1-Hydro-3-vinylhexamethylcyclotetrasiloxane and its polymerization

1,3-Dimethyl-3-vinyl-1,3-dichlorosiloxane is prepared by partial cohydrolysis of methylvinyldichlorosilane and methyldichlorosilane, and its cohydrolysis with sym-tetra-methyldichlorodisiloxane gives 1-hydro-3-vinylhexamethyl-cyclotetrasiloxane. A study is made of the kinetics of the polymerization of the latter in CCL₄ in the presence of H₂PtCl₆ · 6H₂O     

New dinuclear palladium complex with a Chinese-lantern structure

The new dinuclear palladium complex Pd₂(-S,N-SC₇H₅N₂)₄ with a Chinese-lantern structure was synthesized by the reaction of K₂PdCl₄ with 2-mercaptobenzimidazole and structurally characterized by X-ray diffraction analysis.     

Imidazoline ring cleavage in 1,3,6,10-tetraazatetracyclo-[7.3.1.02,7.06,13]trideca-4, 11-dienes,leading to the formation of diquinoxalino[1,2-a∶2′,3′-d]pyrrole derivatives

Dibenzo[d,k]-1,3,6,10-tetraazatetracyclo[7.3.1.0^2,7.0^6,13]trideca-4,11-dienes undergo addition reactions at the C₍₂₎ carbon atom with alcohols and thiols, accompanied by cleavage of the C-N bond of the imidazoline ring, to generate diquinoxalino[1,2-a2,3-d]pyrrole derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 513–522, April, 1987.     

Heterocyclization of compounds containing diazo and cyano groups. 4. Reactions of 2-diazo-2-cyanoacetic acid amides with P4S10 and the lawesson reagent. Synthesis and recyclization of 5-amino-1,2,3-thiadiazole-4-carbothioamides

5-Amino-1,2,3-thiadiazole-4-carbothioamides were obtained in the reaction of carbonyl derivatives of diazoacetonitrile with P₄S₁₀ and the Lawesson reagent. A novel recyclization of 1,2,3-thiadiazole-4-carbothioamides was observed.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 845–849, June, 1987.     

Spectral study of the conversion of porphyrins during interaction with molecular negative ions

In the interaction of ethioporphyrin and of several of its metal derivatives with negative ions of pyridine and anthracene in tetrahydrofuran solutions, an electron transfer takes place which results in the conversion of the pyridine and anthracene ions into neutral molecules, whereas the molecules of the pigment are first transformed into monovalent anions and subsequently into the di-, tri-, tetra-, and sometimes even into the hexavalent anions. In the first stage of this interaction, ferriethioporphyrin is reduced to ferro-ethioporphyrin, whereas the unmetallized pigment and its copper complex are transformed into the disodium derivative of ethioporphyrin. When the temperature is lowered, the rate of the electron transfer from pyridine ions to zinc-ethioporphyrin is decreased, and illumination leads to a substantial rate increase. The photochemical sensitivity of this system is possibly linked to the formation of stable complexes between pigment molecules and pyridine ions.     

A radioanalytical technique to study the behavior of organic toxicants applied to a study of the photodegradation of 2,3,7,8-tetrachlorodibenzo-p-dioxin

A general method for tritium labeling of organic compounds by the use of thermal activation of tritium is described. It allows obtaining uniformly tritium-labeled organic compounds with high specific activity (up to 50 Ci/mmol) which permits tracing the majority of the biodegradation products of compounds studied. More than 40 compounds were labeled using this simple, rapid and inexpensive method. Separation of the biodegradation products is performed by thin layer chromatography. Quantification is performed by direct measurement of the radioactivity by liquid scintillation counting after transfer of the layer from TLC plates into scintillation vials, or by densitometry of autoradiographs. The technique is useful for a wide range of organic compounds, including ones with unknown structure, and can be applied to various in vivo and in vitro studies.     

