Reactions of silanes with

Oxidation. AH inorganic siUcon hydrides are readily oxidized. Silane and disilane are pyrophoric in air and form siUcon dioxide and water as combustion products thus, the soot from these materials is white. The activation energies of the reaction of silane with molecular and atomic oxygen have been reported (20,21). The oxidation reaction of dichlorosilane under low pressure has been used for the vapor deposition of siUcon dioxide (22). 

The polymerization reaction of silanes with Cp2ZrMe2 as catalyst has also been investigated by several research groups. Some evidence for a reaction mechanism proceeding through silylene complexes as intermediates has been given... 

A similar elimination in which the tin is attacked by fluoride anions (cf. the reaction of silanes with F ) has been used179 to synthesize terminal methylene compounds as in equation (75). An analogous reaction sequence using a trimethylsilyl group in place of the trialkyltin group has been published by Hsiao and Shechter180 as part of a synthesis of substituted 1,3-butadienes. 

Another common deposition system is based on the reaction of silane with a hydrocarbon such as propane or benzene in the following simplified reactions ... 

Many catalytic reactions involve the activation of Si—H bonds and consequently the reaction of silanes with platinum(0) has been studied extensively. The reactions of hydrosilanes with transition-metal complexes, including platinum, has been extensively reviewed by Corey and Braddock-Wilking.58... 

The correlation of deposition rate with disilane concentration and the zero-barrier of the reaction of silane with silylene to disilane lead to the conclusion that the latter reaction is the dominant subsequent pathway following the silane fragmentation. Disilane shows two characteristic relaxation times, the slower being identical with the relaxation time of silane. In conclusion, the formation of... 

Alternatively, some conclusions can be derived from the relative reactivities of car-banions. For example, DePuy and colleagues13 made use of a clever method involving reactions of silanes with hydroxide ion to deduce acidities of such weak acids as alkanes and ethylene. The silane reacts with hydroxide ion to form a pentacoordinate anion that ejects a carbanion held as a complex with the hydroxysilane rapid proton transfer gives the stable silanoxide ion and the carbon acid (equation 5). 

Reaction of silanes with chlorine or bromine is violent. 

Several reactions of halogen-substituted carbon-centered radicals with silanes have been studied, but limited kinetic information is available for reactions of halogen-substituted radicals with tin hydrides. A rate constant for reaction of the perfluorooctyl radical with Bu3SnH was determined by competition against addition of this radical to styrenes, reactions that were calibrated directly by LFP methods.93 At ambient temperature, the n-C8F17 radical reacts with tin hydride two orders of magnitude faster than does an alkyl radical, consistent with the electron-deficient nature of the perflu-oroalkyl radical and the electron-rich character of the tin hydride. Similar behavior was noted previously for reactions of silanes with perhaloalkyl radicals. 

Despite the potential for atomic-scale manipulation of interfaces displayed by molecular-beam epitaxial growth, a majority of the vapor-phase growth of silicon is accomplished by the reaction of silane with silicon substrates This... 

Ion cyclotron resonance (ICR) spectroscopy has been used to determine the reaction enthalphy (A//r) of hydride-transfer reaction of silanes with various hydrocarbons having known hydride affinities (Reaction 2.19). The hydride affinities of R3Si+, D//(X3Si+—H ) = Affbase, were obtained from Equation (2.20) and are summarized in Table 2.6 [30,31]-... 

Scheme 9.5. Reactions of Silanes with a,p-Unsaturated Carbonyl Compounds... 

The Harrod group has investigated dehydrocoupling reactions of silanes with amines, hydrazines, and ammonia. In the presence of catalytic amounts of CuCl, hydrosilanes react with primary amines to give silazanes in high yields.180 For example, the reaction of phenylmethylsilane with benzylamine leads to a mixture of three products, with dependence on initial molar ratio of silane to amine [Eq. (72)]. Equimolar silane to amine ratio leads to formation of 1 as major product, whereas 2 is the main product if a 2 1... 

Vinylsilanes react with boron trichloride to give the corresponding borodesilylation products in good yield which, in turn, can be transformed into boronic esters 124 by alcoholysis (equation 102). The initial dichloroorganoborane products can be used directly in the Suzuki-Miyaura cross-coupling reaction192. Replacement of a carbon-silicon bond by a carbon-tin bond in fluorinated alkenes (e.g. 125) can be achieved by the reaction of silanes with Bu3SnCl and KF in DMF under mild conditions (equation 103)193. It is... 

An alternative mechanism for the base-promoted reaction of silanes with silica has been described by Blitz et al.83 In this mechanism, the base attacks directly to the surface silanols. The bonded amine renders the silanol more nucleophilic which then attacks the silicon atom of an approaching silane, giving rise to a pentacoordinate intermediate. 

Reaction of silanes with a Ti=S complex to form an S-Si bond is reversible and analogous to that for H2 addition (Scheme 7) (106). 

The only homogeneous catalyst that has been systematically studied for the reaction of silanes with ammonia is Cp2TiMe2.147 This catalyst is effective for tertiary, secondary, and primary organosilanes, but the products from secondary and primary organosilanes are quite complex and strongly dependent on the reaction conditions. Reasonable rates were achieved at temperatures of 70 to 100°C, at partial pressures of 1 to 2 atm NH3, and at a catalyst concentration of ca. 1 mol % relative to silane. Some typical results are shown in Table V. 

Reactions of silanes with cyclopentadienyl Ta imides are a new method to yield hydrides. Addition of the... 

In reactions of silanes with complexes containing metal-group-IVB bonds metal-bonds are formed by exchange ... 

Other established routes to silicon nitride involve silicon sulfide intermediates (equations 5a and 5b) (8, 9), the reaction of silane with ammonia (equation 6) (10), or the reactions of various chlorosilanes such as silicon tetrachloride with ammonia (equations 7-8) (11-17) ... 

In this article we concentrate on the first step of the reactions, viz. the initial reaction of silanes with the square-planar Pt(II) complexes (PnN)Pt(X)CH3 (X = CH3, H, Cl, SiH3). Only stereochemical aspects of the initial oxidative addition/reductive elimination reactions (Scheme 1) are considered in this contribution. Energetic aspects and details of the reaction mechanisms were discussed elsewhere [4 - 6], Some of the conversions of the Pt(II) complexes shown in Scheme 1 are endothermic, and therefore only occur if succeeded by another energy-releasing reaction, for example in a catalytic cycle. 

There are three main batch process protocols for reaction of silanes with Grignard reagents. Addition of the silane to the Grignard reagent (normal addition) is preferred when full substitution is desired. The reaction is single-pot , in that the Grignard can be formed and then reacted without transfer. An example of a product produced by normal addition is triethylsilane. Addition of the Grignard to the silanes (reverse addition) is preferred... 

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