A. Ya. Kaminskii

Electronic Structure and Structure of Ion Pairs of Anionic σ Adducts of Polynitroarenes with Acetonate Ion

The anionic Yanovskii σ adducts of 1,3,5-trinitro- and 1,3-dinitrobenzenes, 1,3-dinitronaphthalene, and 3,5-dinitrobenzoic acid with sodium, potassium, and tetrabutylammonium acetonates in low-polarity solvents exist mostly as contact ion pairs, while in polar solvents, as solvent-separated ion pairs and free ions. Lowering the temperature increases the fraction of solvent-separated ion pairs in low-polarity solvents and of free ions in polar solvents, by shifting the equilibria to stronger solvated ionic species. By quantum-chemical calculations of the geometry and electronic structure of the anions and of the electronic absorption spectra of the free ions and ion pairs, as well as by a spectrophotometric study of σ adducts with solvents of various polarity it was established that the cation on ion-pair formation coordinates with the 4-nitro group with respect to the pyramidal node.

3-Azabicyclo[3.3.1]nonane Derivatives: III. Synthesis of 3-Substituted 9-Acetonyl-1,5-dinitro-3-azabicyclo[3.3.1]-non-6-en-8-ones by Mannich Condensation of the Janovsky σ-Adduct of 2,4-Dinitrophenol with Acetonide Ion

A number of 9-acetonyl-1,5-dinitro-3-azabicyclo[3.3.1]non-6-en-8-one derivatives were synthesized by Mannich condensation of 3-acetonyl-2,4-bis(aci-nitro)cyclohex-5-en-1-one disodium salt with formaldehyde and primary amines.

Role of Association of Yanovskii Anionic σ Adducts in Their Oxidation with Quinones

In oxidation of 1,3-dinitro- and 1,3,5-trinitrobenzene acetonate σ adducts (Yanovskii complexes) with sodium, potassium, and tetrabutylammonium cations in acetonitrile and tetrahydrofuran (290-313 K), ion pairs are less reactive than free ions, which is explained by charge redistribution in the ring of the σ adducts, decreasing the electron-donor power of the associated anion. Separation of the apparent rate constants into ionic and ion-pair contributions showed that the reactivity of the ion pairs depends on the radius of their cation. The revealed kinetic regularities are interpreted on the basis of AM1 semiempirical quantum-chemical calculations of the ions and ion pairs with lithium cation.

Kinetic Effects of Electrolytes in Oxidation of Sodium, Potassium, and Tetrabutylammonium 1-Acetonyl-2,4-dinitrocyclohexa-2,5-dienides with 1,4-Benzoquinone

The kinetics of oxidation of sodium, potassium, and tetrabutylammonium 1-acetonyl-2,4-dinitro- cyclohexa-2,5-dienides with 1,4-benzoquinone in acetonitrile and tetrahydrofuran was studied spectrophotometrically. The reaction is of the first order with respect to the substrate and quinone and of the total second order. In the course of the process, a charge-transfer complex with an absorption maximum at about 716 nm is formed, accelerating the reaction. The rates of its accumulation and consumption increase with increasing concentrations of reactants and decrease on addition of sodium or tetrabutylammonium perchlorate. The factors facilitating association of σ adducts in solution (increase of the concentration in THF, addition of NaClO4 or [N(C4H9)4]ClO4), decelerate oxidation owing to decrease of the negative charge in the cyclohexadienide ring of the contact ion pair of the σ adduct as compared to the free ion.

Reactions of Aromatic Nitro Compounds: LXXIV. Azo Coupling of Anionic Nitroarene σ-Complexes with Aromatic Diazo Compounds. Effect of Reaction Conditions on the Yield of Nitroazobenzenes

Effect of a number of factors on the yield of nitroazobenzenes in the reaction of 4-nitro- and 4-dimethylaminobenzenediazonium tetrafluoroborates with anionic σ adducts derived from 1,3-dinitrobenzene was studied. Conditions were found which allow nitroazobenzenes to be prepared in 80-90% yield.

Electronic structure of anionic ? complexes of m-dinitrobenzene and its derivatives

It has been established as a result of calculations of the electronic structure of products of the addition of nucleophilic agents (H− and CH3−) to m-dinitrobenzene and its derivatives by the CNDO/S method that the negative charge of these anions is delocalized over the π system of the cyclohexadiene ring (∿50%) and the nitro groups (15–20% each), of which the nitro group in the para position (to the sp3-hybridized carbon atom) is more negatively charged. A certain fraction of the charge of the anion is distributed according to an induction mechanism to the hydrogen atoms and the geminal substituents. The data on the bond orders and the distribution of charges attest to the quinoidal structure of the carbon ring in the a complexes. The results of the calculations make it possible to predict the direction of the reactions of the anionic σ complexes with electrophilic and nucleophilic reagents. The calculated values of the total energies of the σ complexes correctly reflect their relative stability.

DIE UMSETZUNG VON ACETON MIT DEM ANION‐RADIKAL UND DEM DIANION DES M‐DINITROBENZOLS

Bei der Umsetzung des Dianions des Cyclooctatetraens (I) mit m-Dinitrobenzol (II) bilden sich das Radikalanion (III) und das Dianion (IV).