Mechanical Properties and Structure of Zinc-Containing Latex-Silicate Composites

The sol-gel technology is highly efficient for improving mechanical and thermal properties of polydiene elastomers by creating in them additional inorganic networks composed mainly of silica or silicates. The incorporation of modifying Zn ions into polydiene latex-silica systems increases considerably their mechanical characteristics due to an increase of the interaction between the organic and inorganic networks. Interpenetrating polydiene-silica networks were prepared by cohydrolysis of tetraethoxysilane and zinc acetate in natural Qualitex or synthetic butadiene-styrene latexes and then by aging and drying the liquid compositions at room temperature and vulcanizing at 90°C. Their structure and properties were studied by the IR spectroscopy, TMA and by tensile testing of the prepared films. The studied system was shown to be extremely suitable for obtaining latex films with improved elastic and strength characteristics. For example, the elastic modulus values of the Qualitex films containing 2–5% SiO₂ and 0.1–0.2% ZnO, are 4–9 and 6–11 times higher than those of the films prepared without zinc and of the pure latex films respectively. The possible structure roles of zinc ions at various stages of film preparation and vulcanization are discussed on the base of the results of IR and TMA studies.     

Effect of the Λ n interaction on the cross section of the reaction γd → K+Λ n

Taking into account the n interaction, a nonrelativistic graphical technique is used to calculate the differential cross section of the reaction d K⁺ n as a function of photon energy, K⁺-momentum, and angle of emission of the K⁺. The kinematic region in which variation of the n-scattering parameters gives the most noticeable effect is separated out.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 104–106, August, 1978.The author thanks G. M. Radutskii and V. A. Filimonov for many useful discussions.     

Formation and Transformations of Polynuclear Hydroxo- and Oxotrimethylacetate Complexes of Ni(II) and Co(II)

Transformations of polymeric trimethylacetate complexes [M(OH) _n (OOCCMe₃)_{2 – n} ] _m (M = Ni (I) and Co (II)) and clusters Ni₉(₄-OH)₃(₃-OH)₃(-O,O-OOCCMe₃)(-O,O"-OOCCMe₃)₇(₃-O,O,O"-OOCCMe₃)₃(₄-O,O,O",O"-OOCCMe₃)(HOOCCMe₃)₄(III) and Co₆(₃-OH)₂(-OOCCMe₃)₁₀(HOOCCMe₃)₄(VIII), which are formed from Iand IIupon their recrystallization from nonpolar solvents, were studied. It was shown that the action of N-phenyl-o-phenylenediamine (L) on Ior IIIresults, depending on the solvent, in different tetranuclear clusters with the hydroxo bridges. For example, in benzene, the L₂Ni₄(₃-OH)₂(HOOCCMe₃)₄(-OOCCMe₃)₆complex (IX) is formed; its L molecules are coordinated in a monodentate way, whereas in acetonitrile, they chelate to give the {[o-C₆H₄(NH₂)(NHPh)]₂Ni₄(₃-OH)₂(MeCN)₂(OOCCMe₃)₂(-OOCCMe₃)₄} compound (X). Heating of Xin the presence of atmospheric oxygen yields IX, the mononuclear bissemiquinonediimine [o-C₆H₄(NH)(NPh)]₂Ni complex (XI), and water. It was noted that the use of aniline in these reactions affords, independent of the nature of the solvent, only one (NH₂C₆H₅)₂Ni₄(₃-OH)₂(HOOCCMe₃)₄(-OOCCMe₃)₆cluster (VI); in acetonitrile, this cluster is formed as the solvate VI· 2HOOCCMe₃(VIa). When treated with ethanol, Iand IIIgive the Ni₄(EtOH)₆(₃-OH)₂(₂-OOCCMe₃)₄(OOCCMe₃)₂cluster (V), which is structurally close to the known cobalt-containing analog IV. Thermolysis of IVin decalin at 170° causes its dimerization, giving the octanuclear Co₈(₄-O)₂( _n -OOCCMe₃)₁₂complex (VII) with the tetradentate oxo bridges.