René Poilblanc

Structural study of iron carbonyl derivatives: IV. Synthesis and crystal and molecular structure of syn-[μ-(SCH3)Fe(CO)2P(CH3)3]2

Summary The preparation of the compound [μ-(SCH 3 )Fe(CO) 2 L] 2 , with L = P(CH 3 ) 3 , is described. Spectroscopic studies show that this compound exists as syn and anti isomers, with respect to the orientation of the SCH 3 groups relative to the metal-metal bond. The crystal and molecular structure of the syn isomer has been determined by a single-crystal X-ray study. The complex crystallizes in the tetragonal space group P 4 1 2 1 2 (or P 4 3 2 1 2) with Z = 8. The intensities were measured on a Nonius CAD-4 automatic diffractometer. The structure has been refined to R and R″ values of 0.058 and 0.050 respectively, for 2156 independent reflections. The molecular structure contains two Fe(CO) 2 P(CH 3 ) 3 moieties (with the phosphine ligands in axial positions) bridged through the sulfur atoms of the syn -SCH 3 groups. The iron-iron bond length is 2.518(1)A. A comparison is made with similar iron carbonyl derivatives without phosphine substituents.

Facile synthesis of amino-functionalised cyclopentadienyl sodium compounds and subsequent formation of rhodium complexes: Proton—deuterium exchange for the sodium salts

Synthesis, isolation and characterisation of sodium salts of amino-substituted cyclopentadienyl compounds was carried out for the first time: these can be made on a large scale and stored easily, thus facilitating easy manipulation and applications. Rhodium derivatives, including Rh( η 5 -C 5 H 4 )CH(CH 2 CH 2 ) 2 NMe(coe) 2 (coe = cyclo-octene), were synthesised, of which the crystal structure is reported.

Complexes dinucleaires pontes des metaux d8: VII. Reactions d'addition oxydante d'halogenures d'alkyle et d'acycle aux complexes μ-halogenes du rhodium(i) [RhX(CO)(PR3)]2. Structure cristalline de [RhCl(CO)(PMe2Ph)(Me)(Br)]2

Abstract The halogen bridged binuclear complexes of rhodium(I) [RhCl(CO)(PR 3 )] 2 undergo oxidative addition with methyl halides to yield the complexes [RhCl(CO)(PR 3 )(Me)(X)] 2 (X = Cl, Br). The crystal and molecular structures of [RhCl(CO)(PMe 2 Ph)(Me)(Br)] 2 have been determined from a single crystal by use of X-ray crystallographic methods. The space group is Pca 2 1 or Pacm with a 19.501(5), b 10.381(4), c 13.641(5) e Z = 4. Parameters of 30 nonhydrogen atoms in the space group Pca 2 1 were refined by the full-matrix least squares technique to a conventional R factor of 0.073. In a binuclear unit, each rhodium atom is in an octahedral environment being bonded to a carbonyl group, a methyl group and a tertiary phosphine ligand and three halogen atoms for which, due to a disorder phenomenon, the diffusion factors have been determined as the average between those of chlorine and bromine atoms. In solution the cis -migration of the methyl groups occurs, leading to the acetyl complexes. In the case of CH 3 I, it is shown that an equilibrium is present in solution: [RhCl(CO)(PR 3 (Me)(I)] 2 ⇌ [RhCl(COMe)(PR 3 )(I)(solvant)] 2 ] Carbonylation reactions shift this equilibrium to give the complexes [RhCl(CO)(COMe)(PR 3 (I)] 2 . Such complexes are readily prepared by direct oxidative addition of acyl halides to the compounds [RhCl(CO)(PR 3 )] 2 .

Preparation of polymer-anchored dinuclear rhodium(I) catalysts attached by the bridging groups

Abstract We describe a method to anchor dinuclear rhodium(I) complexes by substitution of the chlorine bridge in Rh 2 (μ-Cl) 2 L 4 with LiSR where R represents a polymeric chain. The catalytic activity of such complexes compares well with that observed in homogeneous phase.

Half-sandwich ruthenium complexes of a P–O bifunctional ligand. X-Ray crystal structure of [Ru(η-C5Me5)(OC6H4PPh2){PPh2(C6H4OH)}]

The reaction of the phosphine PPh2(C6H4OH) with a reduced solution of [{Ru(η-C5Me5)Cl2}n](1) by zinc in methanol produces [Ru(η-C5Me5)(OC6H4PPh2){PPh2(C6H4OH)}](4). This complex crystallizes in the monoclinic system, space group P21/c, with a= 11.070(1), b= 18.582(2), c= 19.393(2)A, and β= 106.05(1)° and was refined to R= 0.028 with 4 383 reflections having (Fo2) > 3σ(Fo2). The X-ray structure shows the compound to exhibit strong hydrogen bonding between the hydroxyl proton of the phosphine and the oxygen group of the chelating phenoxy diphenylphosphine ligand [O ⋯ O 2.534(3), O–H 0.97(3), and H ⋯ O 1.57(3)A]. Compound (4) is unreactive towards H2, NaBH4, LiBHEt3, CF3CO2H, and MeI probably because of electronic and co-ordinative saturation. Reaction of the hydroxyphosphine with [{Ru(η-C5Me5)Cl}4] followed by addition of NEt3 leads to an insoluble solid (5) of the same composition as (4) but proposed to be oligomeric. Compound (5) is again unreactive except with HBF4·Et2O in the presence of which it decomposes. Reaction of PPh2(C6H4OSiMe3) with a reduced solution of (1) in methanol affords [Ru(η-C5Me5)(OC6H4PPh2){PPh2(C6H4OSiMe3)}](6) whereas addition of PPh2(C6H4OH) to (1) followed by reduction with NaBH4 in ethanol affords the trihydride [Ru(η-C5Me5)H3{PPh2(C6H4OH)}](8).

