Vibronic properties of 2-azaanthracene and its derivatives

We report an experimental and theoretical (PPP method) study of the UV absorption spectra of 2-azaanthracene and four of its methyl-substituted derivatives. We find that the p bands of these compounds consist of two different vibronic ^* bands. Our experimental and theoretical results suggest a rule for evaluating the effect of methyl groups on ^* transition energies as a function of the charge on the atoms. We interpret the reasons for the different effects of a polar solvent and hydrogen bonding on the ^* bands of these compounds.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 7–15, June, 1977.     

Mass spectra of benzylpyridines

The mass spectra of dimethylbenzyl- and dimethyldibenzylpyridines at different ionizing electron energies were investigated. The anomalously low intensities of the molecular ion peaks of 3,4-dibenzylpyridines, as compared with the 2,5-isomers, and the greater probability of the formation of primary (M-2)⁺ ions in the mass spectra are explained by the synchronous loss of a neutral H₂ particle and the formation of cyclic fragment ions from the weakly excited molecular ions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 70–73, January, 1973.     

On real matrices with positive definite symmetric component

Inequalities concerning real square matrices A with positive definite symmetric component A+A^*are derived from certain inertia relations which hold for any complex (not necessarily real) square matrices A with positive definite

A+A^*     

Peculiarities of Morphology of Tin Microcrystals Electroplated under Galvanostatic Conditions

Russian Journal of Electrochemistry - Specific features of morphology of structure of tin microcrystals, which form during the electrodeposition under the galvanostatic conditions on the...     

Denitrocyclization in synthesis of dibenzo[b,f][1,4]thiazepin‐11(10h)‐ones and their derivatives

A convenient synthesis of the novel dibenzo[b,f][1,4]thiazepin‐11(10H)‐ones is reported. As a key step, the synthetic route includes intramolecular aromatic denitrocyclization of 2‐(2,4‐dinitro‐phenylsulfanyl)‐benzoic acid amides. Efficient procedures for denitrocyclization in the presence of different bases are developed. Reduction of the nitro group in the obtained heterocycles resulted in formation of primary amines, which were transformed into amides by acylation with different carboxylic acids. The synthesized compounds have a great potential of bioactivity and are useful objects for biomedicinal screening.     

On the Minimum Length of Fluorescence Enhancement upon Laser Pumping of Randomly Inhomogeneous Media

JETP Letters - Intense laser radiation leads to irreversible changes in the crystal structure of a target, which are used in laser shock peening technologies. Processes determining the thickness of...     

Esters of (1,2, 5-trimethyl-4-hydroxy-4-piperedyl)- and phenyl-(1,2, 5-trimethyl-4-hydroxy-4-piperidyl) acetic acids

The methyl ester of a new hydroxy acid of the piperidine series (-phenyl--(1,2, 5-trimethyl-4-hydroxy 4-piperidyl)acetic acid) has been prepared. Ethyl -(1,2, 5-trimethyl-4-hydroxy-4-piperidyl)acetate has been converted into the substituted pyridine, 1,1-diphenyl-2-(2-5-dimethyl-4-pyridyl)ethylene.     

Evolution of the morphology of small pentagonal particles and microcrystals during the electrodeposition of silver in a potentiostatic regime

A procedure for obtaining icosahedral and decahedral small particles and microcrystals of silver is presented. The evolution of the morphology during growth is studied in detail. Mechanisms of the relaxation of elastic stress fields in small silver particles and microcrystals with pentagonal symmetry are found experimentally.