Diphosphane
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| Names | |||
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| IUPAC name
Diphosphane
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| Systematic IUPAC name
Diphosphane (substitutive) Tetrahydridodiphosphorus(P—P) (additive) | |||
| Other names
Diphosphine
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| Identifiers | |||
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3D model (JSmol)
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PubChem CID
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| Properties | |||
| Page Module:Chem2/styles.css has no content.P2H4 | |||
| Melting point | −99 °C (−146 °F; 174 K) | ||
| Boiling point | 63.5 °C (146.3 °F; 336.6 K) (Extrapolated, decomposes) | ||
| Related compounds | |||
Other anions
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ammonia hydrazine triazane | ||
Other cations
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diphosphines | ||
Related Binary Phosphorus halides
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diphosphorus tetrafluoride diphosphorus tetrachloride diphosphorus tetrabromide diphosphorus tetraiodide | ||
Related compounds
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phosphane triphosphane diphosphene diphosphenes | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Template:Chembox Footer/trackingTemplate:Short description
Diphosphane, or diphosphine, is an inorganic compound with the chemical formula Page Module:Chem2/styles.css has no content.P2H4. This colourless liquid is one of several binary phosphorus hydrides. It is the impurity that typically causes samples of phosphine to ignite in air.
Properties, preparation, reactions
Diphosphane adopts the gauche conformation (like hydrazine, less symmetrical than shown in the image) with a P−P distance of 2.219 angstroms. It is nonbasic, unstable at room temperature, and spontaneously flammable in air. It is only poorly soluble in water but dissolves in organic solvents. Its 1H NMR spectrum consists of 32 lines resulting from an A2XX'A'2 splitting system.[1]
Diphosphane is produced by the hydrolysis of calcium monophosphide, which can be described as the Ca2+ derivative of Page Module:Chem2/styles.css has no content.P4−2. According to an optimized procedure, hydrolysis of 400 g of CaP at −30 °C gives about 20 g of product, slightly contaminated with phosphine.[citation needed]
Reaction of diphosphane with butyllithium affords a variety of condensed polyphosphine compounds.
Organic diphosphanes
A variety of organic derivatives of diphosphane are known, but asymmetric diphosphanes are only stable at cryogenic temperatures. Otherwise, the substituents facily redistribute on the phosphorus centers to give a mixture of products. On the other hand, there appears to be a substantial barrier to chiral inversion.[2]
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The simplest synthesis method heats a phosphorus halide and a phosphane:
- Page Module:Chem2/styles.css has no content.Ph2PCl + HPPh2 → Ph2P−PPh2 + HCl↑
Alkali metals can replace the hydrogen in that reaction (i.e., a dialkylphosphide), and in some rare cases a dialkylamine can replace the halide. Symmetric diphosphanes are easily prepared by reductive coupling, e.g. tetraphenyldiphosphine from chlorodiphenylphosphine:
- Page Module:Chem2/styles.css has no content.2 ClPPh2 + 2 Na → Ph2P−PPh2 + 2 NaCl
Ultraviolet radiation decomposes mercury(II) dialkylphosphides to the metal and a dialkylphosphane.Lua error in package.lua at line 80: module 'Module:Footnotes/anchor_id_list' not found.
The methyl compound Page Module:Chem2/styles.css has no content.P2Me4 is prepared by the reduction of Page Module:Chem2/styles.css has no content.Me2P(S)−P(S)Me2, which is produced by methylation of thiophosphoryl chloride with methylmagnesium bromide.[3]
See also
References
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- ^ Page Module:Citation/CS1/styles.css has no content.Marianne Baudler, Klaus Glinka (1993). "Monocyclic and polycyclic phosphines". Chem. Rev. 93 (4): 1623–1667. doi:10.1021/cr00020a010.
- ^ Page Template:Citation/styles.css has no content.Phosphorus: Chemistry, Biochemistry and Technology, Sixth Edition, 2013, D.E.C. Corbridge, CRC Pres, Taylor Francis Group, Template:ISBN. pp. 421-422.
- ^ Page Module:Citation/CS1/styles.css has no content.Butter, S. A.; Chatt, J. (1974). "Ethylenebis(dimethylphosphine)". Inorganic Syntheses. Vol. 15. p. 185. doi:10.1002/9780470132463.ch41. ISBN 9780470132463.
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