To use all functions of this page, please activate cookies in your browser.
my.chemeurope.com
With an accout for my.chemeurope.com you can always see everything at a glance – and you can configure your own website and individual newsletter.
- My watch list
- My saved searches
- My saved topics
- My newsletter
1,2-Bis(diphenylphosphino)ethane
1,2-Bis(diphenylphosphino)ethane (dppe) is a commonly used bidentate ligand in coordination chemistry. Dppe is almost invariably chelated, although there are examples of unidentate (e.g., W(CO)5(dppe)) and of bridging behavior.[1] Additional recommended knowledge
PreparationThe preparation of dppe is conducted via the alkylation of NaPPh2 which is typically prepared from triphenylphosphine (P(C6H5)3) as follows:[2]
NaP(C6H5)2, which is readily air-oxidized, is treated with 1,2-dichloroethane (ClCH2CH2Cl) to give dppe:
Reactions of dppeReductionThe reduction of dppe by lithium to give PhHP(CH2)2PHPh has been reported.[3]
Hydrolysis by water gives:
OxidationTreatment 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.[4] Selective mono-oxidation of dppe can be achieved by reaction with PhCH2Br to give dppeO.
This is followed by purification and alkaline catalyzed hydrolysis of the mono-phosphonium salt.
Coordination complexes of dppeCoordination complexes of dppe, and diphosphine ligands in general, are almost entirely used as homogeneous catalysts for a wide range of reactions. Chiral diphosphines are especially important to the pharmaceutical industry[5] for their ability to catalyze asymmetric reactions[6] Two simple coordination complexes of dppe include Pd(dppe)2 and Ir(dppe)2. Pd(dppe)2 can be prepared by reduction of Pd(II) with NaBH4. It is most conveniently prepared, however, in situ from Pd(OAc)2.[4] References
Categories: Aromatic compounds | Chelating agents | Tertiary phosphines |
|||||||||||||||||||
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "1,2-Bis(diphenylphosphino)ethane". A list of authors is available in Wikipedia. |