Sulfur silicon—oxygen bonds

Among the silicon-chalcogen double-bond compounds, the silicon-sulfur doubly-bonded compounds (silanethiones) are considered to be easier to synthesize, since it has been predicted by the theoretical calculations that a silicon-sulfur double bond is thermodynamically and kinetically more stable than a silicon-oxygen double bond (silanone)13,14. According to the calculations, the lower polarization of Si=S compared to Si=0 should lead to a lower reactivity of Si=S. In addition, H2Si=S (1) is calculated to be by 8.9 kcal mol-1 more stable than its divalent isomer, H(HS)Si , whereas H2Si=0 (2) is by 2.4 kcal mol-1 less stable than H(HO)Si . 

The sulfur-oxygen bond is an important feature of sulfur chemistry, just as the silicon-oxygen bond is of silicon chemistry. The best-known simple oxides are the dioxide, SO2, and the trioxide, SO3 (although highly reactive lower oxides SO and S2O have been described). The bonding in SO2 and SO3 is usually described in terms of S=0 double bonds, VSEPR theory predicting the shapes shown in Structures 12.14-12.17. 

Covalent bonds are very strong bonds formed when atoms share electrons with neighboring atoms. Sulfur, and both of carbon s natural forms, graphite and diamond, are covalently-bonded minerals. So is quartz, which contains only silicon and oxygen. 

B. By oxidation Carbon-Phosphorus Bond Carbon-Silicon Bond Carbon-Halogen Bond Oxygen-Oxygen Bond Sulfur-Sulfur Bond... 

In the case of base-induced elimination, the Peterson alkenation relies on the strong bond formed between silicon and oxygen, and the ready propensity for silicon to be attacked by alkoxide, to drive the reaction. In the original study by Peterson, the -silylcarbinols were prepared by the addition of (trimethylsilyl)methylmagnesium chloride to the carbonyl. The caibinols were subsequently eliminated by treatment with sodium or potassium hydride or with sulfuric acid to form the methylene derivatives in excellent yield. The Peterson reaction has proven to be of general utility in the synthesis of alkenes. ... 

The silicon-halogen, silicon-oxygen, and silicon-sulfur bonds of the haiogenosil-anes, siiyl ethers, and siiyi thioethers are cleaved by reaction with LAH, AIH3, or DIBAH, and the corresponding siiyl hydrides are obtained [CGI, CG2]. Ultrasound activation can be applied [LG2] (Figure 5.9), Anionic pentacoordinated silicon compounds are reduced to hydrogenosilanes by LAH or DIBAH [BC6]. 

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