1910-42-5Relevant articles and documents
Stimulus-Mediated Ultrastable Radical Formation
Kuehnel, Moritz F.,McCune, Jade A.,Reisner, Erwin,Scherman, Oren A.
, (2020)
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An Aqueous Redox-Flow Battery with High Capacity and Power: The TEMPTMA/MV System
Janoschka, Tobias,Martin, Norbert,Hager, Martin D.,Schubert, Ulrich S.
, p. 14427 - 14430 (2016)
Redox-flow batteries (RFB) can easily store large amounts of electric energy and thereby mitigate the fluctuating output of renewable power plants. They are widely discussed as energy-storage solutions for wind and solar farms to improve the stability of the electrical grid. Most common RFB concepts are based on strongly acidic metal-salt solutions or poorly performing organics. Herein we present a battery which employs the highly soluble N,N,N-2,2,6,6-heptamethylpiperidinyl oxy-4-ammonium chloride (TEMPTMA) and the viologen derivative N,N′-dimethyl-4,4-bipyridinium dichloride (MV) in a simple and safe aqueous solution as redox-active materials. The resulting battery using these electrolyte solutions has capacities of 54 Ah L?1, giving a total energy density of 38 Wh L?1at a cell voltage of 1.4 V. With peak current densities of up to 200 mA cm?2the TEMPTMA/MV system is a suitable candidate for compact high-capacity and high-power applications.
Aspects of Artificial Photosynthesis. Photosensitized Electron Transfer and Charge Separation in Redox Active Surfactant Aggregates
Kurihara, Kazue,Tundo, Pietro,Fendler, Janos H.
, p. 3777 - 3782 (1983)
Photosensitized electron transfer and charge separation have been demonstrated by steady-state and nanosecond laser flash photolysis in the presence of redox active surfactant aggregates prepared from CH2=C(CH3)COO(CH2)11(C5H4N+)2CH3, Br-, I- (RMV2+).Tris(2,2'-bipyridine)ruthenium chloride (Ru(bpy)32+) has been used as a sensitizer.Forward electron transfer from excited Ru(bpy)32+ to RMV2+ aggregates has been shown to be faster than that from Ru(bpy)32+ to methylviologen (MV2+) in homogeneous solutions.Conversely, the undesirable back-reactionbetween the reduced electron acceptor RMV+. and the oxidized sensitizer Ru(bpy)33+ has been found to be considerably retarded compared to the reaction between MV+. and Ru(bpy)32+.Further, unlike MV+., RMV+. decayed by a two-step process.These results have been rationalized in terms of a mechanism which requires most of the photosensitized forward electron transfer to occur on the surface of RMV2+ aggregates.Subsequently, some of the oxidized sensitizer escapes the potential field of RMV2+ and charge recombination is retarded by electrostatic repulsion between the positively charged aggregates and Ru(bpy)33+.
A supramolecular switch based on three binding states of a pyrene derivate: A reversible three-state switch with only two stimuli
Chen, Hao,Yang, Hui,Xu, Wenchao,Tan, Yebang
, p. 13311 - 13317 (2013)
A fluorescent molecule, N-methyl-pyrenemethylammonium (MPA+), can be encapsulated inside cucurbit[8]uril's (CB[8]) cavity to form a binary host-guest complex. And the binary complex can further binds methyl viologen (MV2+), yielding a ternary complex. With only two chemical stimuli, cucurbit[7]uril (CB[7]) and amantadine hydrochloride (AD), the three binding states of MPA+, unbound MPA+, the binary complex and the ternary complex, can transform reversibly and exert three different fluorescence outputs.
Salt Effects on the Apparent Stability of the Cucurbit[7]uril-Methyl Viologen Inclusion Complex
Ong, Winston,Kaifer, Angel E.
, p. 1383 - 1385 (2004)
The effects of the medium ionic composition on the apparent equilibrium association constant (K) for the formation of a 1:1 inclusion complex between the guest methyl viologen (MV2+) and the host cucurbit[7]uril (CB7) were studied in aqueous solutions. The K values were found to decrease with increasing ionic strength, with more pronounced effects for solutions containing divalent Ca2+ ions than for solutions containing monovalent Na+ ions. The competing ion-dipole interactions between Ca2+ or Na+ and MV2+ ions appear to be responsible for the remarkable modulation of the K values observed in this work.
