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Diphosphane Ligand (diphosphane + ligand)
Selected AbstractsAn Atropo-Stereogenic Diphosphane Ligand with a Proximal Cationic Charge: Specific Catalytic Properties of a Palladium Complex ThereofEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2008Nathalie Debono Abstract A class of cationic diphosphane ligands combining phosphane and amidiniophosphane moieties is illustrated on the N -methyl,N -naphthylbenzimidazolium framework. The palladium(II) complex thereof is described and compared to the corresponding complex of the analogous neutral diphosphane. Contrary to first-level expectations, the N2C,P and N2CP,Pd bonds in the cationic diphosphane complex are not longer than those occurring in its neutral counterpart. In the cationic ligand, the proximal positive charge is indeed conjugated to one phosphanyl group, and the coordination scheme is tentatively interpreted by resonance of the phosphane,metal dative bond (+N2C,P:,[Pd]) with a carbene,phosphenium dative bond (N2C:,[+P:,Pd]). Despite this peculiar structural feature, the electronic , donation (vs. , acceptation) towards the palladium centre remains lowered in the cationic ligand. This specific property can be a priori valuable in a catalytic process where oxidative addition is not the limiting step. It is indeed shown that although the neutral complex is more active in Suzuki coupling reactions, the cationic complex is more active in Sonogashira-type coupling reactions involving predissociated halide substrates, namely an acyl chloride. These likely atropo-chiral ligands deserve to be resolved for application in asymmetric catalysis.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Chiral Oxo- and Oxy-Functionalized Diphosphane Ligands Derived from Camphor for Rhodium(I)-Catalyzed Enantioselective Hydrogenation.CHEMINFORM, Issue 19 2003Igor V. Komarov Abstract For Abstract see ChemInform Abstract in Full Text. [source] Reactivity and X-ray Structural Studies in Ligand Substitution of [Cp/(Ind)Ru(dppf)Cl] , Epimerisation in [Cp/(Ind)Ru(Josiphos)Cl] {Cp = ,5 -C5H5, Ind = ,5 -C7H9, dppf = 1,1,-Bis(diphenylphosphanyl)ferrocene, Josiphos = (R)-(,)-1-[(S)-2-(Diphenylphosphanyl)ferrocenyl]ethyldicyclohexylphosphane}EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2007Sin Yee Ng Abstract Ligand substitution of [(Ind)Ru(PPh3)2Cl] (1) led to the isolation of [(Ind)Ru(PPh3){Ph2P(CH2)2C9H7}Cl] (2), [(Ind)Ru(dppf)Cl] (3) and [(Ind)Ru{(Ph2PCH2)3CMe}]PF6 ([4]PF6), and diastereoisomers [(R)- and (S)-(Ind)Ru(Josiphos)Cl] [(R)- 5 and (S)- 5], where (R)-(S)-Josiphos is the ferrocene-based chiral diphosphane ligand (R)-(,)-1-[(S)-2-(diphenylphosphanyl)ferrocenyl] ethyldicyclohexylphosphane. The Cp analogues of 5, viz. (R)- 6 and (S)- 6, were also obtained from [CpRu(PPh3)2Cl] (1a). Josiphos-dependent epimerisation was observed, with conversion of the (S) isomer to the (R) isomer in both cases. Chloride abstraction of 3 with NaPF6 in CH3CN and NaN3 in EtOH gave [(Ind)Ru(dppf)(CH3CN)]PF6 ([7]PF6) and [(Ind)Ru(dppf)(N3)] (8), respectively. The azido ligand in 8 underwent [3+2] dipolar cycloaddition with dimethyl acetylenedicarboxylate to give a N -bound bis(methoxycarbonyl)-1,2,3-triazolato complex, 9. X-ray crystal structures of the new complexes, except (R)- 5, (S)- 5 and (S)- 6, have been determined. