Bis(diphenylphosphino)methane

1,1-bis(diphenylphosphino)methane
Names
	Preferred IUPAC name Methylenebis(diphenylphosphane)
	Other names Methylenebis(diphenylphosphine); dppm
Identifiers
CAS Number	2071-20-7 ;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL307780 ;
ChemSpider	67509 ;
ECHA InfoCard	100.016.541
EC Number	218-194-2;
PubChem CID	74952;
UNII	I5O2HZR38V ;
CompTox Dashboard (EPA)	DTXSID10174766 ;
	InChI InChI=1S/C25H22P2/c1-5-13-22(14-6-1)26(23-15-7-2-8-16-23)21-27(24-17-9-3-10-18-24)25-19-11-4-12-20-25/h1-20H,21H2 Key: XGCDBGRZEKYHNV-UHFFFAOYSA-N ; InChI=1/C25H22P2/c1-5-13-22(14-6-1)26(23-15-7-2-8-16-23)21-27(24-17-9-3-10-18-24)25-19-11-4-12-20-25/h1-20H,21H2 Key: XGCDBGRZEKYHNV-UHFFFAOYAH;
	SMILES P(c1ccccc1)(c2ccccc2)CP(c3ccccc3)c4ccccc4;
Properties
Chemical formula	C25H22P2
Molar mass	384.399 g·mol−1
Appearance	White crystalline powder
Melting point	118 to 122 °C (244 to 252 °F; 391 to 395 K)
Solubility in water	Insoluble in water
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P271, P280, P302 P352, P304 P340, P305 P351 P338, P312, P321, P332 P313, P337 P313, P362, P403 P233, P405, P501
Safety data sheet (SDS)	External MSDS
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

1,1-Bis(diphenylphosphino)methane (dppm), is an organophosphorus 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 can bond to metals with two phosphorus donor atoms. The natural bite angle is 73°.^[2]

Synthesis and reactivity

1,1-Bis(diphenylphosphino)methane was first prepared by the reaction of sodium diphenylphosphide (Ph₂PNa) with dichloromethane:^[3]

Ph₃P 2 Na → Ph₂PNa NaPh

2NaPPh₂ CH₂Cl₂ → Ph₂PCH₂PPh₂ 2 NaCl

The methylene group (CH₂) in dppm (and especially its complexes) is mildly acidic. The ligand can be oxidized to give the corresponding oxides and sulfides CH₂[P(E)Ph₂]₂ (E = O, S). The methylene group is even more acidic in these derivatives.

Coordination chemistry

As a chelating ligand, 1,1-bis(diphenylphosphino)methane forms a four-membered ring with the constituents MP₂C. The ligand promotes the formation of bimetallic complexes that feature five-membered M₂P₂C rings. In this way, dppm promotes the formation of bimetallic complexes. One such example is the dipalladium chloride, Pd₂Cl₂(dppm)₂. In this complex, the oxidation state for the Pd centres are I. Bis(diphenylphosphino)methane gives rise to a family of coordination compounds known as A-frame complexes.^[4]

Ball-and-stick model of [Pd₂Cl₂(dppm)₂].^[5]

References

^ Humphrey, Mark G.; Lee, Jeanne; Hockless, David C.R.; Skelton, Brian W.; White, Allan H. (1993). "Mixed-Metal Cluster Chemistry". Organometallics. 12 (3468): 3468. doi:10.1021/om00033a017.
^ Birkholz, Mandy-Nicole; Freixa, Zoraida; van Leeuwen, Piet W. N. M. (2009). "Bite angle effects of diphosphines in C–C and C–X bond forming cross coupling reactions". Chemical Society Reviews. 38 (4): 1099. doi:10.1039/B806211K. PMID 19421583.
^ W. Hewertson & H. R. Watson (1962). "The preparation of di- and tri-tertiary phosphines". J. Chem. Soc. 12: 1490–1494. doi:10.1039/JR9620001490.
^ Albéniz, Ana C. & Espinet, Pablo (2006). "Palladium: Inorganic & Coordination Chemistry". Encyclopedia of Inorganic Chemistry. Encyclopedia of Inorganic Chemistry. doi:10.1002/0470862106.ia178. ISBN 0-470-86078-2.
^ G. Besenyei; L. Párkányia; E. Gács-Baitza; B. R. James (January 2002). "Crystallographic characterization of the palladium(I) dimers, syn-Pd2Cl2(dppmMe)2 and Pd2Cl2(dppm)2; solution conformational behavior of syn- and anti-Pd2Cl2(dppmMe)2 and their (μ-Se) adducts [dppmMe=μ-1,1-bis(diphenylphosphino)ethane, and DPPM=μ-bis(diphenylphosphino)methane]". Inorg. Chim. Acta. 327 (1): 179–187. doi:10.1016/S0020-1693(01)00682-X.

[1] Humphrey, Mark G.; Lee, Jeanne; Hockless, David C.R.; Skelton, Brian W.; White, Allan H. (1993). "Mixed-Metal Cluster Chemistry". Organometallics. 12 (3468): 3468. doi:10.1021/om00033a017.

[vanLeeuwen-2] Birkholz, Mandy-Nicole; Freixa, Zoraida; van Leeuwen, Piet W. N. M. (2009). "Bite angle effects of diphosphines in C–C and C–X bond forming cross coupling reactions". Chemical Society Reviews. 38 (4): 1099. doi:10.1039/B806211K. PMID 19421583.

[3] W. Hewertson & H. R. Watson (1962). "The preparation of di- and tri-tertiary phosphines". J. Chem. Soc. 12: 1490–1494. doi:10.1039/JR9620001490.

[4] Albéniz, Ana C. & Espinet, Pablo (2006). "Palladium: Inorganic & Coordination Chemistry". Encyclopedia of Inorganic Chemistry. Encyclopedia of Inorganic Chemistry. doi:10.1002/0470862106.ia178. ISBN 0-470-86078-2.

[5] G. Besenyei; L. Párkányia; E. Gács-Baitza; B. R. James (January 2002). "Crystallographic characterization of the palladium(I) dimers, syn-Pd2Cl2(dppmMe)2 and Pd2Cl2(dppm)2; solution conformational behavior of syn- and anti-Pd2Cl2(dppmMe)2 and their (μ-Se) adducts [dppmMe=μ-1,1-bis(diphenylphosphino)ethane, and DPPM=μ-bis(diphenylphosphino)methane]". Inorg. Chim. Acta. 327 (1): 179–187. doi:10.1016/S0020-1693(01)00682-X.

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