Theoretical photoelectronic spectra of molybdenum, tungsten, and rhenium disilicides

Photoelectronic spectra of volume samples of molybdenum, tungsten, and rhenium disilicides are theoretically investigated as functions of the excitation energy (hv = 12–1486 eV) by the method of linearized attached plane waves. The main contribution to the spectrum at low (hv = 12–52 eV) and very high (hv = 1486 eV) excitation energies is given by the metal d-states, while the contribution of the Si p-states is dominant at intermediate excitation energies. An analysis of the calculated results demonstrates that the main peak of the photoelectronic spectra is displaced by 0.2 eV toward the bottom of the valence band when going from MoSi₂ to WSi₂; it is displaced by 0.3 eV when going from WSi₂ to ReSi_1.75. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 75–80, July, 2006.     

Cl35 NQR spectra and the transmission effects in the series RSO2Cl

Conclusions It was shown by correlating the Cl³⁵ NQR frequencies with the Taft _I and _c parameters that the effect of substituents, which are either capable of conjugation (Hal, OR, NR₂) or are alkyl groups, is transmitted to the chlorine atom through the SO₂Cl group by a practically purely inductive means.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 486–488, February, 1970.     

Benzindoles. 23. 2-formyl- and 3-formyl-4,5-benzindoles

It is shown that, in addition to the usually formed 3-formyl-4,5-benzindole, 2-formyl-4,5-benzindole can be obtained via the Vilsmeier reaction. The IR, PMR, and UV spectra of the 2- and 3-formyl isomers are compared, and their possible conformations are discussed.See [1] for Communication 22.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 343–345, March, 1984.     

Porphyrins. 33. Proton magnetic resonance spectra of hematoporphyrin derivatives. properties of a dimethoxy derivative (dimegin) in aqueous solution

The PMR spectra of derivatives of hematoporphyrin IX have been investigated in organic and aqueous solution. It has been shown that the presence of the two chiral centers at positions 2 and 4 of the macrocycle is displayed in the specific splitting of the signals of the meso protons. The structures of dimeric associates of 2,4-di(-methoxyethyl)-deuteroporphyrin IX (dirnegin) have been studied in aqueous solution over a wide pH range and have the structure of a skewed sandwich according to PMR data.For Communication 32, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 198–204, February, 1996.     

1H NMR and IR Spectroscopic Study of the Structure of the Major Component of the 99mTc HMPAO (Hexamethylpropyleneamino Oxime) Radiopharmaceutical Preparation

d,l-Hexamethylpropyleneamino oxime (HMPAO) was synthesized and isolated from a mixture of d,l - and meso-isomers. The structure of the conformers was studied using ¹H NMR spectroscopy over a broad range of pH. A method for estimating the amount of meso-form present in the mixture of isomers was proposed. It was shown that specific features of the IR spectra depend on the structure of the isomers and on the difference between the packing of molecules in the crystal lattice.     

Benzindoles

The previously undescribed tetrahydro[4, 5]- and tetrahydro[6, 7]benzindoles and some of their derivatives were synthesized by Fischer cyclization of pyruvic acid 5- and 6-tetralinylhydrazones. A linear isomer — tetrahydro[5, 6]benzindole^–and its derivatives were obtained only in a mixture with tetrahydro[4, 5]-benzindole. The geometrical isomers of the pyruvic acid hydrazones were isolated and characterized. A method for the separation of the mixtures of 5- and 6-aminotetralins was developed. The structures of the isolated compounds were confirmed by the PMR and IR spectral data.See [1] for communication XIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 634–640, May, 1978.     

Porphyrins

Treatment of porphyrins or their copper complexes containing meso-dimethylaminomethyl or meso-dimethylformaldimino groups with lithium borohydride or diborane leads to the corresponding aminoborane derivatives. The reaction of the aminoboranes with trifluoroacetic acid was investigated, and trifluoroacetoxyborane complexes were isolated.     

Sulphur electric properties at superhigh pressure around the polymerization temperatures

Abstract

The electrical resistivity temperature dependence of S has been studied in the diamond anvil cell (DAC) of the “rounded cone-plane” type. The pressure is about 50 GPa. The experimental data analysis shows the polymerization between 380–410 K. The electrical resistivity temperature dependence is distorted by a number of maxima, some of them being shifted along the temperature axis towards the lower temperature and disappear with increasing transport current.