Thiophosphoryl bromide explained

Thiophosphoryl bromide is an inorganic compound with the formula .

Preparation

Thiophosphoryl bromide can be prepared by heating phosphorus tribromide with phosphorus pentasulfide, or with elemental sulfur in an inert atmosphere at 130 °C.^[1]

Thiophosphoryl bromide is one product of the bromination of in cold carbon disulfide:

Structure and properties

Thiophosphoryl bromide has tetrahedral molecular geometry and C_3v molecular symmetry. According to gas electron diffraction, the phosphorus–sulfur bond length is 1.895 Å and the phosphorus–bromine bond length is 2.193 Å, while the bond angle is 116.2° and the bond angle is 101.9°.^[2]

Thiophosphoryl bromide is soluble in carbon disulfide, chloroform and diethyl ether.

Reactions

Like other phosphoryl and thiophosphoryl halides, thiophosphoryl bromide readily hydrolyses, undergoes nucleophilic substitution and forms adducts with Lewis acids.^[3] Reaction with lithium iodide generates the mixed thiophosphoryl halides and but not thiophosphoryl iodide, .^[4] Thiophosphoryl bromide is of use in organic synthesis for reducing sulfoxides to thioethers,^[5] and sulfines to thioketones.^[6]

Notes and References

1. Book: The Chemistry of Phosphorus . Permanon Texts in Inorganic Chemistry . 3 . Arthur D. F. Toy . 1975 . Permanon Press . 9781483139593 . 438.
2. An electron diffraction determination of the molecular structures of phosphoryl bromide and thiophosphoryl bromide . E. Jean . Jacob . Donald D. . Danielson . Svein . Samdal . . 1980 . 62 . 2 . 143–155 . 10.1016/0022-2860(80)85232-X . 1980JMoSt..62..143J.
3. Adducts of thiophosphoryl compounds with metal halides. Part III: Addition compounds of phosphoryl bromide and thiophosphoryl bromide . W. . van der Veer . F. . Jellinek . . 1970 . 89 . 8 . 833–844 . 10.1002/recl.19700890809.
4. The identification of some new thiophosphoryl compounds containing P–I bonds by means of ³¹P N.M.R. spectroscopy . K. B. . Dillon . M. G. . Craveirinha Dillon . T. C. . Waddington . . 13 . 8 . 1977 . 349–353 . 10.1016/0020-1650(77)80109-8.
5. Thiophosphoryl bromide: a new reagent for the reduction of sulfoxides to sulfides . I. W. J. . Still . J. N. . Reed . K. . Turnbull . . 1979 . 20 . 17 . 1481–1484 . 10.1016/S0040-4039(01)86183-9.
6. Phosphorus Pentasulfide and Thiophosphoryl Bromide: Facile Reagents for the Reduction of Sulfines to Thiones . J. A. M. . Kuipers . B. H. M. . Lammerink . I . W. J. . Still . B. . Zwanenburg . Synthesis . 1981 . 1981 . 4 . 295–297 . 10.1055/s-1981-29423 . 98302665 .