{{chembox |Watchedfields = changed |verifiedrevid = 477201820 |ImageFile = Dppm-2D-skeletal.png |ImageFile1 = Dppm-from-xtal-3D-balls.png |Name = 1,1-bis(diphenylphosphino){{shy}}methane |PIN = Methylenebis(diphenylphosphane) |OtherNames = Methylenebis(diphenylphosphine)<br/>dppm |Section1={{Chembox Identifiers |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 |SMILES = P(c1ccccc1)(c2ccccc2)CP(c3ccccc3)c4ccccc4 |InChIKey = XGCDBGRZEKYHNV-UHFFFAOYAH |ChEMBL_Ref = {{ebicite|correct|EBI}} |ChEMBL = 307780 |PubChem = 74952 |EC_number = 218-194-2 |StdInChI_Ref = {{stdinchicite|correct|chemspider}} |StdInChI = 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 |StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |StdInChIKey = XGCDBGRZEKYHNV-UHFFFAOYSA-N |CASNo_Ref = {{cascite|correct|CAS}} |CASNo = 2071-20-7 |UNII_Ref = {{fdacite|correct|FDA}} |UNII = I5O2HZR38V |ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |ChemSpiderID = 67509 }} |Section2={{Chembox Properties |C=25|H=22|P=2 |Appearance = White crystalline powder |Solubility = Insoluble in water |MeltingPtC = 118 to 122 }} |Section3={{Chembox Hazards | GHSPictograms = {{GHS07}} | GHSSignalWord = Warning | HPhrases = {{H-phrases|315|319|335}} | PPhrases = {{P-phrases|261|264|271|280|302+352|304+340|305+351+338|312|321|332+313|337+313|362|403+233|405|501}} | ExternalSDS = [http://www.coleparmer.com/Catalog/Msds/19897.htm External MSDS] }} }} '''1,1-Bis(diphenylphosphino)methane''' ('''dppm'''), is an organophosphorus compound with the formula CH<sub>2</sub>(PPh<sub>2</sub>)<sub>2</sub>. Dppm, a white, crystalline powder, is used in inorganic and organometallic chemistry as a ligand.<ref>{{cite journal |author1=Humphrey, Mark G. |author2=Lee, Jeanne |author3=Hockless, David C.R. |author4=Skelton, Brian W. |author5=White, Allan H. | year = 1993 | title = Mixed-Metal Cluster Chemistry | journal = Organometallics | volume = 12 | issue = 3468 | doi = 10.1021/om00033a017 | pages = 3468}}</ref> 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°.<ref name="vanLeeuwen">{{cite journal |last1=Birkholz |first1=Mandy-Nicole |last2=Freixa |first2=Zoraida |last3=van Leeuwen |first3=Piet W. N. M. |title=Bite angle effects of diphosphines in C–C and C–X bond forming cross coupling reactions |journal=Chemical Society Reviews |date=2009 |volume=38 |issue=4 |pages=1099–1118 |doi=10.1039/B806211K |pmid=19421583}}</ref>
==Synthesis and reactivity== 1,1-Bis(diphenylphosphino)methane was first prepared by the reaction of sodium diphenylphosphide (Ph<sub>2</sub>PNa) with dichloromethane:<ref>{{cite journal | journal = J. Chem. Soc. | year = 1962 | pages = 1490–1494 | doi = 10.1039/JR9620001490 | title = The preparation of di- and tri-tertiary phosphines | author = W. Hewertson | author2 = H. R. Watson | name-list-style = amp | volume = 12}}</ref> :Ph<sub>3</sub>P + 2 Na → Ph<sub>2</sub>PNa + NaPh :2NaPPh<sub>2</sub> + CH<sub>2</sub>Cl<sub>2</sub> → Ph<sub>2</sub>PCH<sub>2</sub>PPh<sub>2</sub> + 2 NaCl
The methylene group (CH<sub>2</sub>) in dppm (and especially its complexes) is mildly acidic. The ligand can be oxidized to give the corresponding oxides and sulfides CH<sub>2</sub>[P(E)Ph<sub>2</sub>]<sub>2</sub> (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 MP<sub>2</sub>C. The ligand promotes the formation of bimetallic complexes that feature five-membered M<sub>2</sub>P<sub>2</sub>C rings. In this way, dppm promotes the formation of bimetallic complexes. One such example is the dipalladium chloride, Pd<sub>2</sub>Cl<sub>2</sub>(dppm)<sub>2</sub>. 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.<ref>{{cite encyclopedia | encyclopedia = Encyclopedia of Inorganic Chemistry | year = 2006 | doi = 10.1002/0470862106.ia178 | author = Albéniz, Ana C. | author2 = Espinet, Pablo | name-list-style = amp | chapter = Palladium: Inorganic & Coordination Chemistry | isbn = 0-470-86078-2}}</ref>
[[File:Pd2Cl2(dppm)2-from-xtal-3D-ball-stick-hybrid.png|thumb|center|200px|Ball-and-stick model of [Pd<sub>2</sub>Cl<sub>2</sub>(dppm)<sub>2</sub>].<ref>{{cite journal | journal = Inorg. Chim. Acta | volume = 327 | issue = 1 |date=January 2002 | pages = 179–187 | author = G. Besenyei | author2 = L. Párkányia | author3 = E. Gács-Baitza| author4 = B. R. James | doi = 10.1016/S0020-1693(01)00682-X | title = Crystallographic characterization of the palladium(I) dimers, ''syn''-Pd<sub>2</sub>Cl<sub>2</sub>(dppmMe)<sub>2</sub> and Pd<sub>2</sub>Cl<sub>2</sub>(dppm)<sub>2</sub>; solution conformational behavior of ''syn''- and ''anti''-Pd<sub>2</sub>Cl<sub>2</sub>(dppmMe)<sub>2</sub> and their (μ-Se) adducts [dppmMe=μ-1,1-bis(diphenylphosphino)ethane, and DPPM=μ-bis(diphenylphosphino)methane]}}</ref>]]
==References== {{reflist}}
Category:Diphosphines Category:Phenyl compounds