| IUPAC name
| Other names
|Molar mass||76.079 g/mol|
|Appearance||Colorless volatile liquid|
|Density||0.738 g/cm3 (20 °C)|
|Melting point||−86 °C (−123 °F; 187 K)|
|Boiling point||38 °C (100 °F; 311 K)|
|Solubility||Miscible with THF, toluene|
|Vapor pressure|| 374.3 mmHg at 20 °C|
1232.6 mmHg at 55 °C
|Safety data sheet||Sigma-Aldrich|
|Flash point||−19 °C (−2 °F; 254 K)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Trimethylphosphine is the organophosphorus compound with the formula P(CH3)3, commonly abbreviated as PMe3. This colorless liquid has a strongly unpleasant odor, characteristic of alkylphosphines. It is often used as ligand in coordination chemistry.
Trimethylphosphine is a weak base, but does form stable salts with strong acids.
Trimethylphosphine is a highly basic ligand that forms complexes with most metals. As a ligand, trimethylphosphine's Tolman cone angle is 118°.
Being a relatively compact phosphine, several can bind to a single transition metal, as illustrated by the existence of Pt(PEt3)4. Its complex with silver iodide, AgI(PMe3) is an air-stable solid that releases PMe3 upon heating.
Trimethylphosphine is a volatile toxic colorless liquid, with a strong repulsive odor, described by some as somewhere between smelly goat and vomit. It is miscible with many organic solvents.
This compound is sold by many chemical suppliers, but due to its hazards it's hard to acquire and quite expensive.
Trimethylphosphine can be prepared by the treatment of triphenyl phosphite with methylmagnesium chloride:
- 3 CH3MgCl + P(OC6H5)3 → P(CH3)3 + 3 C6H5OMgCl
The synthesis is conducted in dibutyl ether, from which the more volatile PMe3 can be distilled.
- Ligand in coordination chemistry
- Make trimethylphosphine oxide
Trimethylphosphine is pyrophoric and very toxic.
Trimethylphosphine must be kept in airtight containers, in specially designed storage cabinets, in a dry and well ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Recommended storage temperature 2 - 8 °C
Trimethylphosphine is best neutralized by burning it outside or in a special incinerator.
Trimethylphosphine converts to non-pyrophoric phosphine oxide by treatment with dilute bleach.