The five-coordinate complexes of the type [RuCl(PNNP)]PF 6 (PNNP ) tetradentate ligand with a P 2 N 2 donor set) are prepared by chloride abstraction from [RuCl 2 (PNNP)]. A mixture of ∆-cis-β-and Λ-cis-β-[RuCl 2 (1a-κ 4 P,N,N,P)] (2a; 1a ) N, N′-bis[o-(diphenylphosphino)benzylidene]-2,2′-diimino-1,1′-(S)-binaphthylene), prepared by reaction of 1a with [RuCl 2 -(PPh 3 ) 3 ], reacts with Tl[PF 6 ], giving the five-coordinate [RuCl(1a-κ 4 P,N,N,P)]PF 6 (3a). The related trans-[RuCl 2 (1b-κ 4 P,N,N,P)] (2b; 1b ) N, N′-bis[o-(diphenylphosphino)benzylidene]-(1S,2S)-diiminocyclohexane) reacts with Tl[PF 6 ] to give [RuCl(1b-κ 4 P,N,N,P)]PF 6 (3b). With the amino ligand N, N′-bis[o-(diphenylphosphino)benzylidene]-(1S,2S)-diaminocyclohexane (1c), the aqua complex [RuCl(OH 2 )(1c-κ 4 P,N,N,P)]PF 6 (5c) is obtained by reaction of Tl-[PF 6 ] with [RuCl 2 (PPh 3 )(1c-κ 3 P,N,N)] (4), which has been isolated and structurally characterized. The reactivity of the five-coordinate 2b with CO and oxygen donors such as water, Et 2 O, THF, and methanol is reported. Both 3 and 5 catalyze the asymmetric epoxidation of olefins with hydrogen peroxide as oxidant. Enantiomeric excesses up to 42% were obtained in the enantioselective epoxidation of styrene and of other unfunctionalized olefins. The reaction is highly stereospecific, as the epoxidation of (Z)-2-methylstyrene gives a cis:trans ratio of 99:1.

Iridium complexes relevant to the catalytic enantioselective hydrogenation of 2-methyl-6-ethylphenyl-1'-methyl-2'-methoxyethylimine (MEA-imine, 1) in the Syngenta Metolachlor (3) process were prepared and characterized. Reaction of the diphosphane (S)-1-[(R)-2-(diphenylphosphanyl)ferrocenyl]ethyldi(3,5-xylyl)phosphane ((S)-(R)-Xyliphos, (S)-(R)-4) with [Ir(2)(micro-Cl)(2)(cod)(2)] (cod=1,5-cyclooctadiene) afforded [Ir(Cl)(cod)[(S)-(R)-4]] (7), which reacted with AgBF(4) to form [Ir(cod)[(S)-(R)-4]]BF(4) (8). Complexes 7 and 8 reacted with iodide to yield [Ir(I)(cod)[(S)-(R)-4]] (9). When 9 was treated with one and two equivalents of HBF(4), two isomers of the cationic Ir(III) iodo hydrido complex [Ir(I)(H)(cod)[(S)-(R)-4]]BF(4) were solated (10 and 11, respectively). Complex 9 was oxidized with one equivalent of I(2) to give the iodo-bridged dinuclear species [Ir(2)I(2)(micro-I)(3)[(S)-(R)-4](2))]I (12). [Ir(2)(micro-Cl)(2)(coe)(4)] (coe=cyclooctene) reacted with (S)-(R)-4 to yield the chloro-bridged dinuclear complex [Ir(2)(micro-Cl)(2)[(S)-(R)-4](2)] (13). Complexes 7-12 were structurally characterized by single-crystal X-ray diffraction and tested as single-component catalyst precursors for enantioselective hydrogenation of MEA-imine. Complex 10 and dinuclear complex 12 gave the best catalytic results. Efforts were also directed at isolating substrate- or product-catalyst adducts: Treatment of 8 with 2,6-dimethylphenyl-1'-methyl-2'-methoxyethylimine (DMA-imine, 14, a model for 1) under H(2) allowed four isomers of [Ir(H)(2)[(S)-(R)-4](14)]BF(4) (18-21) to be isolated. These analytically pure isomers were fully characterized by 2D NMR techniques. X-ray structural analysis of an Ir(I)-imine adduct, namely, [Ir(C(2)H(4))(2)(14)]BF(4) (25), which was prepared by reacting [IrCl(C(2)H(4))(4)] with [Ag(14)(2)]BF(4) (16), confirmed the kappa(2) coordination mode of imine 14.

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The five-coordinate fluoro complex [RuF(dppp) 2 ]PF 6 (1a) has been prepared by reacting [RuCl(dppp) 2 ]PF 6 (1b) with TlF (dppp ) 1,3-bis(diphenylphosphino)propane). An X-ray investigation of 1a shows a distorted trigonal bipyramidal geometry (Y-shaped). The 16electron complex 1a reacts with a number of donors, including CO, H 2 , and F -. The X-ray structure of trans-[RuF(CO)(dppp) 2 ]PF 6 (2aBPh 4 ) suggests that the π-donor ability of the fluoro ligand is only slightly higher than that of chloride. The reaction of 1a with [Me 4 N]F gives cis-[RuF 2 (dppp) 2 ] (3), a rare difluoro complex not stabilized by π-acidic co-ligands. The Ru-F bond of 1a is hydrogenolyzed upon reaction with H 2 to give [RuH(η 2 -H 2 )(dppp) 2 ] + . The coordinatively unsaturated complex 1a reacts with activated haloalkanes R-X (X ) Cl or Br) in 1:1 molar ratio to give the fluorinated organic derivative and [RuX(dppp) 2 ] + . The halide metathesis proceeds instantaneously and quantitatively with (E)-3-bromo-1,3diphenylpropene and chlorotriphenylmethane. Substrate conversion decreases with decreasing substitution at the halogen-bearing carbon atom.

The diphosphine (S,S)-Me2Si(CH2P(1-Np)(Ph))2 (1-Np = 1-naphthyl) (1), containing stereogenic P atoms, is prepared with high diastereo- and enantiomeric purity by a multistep asymmetric synthesis via its borane adduct (S,S)-Me2Si(CH2P(1-Np)(Ph)(BH3))2 (2), obtained by selective methyl lithiation of the enantiomerically pure phosphine borane (S)-P(1-Np)(Ph)(Me)(BH3) (3) and coupling onto Me2SiCl2. The absolute configuration of 3 is established by X-ray studies. Reacting 2 with morpholine gives free diphosphine (S,S)-1 with a (S,S):(R,R) enantiomeric ratio better than 99:1. The Rh(I) and Ru(II) derivatives [Rh(diene)((S,S)-1)] (diene = norbornadiene, 4a; 1,5-cyclooctadiene, 4b) and [RuCl2(PPh3)((S,S)-1)] (5) are prepared and tested as catalyst precursors in enantioselective reactions with standard substrates. In the presence of 4b as catalyst precursor, a series of dehydroamino acid derivatives are hydrogenated with up to 97.7% ee. Complex 5 catalyzes the hydrogenation of pentane-2,4-dione to (S,S)-pentane-2,4-diol with up to 56% ee. Ligand 1 gives enantioselection also in the Pd-catalyzed allylic alkylation of 1,3-diphenyl-3-acetoxypropene with dimethyl malonate (27% ee).