2154-65-6Relevant academic research and scientific papers
Distribution of the products of benzhydryl bromide heterolysis in the presence of triphenylverdazyl in aprotic solvents
Serebryakov,Kryzhanovskaya,Dzhurinskaya
, p. 798 - 800 (2006)
The distribution of products of benzhydryl bromide heterolysis in the presence of triphenylverdazyl in anhydrous nitrobenzene and propylene carbonate, as well as in anhydrous acetonitrile in the presence of benzyltriethylammonium chloride was studied. In kinetic experiments the contribution of verdazyl alkylation was always minor, and verdazyl was mostly consumed in the reaction with HBr evolved during solvolysis. Thus, triphenylverdazyl is not an indicator of the solvent-separated ion pair of benzhydryl bromide. Pleiades Publishing, Inc., 2006.
Is triphenylverdazyl an indicator for solvent-separated ion pair?
Serebryakov,Kryzhanovskaya,Dzhurinskaya,Kladova,Azarova
, p. 1331 - 1335 (2005)
The hypothesis implying complete capture of solvent-separated ion pairs by triphenylverdazyls used as internal indicators for unimolecular heterolysis of organic compounds was critically analyzed. Products of heterolysis of diphenylmethyl bromide in anhyd
Triarylverdazyl radicals as promising redox-active components of rechargeable organic batteries
Burtasov, A. A.,Chernyaeva, O. Yu.,Kostryukov, S. G.,Kozlov, A. Sh.,Pryanichnikova, M. K.,Tanaseichuk, B. S.
, p. 1321 - 1328 (2020/09/07)
A novel design of electroactive components of rechargeable organic batteries based on stable verdazyl radicals bearing various substituents is proposed. 3-Positioned aromatic substituents at the verdazyl moiety affect the reduction potentials and almost do not affect the oxidation potential, while 1-positioned aromatic substituents affect contrariwise the oxidation potential of this radical without any influence on the reduction potential. The acquired electrochemical data allowed us to reveal the structure—potential relationship for the cathodic and anodic processes, which provided the design of triarylverdazyl radicals possessing record-breaking parameters of the “electrochemical gap”.
Synthesis and Electrochemical Properties of 2-(4-R1-Phenyl)-6-(4-R2-phenyl)-4-phenyl-3,4-dihydro1,2,4,5-tetrazin-1(2H)-yls
Akhmatova, A. A.,Balandina, A. V.,Chernyaeva, O. Yu.,Kostryukov, S. G.,Kozlov, A. Sh.,Kraynov, E. V.,Lukshina, Yu. I.,Pryanichnikova, M. K.
, p. 341 - 351 (2020/04/27)
Abstract: A new methodology for creating electroactive components for organic batteries,based on the construction of a molecular platform including stable3,4-dihydro-1,2,4,5-tetrazin-1(2H)-ylradicals was described. A series of2-(4-R1-phenyl)-6-(4-R2-phenyl)-4-phenyl-3,4-dihydro-1,2,4,5-tetrazin-1(2H)-yls with substituents of various nature wasobtained. It was shown that the substituents R1 inthe aromatic ring at position 2 of the tetrazinyl fragment influence the valueof the oxidation potential in the radical, but do not influence the value of thereduction potentials, while the substituent R2 of thearomatic ring at position 6 influence the values of the reduction potentials andpractically do not influence oxidation potential values. Based on the obtainedelectrochemical data, a correlation structure–potential value was revealed forthe cathodic and anodic process, with the help of which triarylsubstituted3,4-dihydro-1,2,4,5-tetrazin-1(2H)-ylradicals with high values of the electrochemical gap were obtained.
Electrochemical studies of verdazyl radicals
Gilroy, Joe B.,McKinnon, Stephen D. J.,Koivisto, Bryan D.,Hicks, Robin G.
, p. 4837 - 4840 (2008/03/18)
(Chemical Equation Presented) The redox properties of verdazyl radicals are presented using cyclic voltammetry techniques. These radicals can be reversibly reduced as well as oxidized. Electron-donating and -withdrawing substituents have significant effects on the oxidation and reduction potentials as well as the cell potential (Ecell = |Eox° - E red°|) for these radicals; a correlation between the electron spin distribution and redox properties is developed.
Kinetics and mechanisms of the electron transfer reactions of oxo-centred carboxylate bridged complexes, [Fe3(μ3-O)(O 2CR)6L3]ClO4, with verdazyl radicals in acetonitrile solution
Keeney, Lynette,Hynes, Michael J.