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis, Solution-State and Solid-State Structural Characterization of Monocationic Nitrido Heterocomplexes [M(N)(DTC)(PNP)]+ (M = 99Tc, Re; DTC = Dithiocarbamate; PNP = Heterodiphosphane)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2004Cristina Bolzati Abstract Mono-cationic nitrido heterocomplexes of general formula [M(N)(DTC)(PNP)]+ (where M is 99Tc or Re, DTC is the mono-anionic form of a dithiocarbamate ligand, and PNP is a diphosphane ligand with a tertiary amine-containing five-membered spacer) were prepared by ligand-exchange reactions with the labile precursors [M(N)Cl2(PPh3)2] in dichloromethane/alcohol mixtures. The molecular structure of the representative rhenium complex [Re(N)(dedc)(pnp2)][PF6] (1) displays a distorted, square-pyramidal geometry with the dithiocarbamate sulfur and the diphosphane phosphorus atoms spanning the four coordination positions on the equatorial plane. If the additional interactions between the nitrido nitrogen and the weakly bonded transN -diphosphane heteroatom, the molecular geometry can be viewed as pseudo-octahedral. The structure in solution, as established by multinuclear NMR spectroscopy and ESI spectrometry, is monomeric, and identical to that shown in the solid state. Replacement of the phenyl groups on the phosphorous atoms in complexes 1, 2, 5, and 6 with alkyl groups modified neither the course of the reaction nor the composition of the resulting complexes. These results, together with the observation that no symmetrical complexes containing two identical bidentate ligands were produced in these reactions, strongly supports the conclusion that a mixed coordination sphere, composed by a combination of ,-donor and ,-acceptor atoms around the [M,N]2+ group, constitutes a highly stable system. Compounds containing dangling alkyl-substituted groups in the outer sphere (3, 4, 7, and 8) were fully characterized by multinuclear NMR spectroscopy and ESI mass spectrometry. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Synthesis, Characterization, and Electrochemical Properties of Novel Transition Metal,Fullerene Complexes Containing Di- and Tetraphosphane LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2006Li-Cheng Song Abstract This paper reports the synthesis, characterization, and some properties of transition metal,fullerene complexes containing trans -1,1,-bis(diphenylphosphanyl)ethylene (dppet, trans -Ph2PCH=CHPPh2) and N,N,N,,N,-tetra(diphenylphosphanylmethyl)ethylene diamine (dppeda, [(Ph2PCH2)2NCH2]2), including [(,2 -C60M)(dppet)2] (M = Pt 1, Pd 2), [(,2 -C60M)(dppet)]2 (M = Pt 3, Pd 4), [(,2 -C60Pd)(,2 -C60Pt)(dppet)2](5), [(,2 -C60Pd)(,2 -C70Pd)(dppet)2] (6), [(,2 -C70Pd)(dppet)]2 (7), [(,2 -C60M)(dppeda)] (M = Pt 8, Pd 9), and [(,2 -C60M)2(dppeda)] (M = Pt 10, Pd 11). Interestingly, while complexes 1, 2, 8, and 9 are the first examples of metallacyclopropafullerene diphosphane ligands containing fullerene cores, complexes 3,7, 10, and 11 are the first group 10 metal-containing, dumbbell-shaped bisfullerenes. All the complexes 1,11 were characterized by elemental analysis, spectroscopy, and, particularly for 4 and 5, by X-ray crystallography and cyclic voltammetry. Pathways for the formation of 1,11 are suggested. