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.

Preparation

The preparation of dppe entails the alkylation of NaP(C6H5)2 with 1,2-dichloroethane:

Reactions

The reduction of dppe by lithium give the disecondary phosphine: Hydrolysis gives the bis(secondary phosphine). Treatment of dppe with hydrogen peroxide produces the phosphine oxides (C6H5)2P(O)CH2CH2P(C6H5)2 and (C6H5)2P(O)CH2CH2P(O)(C6H5)2. Selective mono-oxidation of dppe can be achieved by benzylation followed by hydrolysis: 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. The natural bite angle is 86°.

Related compounds