PMe3

PMe3, or trimethylphosphine, is an organophosphorus compound with the formula P(CH3)3. It is a colorless, volatile, and air-sensitive tertiary phosphine that is widely used as a ligand in organometallic chemistry and homogeneous catalysis.

In terms of structure, the phosphorus atom bears a lone pair and three carbon substituents, giving a roughly pyramidal geometry. The three methyl groups donate electron density to an attached metal center, making PMe3 a strong sigma donor and relatively poor pi-acceptor compared with some aryl phosphines. The compound is typically stored under inert atmosphere and is readily oxidized by air to phosphine oxide derivatives.

Applications: PMe3 is used as a ligand for a range of transition metals (e.g., nickel, palladium, rhodium) to support hydroformylation, hydrogenation, and carbonylation catalysts, among others. It can form adducts with metal carbonyls such as Ni(CO)3(PMe3) and Pt(PMe3)4. In synthesis, it also serves as a reagent to generate phosphonium salts by alkylation; tertiary phosphines can be converted to phosphonium salts via reaction with alkyl halides.

Safety: PMe3 is toxic by inhalation and skin exposure; it is also flammable and reacts with air and moisture, so handling is typically conducted under inert atmosphere in a fume hood with appropriate protective equipment. Keep containers sealed and away from oxidizers.