Rhodium(I) complexes of α-keto-stabilised 1,2-bis(diphenylphosphino)alkane mono ylides
Rhodium(I) complexes of the hybrid ylide-phosphine ligands, Ph2P(CH2)nPPh2(CHC(O)C6H5) (n = 1: dppm-yl, or 2: dppe-yl) have been synthesised from [Rh(μ-C1)(COD)]2 (COD = 1,5-cyclooctadiene) and characterized by NMR spectroscopic and X-ray structural methods. The dppe-yl behaves as an ambidentate ligand; it functions as a monodentate P-donor ligand with a dangling ylidic carbon in the neutral chloro complex, [(COD)Rh(Cl)(dppe-yl)] (1), whereas replacement of the chloride by a non-coordinating counter anion results in the formation of the complexes, [(COD)Rh(L-L’)]+ (L-L’ = dppe-yl (2) or dppm-yl (3)) respectively in which the ligands are bonded to the metal via the phosphorus and the ylidic carbon atoms. The 1,5-cyclooctadiene (COD), present in the Rh(I) precursor, remains intact in the products. The structures of1,2 and3 have been confirmed by X-ray crystallography.
α-Stabilized phosphoylides as versatile multifunctional ligands
The coordination properties of α-stabilized phosphorus ylides show that these compounds can behave as ambidentate ligands towards palladium(II) complexes. Bonding through the carbon atom or through the heteroatom (O, N) and the coordination site can be conditioned by adequate choice of the organometallic precursor. On the other hand, the bis-ylide Ph3PC(H)–C(O)–C(H)PPh3 coordinates as a C,C-chelating ligand towards Pd(II) complexes and it can undergo an intramolecular orthometallation in different ways, leading to substrates that are adequate for the synthesis of polynuclear derivatives with or without a metal–metal bond.
Two alternatives for the synthesis of non-cyclic phosphino-methanide derivatives of gold
Abstract The reaction of phosphine–phosphonium derivatives, such as [AuX(PPh 2 CH 2 PPh 2 Me)]ClO 4 or [Au(C 6 F 5 ) 3 (PPh 2 CH 2 PPh 2 Me)]ClO 4 , or non-cyclic bis(diphenylphosphino)methane-bridging complexes, as [Au(C 6 F 5 ) 2 X(PPh 2 CH 2 PPh 2 )Au(C 6 F 5 )] (X=Cl, C 6 F 5 ) or [Au(C 6 F 5 )(PPh 2 CH 2 PPh 2 )Au(C 6 F 5 )], with acetylacetonate derivatives or gold(I) compounds leads to the synthesis of non-cyclic methanide gold complexes of the types [AuX{PPh 2 C(AuPPh 3 ) 2 PPh 2 Me}]ClO 4 , [Au(C 6 F 5 ) 2 X{PPh 2 CH(AuPPh 3 )PPh 2 Me}]ClO 4 , [Au(C 6 F 5 ) 3 {PPh 2 CH–(AuPPh 3 )PPh 2 }Au(C 6 F 5 )], [N(PPh 3 ) 2 ][Au(C 6 F 5 ) 3 {PPh 2 CH–(AuX)PPh 2 }Au(C 6 F 5 )] or [N(PPh 3 ) 2 ][{Au(C 6 F 5 ) 3 (PPh 2 CH 2 PPh 2 )–Au(C 6 F 5 )} 2 Au].