Triphenylborane

Triphenylborane

Names
Preferred IUPAC name Triphenylborane
Identifiers
CAS Number	960-71-4  Y
3D model (JSmol)	Interactive image
ChemSpider	63579  Y
ECHA InfoCard	100.012.277
EC Number	213-504-2
PubChem CID	70400
UNII	6282553L0G  Y
CompTox Dashboard (EPA)	DTXSID6027345
InChI InChI=1S/C18H15B/c1-4-10-16(11-5-1)19(17-12-6-2-7-13-17)18-14-8-3-9-15-18/h1-15H Y Key: MXSVLWZRHLXFKH-UHFFFAOYSA-N Y InChI=1/C18H15B/c1-4-10-16(11-5-1)19(17-12-6-2-7-13-17)18-14-8-3-9-15-18/h1-15H Key: MXSVLWZRHLXFKH-UHFFFAOYAV
SMILES B(c1ccccc1)(c2ccccc2)c3ccccc3
Properties
Chemical formula	B(C6H5)3
Molar mass	242.13 g·mol−1
Appearance	White crystals
Melting point	142 °C (288 °F; 415 K)
Boiling point	203 °C (397 °F; 476 K) (15 mmHg)
Solubility in water	Insoluble
Structure
Molecular shape	trigonal planar
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H228
Precautionary statements	P210, P240, P241, P280, P370+P378
Related compounds
Related isoelectronic	Triphenylmethyl cation
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N  verify  (what is  YN ?) Infobox references

Triphenylborane is an chemical compound with the chemical formula B(C₆H₅)₃, often abbreviated to BPh₃, 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.

Structure and properties

The core of the compound, BC₃, has a trigonal planar structure. The phenyl groups are rotated at about a 30° angle from the core plane. ^[1]

Even though triphenylborane and tris(pentafluorophenyl)borane are structurally similar, their Lewis acidity is not. BPh₃ is a weak Lewis acid while B(C₆F₅)₃ is a strong Lewis acid due to the electronegativity of the fluorine atoms. Other boron Lewis acids include BF₃ and BCl₃. ^[2]

Synthesis

Triphenylborane was first synthesized in 1922. ^[3] It is typically made with boron trifluoride diethyl etherate and the Grignard reagent, phenylmagnesium bromide. ^[4]

BF₃·O(C₂H₅)₂ + 3 C₆H₅MgBr → B(C₆H₅)₃ + 3 MgBrF + (C₂H₅)₂O

Triphenylborane can also be synthesized on a smaller scale by the thermal decomposition of trimethylammonium tetraphenylborate. ^[5]

[NH(CH₃)₃]⁺[B(C₆H₅)₄]⁻ → B(C₆H₅)₃ + N(CH₃)₃ + C₆H₆

Applications

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. ^[6]

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. ^[6]

References

1. Zettler, F.; Hausen, H. D.; Hess, H. (1974). "Crystal and Molecular Structure of Triphenylborane". J. Organomet. Chem. 72 (2): 157. doi:10.1016/S0022-328X(00)81488-6.
2. Erker, G. (2005). "Tris(pentafluorophenyl)borane: a special boron Lewis acid for special reactions". Dalton Trans. (11): 1883–90. doi:10.1039/b503688g. PMID   15909033.
3. E. Krause & R. Nitsche (1922). "Darstellung von organischen Bor-Verbindungen mit Hilfe von Borfluorid, II.: Bortriphenyl und Phenyl-borsäure". Chemische Berichte . 55 (5): 1261. doi:10.1002/cber.19220550513.
4. R. Köster; P. Binger & W. Fenzl (1974). "Triphenylborane". Inorganic Syntheses. Vol. 15. pp. 134–136. doi:10.1002/9780470132463.ch30. ISBN   978-0-470-13246-3.{{cite book}}: |journal= ignored (help)
5. G. Wittig; P. Raff (1951). "Über Komplexbildung mit Triphenyl-bor". Liebigs Annalen der Chemie . 573: 195. doi:10.1002/jlac.19515730118.
6. C. R. Guibert and J. L. Little, “Alkyl- and Arylboranes,” Ullmanns’s Encyclopedia of Industrial Chemistry, Wiley-VCH Verlag, Weinheim, 2005. doi : 10.1002/14356007.a04_309