Triphenylborane is a chemical compound with the chemical formula , often abbreviated to , where Ph is the phenyl group. It is a white crystalline solid and is both air and moisture sensitive, slowly forming benzene and triphenylboroxine. It is soluble in aromatic solvents.
The core of the compound, , has a trigonal planar structure. The phenyl groups are rotated at about a 30ð angle from the core plane.
Even though triphenylborane and tris(pentafluorophenyl)borane are structurally similar, their Lewis acidity is not. is a weak Lewis acid while is a strong Lewis acid due to the electronegativity of the fluorine atoms. Other boron Lewis acids include and .
Triphenylborane was first synthesized in 1922. It is typically made with boron trifluoride diethyl etherate and the Grignard reagent, phenylmagnesium bromide.
Triphenylborane can also be synthesized on a smaller scale by the thermal decomposition of trimethylammonium tetraphenylborate.
Triphenylborane is made commercially by a process developed by Du Pont for use in its hydrocyanation of butadiene to adiponitrile, a nylon intermediate. Du Pont produces triphenylborane by reacting sodium metal, a haloaromatic (chlorobenzene), and a secondary alkyl borate ester.
Triphenylborane can be used to make triarylborane amine complexes, such as pyridine-triphenylborane. Triarylborane amine complexes are used as catalysts for the polymerization of acrylic esters.