1,2-Bis(diphenylphosphino)ethane
Chemical compound
From Wikipedia, the free encyclopedia
1,2-Bis(diphenylphosphino)ethane (dppe) is an organophosphorus compound with the formula (Ph2PCH2)2 (Ph = phenyl). It is a common symmetrical bidentate ligand in coordination chemistry. It is a white solid that is soluble in organic solvents.
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| Names | |
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| Preferred IUPAC name
(Ethane-1,2-diyl)bis(diphenylphosphane) | |
| Other names
1,2-Bis(diphenylphosphino)ethane Diphos Dppe | |
| Identifiers | |
3D model (JSmol) |
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| 761261 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.015.246 |
| EC Number |
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| 9052 | |
PubChem CID |
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| UNII | |
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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| Warning | |
| 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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Preparation
The preparation of dppe entails the alkylation of NaP(C6H5)2 with 1,2-dichloroethane:[1][2]
- 2 NaP(C6H5)2 + ClCH2CH2Cl → (C6H5)2PCH2CH2P(C6H5)2 + 2 NaCl
Reactions
The reduction of dppe by lithium give the disecondary phosphine:[3]
- (C6H5)2PCH2CH2P(C6H5)2 4 Li → Li(C6H5)PCH2CH2P(C6H5)Li + 2 C6H5Li
Hydrolysis gives the bis(secondary phosphine).
- Li(C6H5)PCH2CH2P(C6H5)Li + 2 H2O → H(C6H5)PCH2CH2P(C6H5)H + 2 LiOH
The bis(dppe) complex HFeCl(dppe)2 is one of the most accessible transition metal hydrides.
Treatment of dppe with hydrogen peroxide produces the phosphine oxides (C6H5)2P(O)CH2CH2P(C6H5)2 and (C6H5)2P(O)CH2CH2P(O)(C6H5)2.[4] Selective mono-oxidation of dppe can be achieved by benzylation followed by hydrolysis:
- (C6H5)2PCH2CH2P(C6H5)2 + C6H5CH2Br → (C6H5)2PCH2CH2P(C6H5)2(CH2C6H5)]Br
- (C6H5)2PCH2CH2P(C6H5)2(CH2C6H5)]Br + NaOH → (C6H5)2PCH2CH2P(O)(C6H5)2 + C6H5CH3 + NaBr
Hydrogenation of dppe gives the ligand bis(dicyclohexylphosphino)ethane.
Coordination complexes
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]