Noncommutative differential geometry related to the Young-Baxter equation

An analogue of the differential calculus associated with a unitary solution of the quantum Young-Baxter equation is constructed. An example of a ring sheaf is considered in which local solutions of the Young-Baxter quantum equation are defined but there is no global section. Bibliography: 13 titles. Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 199, 1992, pp. 51–70. Translated by I. A. Izergina.     

Distance dependence of electron transfer in rigid,cofacially compressed,pi-stacked porphyrin-bridge-quinone systems

The electron-transfer (ET) dynamics of a series of unusually rigid pi-stacked porphyrin-quinone (P-Q) systems, in which sub-van der Waals interplanar distances separate juxtaposed porphyryl, aromatic bridge, and quinonyl components of these assemblies, are reported. The photoinduced charge separation (CS) and thermal charge recombination (CR) ET reactions of [5-[8'-(2',5'-benzoquinonyl)-1'-naphthyl]-10,20-diphenylporphinato]zinc(II) (1a-Zn), [5-[8'-(4'-[8'"-(2'"',5'"'-benzoquinonyl)-1'"-naphthyl]-1'-phenyl)-1'-naphthyl]-10,20-diphenylporphinato]zinc(II) (2a-Zn), and [5-(8'-[4'-(8'"-[4'"'-(8'"-[2'"',5'"'-benzoquinonyl]-1'"-naphthyl)-1'"'-phenyl]-1'"-naphthyl)-1'-phenyl]-1'-naphthyl)-10,20-diphenylporphinato]zinc(II) (3a-Zn) in CH(2)Cl(2) were investigated by pump-probe transient absorption spectroscopy. Analyses of these data show that the phenomenological ET distance dependence (beta) for both the CS and CR reactions in these systems is soft (beta(CS) = 0.43 A(-1); beta(CR) = 0.35 +/- 0.16 A(-1)). This work demonstrates that simple aromatic building blocks such as benzene, which are characterized by highly stabilized filled molecular orbitals and large HOMO-LUMO gaps, can provide substantial D-A electronic coupling when organized within a pi-stacked structural motif that features a modest degree of arene-arene interplanar compression.     

Displacement of metal atoms from salts by hydrogen and the role of this reaction in chain processes

The interaction of hydrogen atoms with a variety of alkali metal and alkaline-earth metal salts results not only in the recombination of these atoms but also in the displacement, into the gas phase, of free radicals (CaCl^·(A ¹ P _1/2, B ² S ⁺) and CaF^·(A ² P)) and metal atoms, including their excited species, which are detected spectroscopically. Transmission spectra indicate that the NaCl surface undergoes metallization when treated with a high-frequency discharge and a rarefied hydrogen flame. Combustion is affected by the gas-phase hydrogen atoms involved in the chain reaction and by the varying composition and properties of the surface. The concentration of Na atoms over the NaCl surface at 770 K is 10⁹?10¹¹ cm^?3 in a stream of H atoms at 1 Torr and in the 2H₂ + O₂ flame at 4 Torr. The concentration of sodium atoms in the ² P _3/2 and ² P _1/2 excited states is ～5 × 10⁶?5 × 10⁸ cm^?3. The role of the discovered reactions in combustion, pyrolysis, and plasma chemistry is discussed.     

Synthesis of 1, 2-diazabicyclo [4.4.0] decane and its derivatives

A new heterocyclic system, 1, 2-diazabicyclo [4.4.0] decane is synthesized, starting from-(piperidyl-2) propionic acid. The latter is converted to-(1-nitrosopiperidyl-2)-propionic acid, and thence, via-(1-aminopiperidyl-2) propionic acid, to 3-keto-1, 2-diazabicyclo [4.4.0] decane. Derivatives of 1, 2-diazabicyclo [4.4.0] decane with a substituent at position 2 are prepared.     