Bis(diphenylphosphino)methane complexes of ruthenium(0) and ruthenium(II)

[Ru(cod)(cot)](cod = cyclo-octa-1,5-diene, cot = cyclo-octa-1,3,5-triene) reacts with two equivalents of bis(diphenylphosphino)methane (dppm) to yield [Ru (cod)(dppm)2], a compound containing both a monodentate and a bidentate dppm. This reacts in turn with [Ru(cod)(cot)] to give [Ru2(cod)2(cot)(dppm)2] in the solid state, with CO to give [Ru(CO)(cod)(dppm)] and [Ru(CO)2(cod)(dppm)], and with H2 to give a 1 : 4 mixture of trans- and cis-[RuH2(dppm)2]. The reaction of the dihydride with CHCl3 and HBF4 produces trans-[RuHCl(dppm)2] and trans-[RuH(dppm)2(H2)O]BF4, respectively. [RuH2(PPh3)4] reacts with dppm to give the mononuclear complex, [RuH2(dppm)(PPh3)2]. The structures of the different complexes were determined mainly using 1H and 31P n.m.r. spectroscopy.

Preparation, characterization and X-ray crystal structure of Ru2H6N2(PPH3)4, a compound containing four bridging hydrides and a ruthenium–ruthenium double bond

The compound obtained by recrystallisation under N2 of the hydrogenation product of Ru(styrene)2(PPh3)2 has been shown to be Ru2H6N2(PPh3)4, a compound containing four bridging hydrides and a short Ru–Ru distance which is consistent with a metal–metal doubel bond; 1H and 31P n.m.r. spectra have allowed us to propose that the crude hydrogenation product is a mixture of RuH6(PPh3)2 and Ru2H8(PPh3)4.

NMR and IR studies of the bonding properties of the ethylene-rhodium complexes RhCl(C2H4)(L)(L′), L = C2H4, CO, PR3, and L′ = 2,6-lutidine

Abstract A series of complexes of general formula RhCl(C 2 H 4 )(L)(2,6-lutidine), L = CO, C 2 H 4 , PR 3 , has been studied by infrared and NMR spectroscopies. For L =C 2 H 4 , the ethylenic ligand molecules are non equivalent and in the cases L = CO and PR 3 , two isomers are detected in solution; the spectroscopic data ( v CO, VTP of 1 H NMR, 13 C NMR) and the ligand exchange studies are discussed in terms of differences in lability, rotational mobility and σ-donor properties of the ethylene groups trans to the chloride ligand and those trans to the amine ligand. The trans influence and trans effect of chloride appear to be smaller than those of 2,6-lutidine, and the σ donation from ethylene to rhodium(I) becomes more favorable in the order N The synthesis of a dinuclear species of the type (RhCl(C 2 H 4 )(PMe 3 )) 2 , from RhCl(C 2 H 4 ) 2 (2,6-lutidine), by displacement of the sterically hindered amine ligand, is also reported.

Reactions of ruthenium triphenylphosphine complexes with diazadienes. Part 3. Preparation, characterization, X-ray crystal structure, and reactivity of a formally ruthenium(0) tris(α-di-imine) complex

The reaction between [RuH2(PPh3)4] or [RuH(C6H4PPh2)(PPh3)2(C2H4)] and 3 equivalents of the α-di-imine p-MeOC6H4NCHCHNC6H4OMe-p(L) produces black crystalline [RuL3]. This complex is diamagnetic below –10 °C and becomes paramagnetic at higher temperature. The X-ray crystal structure and u.v. spectra show that the three ligands are equivalent. The complex can be considered as containing 20-electron ruthenium(0). It is rapidly oxidized by molecular oxygen to [RuL3]2+. Crystals of [RuL3]·C6H5CH3 are triclinic, space group P, with a= 14.269(2), b= 24.999(2), c= 13.967(2)A, α= 92.04(1), β= 95.01(1), γ= 104.33(1)°, and Z= 4. The structure was refined using 3 867 ‘observed’ reflections to a final R value of 0.109.

Preparation and characterization of novel tris-α-di-imino-complexes of ruthenium(0) and ruthenium(II). X-Ray crystal and molecular structure of the electron-rich complex tris-[1,2-bis-(p-methoxy-phenyliminoethane)]ruthenium(0)–toluene

The reaction between [RuH2(PPh3)4] or[RuH-(C6H4PPh2)(PPh3)2(C2H4)] and the α-di-imine dad [(p-Me-OC6H4NCH)2] produces in high yield the black crystal line complex [Ru(dad)3]0, a formally 20-electron derivative of ruthenium (0), the structure of which has been confirmed by an X-ray study; the complex is diamagnetic in the solid state and is rapidly oxidized by molecular oxygen into [Ru(dad)3]2+.