Triphenylphosphine is a member of the class of tertiary phosphines that is phosphane in which the three hydrogens are replaced by phenyl groups. It has a role as a reducing agent. It is a member of benzenes and a tertiary phosphine. ChEBI. Triphenylphosphine (PPh3) is an organophosphorus reagent with molecular formula C18H15P and CAS number 603-35-0. It is widely used as a nucleophilic phosphorus donor and coordinating ligand in homogeneous catalysis, as a reagent in Mitsunobu and Staudinger reactions, and as a mild inorganic reducing agent for halides and some organic functional groups. PPh3 is a crystalline, moderately air sensitive compound with a melting point near 80 to 83 C and a density around 1.08 to 1.10 g mL-1. It is soluble in aromatic and chlorinated organic solvents and reacts slowly with oxygen to form triphenylphosphine oxide. Typical analytical identifiers include 31P NMR chemical shift near -5 to -7 ppm in CDCl3 and characteristic aromatic signals in 1H and 13C NMR spectra.
Parent: Triphenylphosphine
Commercial triphenylphosphine is typically supplied with purity grades from technical 95 to 99.9 percent; common related impurities and their typical amounts are triphenylphosphine oxide (TPPO) 0.1 to 3.0 percent depending on grade and storage history, residual solvents and low boiling volatiles 0.01 to 0.5 percent, water not more than 0.2 percent for reagent grade, and trace metal contaminants often below 10 ppm for high purity batches. Other related phosphorus species such as diphenylphosphine or small amounts of substituted triarylphosphines are usually below 0.1 to 0.5 percent. TPPO forms by oxidation on exposure to air or protic solvents and is the most common degradation product; purification methods include recrystallization from ethanol or hexane and column chromatography over silica or neutral alumina to reduce TPPO to subpercent levels.
Triphenylphosphine is used as a nucleophilic phosphorus reagent, a ligand in transition metal catalysis, and as a mild reducing agent in organic synthesis; typical applications include formation of organophosphorus intermediates, activation steps in cross coupling and hydrogenation catalysts, Mitsunobu and Staudinger reactions, and as a scavenger for halides and peroxides.
PPh3 is a neutral, monodentate soft donor ligand that binds through phosphorus; it is a sigma donor with modest pi-acceptor ability, commonly classified as a strong field phosphine ligand whose steric and electronic properties can be tuned by substitution on the phenyl rings.
Triphenylphosphine oxide is primarily a byproduct of reactions using PPh3 but can be isolated and used as a ligand in some metal complexes, a high boiling polar aprotic solvent additive, or as a reagent in crystallography and materials chemistry; it is also a common impurity that is removed when pure PPh3 is required.
Triphenylphosphine is harmful if swallowed and can cause skin and eye irritation; it is combustible and may oxidize on exposure to air to form TPPO, so it should be handled under an inert atmosphere for sensitive operations, with appropriate personal protective equipment and proper ventilation.
