Chemical Properties
Triphenylsilane is an off-white solid that is soluble in most organic solvents. It is used in certain cases for the preparation of triphenylsilyl ethers, which serve as alcohol-protecting groups. The triphenylsilyl group is considerably more stable (about 400 times) than the TMS group toward acidic hydrolysis.
Uses
Triphenylsilane acts as a reactant or reagent for catalytic hydrogen deuterium exchange reactions of silanes, to be oxidized by carbon nanotube-gold nanohybrids, for hydrolysis by ruthenium complexes, for hydrosilylation to produce enolsilanes, for synthesis of bromosilanes, for ozone oxidation of silyl-alkenes for synthesis of α-O-silylated acyloin derivatives. It is used to synthesize hydrido silyl and bis(silyl) bis(imidazolinylidene) nickel complexes.
Preparation
Triphenylsilane can be synthesized by reducing phenylsilane (PhSiH3) with a reducing agent such as lithium aluminum hydride (LiAlH4). The overall reaction equation is as follows:
3 PhSiH3 + 2 LiAlH4 → C18H16Si + 2 LiH + 2 AlH3
This reaction is typically carried out in anhydrous conditions and under inert gas atmosphere.
Application
More effective radical-based reagent for reduction of organic halides than the trialkylsilanes.
Compares well with tri-n-butyltin hydride in reduction of enones to ketones.
Shows good selectivity in the reduction of cyclic hemiacetals.
Converts O-acetyl furanoses and pyranoses to deoxy sugars.
Hexaphenyldisiloxane can be conveniently made by the action of aqueous alkali on triphenylsilane, Ph3SiH.
Tristriphenylsilylbismuth, (Ph3Si)3Bi, is made similarly from triethylbismuth and triphenylsilane: Et3Bi+3Ph3SiH==Heat==(Ph3Si)3Bi+3EtH.
storage
This reagent is stable in the air. Because the toxicogical properties are unknown, it should be handled in a well-ventilated fume hood. Contact with the eyes and skin should be avoided.
Purification Methods
Purify it by recrystallisation from MeOH. [Gilman & Zuech J Am Chem Soc 81 5925 1959, Westermark Acta Chem Scand 9 947 1955, IR: Kaplan J Am Chem Soc 76 5880 1954, Beilstein 16 II 605, 16 III 1199, 16 IV 1369.]