, p. 1524 - 1531 (2007/10/03)
A range of oxo-centred, carboxylate bridged tri-iron complexes of general formula [Fe3(μ3-O)(O2CR)6L 3]ClO4 (R = CH2CN, CH2F, CH 2Cl, CH2Br, p-NO2C6H4; L = pyridine, 3-methylpyridine, 4-methylpyridine, 3,5-dimethylpyridine, 3-cyanopyridine and 3-fluoropyridine) have been prepared and characterised. The choice of R and L was dictated by the requirement that the complexes undergo a one-electron reduction when reacted with verdazyl radicals. All except the complexes where L = pyridine and R = CH2CN, CH2Cl and p-NO2C6H4 have not been previously reported. The redox behaviour of these compounds has been investigated using cyclic voltammetry in acetonitrile in the absence and in the presence of free L. In general, all complexes exhibited reversible one-electron reductions. Electrochemical behaviour improved in the presence of an excess of L. The kinetics of the electron transfer reaction observed when acetonitrile solutions of the complexes were reacted with a range of verdazyl radicals were monitored using stopped-flow spectrophotometry. Under the experimental conditions, the reactions were quite rapid and were monitored under second-order conditions. Marcus linear free energy plots indicated that the outer-sphere electron transfer reactions were non-adiabatic in nature. Nevertheless, application of the self-exchange rate constants of the verdazyl radicals, k11, and the tri-iron complexes, k22, to the Marcus cross-relation resulted in calculated values of the cross-reaction rate constant, k12, that were within a factor of five of the experimentally determined value. The Royal Society of Chemistry 2005.
Comparison of Spectroscopic and Electrochemical Studies of Disproportionation Equilibria of 1,3,5-Triphenylverdazyl Radical in DMF Containing Carboxylic Acids
Jaworski, Jan S.,Krawczyk, Irena
, p. 43 - 50 (2007/10/02)
Stoichiometry and equilibrium constants for the disproportionation of the title radicals in N,N-dimethylformamide containing salicilic, chloroacetic, and phenylacetic acids were determined on the basis of absorption spectra.On the other hand, only apparent equilibrium constants depending on concentrations of an acid and a radical could be obtained from electrochemical measurements at a mercury electrode.Significant differences in reaction stoichiometry and in order of magnitudes of disproportionation constants found under spectroscopic and electrochemical conditionswere discussed in terms of an influence of the electric field in the double layer on the distribution of different associates formed by verdazyl species with acids.Keywords: Disproportionation equilibrium; Effect of the electrode field.
DISSOCIATION ENERGY OF THE N-H BOND IN 2,6-DIARYL-4-PHENYL-1,2,3,4-TETRAHYDRO-SYM-TETRAZINES AND THE COMPARATIVE REACTIVITY OF SYM-TETRAZINYLS IN DEHYDROGENATION OF HYDRAZOBENZENE
Misyura, A. V.,Polumbrik, O. M.,Markovskii, L. N.
, p. 381 - 387 (2007/10/02)
The equilibrium constants in the reactions of 2,6-diaryl-4-phenyl-1,2,3,4-tetrahydro-sym-tetrazines with 2,2,6,6-tetramethyl-4-oxopiperidin-1-oxyl in heptane were determined by spectrophotometric and ESR methods.The dissociation energies of the N-H bond is the sym-tetrazines were determined.Results are given which indicate that the substituents in the phenyl ring at the C6 and N2 atoms have effects substantially different and opposite in sign on the thermochemical value of the dissociation energy of the N-H bond in sym-tetrazines.The sym-tetrazines with donatingsubstituents at the C6 atom and accepting substituents at the nitrogen atom are characterized by the largest dissociation energy for the N-H bond.The kinetics of the dehydrogenation of hydrazobenzene by sym-tetrazinyls in acetonitrile were investigated.It was found that there is an inverse relationship between the activation energies of the reaction and the dissociation energy of N-H bond in sym-tetrazines.The reaction mechanism is discused.
REACTION OF 2,4,6-TRIPHENYLVERDAZYL WITH TRIFLUOROMETHYLSULFONYLCARBETHOXYDIBROMOMETHANE
Tomilenko, E. I.,Ogoiko, P. I.,Staninets, V. I.
, p. 1226 - 1228 (2007/10/02)
An unusual acylation of 2,4,6-triphenylverdazyl by trifluoromethylsulfonylcarbethoxydibromomethane in benzene has been discovered leading to 1-ethoxalyl-2,4,6-triphenyl-1,2,3,4-tetrahydro-sym-tetrazine (1-ethoxalyl-2,4,6-triphenylleukoverdazyl).
STRENGTH OF N-H BOND IN 2,4-DIPHENYL-6-(4-X-PHENYL)-1,2,3,4-TETRAHYDRO-sym-TETRAZINES (LEUCOVERDAZYLS)
Polumbrik, O.M.,Ryabokon', I.G.,Skorobagat'ko, E.P.,Nesterenko, A.M.,Markovskii, L.N.
, p. 922 - 927 (2007/10/02)
The equilibrium contstants in the reactions of triphenylleucoverdazyls substituted at the para position of the C6-phenyl ring with 2,2,6,6-tetramethyl-4-oxopiperidin-1-oxyl in heptane were determined by spectrophotometry and ESR.At 20 deg C the equilibrium is displaced toward the formation of the more stable verdazyl radicals.The strengths of the N-H bonds in the leucoverdazyls were determined.The enthalpy of solvation of triphenylverdazyl in acetonitrile was obtained (-15.6 kJ/mole).The kinetics of exchange of hydrogen between the triphenylverdazyls and 2,2,6,6-tetramethyl-4-oxopiperidine-1-hydroxylamine in acetonitrile were studied.The mechanism of the reaction, which inlcudes the formation of a hydrogen bond between the reagents in an activated complex, is discussed.It was concluded that the reactivity of the triphenylverdazyls in the abstraction of hydrogen from organic compounds is determined to a significant degree by the strength of the N-H bond which forms in the leucoverdazyls.
