4,4′‐Bipyridyl N,N′‐dioxide–3‐hydroxy‐2‐naphthoic acid (1/2)

4,4′‐Bipyridyl N,N′‐dioxide crystallizes with 3‐hydr­oxy‐2‐naphthoic acid to give a centrosymmetric three‐component adduct, C₁₀H₈N₂O₂·2C₁₁H₈O₃, which is engineered into a two‐dimensional layer structure by two kinds of π–π inter­actions. Weak C—H⋯O inter­actions further link the two‐dimensional structure into a three‐dimensional structure.     

Acid-base interactions and adhesion capacity in the system constituted by an epoxy coating and a metal

Free surface energy and acidity parameter of solid surfaces of polyepoxides used as anticorrosive coatings were measured. Formulations of epoxy resins with various curing agents were studied. The adhesion capacity of epoxy films to various metallic surfaces was evaluated.     

Electrochemical reduction of 4-(nitrophenyl)-1,2- and 4-(nitrophenyl)-1,4-dihydropyridines and the ESR spectra of the obtained free-radical particles

In the course of electrochemical generation the intermediate reaction products (free radicals of the nitro-and nitrosophenyl type, which appear on the cyclic voltammetric curves) were identified by ESR. The N-substituted derivatives are characterized by reduction of the dihydropyridine ring. The 4-nitrophenyl derivatives are characterized by the absence of intramolecular electron transfer during electrochemical reduction. In the case of the corresponding derivatives of 1,2-dihydropyridine intramolecular transfer of electrons and protons is possible under these conditions. Combined schemes of the primary and secondary chemical reactions involved in the electrochemical reduction of the investigated compounds are presented. It was established that the substances investigated with reference to the mechanism of the electrochemical transformations include the antihypertensive nifedipine (corinfar, fenigidine).Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 219–233, February, 1997.     

铜(Ⅱ)-4-(喹啉-8′-甲基)-1,4,7,10-四氮杂环十三烷-11,13-二酮-α-氨基酸或5-取代邻菲罗啉两类三元配合物的稳定性研究

用 p H法在 (2 5.0± 0 .1 )℃ ,I=0 .1 mol· dm-3 KNO3 条件下 ,测定 Cu( ) - 4 - (喹啉 - 8′-甲基 ) - 1 ,4,7,1 0 -四氮杂环十三烷 - 1 1 ,1 3-二酮 -α-氨基酸或 5-取代邻菲罗啉两类三元配合物的稳定常数 ;研究了带甲基喹啉侧基大环多胺配体与 Cu( )离子的配位能力、配位方式 ;发现这两类三元体系配合物有特殊的稳定性 ;而且它们的稳定性与配体α-氨基酸及 5-取代邻菲罗啉酸碱强度之间的直线自由能关系的变化趋势相反 ;探讨了 Cu( )和 5-取代邻菲罗啉之间的 d- p反馈π键及其取代基 Hammett诱导效应的关系。     

火焰原子吸收光谱法测定南湖菱中矿质元素

用火焰原子吸收光谱法测定嘉兴南湖菱中钾、钠、钙、镁、铁、铜、锌、锰、镉、铅金属元素的含量。结果表明，南湖菱中有较高的矿物质营养价值，有害元素的含量低于国家食品允许标准。     

Theoretical study of the unimolecular decomposition mechanisms of energetic TNAD and TNAZ explosives

Calculation methods based on hybrid Density Functional Theory (DFT) with the basis sets of the B3LYP/6‐31+G(d)//B3LYP/4‐31G(d) method and the differential overlap (INDO) program were used to derive reasonable decomposition mechanisms of 1,4,5,8‐tetranitro‐1,4,5,8‐tetraazadecalin (TNAD) and 1,3,3‐trinitroazetidine (TNAZ) explosives. All possible decomposition species and transition states, including intermediates and products, were identified and their corresponding enthalpy of formation and Gibbs free energy of formation were obtained using polyparametric modification equations. INDO bond energy calculation results reveal the weakest bonding site for reference and determine where cleavage can occur easily. This work is concerned mainly with eliminating HONO (cis or trans form). The activation energy for trans‐form HONO elimination is lower than that of cis‐form HONO elimination in the initial steps of both TNAD and TNAZ decomposition, being 18.5 kJ/mol and 33.3 kJ/mol, respectively. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Features of complexing of molecular NMR relaxation probes with cellulose acetates in solutions

The method of active and inert NMR relaxation probes can be used for determining the degree of substitution of cellulose acetates. The formation of hydrogen bonds between the hydroxyl and acetate groups of cellulose acetate is more probable than between the hydroxyl groups, which results in relative large shielding of the free OH groups in the polymer in samples with high degrees of substitution.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1761–1765, August, 1989.We would like to thank N. I. Naimark for providing the samples of the cellulose acetates.     

Mechanism and products of electrochemical reduction of 4-nitrophenyl-2,6-dimethyl-3,5-dicyano-1,4-dihydropyridines in dimethylformamide

Free anion radicals of the nitrobenzene and nitrosobenzene type, which were identified by EPR spectroscopy, are formed in the electrochemical reduction of isomeric 4-(nitrophenyl)-2,6-dimethyl-3,5-dicyano-1,4-dihydropyridines on mercury and solid electrodes. Reduction of the dihydropyridine ring is observed only for N-substituted p- and m-nitrophenyl derivatives of 1,4-dihydropyridine. An intermediate with a 2-pyridonemethide structure was identified; a set of primary and secondary chemical reactions that are associated with the electrolytic reduction of the investigated compounds is presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1494–1505, November, 1988.     

Mass spectra of alliosterol and its dehydration product and of allosides A and B

The EI and LSIMS mass spectra of alliosterol and its dehydration product and of allosides A and B have been studied. The spectra of alliosterol show features characteristic for sterols of the cholestane series. A comparison of the B/E spectra of some fragments of the ions from alliosterol and its dehydro product has shown the unimportance of the conversion of the former into the latter under mass-spectrometric conditions.Institute of Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 344–349, May–August, 1992.     

Heterocyclic nitro compounds

The IR and Raman spectra of a number of anions of the nitro derivatives of 1,2,4-triazole were investigated. On the basis of the position of the absorption maxima of the asymmetric and symmetric t vibrations of the nitro group, it is assumed that the nitro groups in the 3 and 5 positions of the triazole ring are coplanar, which should lead to an increase in the participation of the nitro group in the de localization of the negative charge of the anion. Shifts of the frequencies as a function of the nature of the cation (NH₄, Na, K, Cs) were not detected in the IR spectra of the crystalline salts. In addition, the IR spectra of the crystalline salts are similar (with respect to the frequencies) to the spectra of aqueous solutions of the salts, which may serve as proof of the identical structure of the anions in crystals and aqueous solutions.See [1] for communication XII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 120–123, January, 1972.