Thermodynamics of the Interaction of the Ni<Superscript>2+</Superscript> Ion with the L-β-Phenyl-α-Alanine Anion in Aqueous Solution

The enthalpies of the interaction of the L-β-phenyl-α-alanine anion with the Ni²⁺ ion in aqueous solution were measured by calorimetry for the ionic strength I = 0.5, 1.0, and 1.5 (KNO₃ as a supporting electrolyte) at 298.15 K. The thermodynamic parameters of the formation of Ni(II) complexes with phenylalanine in aqueous solution were calculated. The effect of the ligand structure on the thermodynamic parameters of complexation reactions in solution was discussed.     

Stability and Oscillations of Solutions of Integro-Differential Equations of Pendulum—like Systems

A system of nonlinear differential equations of the type on a domain of ?ⁿ is studied. Functional relations between the f_j's, j = 1, …, n, and other necessary conditions are deduced when at each point of the domain the system has a manifold of local solutions. A structure theorem, that makes possible to reduce the problems of the system, e.g. the global solvability of it, to the corresponding questions for a connection of the type ?_z?w = g(z, w) in a fibre bundle over a Riemann surface is proved, and through this reduction we obtain theorems of identity, extension, global factorization, and so on, for the solutions of the system. As an example, a system of nonlinear differential equations of the type is studied and its global solutions are constructed.     

Sensing Element of a Benzopurpurin 4B-Based Optical Sensor for Determining the Acidity of Etch Solutions

Deposition conditions are studied, and a Langmuir–Blodgett film (LBF) based on the benzopurpurin 4B indicator immobilized in the polyamide acid salt matrix is obtained. The protolytic properties of the indicator are studied in water, micelles of cationic and nonionic surfactants, and LBFs. It is shown that, in going from water to the cited micelles and LBFs, pK _ind is shifted to the acidic region by 3.25, 1.18, and 2.30 pH units, respectively. The possibility of using the produced LBF as the sensing element of an optical sensor for the determination of the acidity of solutions in the pH range 1–0 is demonstrated. The LBF is applied to the determination of the acidity of solutions in etch baths. The response time in the operating range is 10–20 s; the standard deviation is no more than 4%.     

New acylated flavone glycoside fromGnaphalium uliginosum

A new acylated flavone glycoside has been isolated for the first time from the herb marsh cudweed, and for it the structure of 6-caffeyl-7--D-glucopyranosyloxy-4,5-dihydroxy-3,6dimethoxyflavone has been established. In addition, the aglycone, identified as 4,5,7-trihydroxy-3,6-dimethoxyflavone has been isolated. The identifications were made on the basis of UV, IR, PMR, and mass spectra, the products of alkaline and acid hydrolyses, and the results of elementary analysis, melting points, and specific rotations.Vitebsk Medical Institute. All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 311–315, May–June, 1979.     

Study of the formation of polyimide from complexes of benzophenonetetracarboxylic acid diester with different diamines. 2. Features of thermal imidization of the molecular complex of benzophenonetetracarboxylic acid diester with 2,6-diaminopyridine

H-bond complexes of benzophenonetetracarboxylic acid dimethyl ester with 2,6-diaminopyridine (BZPE·DAP) have a dimeric structure in which one of the amino groups of the diaminopyridine participates in the formation of an H bond and the other does not form strong intermolecular bonds. During thermal imidization, the relative reactivity of the free amino group is lower than the reactivity of the group bound in the complex. In the BZPE·DAP system, 10% of the free amino groups remain after completion of imidization and they disappear at a high temperature. It is hypothesized that they can participate in the formation of interchain imide bonds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 530–533, March, 1990.     

Possible Shubnikov's formulas of chemical compounds

M. V. Lomonosov Moscow State University. Translated fromZhumal Struktumoi Khimii, Vol. 36, No. 4, pp. 760–763, July–August, 1995     

Thermodynamics of phenylated polyphenylene between 0 and 340 K

In an adiabatic vacuum calorimeter, the temperature dependence of the heat capacity C _p of phenylated polyphenylene and initial comonomer 1,4-bis(2,4,5-triphenylcyclopentadienone-3-yl)benzene was studied between 6 and 340 K with an uncertainty of about 0.2%. In a calorimeter with a static bomb and an isothermal shield their energies of combustion DUcomb were measured. From the experimental data, the thermodynamic functions C _p ⁰ (T), H ⁰(T)-H ⁰(0), S ⁰(T)-S⁰(0), G ⁰(T)-H ⁰(0) were calculated from 0 to 340 K, and standard enthalpies of combustion ΔH _comb ⁰ and thermodynamic parameters of formation-enthalpies ΔH _f ⁰, entropies ΔH _f ⁰, Gibbs functions ΔG _f ⁰ - of the substances studied were estimated at T=298.15 K at standard pressure. The results were used to calculate the thermodynamic characteristics (ΔH _f ⁰ ,ΔS _f ⁰, ΔG _f ⁰) of phenylated polyphenylene synthesis in the range from 0 to 340 K. This revised version was published online in July 2006 with corrections to the Cover Date.     

Influence of the properties of an oxide film on the oxidation of aluminium powders

The structure of oxide films of aluminium powders has been established to depend on the size of its particles. The temperature dependence of the oxidation of the powder in air is ascribed to changes in both the structure of the oxide laver and the pressure of saturated aluminium vapor. The porous, permeable product consists of hollow microspheres of -Al₂O₃.

---

. , . , –Al₂O₃.

     

New synthesis of benzo[b][1,6]naphthyridines and pyrido[4,3-b]benz[f]azepines from lactim ethers of 3,4-dihydrocarbostyril and 1H-2,3,4,5-tetrahydrobenz[b]azepin-2-one

Condensation of lactim ethers of 3,4-dihydrocarbostyril and 1H-2,3,4,5-tetrahydrobenz[b]azepin-2-one with malonodinitrile, cyanoacetamide, and ethyl cyanoacetate gave the corresponding 2-methylidene derivatives. Their reactions with dimethylformamide diethyl acetal followed by cyclization into benzo[b][1,6]naphthyridines and pyrido[4,3-b]benz[f ]azepines were studied. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 995–1002, May, 2007.     

Synthesis and structure of mesomorphic 2-cyano-5-[p-alkyl(alkoxy)phenyl]-pyridines

Liquid-crystal 2-cyano-5-[p-alkyl(alkoxy)phenyl]pyridines were synthesized by the reaction of 1-dimethylamino-3-dimethylimmonia-2-[p-alkyl (alkoxy)phenyl]propene perchlorates with 2-acetylfuran and subsequently through 2-furyl-5-[p-alkyl(alkoxy)phenyl]pyrylium perchlorates and 2- (2-furyl)-5-[p-alkyl (alkoxy)phenyl]pyridines by conversion of the latter to 5-alkyl(alkoxy)phenylpyridine-2-carboxylic acids, from which the cyano derivatives were obtained by the usual scheme through the amides. The intermediate arylfurylpyridines and arylpyridine-2-carboxylic acid imides also display liquid-crystal properties.Translated from Khimiya Geterotskilicheskikh Soedinenii, No. 7, pp. 888–891, July, 1980.