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Unprecedented Stereoselective Synthesis of Catalytically Active Chiral Mo3CuS4 ClustersCHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2006Marta Feliz Dr. Abstract Cluster excision of polymeric {Mo3S7Cl4}n phases with chiral phosphane (+)-1,2-bis[(2R,5R)-2,5-(dimethylphospholan-1-yl)]ethane ((R,R)-Me-BPE) or with its enantiomer ((S,S)-Me-BPE) yields the stereoselective formation of the trinuclear cluster complexes [Mo3S4{(R,R)-Me-BPE}3Cl3]+ ([(P)- 1]+) and [Mo3S4{(S,S)-Me-BPE}3Cl3]+ ([(M)- 1]+), respectively. These complexes posses an incomplete cuboidal structure with the metal atoms defining an equilateral triangle and one capping and three bridging sulfur atoms. The P and M symbols refer to the rotation of the chlorine atoms around the C3 axis, with the capping sulphur atom pointing towards the viewer. Incorporation of copper into these trinuclear complexes affords heterodimetallic cubane-type compounds of formula [Mo3CuS4{(R,R)-Me-BPE}3Cl4]+ ([(P)- 2]+) or [Mo3CuS4{(S,S)-Me-BPE}3Cl4]+ ([(M)- 2]+), respectively, for which the chirality of the trinuclear precursor is preserved in the final product. Cationic complexes [(P)- 1]+, [(M)- 1]+, [(P)- 2]+, and [(M)- 2]+ combine the chirality of the metal cluster framework with that of the optically active diphosphane ligands. The known racemic [Mo3CuS4(dmpe)3Cl4]+ cluster (dmpe=1,2-bis(dimethylphosphanyl)ethane) as well as the new enantiomerically pure Mo3CuS4 [(P)- 2]+ and [(M)- 2]+ complexes are efficient catalysts for the intramolecular cyclopropanation of 1-diazo-5-hexen-2-one (3) and for the intermolecular cyclopropanation of alkenes, such as styrene and 2-phenylpropene, with ethyl diazoacetate. In all cases, the cyclopropanation products were obtained in high yields. The diastereoselectivity in the intermolecular cyclopropanation of the alkenes and the enantioselectivity in the inter- or intramolecular processes are only moderate. La reacción de escisión de la fase polimérica {Mo3S7Cl4}ncon la fosfina quiral (+)-1,2-bis[(2R,5R)-2,5-(dimetilfosfolan-1-il)]etano, (R,R)-Me-BPE, o con su enantiómero, (S,S)-Me-BPE, conduce a la formación estereoselectiva de los complejos clúster trinucleares [Mo3S4(R,R -Me-BPE)3Cl3]+([(P)- 1]+) y [Mo3S4(S,S -Me-BPE)3Cl3]+([(M)- 1]+), respectivamente. Estos complejos poseen una estructura de cubo incompleto, dónde los átomos metálicos definen un triángulo equilátero, con un azufre unido a tres átomos de molibdeno y tres azufres puente. Los símbolos P y M hacen referencia a la rotación de los átomos de cloro alrededor del eje C3, con el azufre apuntado dirigido hacia el observador. La incorporación de cobre a estos complejos trinucleares conduce a compuestos heterodimetálicos con estructura tipo cubano de fórmula [Mo3CuS4(R,R -Me-BPE)3Cl4]+([(P)- 2]+) y [Mo3CuS4(S,S -Me-BPE)3Cl4]+([(M)- 2]+) donde la quiralidad del precursor trinuclear se mantiene en el producto final. Los complejos catiónicos [(P)- 1]+, [(M)- 1]+, [(P)- 2]+y [(M)- 2]+combinan la quiralidad del esqueleto clúster con la de los ligandos difosfina. El clúster racémico [Mo3CuS4(dmpe)3Cl4]+(dmpe=1,2-bis(dimetilfosfino)etano), así como los complejos Mo3CuS4 enantioméricamente puros [(P)- 2]+o [(M)- 2]+son catalizadores eficaces para la reacción de ciclopropanación intramolecular de 1-diazo-5-hexen-2-ona (3) y para la ciclopropanación intermolecular de alquenos, estireno y 2-fenilpropeno, con etil diazoacetato. En todos los casos los productos de ciclopropanación se obtienen con rendimientos elevados. La diastereoselectividad en la ciclopropanación intermolecular de alquenos y la enantioselectividad en los procesos tanto inter- como intramoleculares son únicamente moderadas. [source] | ||||||||||