72409-67-7Relevant academic research and scientific papers
Proton-Transfer and Electron-Transfer Processes in Reaction of p-Nitrotoluene with Bases. A Spectrophotometric Study
Buncel, E.,Menon, B. C.
, p. 3499 - 3507 (1980)
The interaction of p-nitrotoluene (PNT) with a variety of basic systems has been studied spectrophotometrically.The bases employed, in decreasing order of base strength, were potassium hydride, dimsyl potassium, triphenylmethylpotassium, fluorenylpotassium, and potassium p-nitroanilide, while the solvents used were dimethyl sulfoxide, tetrahydrofuran, and dimethoxyethane, with 18-crown-6 ether present in the latter two cases.The major species produced in the reactions were p-nitrobenzyl anion (PNT-), p-nitrotoluene radical anion (PNT-.), and p,p'-dinitrostilbene radical anion (DNS-.).The principal processes in the PNT-base systems are believed to be (i) PNT + B- PNT- + BH; (ii) PNT + B- PNT-. + B.; (iii) PNT- + PNT PNT. + PNT-..DNS-. is formed through secondary processes via p,p'-dinitrobibenzyl.Discussion of process (i) is given in terms of the relative pKas of PNT and the respective BH species, while (ii) is analysed on the basis of the reduction potential of PNT and the oxidation potential of B-.For the case of the PNT/Ph3C- system, the electron-transfer process (ii) is kinetically preferred but this equilibrium is rapidly established.On the other hand the proton-transfer process (i) is greatly favored thermodynamically and is effectively irreversible; as a result the proton transfer predominates.This is in accord with observation of PNT- as the initially formed species in this system.The processes occurring in the other base systems are similarly analysed.The assignment of the absorption due to the p-nitrobenzyl anion is at variance with an earlier literature report deduced from examination of the PNT/t-BuOK/t-BuOH system.Electron-transfer and proton-transfer processes in the PNT/t-BuO- system are also discussed.
U.v.-visible and E.s.r. Probing of the Reactions of the Photogenerated p-Nitrobenzyl Anion in Aqueous Media
Craig, Bruce B.,Pace, M. Dale
, p. 1144 - 1146 (1987)
U.v.-visible and e.s.r. probing of the photogenerated p-nitrobenzyl anion in aqueous media indicate that dimerisation may be a prominent decay mode; this is followed by electron transfer to the parent nitroaromatic.
Lifetimes of α-Dialkoxy Carbocations Produced via Radical Cations Generated by Electron Transfer and Photoionization in Aqueous Solution
Steenken, S.,McClelland, R. A.
, p. 4967 - 4973 (2007/10/02)
One-electron oxidation of acetals PhCH2CR(OR')2 by reaction with photolytically produced SO4.- or by biphotonic photoionization (λ = 248 nm) in aqueous solution leads to the benzyl radical PhCH2. and to α-dialkoxymethyl carbocations RC(+)(OR')2.The reaction proceeds via a radical cation intermediate which undergoes rapid (k >/= 7*1E7 s-1) heterolytic C-C fragmentation.The cations thus formed react with water with rate constants k(H2O) which have been measured by time-resolved conductance (R = H, alkyl, Ph) and optical (R = Ph) methods.A total of 24 acyclic and cyclic cations have been kinetically characterized, with values of k(H2O) ranging from 4.6*1E7 s-1 (4,4,5,5-tetramethyl-1,3-dioxolan-2-ylium) to 8.6*1E7 s-1 (2-phenyl derivative of the above cation).Replacement of R = H by methyl leads to an increase in the lifetime by a factor of about 1000.However, the substitution of R = Me by bulkier alkyl groups (e.g. tBu) does not further kinetically stabilize (in the case of the cyclic cations) or it even destabilizes the cations (with the acyclic systems).The effect of R = Ph depends on whether the cation is cyclic or acyclic: In the acyclic case steric interaction between the ortho hydrogens of the phenyl ring and the OR' substituents prevents complete coplanarity at Cα as a result of which charge delocalization to the phenyl ring becomes less efficient, i.e. the kinetic stability of the cation is not increased relative to the cation with R = Me.In the case of the sterically uncongested cyclic systems, Ph leads to an increase of stability compared to Me.A heterolytic C-C fragmentation of an electronically excited neutral compound to a carbanion and a carbocation has also been characterized, with the acetals 2-phenyl-2-(x-nitrobenzyl)-1,3-dioxolane (x = para or meta).
STUDY OF THE ALKALINE CLEAVAGE OF THE P-C BOND IN PHOSPHINE OXIDES AND DERIVATIVES OF TRICHLOROMETHANEPHOSPHONATE
Aksnes, Gunnar,Gierstae, Roald,Wulvik, Erik A.
, p. 141 - 152 (2007/10/02)
A study of alkaline decomposition of aromatic phosphine oxides containing p- and o-nitrobenzyl, and trichloromethyl as leaving groups, is reported.The property of the trichloromethyl group as leaving group, and the CCl3--group's further decomposition in the hydrolysis of diethyl and disodium trichloromethanephosphonates, have also been investigated.
A Spectrophotometric Study of 4-Nitro-, 2,4-Dinitro- and 2,4,6-Trinitrobenzyl Carbanions. Decarboxylation of (Nitrophenyl)acetate Anions
Buncel, E.,Venkatachalam, T. K.,Menon, B. C.
, p. 413 - 417 (2007/10/02)
A spectrophotometric study of the reactions of the potassium salts of (2,4,6-trinitrophenyl)acetic acid (3), (2,4-dinitrophenyl)acetic acid (4), and (4-nitrophenyl)acetic acid (5) in Me2SO, THF, and DME is reported, including the effect of catalysis by crown ether 1.These processes are believed to give rise to the corresponding carbanions resulting from decarboxylation.The UV-visible spectrum of the species obtained from reaction of 3 agrees well with literature data for the expected carbanion 6, but there is some discrepancy regarding the species derived from 4 and 5.From the decay of the absorption spectra with time, the stabilities of the benzyl carbanions in these systems correspond to 2,4,6-trinitrobenzyl > 2,4-dinitrobenzyl > 4-nitrobenzyl.
