Broadening and Shift of the D1 and D2 Lines of Rb Atoms by Neon: Resolving Hyperfine Components in a Half-Wave Cell Using Double Differentiation with Respect to Frequency

Optics and Spectroscopy - A cell with a submicron thickness was used to measure the broadening and shift of the D1 and D2 lines of Rb atoms by neon. The resolution of hypefine components...     

Vinylacetylene chemistry

It is shown that heating vinylacetylenic piperidols I with phosphorus oxychloride in pyridine solution gives dienynes II, the structure of which is determined, in the case of II (R=H), by means of IR spectra and PMR. Hydration of the dienynes II (R=H, Me) in the presence of mercuric sulfate in methanol solution gives -methoxyketones III (R=H, Me). It is also shown that III and aqueous solutions of ammonia or primary amines give the bicyclic piperid-4-ones IV. In the synthesis of IV (R=H, R₁ = i-Pr, Bu) imines V are obtained, which on hydrolysis give piperidones IV (R = H, R₁ = i-Pr, Bu). When the ß-methoxyketone III (R = H) is heated with 5% sulfuric acid in the presence of mercuric sulfate, chroman-4-one is formed.     

Synthesis of 1,2,4-substituted hexahydropyridazines and X-ray structural investigation of 4-hydroxyimino-2-methyl-1-phenethylhexahydropyridazine

A series of new 1,2,4-substituted hexahydropyridazines was prepared in order to evaluate qualitatively and quantitatively the role and influence of substituents on the biological activity of this system. An X-ray structural investigation of 4-hydroxyimino-2-methyl-1-phenethylhexahydropyridazine was performed. The compounds considered exhibit moderate local anesthetic, antihistaminic, and anticonvulsive activity.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 539–541, March, 1993.     

Liquid-phase hydroformylation of 2,3- and 2,5-dihydrofurans

The synthesis of 3-formyl derivatives of the tetrahydrofuran series was carried out by hydroformylation of 2,3-dihydrofuran and 2,5-dimethoxy-2,5-dihydrofuran in the presence of HRh(CO)(PPh₃)₃. The influence of the temperature, pressure, catalyst concentration, and the nature of the solvent on the conversion of dihydrofuran, the composition of aldehydes obtained and the selectivity of their formation was investigated.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2569–2571, November, 1989.     

The structure of 4-anilinopiperidine analgesics. III. The structure of the acid sulfate of 1(e)-(2-phenethyl)-2(e), 5(e)-dimethyl-4(e)-(N-propylylanilino) piperidine

Institute of Fine Organic Chemistry, Academy of Sciences of the Armenian SSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 31, No. 2, pp. 141–145, March–April, 1990.     

Structure of 4-anilinopiperidine analgesics. I. The structure of the 2:1 solvate of 1(e)-(2-phenethyl)-2(e),5(a)-dimethyl-4(e)-(N-propionylanilino)-piperidine bisulfate monohydrate with cyclohexanone

An x-ray diffraction structural analysis was carried out using Cu radiation with 2975 reflections, 64° to R=0.073 for the bisulfate of the major component of the narcotic analgesic, phenaridine (1-(2-phenethyl)2,5-dimethyl-4-(N-propionylanilino)-piperidine citrate). The crystals studied obtained from cyclohexanone are a double solvate containing 1/2 randomly disordered cyclohexanone molecule and one water molecule per formal salt unit. The unit cell parameters for the monoclinic crystals are as follows: a=15.231(2), b=14.946(2), c=13.070(2) Å, -104.23(1)°, space group P2₁/c, Z=4. The methyl groups in the compound studied occupy the 2-equatorial and 5-axial positions relative to the piperidine ring. Taking account of the equatorial positions of the substitutents at the 1- and 4-positions of the piperidine ring, the compound designated should be designated the rel-(1R,2R,4S,5R) isomer. The cation has an extended conformation with ordinary geometric parameters. The relative arrangement of the pharmacophoric groups in the cation (benzene rings A and F, piperidine ring D, and the amide fragment) is similar to that for the groups in T-shaped morphine-like molecules.Institute of Fine Organic Chemistry, Academy of Sciences of the Armenian SSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 5, pp. 102–107, September–October, 1989.     

Using localized surface plasmons to modify the optical properties and conformational rearrangements of organic dye molecules

Optical properties of the molecular layers of cyanine dyes and their modification in a nearby field of silver nanoparticles on a sapphire substrate are investigated experimentally. Enhancement of the fluorescence and absorption intensity of organic molecules in the presence of silver nanoparticles is observed. The results from photomodifications of the molecular layers’ absorption properties with and without the presence of silver nanoparticles are described.     

Fine structures and switching of electrical conductivity in labyrinth silver films on sapphire

Changes in electrical resistance of silver films were measured in the range from 10¹³ to 10³ Ω during thermal deposition on sapphire in a high vacuum, after the deposition over time, and under an applied voltage. The dependences of the electrical resistance of the films on their thickness and deposition rate were determined. It was established that, with an increase in the film thickness from 2 to 10 nm during the deposition at rates of 0.6 and 0.1 Å/s, the resistance decreases by 7.5 and 4 orders of magnitude, respectively. The measured dependences of the resistance on the deposition time were found to be close to exponential. The room-temperature resistance of 10-nm-thick films deposited at different rates changed spontaneously by 3–4 orders of magnitude in different ways: the resistance of the slowly deposited films spontaneously increased, whereas in the rapidly deposited films, it spontaneously decreased. After fine annealing, the steady-state resistance changed also differently: it increased by 2 orders of magnitude in the former case and by 9 orders of magnitude in the latter case. Under voltages above 5 V, the resistance of the rapidly deposited films abruptly decreased from ～10¹² to ～10⁶ Ω, and these films became ohmic. After fine annealing, they became again high-ohmic. Under voltages above 5 V, the high-ohmic films thus obtained became again low-ohmic. This cycle of electrical conductivity switching was reproduced many times. The observed phenomena were explained in the framework of the hypothesis of the formation of fine metastable structures in channels of labyrinth films, namely, protrusions and bridges that bring together the boundaries of islands and connect them into conducting clusters, respectively.