Adiabatic theory of the vibronic states of the topological isomers of polyatomic molecules. Calculation of optimal conditions for optical stimulation of isomeric rearrangements

The problem of calculating the probability of optical transitions between the topological isomers of polyatomic molecules is considered. It is shown that the adiabatic approximation can be extended to this case. It is suggested that under certain conditions an “unoccupied” isomeric state can be populated or light-stimulated accumulation of one isomer can be achieved. This opens up prospects for designing molecular elements for computer memory. V. I. Vernadskii Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 6, pp. 994–1005, November–December, 1996. Translated by I. Izvekova     

Crystal-chemical mechanism in the fundamental absorption of MgO crystal

Correlations between structural, thermal, and optical properties of MgO are shown as linear dependences of the energy ε of the photons absorbed by the crystal on the enthalpy of sublimation ΔH of the crystal to molecules, atoms, ions, and electrons. This dependence holds true only if in different schemes of crystal sublimation the values of ΔH are calculated for the cell MgO rather than its formula unit. M. V. Lomonosov Moscow State University, Geological Faculty. IGEM, Moscow. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 2, pp. 283–288, March–April, 1996. Translated by I. Izvekova     

Algorithm for estimating molecular dissymmetry

A simple criterion for estimating molecular dissymmetry and an algorithm of its calculation are suggested. Calculations are performed for compounds belonging to different point groups. The new molecular characteristic may be used to predict the magnitude and sign of optical rotation. Chelyabinsk State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 3, pp. 500–506, May–June, 1998.     

Structural,vibrational, and energy characteristics of halide molecules of group II–V elements

Correlations between the internuclear distances r(M-X), the bond energies E(M-X), and the valence force constants f_r for di- and trihalides of Group II–V elements are established. Some missing values are estimated. Ivanovo State Chemical Technological Academy. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 5, pp. 859–875, September–October, 1996. Translated by L. Smolina Ivanovo State Chemical Technological Academy. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 5, pp. 859–875, September–October, 1996.     

Action of gaseous ammonia and water on neodymium diphthalocyanine

The method of flow injection into the gas flow with detection of current resistance of the film was used to investigate the action of ammonia and water vapor on neodymium diphthalocyanine film. The value and sign of the electrophysical response are reversible at 18–22°C. When the film contacts with vapor, the current is changed within a few seconds, whereas the relaxation to the initial value when vapor is removed occurs within tens of seconds. The response parameters are suitable for developing effective sensors based on resistant films. No optical changes in the absorption spectra of the films were observed in the 400–800 nm region under the action of ammonia and water vapor. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1446–1447, July, 1998.     

Blue and green centers in natural apatites by ERS and optical spectroscopy data

Using ESR and optical spectroscopy we showed that the blue coloring is imparted to natural apatites by SO ₃ ⁻ radicals and the green coloring is due to SiO ₃ ⁻ radicals complexed with rare earth ions, SiO ₃ ⁻ -(Ce³⁺+K). The role of U⁴⁺ and Th⁴⁺ isomorphous actinide ions in the process of color center formation is investigated. United Institute of Geology, Geophysics, and Mineralogy, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Struktumoi Khimii, Vol. 36, No. 1, pp. 89–101, January–February, 1995. Translated by L. Smolina     

Reactions of calix[4]resorcinolarene anions with esters of carboxylic acids in H2O−DMF solvent

Reactions of calix[4]resorcinolarene anions withpara-nitrophenyl carboxylates in the H₂O−DMF medium were studied. The kinetics of this process was measured by optical spectroscopy and potentiometric titration; the step of formation of acylated calixarene and the subsequent step of its hydrolysis were detected. Self-association of long-chain calixarenes into micelles decreases their reactivity with respect to that of the monomers. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya No. 2, pp. 258–261, February, 2000.     

Oxidation of aryl vinyl sulfides in the ButOOH−Ti(OPri)4−(R,R)-diethyl tartrate system

Oxidation of aryl vinyl sulfides into aryl vinyl sulfoxides in the Bu¹OOH−Ti(OPrⁱ)₄−(R,R)-diethyl tartrate system was studied. The process afforded low optical yields (no more than 5%). A model of the oxidation was proposed that allows interpreting the dependence of the reaction enantioselectivity on the structure of a substrate. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1872–1873, September, 1998.     

