Synthesis,properties, and antianemic activity of new metal complexes of sodium pectinate with iron and calcium

A new water-soluble complex based on sodium pectinate with iron and calcium (P-NaFeCa) was synthesized. The regularities of the complexation of sodium pectinate (with a 35% content of COONa groups) with biogenic metals Ca and Fe were studied. The content of macro- and microelements was determined by atomic emission spectrometry; the product was identified by IR spectroscopy. Using atomic force microscopy, it was found that the average particle size of P-NaFeCa is ~170 nm. The efficiency of P-NaFeCa (per os) was studied for the first time in animals with hemolytic anemia modeled by administration of phenylhydrazine. It was experimentally shown that in vivo P-NaCaFe at a dose of 60 mg kg^–1 containing 50% of the recommended therapeutic dose of iron helps to recover the number of erythrocytes and mean concentration hemoglobin in erythrocyte, which indicates the efficiency of P-NaCaFe as an agent restoring the blood parameters after exposure to hemolytic poisons.

     

Numerical modeling of the motion of a torsion balance in the problem of measuring the Newtonian gravitational constant

The motion of a torsion balance with five degrees of freedom has been numerically simulated. It has been shown that the oscillations along the swing degrees of freedom are excited by the random noise of the seismic origin and their amplitude varies with time. It has been shown also that the nonlinear couplings between the swing and torsion degrees of freedom result in the appearance of combination oscillations. The methods for effectively suppressing these combination oscillations have been considered.     

Reactions of sodium pentaphosphacyclopentadienide with half-sandwich iron complexes

Reactions of sodium pentaphosphacyclopentadienide NaP₅ with half-sandwich iron phosphine complexes gave pentaphosphaferrocenes or ferrocenes, depending on the nature and number of substituents in the cyclopentadienyl ring.     

Cycloaddition reactions of 1-Alkyl-3,4,5-triphenyl-1,2-iphosphacyclopenta-2,4-dienes in the coordination sphere of tungsten carbonyl

1-Alkyl-3,4,5-triphenyl-1,2-diphosphacyclopenta-2,4-dienes react with tungsten hexacarbonyl under the conditions of “indirect” replacement of the carbonyl group to give 1: 1 complexes; [4+2] cycloaddition reactions of these complexes with maleic acid derivatives and substituted acetylenes afford tungsten carbonyl complexes containing 10-alkyl-1,10-diphosphatricyclo[5.2.1.0^2.6]deca-8-ene-3,5-diones and 1-alkyl-2,3-diphenylphosphirenes, respectively.     

Measurement of Density Inhomogeneity for Glass Pendulum

The density inhomogeneity of a glass pendulum is determined by an optical interference method. The relative variations of the densities over a volume with sizes of 5 × 5×5 mm^3 are （0.64 ± 0.97） × 10^-5 and （0.99 ± 0.92） × 10^-5 for the K9 glass and silica glass pendulum, respectively. These variations of densities contributing to the relative uncertainties of the Newtonian gravitational constant G are 0.20 ppm and 0.21 ppm in our experiment on measurement of G.     

Space Navigation by X-Ray Pulsars

This review considers the problem of autonomously determining the position of a spacecraft in space based on the analysis of pulses emitted by X-ray pulsars. The characteristics of the prospective equipment and lists of pulsar candidates for reference sources are given. The navigation algorithm and resulting accuracy characteristics are substantiated.     

NMR study of the Ni complexes based on 1-alkyl-1,2-diphospholes

Russian Chemical Bulletin - The structures of the nickel complexes based on 1-alkyl-1,2-diphospholes in a solution were determined using 1D/2D homo- and heterocorrelation NMR experiments. The...     

DFT study of substitution effect on the geometry, IR spectra, spin state and energetic stability of the ferrocenes and their pentaphospholyl analogues

Optimal structures, vibrational spectra and thermochemical characteristics of ferrocenes and pentaphosphaferrocenes containing up to five methyl substituents in the cyclopentadienyl ring are found with the use of DFT computations. It is shown that the non-substituted ferrocenes and pentaphosphaferrocenes as well as the species with small number of methyl substituents adopt eclipsed conformations. Increasing the number of the methyl substituents results either in the conformational equilibria between the eclipsed and staggered forms or in complete shift to the staggered conformations. These effects, as well as elongation of CC bonds of the Cp ring and growth of Fe-Cp and Cp-P₅ distances with growing number of methyl groups can be explained by repulsive interactions of the methyl groups with each other or with phosphorus atoms of the pentaphospholyl ligands. The pentaphosphaferrocenes are predicted to be stable towards disproportionation to homoleptic sandwich complexes. This stability grows as the number of methyl substituents in cyclopentadienyl ring increases, which is a result of stronger Fe-P₅ bonding in the methyl substituted pentaphosphaferrocenes relative to the non-substituted species, and destabilization of the homoleptic ferrocenes because of Me?Me repulsion. A huge energy gap between the low- and high-spin states of the ferrocenes and pentaphosphoferrocenes is predicted, though introduction of methyl substituents causes a moderate decrease of the gap. Transition from low- to high-spin state should result in pronounced changes of geometry and IR spectra of the ferrocenes, which suggests that IR spectroscopy can be used for diagnostics of spin state of iron complexes.     

Trisodium heptaphosphide in reactions with alkyl and aryl tosylates

Reactions of trisodium heptaphosphide with alkyl tosylates gave dialkylheptaphosphides or trialkylheptaphosphines, depending on the stoichiometric ratios of the starting reagents. A method for determination of the coupling constants of the asymmetric isomer of trialkyl-heptaphosphines was proposed. Reactions of the heptaphosphide trianion with aryl tosylates yielded disodium hexadecaphosphide. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 289–293, February, 2007.