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.
Reactivity of mercury(II) halides with the unsymmetrical phosphorus ylide Ph2PCH2CH2PPh2C(H)C(O)Ph: Crystal structure of {HgI2[PPh2CH2CH2PPh2C(H)C(O)Ph]}n
Abstract The unsymmetrical phosphorus ylide, Ph2PCH2CH2PPh2 C(H)C(O)Ph is shown to react with Hg(II) halides to form polymeric products with the composition {HgX2[PPh2CH2CH2PPh2C(H)C(O)Ph]}n, where X = Cl (1), Br (2), I (3). The complexes have been characterized by elemental analysis, IR, 1H, 31P NMR spectra as well as by ESI mass spectra. In product 1 the ylide exhibits a P, C-bridging mode of coordination, while in 2 and 3 it shows a monodentate P-coordination with the dangling ylide. The structure of complex 3 has been characterized crystallographically. The monomeric –Hg–I–Hg– bridging in 3 leads to a zig-zag polymeric chain in which mercury assumes a distorted tetrahedral geometry.
Phosphorus ylide-containing niobium complexes: preparation and characterization of homo- and heteronuclear compounds with an α-keto ylide ligand
Abstract The reactions have been studied between [{NbCl 3 (dme)} n ] or [NbCl 3 (dme)(RC CR′)] with a heterocycle containing α -keto stabilized phosphorus ylide, 2-TCMP=[{2-thiazolylcarbonyl}methylene]triphenylphosphorane, and these reactions give the α -keto ylide-containing niobium complexes [{NbCl 3 (2-TCMP)} 2 ] ( 1 ) and [NbCl 3 (2-TCMP)(RC CR′)], R=R′=Ph ( 2 ); R=R′=Me ( 3 ); R=R′=Et ( 4 ); R=Ph, R′=Me ( 5 ); R=Ph, R′=Et ( 6 ); R=Ph, R′=Pr ( 7 ); R=Ph, R′=SiMe 3 ( 8 ), respectively. The reactivity of 5 towards different reagents has also been investigated. Compound 5 reacts with MeLi to give, through a deprotonation process of a phenyl ring, the ortho -metallated complex [N bCl 2 {NOSC 4 H 2 CHPPh 2 (C 6 H 4 )-O,N}] 2 ( 9 ), with the loss of the alkyne ligand. Furthemore, 5 reacts with [AuPPh 2 R]CF 3 SO 3 and AgCF 3 SO 3 to give the heterometallic complexes [NbCl 3 (2-TCMP)Au PPh 2 R] 2 (CF 3 SO 3 ) 2 , R=Ph ( 10 ), R=C 3 H 2 SN ( 11 ), and [NbCl 3 (2-TCMP)Ag] 2 (CF 3 SO 3 ) 2 ( 12 ), respectively, with the loss of the alkyne ligand in each case.