S. V. Basenko

Cleavage of siloxanes with organyltrifluoro- and diorganyldifluorosilanes

Abstract Hexamethyldisiloxane is cleaved with organyltrifluoro- or diorganyldifluorosilanes as low as 20°C in the absence of catalysts to form earlier unknown 1,1,1-trimethyl, 3-organyl-3,3-difluoro- or 1,1,1-trimethyl-, 3,3-diorganyl-3-difluorodisiloxanes with the general formula R 4- n SiF n - 1 OSi(CH 3 ) 3 ( n = 2-3) in 57-97% yield. The SiO bond in 1,1,3,3-tetramethyldisiloxane is broken with organyltrifluoro- or diorganyldifluorosilanes in a similar manner but more slowly to give 1,1-dimethyl-, 3-organyl-, 3,3-difluoro- or 1,1-dimethyl, 3,3-diorganyl-, 3-fluorodisiloxanes with the general formula R 4- n SiF n -1 OSi-H(CH 3 ) 2 ( n =2-3) in 50-70% yield. The reaction of phenyltrifluorosilane with 1,1,1,3,3,5,5,5-octamethyltrifluorosiloxane leads to 1,1,1,3,3-pentamethyl-, 5,5-difluoro-, 5-phenyltrisiloxane, whereas the reaction with tetrakis (trimethylsiloxy)siloxane gives tri(trimethylsiloxy)difluoro(phenyl)silane. Even under normal conditions of storage, the cleavage products disproportionate readily in different directions. The ability of these compounds to disproportionation depends on the nature of the substituents attached to the silicon atom and the number of fluorine atoms in the molecule.

Reactions of organylhalosilanes with 1,1,3,3-tetra- and hexamethyldisilazane

Organylchlorosilanes, and also SiCl4, decompose 1,1,3,3-tetra- and hexamethyl-disilazanes with formation of hitherto unknown organylchlorosilazanes of general formulas R4−nSiCln−1NHSiH(CH3)2 and R4−nSiCln−1NHSi(CH3)3 (n=2−4) in yields of 54–98%. The IR and mass spectra of the prepared compounds were studied.

Reactions of organyltrifluoro- and diorganyldifluoro- silanes with 1,1,3,3-tetramethyldisiloxane

Abstract1,1,3,3-Tetramethyldisiloxane is decomposed by organyltrifluoro- and diorganyl- difluorosilanes already at 20‡C in the presence of catalysts with formation of hitherto unknown 1,1-dimethyl-3,3-diorganyl-3-fluoro- and 1,1-dimethyl-3-organyl-3,3-difluorodisiloxanes of general formula R4−nSiFn−1OSiH(CH3)2 (n=2−3) in yields of 50–70%. On storing these decomposition products easily disproportionate in various directions, in which their propensity to disproportionation is determined by the nature of the substituents at the silicon atoms and the number of fluorine atoms in the molecule.

Alkoxy(acyloxy)silanes

ConclusionsAlkoxychlorosilanes react with trimethylacyloxysilanes to give the difficultly accessible alkoxy(acyloxy)silanes of general formula (RO)nSi(OCOR)4-n (n=1–3) in 60–80% yields.

A chromato-mass spectrometric study of the disproportionation of organylfluorosiloxanes

ConclusionA chromato-mass spectrometric study showed the tendency of organylfluorosiloxanes to undergo disproportionation depending on the nature of the substituents and number of fluorine atoms in the molecule.

Chromato-mass spectral study of the reactions of organylsiloxanes with metal oxides

A study was carried out on the reaction of 1,1,3,3-tetramethyldisiloxane with metal oxides such as CuO, HgO, and Sb2O5 in the presence of compounds containing a siloxane bond such as hexamethyldisiloxane, octamethylcyclotetrasiloxane, and trimethylacetoxysilane, which, at 100–110°C over 0.5–10 h, leads to the formation of linear organyl siloxanes (CH3-[-Si(CH3)2O-]n-Si(CH3)3, CH3-[-Si(CH3)2O-]n-Si (CH3)2H, and H-[-Si(CH3)2O-]n-Si(CH3)2H, where n=2–6, and cyclic organylsiloxanes. The reaction does not proceed in the presence of aluminum, bismuth, germanium, and lead oxides.

Investigation of silyl-substituted alkylthioacetates by IR and UV spectroscopy,1H and29Si NMR, and mass spectrometry

ConclusionsThe IR, UV, NMR, and mass spectra of silyl-substituted alkylthioacetates have been investigated. Intramolecular coordination of the carbonyl group with the silicon atom has been shown to exist in molecules of trifluoroaeetylthiomethylsilane in the condensed state and in a polar solvent (acetonitrile).

Mechanism for reaction of trimethylacetoxysilane with alkoxystibines and organylalkoxystannanes

ConclusionsThe high resolution chromato-mass spectrometry method was used to study the mechanism for the reaction of trimethylacetoxysilane, labeled with18O, with triethoxystibine and triethylmethoxystannane, and it was shown that the reaction proceeds via the formation of two types of intermediate cyclic complexes.

PMR and mass spectra of 1-organylsilatrane-3,7,10-triones

ConclusionsPMR and mass spectra of a series of 1-organylsilatrane-3,7,10-triones were studied, and paths of their dissociative ionization were proposed.