Triphenylsilane

Structural formula
General
Surname	Triphenylsilane
other names	1,1 ′, 1 ′ ′ - silylidynetrisbenzene NSC 12565 Triphenylhydridosilanes
Molecular formula	C 18 H 16 Si
Brief description	colorless solid
External identifiers / databases
CAS number 789-25-3 EC number 212-333-0 ECHA InfoCard 100.011.212 PubChem 6327682 Wikidata Q63391650
properties
Molar mass	260.41 g mol −1
Physical state	firmly
Melting point	43-45 ° C
boiling point	152 ° C (at 3 hPa )
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 315-319 P: 305 + 351 + 338
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Triphenylsilane is a chemical compound from the group of organosilicon compounds .

Extraction and presentation

Triphenylsilane, by hydrogenation of chlorotriphenylsilane with a reducing agent such as lithium aluminum hydride or lithium hydride are obtained:

${\displaystyle \mathrm {4\ ClSi(C_{6}H_{5})_{3}+\ LiAlH_{4}\ {\xrightarrow {}}\ 4\ HSi(C_{6}H_{5})_{3}\ +\ LiCl\ +\ AlCl_{3}} }$

The preparation from trichlorosilane by reaction with phenylmagnesium bromide in a Grignard reaction is also possible:

${\displaystyle \mathrm {HSiCl_{3}+3\ (C_{6}H_{5})MgBr\ {\xrightarrow {}}\ HSi(C_{6}H_{5})_{3}\ +3\ MgBrCl} }$

properties

Silanes such as triphenylsilane are essentially stable to hydrolysis . In the presence of acidic and basic catalysts such as triethylamine or potassium hydroxide , however, it is converted to silanol with evolution of hydrogen :

${\displaystyle \mathrm {(C_{6}H_{5})_{3}SiH+\ H_{2}O{\xrightarrow[{}]{Katalysator}}\ (C_{6}H_{5})_{3}SiOH\ +\ H_{2}} }$

It reacts with amines, in turn, splitting off hydrogen and forming triphenlysilylamines, although triple substitution on the nitrogen atom is not observed:

${\displaystyle \mathrm {2(C_{6}H_{5})_{3}SiH+\ NH_{3}{\xrightarrow[{}]{Katalysator}}\ ((C_{6}H_{5})_{3}Si)_{2}NH\ +\ H_{2}\ \ Katalysator=NaNH_{2}} }$

Reaction with chlorine , bromine and iodine produces the corresponding halides:

${\displaystyle \mathrm {(C_{6}H_{5})_{3}SiH+\ X_{2}\ {\xrightarrow[{}]{}}\ (C_{6}H_{5})_{3}SiX\ +\ HX\ \ X=Cl,Br,I} }$

In the presence of Lewis acids such as aluminum chloride , the chlorides and bromides can also be obtained by reaction with hydrogen chloride or hydrogen bromide :

${\displaystyle \mathrm {2(C_{6}H_{5})_{3}SiH+\ HX\ {\xrightarrow[{}]{AlX_{3}}}\ (C_{6}H_{5})_{3}SiX\ +\ HX\ \ X=Cl,Br} }$

Triphenylsilane reacts with sodium-potassium alloy to form potassium triphenylsilicide, which then dimerizes with another triphenylsilane molecule to form hexaphenyldisilane:

${\displaystyle \mathrm {(C_{6}H_{5})_{3}SiH+\ Na/K\ {\xrightarrow[{}]{}}\ (C_{6}H_{5})_{3}SiK\ +\ NaH} }$

${\displaystyle \mathrm {(C_{6}H_{5})_{3}SiK\ +\ HSi(C_{6}H_{5})_{3}\ {\xrightarrow[{}]{}}\ (C_{6}H_{5})_{3}Si-Si(C_{6}H_{5})_{3}} }$

use

Triphenylsilane is used in preparative chemistry as a reducing agent, especially for halogenated hydrocarbons , alcohols and ketones . For the latter, it is also used as a protecting group .

safety instructions

Triphenylsilane has a flash point of 76 ° C.

Individual evidence

1. ↑ ^{a b c d e f} data sheet triphenylsilanes from Sigma-Aldrich , accessed on September 22, 2018 ( PDF ).
2. ↑ ^{a b c d e f} Barry Arkles: Silanes . In: Gelest (Ed.): Kirk-Othmer Encyclopedia of Chemical Technology . Forth ed. Volume 22 , p. 38–69 (English, gelest.com [PDF; accessed December 10, 2016]).
3. ^ E. Fischer, G. Schott, AD Petrow: Addition and substitution reactions with triorganosilanes . In: Journal for Practical Chemistry . tape 21 , no. 3-4 , September 1963, pp. 157 , doi : 10.1002 / prac.19630210305 .
4. ↑ Gerald L. Larson: Silicon-Based Reducing Agents. (PDF) (No longer available online.) Gelest, formerly in the original ; accessed on July 5, 2015 .  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.