DICHLOROMETHANE ADDITION TO RHODIUM-BETA-DIKETONATE COMPLEXES OF DIPHOSPHINES AND PYRIDYL-SUBSTITUTED DIPHOSPHINES

In the reactions of the pyridyldiphosphine ligands (C6H5)(C5H4N)P(CH2)n-P(C6H5)(C5H4N) (n = 1, DPyPM; n = 2, DPyPE; n = 3, DPyPP) with (β-diketonate)Rh(COD), only the phosphorus atoms coordinate to rhodium. The DPyPE and DPyPP complexes react with dichloromethane to give eventually pyridyl-ylid complexes [(β-diketonate)Rh(Cl)(CH2NC5H4)(C6H5)P(CH2)nP(C6H5)(C5H4N)]Cl. The (chloro)(chloromethyl) complexes thought to be intermediates can be isolated if aryl-diphosphines (C6H5)2P(CH2)nP(C6H5)2 are used in the reaction. The structure of the pyridyl-ylid complex [(dipivaloylmethanate)Rh(Cl)(CH2DPyPE)]Cl has been determined by X-ray diffraction. The rhodium atom is octahedrally surrounded by the two oxygen atoms of the β-diketonate, one axial chlorine, and one axial phosphorus atom (that bearing the pyridyl-ylid group), and the remaining phosphorus atom and the methylene group in the equatorial positions. The ylidic CN bond is rather long (1.510(4) Å). © 1990.