Phosphine sulfide

A phosphine sulfide is an organophosphorus compound with the formula R₃PS. They are typically colorless, air-stable solids. A common example of a tertiary phosphine sulfide is triphenylphosphine sulfide. Phosphine sulfides are sometimes intermediates in the synthesis of tertiary phosphines. Phosphine sulfides are tetrahedral.

Synthesis

Phosphine sulfides are usually prepared by the oxidation of tertiary phosphines with elemental sulfur. The heat of formation of phosphine sulfides from tertiary phosphines and elemental sulfur scale with the basicity of the phosphine.^[1]

Enthalpy for sulfiding various tertiary phosphines
Tertiary phosphine	∆H (kcal/mol) for reaction with S₈	Tertiary phosphine sulfide	CAS No
PCy₃	-30.9 ± 1.9	S=PCy₃	42201-98-9
PBu₃	-28.9 ± 0.3	S=PBu₃	3084-50-2
PMe₃	-27.1 ± 0.4	S=PMe₃	2404-55-9
PMe₂Ph	-26.0 ±0.5	S=PMe₂Ph	1707-00-2
PMePh₂	-23.8 ±0.3	S=PMePh₂	13639-74-2
PPh₃	-21.5 ±0.3	S=PPh₃	3878-45-3

References

^ Capps, Kenneth B.; Wixmerten, Bodo; Bauer, Andreas; Hoff, Carl D. (1998). "Thermochemistry of Sulfur Atom Transfer. Enthalpies of Reaction of Phosphines with Sulfur, Selenium, and Tellurium, and of Desulfurization of Triphenylarsenic Sulfide, Triphenylantimony Sulfide, and Benzyl Trisulfide". Inorganic Chemistry. 37 (12): 2861–2864. doi:10.1021/ic9715862.

[1] Capps, Kenneth B.; Wixmerten, Bodo; Bauer, Andreas; Hoff, Carl D. (1998). "Thermochemistry of Sulfur Atom Transfer. Enthalpies of Reaction of Phosphines with Sulfur, Selenium, and Tellurium, and of Desulfurization of Triphenylarsenic Sulfide, Triphenylantimony Sulfide, and Benzyl Trisulfide". Inorganic Chemistry. 37 (12): 2861–2864. doi:10.1021/ic9715862.

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