1,2-Bis(diphenylphosphino)ethane
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IUPAC name
Ethane-1,2-diylbis(diphenylphosphane)
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| Other names
1,2-Bis(diphenylphosphino)ethane
Diphos Dppe |
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3D model (Jmol)
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| ECHA InfoCard | 100.015.246 |
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| Properties | |
| C26H24P2 | |
| Molar mass | 398.42 g/mol |
| Melting point | 140 to 142 °C (284 to 288 °F; 413 to 415 K) |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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1,2-Bis(diphenylphosphino)ethane (dppe) is a commonly used bidentate ligand in coordination chemistry. Dppe is almost invariably chelating, although there are examples of monodentate (e.g., W(CO)5(dppe)) and of bridging behavior.
The preparation of dppe is conducted via the alkylation of NaPPh2 which is typically prepared from triphenylphosphine (P(C6H5)3) as follows:
P(C6H5)3 + 2 Na → NaP(C6H5)2 + NaC6H5
()
NaP(C6H5)2, which is readily air-oxidized, is treated with 1,2-dichloroethane (ClCH2CH2Cl) to give dppe:
2 NaP(C6H5)2 + ClCH2CH2Cl → (C6H5)2PCH2CH2P(C6H5)2 + 2 NaCl
()
The reduction of dppe by lithium to give PhHP(CH2)2PHPh has been reported.
Ph2P(CH2)2PPh2 + 4 Li → PhLiP(CH2)2PLiPh + 2 PhLi
()
Hydrolysis by water gives:
PhLiP(CH2)2PLiPh + 2 PhLi + 4H2O → PhHP(CH2)2PHPh + 4 LiOH + 2C6H6
()
Treatment of dppe with conventional oxidants such as hydrogen peroxide (H2O2), aqueous bromine (Br2), etc., always produces dppeO in low yield (e.g., 13%) as a result of non-selective oxidation leading to mixtures of the starting material, the monoxide, and dioxide. Selective mono-oxidation of dppe can be achieved by reaction with PhCH2Br to give dppeO.
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