A MALDI mass spectrometry investigation of the compositions of the products of the partial acidolysis of MeSi(OMe)3

The molecular-mass compositions of the products of partial acidohydrolytic polycondensation that are formed during the interaction of MeSi(OMe)₃ with CH₃COOH have been studied via MALDI mass spectrometry. It has been shown that, depending on the molar ratio of MeSi(OMe)₃ and CH₃COOH (m/n), a wide range of oligomethylmethoxysiloxanes with the average composition [MeSiO _n/m (OMe)_{(3 ? 2n/m)}] _p are formed. The analysis of molecular masses and ²⁹Si NMR spectra of the products has revealed various types of molecular structures, which change from linear, branched, and cyclic to polycyclic clusters with condensed cycles after a change in the degree of polycondensation α = 100 × [2n/3m] from 66.67 to 83.33%. At a degree of polycondensation of α = 86.67% or higher, the polycyclic clusters form a spatially crosslinked structure (gel).     

Solvent Regeneration in Direct Synthesis of Alkoxysilanes

A procedure was developed for regeneration of Termolan, solvent used in synthesis of alkoxysilanes, involving its treatment with ethanol to remove alkoxysilanes.     

Energy of a Two-Dimensional Helium Atom in an Excited State

Russian Physics Journal - Using perturbation theory methods and a variational method, we have calculated the energy of a twodimensional helium atom in its lower excited states, this energy showing...     

The Rao–Reiter Criterion for the Amenability of Homogeneous Spaces

We prove that a homogeneous space G/H, with G a locally compact group and H a closed subgroup of G, is amenable in the sense of Eymard–Greenleaf if and only if the quasiregular action π_Φ of G on the unit sphere of the Orlicz space L^Φ(G/H) for some N-function Φ ∈ Δ₂ satisfies the Rao–Reiter condition (P_Φ).     

Molecular and crystal structure of 2,4,4,6,6,8,8-heptamethyl-2-[3-{[2,4,4,6,6-pentakis(dimethylamino)-2,2,4,4,6,6-hexa-hydro-1,3,5,2,4,6-triazatriphosphorine-2-yl]amino}propyl]-cyclotetrasiloxane

Molecular and crystal structure of the title compound has been determined. The (PN)₃ and (SiO)₄ rings form the dihedral angle of 100.1° and with the HNCH₂CH₂CH₂ plane the angles of 110.2° and 75.7° respectively. The molecular packing is built of alternating layers of (PN)₃ and (SiO)₄ beterocycles.     

Cyclization during the reaction of diphenyldiaminosilane with organosilanes

Four-membered cyclosilazans were obtained as a result of the reaction of diphenyldiaminosilane with diphenylsilane and methylphenylsilane in the presence of potassium trimethylsilanolate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 751–752, June, 1972.