1,1-Bis(diphenylphosphino)methane
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| 1,1-bis(diphenylphosphino)methane | |
|---|---|
 |
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| Other names | Methylenebis(diphenylphosphine); dppm |
| Identifiers | |
| CAS number | [2071-20-7] |
| Properties | |
| Molecular formula | C25H22P2 |
| Molar mass | 384.39 g/mol |
| Appearance | White powder or crystalline powder |
| Melting point |
118-122 °C |
| Solubility in water | Insoluble in water |
| Hazards | |
| MSDS | External MSDS |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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1,1-Bis(diphenylphosphino)methane (dppm), is a compound with the formula CH2(PPh2)2. Dppm, a white, crystalline powder, is used in inorganic and organometallic chemistry as a ligand.[1] It is more specifically a chelating ligand because it is a ligand that is attached to the central metals (the phosphorus) by bonds from two or more donor atoms.
[edit] Synthesis
1,1-Bis(diphenylphosphino)methane is prepared by the reaction of triphenylphosphine with sodium to give sodium diphenylphosphide (Ph2PNa), and reacting the diphenylphosphide with dichloromethane:[2]
- Ph3P + 2 Na → Ph2PNa + NaPh
- 2NaP(C6H5)2 + CH2Cl2 → (C6H5)2PCH2P(C6H5)2 + 2NaCl
[edit] Coordination chemistry
As a chelating ligand, 1,1-Bis(diphenylphosphino)methane involves the P-CH2-P group. The hydrogens of the methylene group (CH2) between the two central metals in this compound are acidic in metal complexes. As a result, this chelating ligand is able to act as a hydrogen bond donor, (CH--X) which allows the compound to form dimers. One such example is the palladium chloride dimer, Pd2Cl2(dppm)2. The palladium-metal bonds of the dimer are supported by dppm. In the Pd2Cl2(dppm)2 complex, the oxidation state for the Pd's are +II. 1,1-Bis(diphenylphosphino)methane acts as the bridge that connects the two Pd metals together.[3]
[edit] References
- ^ Humphrey, Mark G.; Lee, Jeanne; Hockless, David C.R.; Skelton, Brian W.; & White, Allan H. (1993). "Mixed-Metal Cluster Chemistry". Organometallics 12 (3468). doi:.
- ^ W. Hewertson and H. R. Watson (1962). "The preparation of di- and tri-tertiary phosphines". J. Chem. Soc.: 1490 - 1494. doi:.
- ^ Albéniz, Ana C. and Espinet, Pablo (2006). "Palladium: Inorganic & Coordination Chemistry". Encyclopedia of Inorganic Chemistry. DOI:10.1002/0470862106.ia178.
