1,2-Bis(diphenylphosphino)ethane (dppe) is an organophosphorus compound with the formula (Ph2PCH2)2 (Ph = phenyl). It is a commonly used bidentate ligand in coordination chemistry. It is a white solid that is soluble in organic solvents.
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Preferred IUPAC name
(Ethane-1,2-diyl)bis(diphenylphosphane) | |
Other names
1,2-Bis(diphenylphosphino)ethane
Diphos Dppe | |
Identifiers | |
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3D model (JSmol)
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761261 | |
ChEBI |
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ChEMBL |
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ChemSpider |
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ECHA InfoCard | 100.015.246 |
EC Number |
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9052 | |
PubChem CID
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UNII |
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CompTox Dashboard (EPA)
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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) |
Hazards | |
GHS labelling: | |
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H302, H315, H319, H332, H335, H410 | |
P261, P264, P270, P271, P273, P280, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P391, P403+P233, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
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The preparation of dppe is by the alkylation of NaPPh2:[1][2]
NaP(C6H5)2, which is readily air-oxidized, is treated with 1,2-dichloroethane (ClCH2CH2Cl) to give dppe:
The reduction of dppe by lithium to give PhHP(CH2)2PHPh has been reported.[3]
Hydrolysis gives the bis(secondary phosphine):
Treatment of dppe with conventional oxidants such as hydrogen peroxide (H2O2), aqueous bromine (Br2), etc., produces dppeO in low yield (e.g., 13%) as a result of non-selective oxidation.[4] Selective mono-oxidation of dppe can be achieved by reaction with PhCH2Br to give dppeO.
Ph2P(CH2)2PPh2 + PhCH2Br → Ph2P(CH2)2PPh2(CH2Ph)+Br−
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(2.3.)
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Ph2P(CH2)2PPh2(CH2Ph)+Br− + NaOH + H2O → Ph2P(CH2)2P(O)Ph2
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(2.4.)
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Hydrogenation of dppe gives the ligand bis(dicyclohexylphosphino)ethane.
Many coordination complexes of dppe are known, and some are used as homogeneous catalysts. Dppe is almost invariably chelating, although there are examples of monodentate (e.g., W(CO)5(dppe)) and of bridging behavior.[5] The natural bite angle is 86°.[6]