Boron-oxygen silicon bond

Alkyl silyl ethers are cleaved by a variety of reagents Whether the silicon-oxygen or the carbon-oxygen bond is cleaved depends on the nature of the reagent used Treatment of alkoxysilanes with electrophilic reagents like antimony tri-fluonde, 40% hydrofluonc acid, or a boron tnfluonde-ether complex results in the cleavage of the silicon-oxygen bond to form mono-, di-, and tnfluorosiloxanes or silanes [19, 20, 21) (equations 18-20)... 

X-Rav Diffraction. Borosilicate molecular sieves have been studied by X-ray diffraction (1.16-20 ). X-ray diffraction techniques have been developed to determine the degree of substitution of the silicate framework by borate tetrahedra (291. The boron-oxygen bond is shorter than the the silicon-oxygen bond, which leads to a contraction of the unit cell for a borosilicate molecular sieve as boron substitution increases. The unit cell volume determined from peak positions in the ranges 2O°<20<35< and 45°<20<5O° or an empirical parameter termed ST (sum of four d spacings) correlated with structural boron content (29). 

This chapter deals with the formation of new C—C bonds by alkylation of sp -hybridized carbanions stabilized by a range of heteroatoms, including oxygen, boron, silicon, phosphorus and the halogens. The properties of the same carbanions with additional stabilization provided by an adjacent double bond are also discussed. 

Oxidative addition to carbon atoms C2 and C3 has been extensively studied but is not covered here 1-10. Carbon-halogen, oxygen-hydrogen, carbon-hydrogen, carbon-carbon, boron-boron, silicon-hydrogen, and other bonds react, yielding complex products. These studies are of little synthetic value except for reactions between the C3 atom and olefins ... 

Bond angles and some bond lengths at the oxygen atom in boron, silicon, phosphorus and sulphur derivatives... 

Boron (like silicon) invariably occurs in nature as 0X0 compounds and is never found as the element or even directly bonded to any other element than oxygen. The structural chemistry of B-O compounds is characterized by an extraordinary complexity and diversity which rivals those of the borides (p. 145) and boranes (p. 151). In addition, vast numbers of predominantly organic compounds containing B-O are known. 

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