Organosilanols Silanols

Organic amines, eg, pyridine and piperidine, have also been used successfully as catalysts in the reactions of organosilanes with alcohols and silanols. The reactions of organosilanes with organosilanols lead to formation of siloxane bonds. Nickel, zinc, and tin also exhibit a catalytic effect. 

Organosilanols are analogous to alcohols the most common are simple silanols of the type R3SiOH, but compounds of the types R2Si(OH)2, silanediols, and RSi(OH)3, silanetriols, are also well known. Between... 

Organosilanols are important intermediates in the synthesis of silicones [5]. Among the different approaches to these species [5], the most convenient is the hydrolysis of organochlorosilanes. This reaction can be transfered to ferrio-chlorosilanes, e. g. la-c, which give the corresponding ferrio-silanols 2a-c in high yield, provided an auxiliary base is present (Eq. (1)). 

The conventional methods for the synthesis of organosilanols can be accomplished by the hydrolysis of the appropriate substituted silane in the presence of catalysts such as an acid or a base.1 This synthetic route, however, had some difficulty when applied to the synthesis of silanol polymers which demanded not only high conversion of the functional groups for polymer modification but also resistance to the transformation of silanols to siloxane by self- or catalytic condensation during the preparation. 

Condensation of organosilanols with transition metal halides is well established [3], but comparable reactions of metallo-silanols, which should provide a convenient entrance into the field of siloxy-bridged multinuclear complexes, has not been realized. In this context we have carried out the reaction of ferrio- and tungsten-silanols L,M-SiMe20H (L M = Cp(OC)2Fe (1) CsR5(OC)2(Me3P)W, R = H (5a), Me(5b)) with the electron deficient metal halides CpnMCh (w = 2, M = Ti, Zr n = 1, M = Ti). 

Due to their important role as intermediates in the technical synthesis of silicones, organosilanols have been the subject of extensive studies over several decades [2], In context with studies on the reactivity of functionalized silicon-transition metal complexes a new type of silanols containing an Si-bonded transition metal has been established. Access to these metallosilanols is opened by the hydrolysis of metallohalosilanes [3] and by the oxygenation of metallosilanes with dimethyl-dioxirane [4]. Recently also a catalytic pathway for the SiH/SiOH conversion in the case of... 

The silanols are organosilicon compounds containing Si-OH groups. Because of their tendency to undergo condensation, with formation of siloxanes and water, until relatively recently this class has been considered dfficult to handle and silanols were little investigated. The chemistry of organosilanols has been the focus of more attention in recent years and sufficient representatives have been isolated in the solid state, and their structures determined by X-ray diffraction [1, 2], to provide an in-... 

Silanol functional groups have been long recognized as reactive intermediates in silicon chemistry. They are formed in the hydrolysis of silanes with various silicon functional groups, such as halosilanes, alkoxysilanes, etc., and then transformed into siloxanes by spontaneous or catalytic condensation. Owing to this tendency, only a limited number of organosilanols have so far been synthesized. 

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