Kinetics and mechanism of thermal decomposition of hydroxylammonium nitrate

The kinetics of thermal decomposition of melted hydroxylammonium nitrate have been investigated by the rate of heat production in the temperature range 84.8–120.9°C. The decomposition proceeds with autocatalysis and up to 60 % of conversion the rate of the process increases proportionally to the square of the degree of decomposition. The initial rate is proportional to the square of the concentration of HNO₃ formed due to dissociation of the salt. The activation energy of this process is 15.3±1.8 kcal/mol. It is suggested that the initial stage the process proceeds via interaction between N₂O₃ and NH₃OH⁺, whereas the subsequent acceleration is due to oxidation of NH₃OH⁺ by nitrogen oxides formed as well as by nitrous acid.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1897–1901, November, 1993.     

Quantization of Poisson pencils and generalized lie algebras

We describe two types of Poisson pencils generated by a linear bracket and a quadratic one arising from a classical R-matrix. A quantization scheme is discussed for each. The quantum algebras are represented as the enveloping algebras of generalized Lie algebras.Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 103, No. 3, pp. 476–488, June, 1995.     

Kinetics and mechanism of nitration of cellulose with the HNO3-CH2Cl2 mixture

Complexing in the HNO₃-CH₂Cl₂ system was confirmed tensimetrically. The kinetics of nitration of wood cellulose by the HNO₃-CH₂Cl₂ mixture were investigated. A large part of the cellulose is nitrated in a first fast reaction in comparison to the HNO₃-H₂SO₄ mixture with the same concentration of HNO₃. The rate of the process is determined by the rate of diffusion of the HNO₃, the rate of the process decreases more rapidly in the case of HNO₃-CH₂Cl₂ than in the HNO₃-H₂SO₄ mixture, which is probably due to the effect of CH₂Cl₂ on the diffusion coefficient of HNO₃.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2445–2450, November, 1989.     

Some reactions of 2-chloro-3-(β-chloroethyl)-4,6-dihydroxypyridine

The chemical properties of 2-chloro-3-(-chloroethyl)-4,6-dihydroxypyridine (I) have been studied. It has been shown that this compound, which is relatively stable in acids and in neutral and, particularly, in alkaline media, readily splits off hydrogen chloride under mild conditions and is converted into derivatives of 2, 3-dihydro-5-azabenzofuran. The dehalogenation of I in an acid medium yielded 3-(-chloroethyl)-4, 6-dihydroxypyridine, which was converted into 4, 6-dichloro-3-(-chloroethyl)pyridine and into 6-chloro-4-methoxy-3-vinylpyridine.     

The kinetics of vapor-phase nitration of cellulose 2. Nitration with nitric acid under static conditions

The regularities of vapor-phase nitration of cellulose with HNO₃ under conditions of natural convection and hindered heat removal in the absence of air were studied using the nonisothermal kinetic method. It was established that the nitration rate at the depth of conversion of 0.08 to 0.7 is described by the kinetic law d/dt =k ₁ p/(1+), wherek ₁ = 10^4.49±0.6 exp(–A/RT) s^–1 atm^–1, = 10^{–35.5±15.7}exp(B/RT),A = 36.6±3.8 kl mol^–1, andB = 203±88 kJ mol^–1. The diffusion mechanism of vapor-phase nitration of cellulose, which explains the high value of activation energies, is discussed. The effective diffusion coefficient of HNO₃ in cellulose at 25 °3.7 · 10^–7 cm² s^–1) and the activation energy of diffusion (38.3±4.2 kJ mol^–1) were estimated.For Part 1, see Ref. l.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1981–1985, August, 1996.     

7-Azaindole derivatives

A study is made of new synthetic routes, based on accessible 3-formyl-7-azaindoles, to 3-substituted 7-azaindole. 2-Phenyl-4-(1-phenyl-4-methyl-7-azaindolyl-3-rnethylene)-1, 3-oxazol-5-one is synthesized, and it is converted to 1-phenyl-4-methyl-7-azatryptophane, 1-phenyl-4-methyl-7-azaindolyl-3-acetic acid,1-phenyl-3-(,-dihydroxypropyl)-4-methyl-7-azaindole, and 1-phenyl-4-methyl-7-azaindolyl-3-pyrotartaric acid.For Part XVIII see [1].