Second harmonic generation in polymers containing dithiosquarylium dye

Polymer layers containing the dye 2,4-bis(1,3,3-trimethyl-2-indolinylidenemethyl)-1,4-dithiosquaraine display second-order nonlinear optical properties. Depending on conditions of preparation of the layers, the monomer form of the dye or the intermolecular charge transfer complex between two dye molecules are responsible for the second harmonic generation. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 86–91, January, 1999.     

Spontaneous raman spectroscopic study of the association of liquid γ-butyrolactone molecules

Self-association of γ-butyrolactone molecules in pure liquid state and in nonpolar solutions is studied by spontaneous Raman spectroscopy. The constant and the enthalpy of formation of cyclic dimers in liquid γ-butyrolactone are calculated. Ufa State Aircraft Technical University. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 6, pp. 1099–1103, November–December, 1996. Translated by L. Smolina     

Disymmetry indices based on optical rotational polarizability of chiral molecules

New molecular disymmetry indices are suggested based on an analysis of the moments of rotational polarizability defining optical activity. It is shown that the fourth moment of rotational polarizability coincides with the electron-kinematic index of chirality, introduced previously by one of the authors. The norm of imaginary frequency rotational polarizability is suggested for use as an additional disymmetry index. Illustrative Hartree-Fock calculations of these chirality indices with the 6-31G basis set are performed for hydrogen peroxide, water trimer, and some amino acids. Kharkov State University. Rostov State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 2, pp. 319–327, March–April, 1998.     

Proceedings of the 12th International Seminar on Intermolecular Interactions and Molecular Conformations

Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 5, pp. 771–774, September–October, 1995.     

Cyclopalladation of Schiff's bases in the ruthenocene series. The possibility of application of the asymmetric version of the reaction to metalloceneimines

p-Tolyliminoalkylruthenocenes—Schiff's bases of the ruthenocene series—react with sodium tetrachloropalladate in the presence of carboxylate anion similarly to their ferrocenyl analogs to give cyclopalladation products. The optical rotation values of the products resulting from carbonylation of palladated ferrocene and ruthenocene aldimines, prepared under conditions of asymmetric catalysis, followed by liberation of the aldehyde group were used to determine the stereochemistry and enantiomeric purity of the cyclopalladation products. Centre Nationale de Recherches Scientifiques, URA 419 4, pl. Jussieu, Bat. F, 75252 Paris, France. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1421–1424, July, 1998.     

Electronic spectra of low-spin bioctahedral Fe(II)−Fe(III) mixed-valence dimers

Moldavian State University. Translated fromZhurnal Struktumoi Khimii, Vol. 36, No. 1, pp. 185–189, January–February, 1995.     

Group-theoretical classification of the resonance states of mixed-valence clusters

Moldova State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 4, pp. 743–747, July–August, 1995.     

Synthesis of o-carborane-C-carboxylates of certain natural terpene alcohols, sterols, phenols, and camphar oxime

Previously unreported esters 1b–20b were synthesized from natural terpene alcohols, sterols, plant phenols, and camphar oxime (1a–20a) by reaction with o-carborane-C-carboxylic acid chloride. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 434–436, September–October, 2006.     

Crystal structure of (BOPDT-TTF)+I 5 − :C10H8O2I5S8

Natural Science Institute of Perm State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 5, pp 193–197, September–October, 1994.     

Equalization of interatomic distances in polymorphous transformations under pressure

High Dynamic Pressures Center, Mendeleevo. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 3, pp. 133–136, May–June, 1994.     

Concentration effects on the1H NMR parameters of rhodamine 6G

Kaliningrad State University. Translated fromZhurnal Struktumoi Khimii, Vol. 36, No. 4, pp. 756–760, July–August, 1995.     

Calculation of rotation matrices for real spherical harmonics

N. G. Chernyshevskii Saratov State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 1, pp. 128–130, January–February, 1994.