Triphenylphosphine chalcogenides are useful sources of stoichiometric chalcogen-atom transfer reagents, which have found use in the formation of iron-chalcogen clusters, and some organic reactions. Triphenylphosphine selenide is an air-stable, commercially available, white solid. The trimethylphosphine analog has also been synthesized in the literature, although it is reported to slowly decompose in air.
Triphenylphosphine selenide: Easily synthesized from triphenylphosphine and potassium selenocyanate according to an Inorganic Syntheses procedure.[1]
Trimethylphosphine selenide:[2] In the glovebox, a round-bottom flask with stir-bar was charged with trimethylphosphine (5.00g, 65.7mmol) and anhydrous diethyl ether (20mL). Selenium powder (5.45g, 69.0mmol) was gradually added, the flask stoppered, and the mixture stirred overnight. The flask was then transferred onto a swivel frit on the Schlenk/Vacuum line and the mixture filtered to separate the filtrate from unreacted selenium. The filtrand was washed with more anhydrous ether to extract remainder product, and the collected filtrates were evaporated under vacuum to yield the product as a white solid. Product can be recrystallized from diethyl ether in the glovebox freezer.
Notes
- Triphenylphosphine selenide is synthesized from potassium selenocyanate instead of elemental selenium to make the purification easier.
- Trimethylphosphine selenide is reported to gradually decompose in air (“On standing particularly in the light and in contact with air it slowly turns pink and finally reddish colored”[3]) and thus should be synthesized/handled under inert atmosphere and anhydrous solvents.
[1] Nicpon, P.; Meek, D. W. Triphenylphosphine Selenide. Inorganic Syntheses, 1967, 10, 157–159. DOI: 10.1002/9780470132418.ch23.
[2] Garcia-Rodriguez, R.; Liu, H. Mechanistic Study of the Synthesis of CdSe Nanocrystals: Release of Selenium. J. Am. Chem. Soc. 2012, 134, 3, 1400-1403.
[3] Renshaw, R. R.; Bell, F. K. Trimethylphosphine and its selenide. J. Am. Chem. Soc. 1921, 43, 4, 916-919.