2782-41-4Relevant academic research and scientific papers
Charge-transfer interaction between poly(9-vinylcarbazole) and 3,5-dinitrobenzamido group or 3-nitrobenzamido group
Yu, Ying,Yao, Yuan,Wang, Liyan,Li, Zesheng
, p. 3275 - 3279 (2010)
We studied the charge-transfer (CT) interaction between poly(9-vinylcarbazole) (PVK) and 3,5-dinitrobenzamido (DBA) group or 3-nitrobenzamido (NBA) group. The complexation equilibrium constant of PVK and N-butyl-3,5dinitrobenzamide was found to be larger
MECHANISM OF ESTER AMINOLYSIS IN APROTIC MEDIA AND SPECIFIC SOLVENT EFFECTS
Nagy, Otto B.,Reuliaux, Victor,Bertrand, Nicole,Mensbrugghe, Anne Van Der,Leseul, Jean,Nagy, Janos B.
, p. 1055 - 1074 (2007/10/02)
The n-butylaminolysis of nitro-substituted 4'-nitrophenyl benzoates and cinnamates as well as of phenylacetates in aprotic solvents is governed by a kinetic law implying higher order terms in nucleophile.It is shown that the attacking nucleophile forms a n-? type molecular complex with the substrate before reaching the transition state in the subsequent kinetic step.This molecular complex is a true reaction intermediate as evidenced by the observed negative activation enthalpy.Other nucleophile molecules intervene as general base catalysts.Tertiary amines also catalyse the reaction.Their catalytic activity is linearly related to their hydrogen bond forming ability and it is not a direct function of their proton basicity.By varying the nucleophile structure, an excellent Broensted relationship could be obtained for the first time in aprotic media, the β of which confirms that the catalytic collapse of tetrahedral intermediate is the rate determining step.The reaction of cinnamates turns out to be less sensitive to structural changes of the substrate than is the reaction of benzoates as shown by the corresponding Hammet ? values.The electronic effects of 2-nitro groups are strongly solvent dependent.Once more, it is established that whenever specific solvent effects (?-donor or n-donor ability) are present, they dominate the overall effect.A general reaction mechanism is proposed which not only explains the various roles played by the nucleophile but also accounts successfully for the great variety of kinetic schemes observed in aprotic media.
One-electron Oxidation of Closed-shell Molecules. Part 3. Oxidative Cleavage of 1,2,2,2-Tetrakis-(p-methoxyphenyl)ethanone with Dibenzoyl and Bis(3,5-dinitrobenzoyl) Peroxides: Mechanistic Changeover of the Peroxide Function from Radical to Molecular Oxidation
Takeuchi, Ken'ichi,Murai, Osamu,Matsui, Shin,Inoue, Takeshi,Kitagawa, Toshikazu,Okamoto, Kunio
, p. 1301 - 1310 (2007/10/02)
1,2,2,2-Tetrakis-(p-methoxyphenyl)ethanone (anispinacolone) (1) is cleaved by dibenzoyl peroxide (2) or bis-(3,5-dinitrobenzoyl) peroxide (3), affording tris-(p-methoxyphenyl)methyl benzoate (or 3,5-dinitrobenzoate) and benzoic (or 3,5-dinitrobenzoic) p-methoxybenzoic anhydride as the principal cleavage products. 13C N.m.r.CIDNP studies by use of labelled anispinacolone (An3*C-*COAn ; *C 90percent 13C) indicated that p-methoxybenzoyl radical is formed, presumably by way of the radical cation +. which is produced by a single-electron transfer (s.e.t.) mechanism.The formation of the p-methoxybenzoyl radical was also indicated by spin-trapping experiments.The decomposition rates of (2) at 50.0 deg C are unaltered on addition of (1) in nonpolar solvents such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, and benzene, whereas those of (3) are markedly accelerated.The cleavage of (1) by (2) is supressed by added 3,4-dichlorostyrene by a factor of 6.7, whereas that of (1) by (3) is almost unaffected.These results suggest that in the case of dibenzoyl peroxide (2) the thermally produced benzoyloxyl radical works as a one-electron acceptor (or oxidant) upon (1), whereas when bis-(3,5-dinitrobenzoyl) peroxide (3) is used the peroxide molecule oxidizes (1), probably by way of an s.e.t. mechanism even in such nonpolar solvents.On the other hand, in polar solvents such as (CF3)2CHOH, teramethylene sulphone, and acetonitrile the decomposition of (2) is accelerated by added anispinacolone, suggesting that the intermolecular s.e.t. reaction is partially involved in such polar solvents.Consequently, the oxidative cleavage of anispinacolone (1) by diaroyl peroxides provides the first example of dichotomy in the s.e.t. reaction of diaroyl peroxides, which can be considered a counterpart of the SN1-SN2 dichotomy in nucleophilic substitution, as far as the molecularity of the peroxide is concerned.
