Triphenylphosphine

Triphenylphosphine (PPh₃) is a phosphine ligand often used in organometallic chemistry and coordination chemistry. It is a common and versatile reagent characterized by its bulky size and its ability to stabilize metal complexes. The compound consists of a phosphorus atom bonded to three phenyl groups.

Properties

Triphenylphosphine is a white, crystalline solid at room temperature. It is soluble in many organic solvents, such as diethyl ether, benzene, and acetone. The molecule is relatively stable in air, although it can slowly oxidize, turning yellow upon prolonged exposure to air due to the formation of phosphine oxide.

Synthesis

The synthesis of triphenylphosphine involves the reaction of chlorobenzene with phosphorus trichloride in the presence of a base such as sodium. This process is known as the Schwenk synthesis:

3 C₆H₅Cl + PCl₃ → P(C₆H₅)₃ + 3 HCl

Applications

Triphenylphosphine finds extensive use in the field of organic synthesis and catalysis. It acts as a ligand for various metal catalysts involved in processes such as the Suzuki coupling and the Mizoroki-Heck reaction. Additionally, it is used in the synthesis of phosphonium salts, which are intermediates in the Wittig reaction for the formation of alkenes.

Safety

Triphenylphosphine is generally considered to be of low toxicity, but it should be handled with care. It can cause irritation to the skin, eyes, and respiratory system. Proper personal protective equipment should be worn when handling this chemical.

See Also

• Phosphine
• Organometallic chemistry
• Coordination chemistry
• Catalysis