Reactions of acyl iodides R1COI (R1=Me, Ph) with trialkyl(alkynyl)silanes,-germanes, and stannanes (R2C≡CMR 3 3 ; M=Si, Ge, Sn) were studied. Acyl iodides reacted with the germanium and tin derivatives with cleavage of the M-Csp bond and formation of the corresponding trialkyl(iodo)germanes and-stannanes R 3 3 MI (M=Ge, Sn) and alkynyl ketones R1C(O)C≡CR2 and R1C(O)C≡CC(O)R1. By contrast, the reaction of acetyl iodide with ethynyl(trimethyl)silane gave only a small amount of 1,2-diiodovinyl(trimethyl) silance as a result of iodine addition at the triple bond. Bis(trimethylsilyl)ethyne failed to react with acetyl iodide.

The thermal transformations and degradation of poly(germasylethyne) were studied in the 20-1000degreesC range using the methods of thermogravimetry, X-ray powder diffraction, elemental analysis, IR and Raman spectroscopy, and scanning electron microscopy. The germanium-containing polymer differs from its silicon-containing analog, first, by a lower crosslinking temperature and, second, by the instability of thermolysis products formed at 300-600degreesC in air, by the evolution of the crystalline phase of germanium in the products of thermolysis at 800degreesC, and by the formation of a hexagonal modification of silicon carbide and graphite under certain conditions of thermolysis at 1000degreesC.

Thermolysis of poly(dimethylsilethyne) and poly(dimethylsilethenesiiethy ne) was studied at temperatures up to 1700 degreesC by the methods of IR and Raman spectroscopy, high-resolution solid-state C-13 NMR spectroscopy, scanning electron microscopy, and thermogravimetric analysis. A continuous evolution of the thermolysis products includes, first, the formation of a silicon carbide phase, crystallization, and beta-alpha transition, and, second, the formation of condensed aromatic structures at the initial stages. the consumption of these groups to accomplish the formation of silicon carbide, and the ordering and subsequent crystallization of carbon phases.

The products formed during thermolysis of organosilicon polymers containing unsaturated carbon-carbon bonds have been studied within the temperature range 20–1700°C by means of XRD, 13 C and 29 Si MAS NMR, and Raman spectroscopy. These products are distinguished by their structural instability. A continuous evolution of the products formed during organic–inorganic thermal transformation involves (i) ordering of the local surroundings of silicon atoms, the formation of a silicon carbide crystalline phase, and the transition from β to α and (ii) consumption of carbon for the completion of silicon carbide formation, carbon phase formation, and ordering.

The thermolysis of [-Si-(CH3)(2)C=C-](n) under vacuum and argon to 1400 degrees C gives silicon carbide containing ceramics. The polymer-ceramics transition was studied using the thermal analysis, infrared spectroscopy, solid-state Si-29 NMR spectroscopy, X-ray diffraction analyses, SEM analysis. The schemes of cross-polymerization of [-Si-(CH3)(2)C=C-](n) are discussed. A distinctive feature of polydimethylsilethyne is the presence of crystal phase conserving its stability up to 600 degrees C which is the starting point of the transition from organic to inorganic material.

The process of trans formation of a new polycarbosilane (polysilethenesilethyne) into a ceramic substance was studied in the temperature range 20-1500 degrees C. The solid products, derived at different stages of the polysilethenesilethyne pyrolysis, were studied by IR spectroscopy, X-ray diffraction analysis, and Si-29 MAS NMR. The chemical species in the gases escaping from the precursor as a result of pyrolysis was identified. One can easily formulate arguments in favor of polysilethenesylethyne due to the simplicity of synthesis, technological efficiency for the production of advanced SiC ceramics, and relatively high ceramic yield.

AbstractReaction of the silyl ethynyl ketones (I) with dithiocarbamic acids, prepared in situ from carbon disulfide (II) and the secondary amines (III) gives the acylvinyl dithiocarbamates (IV).

ChemInformVolume 21, Issue 39 Organoelement Compounds ChemInform Abstract: (Organylethynylchalcogenomethyl)trimethoxysilanes and 1-(Organylethynylchalcogenomethyl)silatranes. M. G. VORONKOV, M. G. VORONKOV Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this authorM. S. SOROKIN, M. S. SOROKIN Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this authorO. G. YAROSH, O. G. YAROSH Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this authorM. F. LARIN, M. F. LARIN Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this authorN. M. BORODINA, N. M. BORODINA Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this author M. G. VORONKOV, M. G. VORONKOV Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this authorM. S. SOROKIN, M. S. SOROKIN Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this authorO. G. YAROSH, O. G. YAROSH Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this authorM. F. LARIN, M. F. LARIN Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this authorN. M. BORODINA, N. M. BORODINA Irkutsk. inst. org. khim. Sib. otd. AN SSSRSearch for more papers by this author First published: September 25, 1990 https://doi.org/10.1002/chin.199039257Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume21, Issue39September 25, 1990 RelatedInformation

We synthesized 1-methyl-1-ethynylsilacyclopentane, which is the first reported 1-ethynylsilacycloalkane. The reactivities of this silahydrocarbon and its magnesium bromide derivative were studied.