TiO2 and CdS Colloids Stabilized by β-Cyclodextrins: Tailored Semiconductor-Receptor Systems as a Means to Control Interfacial Electron-Transfer Processes
Willner, Itamar,Eichen, Yoav
, p. 6862 - 6863 (1987)
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Correlating solution binding and ESI-MS stabilities by incorporating solvation effects in a confined cucurbit[8]uril system
Rauwald, Urs,Biedermann, Frank,Deroo, Stéphanie,Robinson, Carol V.,Scherman, Oren A.
, p. 8606 - 8615 (2010)
The high-throughput characterization of solution binding equilibria is essential in biomedical research such as drug design as well as in material applications of synthetic systems in which reversible binding interactions play critical roles. Although isothermal titration calorimetry (ITC) has been widely employed for describing such binding events, factors such as speed, concentration, and sample complexity would principally favor a mass spectrometry approach. Here, we show a link between ITC and electrospray ionization mass spectrometry (ESI-MS) by incorporating solvation free energies in the study of the ternary complexes of the macrocyclic host cucurbit[8]uril (CB[8]). The binding affinities of 32 aromatic reference complexes were studied by ITC and ESI-MS and combined with solvation data of the guests from an implicit solvation model (SM8) to obtain a correlation between aqueous and gas-phase measurements. The data illustrates the critical importance of solvation on the binding strength in CB[8]'s ternary complexes. Finally, this treatment enabled us to predict association constants that were in excellent agreement with measured values, including several highly insoluble guest compounds.
Pulse Radiolysis of Methyl Viologen in Aqueous Solutions
Solar, Sonja,Solar, Wolfgang,Getoff, Nikola,Holcman, Jerzy,Sehested, Knud
, p. 2467 - 2478 (1982)
Pulse radiolysis of air-free aqueous methyl viologen (MV2+) solutions was carried out at various pH.The attack of e-aq on MV2+, with k(e-aq + MV2+) = 7.5*1010 dm3 mol-1 s-1, leads to the formation of the long-lived radical cation (MV.+), which possesses two absorption maxima at 392.5 nm (ε392.5 = 4200 m2 mol-1) and 600 nm (ε600 = 1450 m2 mol-1).The H-atoms react with MV2+ at pH 1 forming two species, which have superimposed absorption bands.By means of a computer simulation they are resolved in the absorptions belonging to: (1) a protonated form of the radical cation (MV.+H+), which is produced with k(H + MV2+) = (3.5+/-0.2)*108 dm3 mol-1 s-1, has 2 absorption maxima at 390 nm (ε390 = 1700 m2 mol-1) and 595 nm (ε595 = 760 m2 mol-1) and decays by second-order kinetics with k = 3.5*109 dm3 mol-1 s-1; (2) an H-adduct (MV.2+H) on the ring carbon, which is formed with k(H + MV2+) = 2.5*108 dm3 mol-1 s-1, absorbs at 310 nm (ε310 = 900 m2 mol-1) and 470 nm (ε470 = 630 m2 mol-1) and decays by conversion into MV.+H+ in a first-order process with k = 6*103 s-1.For the equilibrium MV.+H+ MV.+ + H+ pK = 2.9+/-0.1 was determined.The presented data explain, at least partly, the instability of MV2+ when used as an electron acceptor in various devices for utilization of solar energy.
A preparation method of paraquat (by machine translation)
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, (2018/06/15)
The invention provides a preparation method of paraquat, including: S1) metal palladium compound in the presence, of formula (I) with a compound represented by the 4 - pyridine boronic acid mixed reaction, to obtain 4, 4 '- bipyridyl; S2) will be the 4, 4' - bipyridyl with chlorodifluoromethane into salt, get the paraquat; wherein X is halogen or amides. Compared with the prior art, this invention has the formula (I) with a compound represented by the 4 - pyridine boronic acid as the raw material, to palladium metal compound as a catalyst, to carry out the cross-coupling reaction to obtain 4, 4' - bipyridyl, with the methyl chloride salt to obtain the paraquat, the method the reaction conversion is high, the reaction time is short, mild reaction conditions, without the need of high-temperature high-pressure, low requirements on equipment, and does not need to carry on the anhydrous solvent processing, at the same time the method after treatment is simple, the separation of the obtained product, the production process is simplified, is suitable for mass production. (by machine translation)