{{Short description|Organic compounds of the form R3–Si–OH}} [[File:Trimethylsilanol.svg|thumb|Structure of trimethylsilanol.]]
In organosilicon chemistry, '''organosilanols''' are a group of chemical compounds derived from silicon. More specifically, they are carbosilanes derived with a hydroxy group ({{chem2|\sOH}}) on the silicon atom.<ref name="Gold Book">{{GoldBookRef|title=silanols|file=S05664}}</ref> Organosilanols are the silicon analogs to alcohols. Silanols are more acidic and more basic than their alcohol counterparts and therefore show a rich structural chemistry characterized by hydrogen bonding networks which are particularly well studied for silanetriols.<ref name="AIC_1995_42_147">{{citation|surname1=Paul D. Lickiss|periodical=Advances in Inorganic Chemistry|title=The synthesis and structure of organosilanols|series=Advances in Inorganic Chemistry |volume=42|year=1995|pages=147–262|language=en|doi=10.1016/S0898-8838(08)60053-7|isbn=978-0-12-023642-8 }}</ref><ref name="CCR_2016_323_87">{{citation|surname1=Rudolf Pietschnig, Stefan Spirk|periodical=Coordination Chemistry Reviews|title=The Chemistry of Organo Silanetriols|volume=323|year=2016|pages=87–106|language=en|doi=10.1016/j.ccr.2016.03.010}}</ref>
== Preparation == Organosilanols can be obtained by hydrolysis of organohalosilanes, such as chlorotrimethylsilane. They can also be prepared by the oxidation of organosilanes with oxidizing agents (R = organic residue): :<chem>R2SiCl2{} + 2 HgO ->[-80^{\circ}C][toluene] R2Si(OH)2{} + 2 Hg^0</chem>
or by hydrolysis in the alkaline:<ref name="Kirk-Othmer">{{cite web|title=Silanes|periodical=Gelest|url=http://www.gelest.com/wp-content/uploads/Silicon_Hydrides.pdf|access-date=2016-12-10|last=Barry Arkles|pages=50}}</ref>
:<chem>(H3C)3SiCl + H2O -> (H3C)3SiOH + HCl</chem> :<chem>R3SiH + H2O -> R3SiOH + H2</chem>
The hydrolysis of silyl ethers generally proceeds only slowly:<ref name="Kirk-Othmer" /> :<chem>(H5C2)3SiOC2H5 + H2O -> (H5C2)3SiOH + HOC2H5</chem>
Hydrolysis of organosilanes is a first-order reaction. The hydrolysis rate of the Si-H bond depends on the type and number of organic residues. Thus, the hydrolysis rate of trialkylsilanes is significantly slower than that of triarylsilanes. This can be explained by a stronger increase in electron density on the silicon atom by the alkyl groups. Correspondingly, the reaction rate of the tri-''n''-alkylsilanes decreases in the series of ethyl, propyl, butyl groups. Trialkylsilanes with ''n''-alkyl residues react by a factor of 10 faster than the analogous silanes with branched alkyl residues.<ref name="ZAAC_1960_306_180">{{citation|surname1=G. Schott, C. Harzdorf|periodical=Zeitschrift für anorganische und allgemeine Chemie|title=Silane. I Alkalische Solvolyse von Triorganosilanen|volume=306|issue=3–4|pages=180–190|date= October 1960|language=de|doi=10.1002/zaac.19603060306 }}</ref>
== Classification == Depending on the substitution pattern of the silicon atom, a further distinction can be made. Organosilanols are classified as: * organosilanetriols, when three hydroxy groups and an organic residue are bound to a silicon atom, e. g. methylsilanetriol, phenylsilanetriol * organosilandiols, when two hydroxy groups and two organic residues are bound to a silicon atom, e. g. dimethylsilanediol, diphenylsilanediol * organosilanols, when one hydroxy group and three organic residues are bound to a silicon atom, e. g. trimethylsilanol, triethylsilanol or triphenylsilanol.
== References == {{Reflist}}
Category:Organosilicon compounds Category:Silanols {{Commonscat|Organosilanols|Organosilanole}}