Products

Reduction of [PtCl6]2− by L-ascorbic acid (H2ASc) in 0.1 M aqueous acid medium has been investigated spectrophotometrically under pseudo-first order condition at [PtCl6]2− = 0.005–0.007 mol dm−3, 0.05 ≤ [H2ASc]/mol dm−3 ≤ 0.3, 298 K ≤ T ≤ 308 K, [H+] = 0.14 mol dm−3, I=0.5 mol dm−3. The redox reaction follows the rate law: d[Pt(IV)]/dt = k[H2ASc][Pt(IV)], where k is the second-order rate constant and [H2ASc] is the total concentration of ascorbic acid. Electron transfer from [H2ASc] to Pt(IV) center leading to the release of two halide ions and formation of the reaction products, square planner Pt(II) halide complex, and dehydrated ascorbic acid is suggested. This redox reaction follows an outersphere mechanism as Pt(IV) complex is substituted inert. Activation parameters were calculated corresponding to rate of electron transfer reaction k. Activation parameters favor the electron transfer reaction.

scholarly journals Electron transfer studies of a conventional redox probe in human sweat and saliva bio-mimicking conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Krishnaveni ◽  
V. Ganesh
Keyword(s):  
Electron Transfer ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Redox Couple ◽  
Liquid Crystalline Phase ◽  
Transfer Reactions ◽  
Redox Probe ◽  
Human Sweat

AbstractModern day hospital treatments aim at developing electrochemical biosensors for early diagnosis of diseases using unconventional human bio-fluids like sweat and saliva by monitoring the electron transfer reactions of target analytes. Such kinds of health care diagnostics primarily avoid the usage of human blood and urine samples. In this context, here we have investigated the electron transfer reaction of a well-known and commonly used redox probe namely, potassium ferro/ferri cyanide by employing artificially simulated bio-mimics of human sweat and saliva as unconventional electrolytes. Typically, electron transfer characteristics of the redox couple, [Fe(CN)6]3−/4− are investigated using electrochemical techniques like cyclic voltammetry and electrochemical impedance spectroscopy. Many different kinetic parameters are determined and compared with the conventional system. In addition, such electron transfer reactions have also been studied using a lyotropic liquid crystalline phase comprising of Triton X-100 and water in which the aqueous phase is replaced with either human sweat or saliva bio-mimics. From these studies, we find out the electron transfer reaction of [Fe(CN)6]3−/4− redox couple is completely diffusion controlled on both Au and Pt disc shaped electrodes in presence of sweat and saliva bio-mimic solutions. Moreover, the reaction is partially blocked by the presence of lyotropic liquid crystalline phase consisting of sweat and saliva bio-mimics indicating the predominant charge transfer controlled process for the redox probe. However, the rate constant values associated with the electron transfer reaction are drastically reduced in presence of liquid crystalline phase. These studies are essentially carried out to assess the effect of sweat and saliva on the electrochemistry of Fe2+/3+ redox couple.

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