Organosilicon compounds, hexacoordinated

OrganometaUic compounds, of transition metals as catalysts for polymerization of vinyl monomers and olefins, 23 263-325 OrganometaUic transformation, molecular analogs, 38 288, 290-291 Organophosphorus substrates, hydrolysis of, effect of cycloamyloses on, 23 235 Organosilicon compounds, hexacoordinated, 34 155... 

Indirect evidence in favor of the coordinative binding is the existence of the hexacoordinated organosilicon compounds. However, a counterargument is that ammonia, possessing a greater ability for coordinative binding than... 

Summary 2-(Trimethylhydrazino)phenyl substituted organosilicon compounds 3, 4, and 5 were prepared. Their NMR spectra reflect the pentacoordination of the silicon center in solution at room temperature. Compound 5 is hexacoordinated in the solid state, whereas 4 shows pentacoordination. The phenyltrimethylhydrazino as well as the dimethylbenzylamino substituent proved to be highly suitable for the intramolecular stabilization of silyl cations. 

It should be noted here that Corriu and co-workers have reported on organosilicon compounds containing C,N-chelating ligands in which the silicon atom is penta- or hexacoordinate (55-58). Such organosilicon compounds are models for the intermediates proposed for the activation of enoxysilanes by F leading to cross-aldolizations or Michael reactions (59). 

This review is not the first to discuss the structural chemistry of organosilicon compounds. There have been a few earlier reviews discussing various aspects of the structural chemistry of organosihcon compounds. The stereochemistry of elements of Group 15 and 16 bonded to silicon was reviewed in 1973 °. In 1985 the geometry of silatranes was reviewed and simulation of the reaction pathway for Sis/2 substitution reactions at tetrahedral silicon using structural data was published. Later on, in 1986, the structural chemistry of tricoordinate silicon was reviewed and the X-ray and NMR studies on penta- and hexacoordinate silicon compounds were summarized. The most comprehensive review on the structural chemistry of organosilicon compounds was published in 1989 by W. S. Sheldrick ... 

The structural chemistry of organosilicon compounds 3. Si-F bond in compounds with hexacoordinate siiicon... 

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