In organosilicon chemistry, organosilanols are a group of chemical compounds derived from silicon. More specifically, they are carbo silanes derived with a hydroxy group (−OH) on the silicon atom. [1] 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. [2] [3]
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):
or by hydrolysis in the alkaline: [4]
The hydrolysis of
silyl ethers generally proceeds only slowly:
[4]
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 tri alkylsilanes is significantly slower than that of tri arylsilanes. 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. [5]
Depending on the substitution pattern of the silicon atom, a further distinction can be made. Organosilanols are classified as:
In organosilicon chemistry, organosilanols are a group of chemical compounds derived from silicon. More specifically, they are carbo silanes derived with a hydroxy group (−OH) on the silicon atom. [1] 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. [2] [3]
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):
or by hydrolysis in the alkaline: [4]
The hydrolysis of
silyl ethers generally proceeds only slowly:
[4]
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 tri alkylsilanes is significantly slower than that of tri arylsilanes. 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. [5]
Depending on the substitution pattern of the silicon atom, a further distinction can be made. Organosilanols are classified as: