- Synthesis and reactivity of silyl iron, cobalt, and nickel complexes bearing a [PSiP]-pincer ligand via Si-H bond activation
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The synthesis and characterization of a series of Ni, Co, and Fe complexes bearing a tridentate bis(phosphino)silyl ligand (κ3-(2-Ph 2PC6H4)2SiMeH, [PSiP]-H, 1) are reported. 1 reacted with Ni(PMe3)4 to afford the mononuclear nickel(0) complex [η2(Si-H)-PSiP]Ni(PMe3) (2). The halogeno nickel complexes [PSiP]Ni(X)(PMe3) (X = Cl (3), Br (4), I (5)) were synthesized in the reactions of 2 with Me3SiCl or MeHSiCl2, EtBr, and MeI. Complex 2 underwent ligand substitution of PMe3 by CO to give [η2(Si-H)-PSiP]Ni(CO) (6). Complex 3 reacted with NaOMe to deliver [PSiP]Ni(OMe)(PMe3) (7) through anionic ligand substitution, while the neutral ligand replacement of PMe 3 by CO in 3 afforded the rare hexacoordinate 20-electron nickel(II) complex [PSiP]Ni(Cl)(CO)2 (8). Unexpectedly, reaction of 1 with NiMe2(PMe3)3 produced the tetracoordinate nickel(0) complex [Me2PSiP]2Ni (9). The complex [Me 2PSiP]Ni(CO)2 (10) was acquired from 9 after the substitution of one [PSiP] ligand by two carbonyl ligands. 1 reacted with Co(PMe3)4 or CoCl(PMe3)3 to afford the hydrido cobalt(II) complex [PSiP]CoH(PMe3) (11) or hydrido cobalt(III) complex [PSiP]Co(H)(Cl)(PMe3) (13). Complex 12, [PSiP]Co(H)(I)(PMe3), could be obtained from the reaction of MeI with 11 or 13. Treatment of 13 with 1 equiv of MeLi or n-BuMgBr in THF resulted in the clean formation of cobalt(I) complex [PSiP]Co(PMe3)2 (14) via reductive elimination. The simple anhydrous inorganic salt NiCl 2 or CoCl2 could also react with 1 in the presence of PMe3 to form the corresponding silyl complexes 3 and [PSiP]Co(Cl)(PMe3) (15) via Si-H bond cleavage. 1 reacted with Fe(PMe3)4 to form the hexacoordinate octahedral hydrido iron(II) complex [PSiP]Fe(H)(PMe3)2 (16). The molecular structures of complexes 2-5, 10, 12, 13, 15, and 16 were determined by X-ray single crystal diffraction. 16 has excellent catalytic reactivity for the reduction of aldehydes and ketones.
- Wu, Siquan,Li, Xiaoyan,Xiong, Zichang,Xu, Wengang,Lu, Yunqiang,Sun, Hongjian
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p. 3227 - 3237
(2013/07/19)
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- Syntheses and properties of molecular nickel(II) hydride, methyl, and nickel(I) complexes supported by trimethylphosphane and (2-diphenylphosphanyl)thiophenolato and -naphtholato ligands
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(2-Diphenylphosphanyl)thiophenol (P^pSH) or (3-diphenylphosphanyl)-2-thionaphthol (P^nSH) react with Ni(PMe3)4 to form NiH(P^pS)(PMe3)2 (1) or NiH(P^nS)(PMe3)2 (2). 1,3-Bis(diphenylphosphanyl)propane (P^P) replaces the monodentate phosphane ligands to give NiH(P^pS)(P^P) (3). NiMe(OMe)(PMe3) or NiMe2(PMe3)3 react with P^pSH to form NiMe(P^pS)(PMe3) (4) and NiMe(P^pS)(PMe3)2 (5), respectively, and P^nSH affords NiMe(P^nS)(PMe3)2 (6), NiMe(P^nS)(PMe3) (7). Dissociation of PMe3 ligands induces transformation of 1 to Ni(P^pS)(PMe3)2 (8) and Ni(P^pS)2. Crystal and molecular structures are given for 1, 5-8, and dynamic solution spectra (NMR, EPR) are discussed.
- Kraikivskii, Peter B.,Frey, Markus,Bennour, Hamdi A.,Gembus, Armin,Hauptmann, Ralf,Svoboda, Ingrid,Fuess, Hartmut,Saraev, Vitaly V.,Klein, Hans-Friedrich
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p. 1869 - 1876
(2009/08/14)
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- Insertion of alkynes into Ni-H bonds: Synthesis of novel vinyl nickel(II) and dinuclear vinyl nickel(II) complexes containing a [P, S]-ligand
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Reactions of alkynes with nickel hydride complexes bearing a [P, S]-ligand and supported by trimethylphosphine were investigated. Tetracoordinate vinyl nickel(II) complexes 3, 5, and 6 with square-monoinsertionplanar geometry were obtained by reacting phenylacetylene, trimethylsilylacetylene, and 1-hexyne with the hydrido nickel complex 1. Reaction of 1,4-bis(trimethylsilylethynyl)benzene with complex 1 proceeds as a monoinsertion and afforded complex 7, while reaction of 1,4-bis(ethynyl)benzene with 1 leads to the dinuclear vinyl nickel(II) complex 8.
- She, Lei,Li, Xiaoyan,Sun, Hongjian,Ding, Jun,Frey, Markus,Klein, Hans-Friedrich
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p. 566 - 570
(2008/10/09)
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- Insertion of Alkynes into Organonickel Functions as a Synthesis of Vinylnickel Compounds
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The diamagnetic vinylnickel compounds trans-Ni(CR1=CR2R3)Cl(PMe3)2 (1a: R1 = R2 = C6H5, R3 = CH3; 2a: R1= C6H5, R2 = R3 = CH3; 3a: R1 = R2 = CH3, R3 = C6H5; 4a: R1 = R2 = R3 = C6H5) and Ni(CR1=CR2R3)(acac)(PMe3) (5: R1 = R2 = C6H5, R3 = CH3) are formed by insertion of diphenylethyne and 1-phenylpropyne into methyl- or phenylnickel moieties as Z isomers, that are thermally equilibrated with their E isomers. 1-Phenylethyne and 1-phenylpropyne selectively produce (1-phenylvinyl)nickel compounds.Exchange of halide gives bromides 1b, 2b, 4b and iodides 1c, 2c, 4c, and a cyanide 1d.Action of LiR (R = Me, CCCMe3) on 1a followed by reductive elimination yields olefins RR1C=CR2R3 while mineral acids or iodine cleave the Ni-C bonds of 1a to give the corresponding olefins (R = H, I).A high-yield synthesis of chloro(phenyl)bis(trimethylphosphane)nickel is also described.
- Klein, Hans-Friedrich,Reitzel, Lutz
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p. 1115 - 1118
(2007/10/02)
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- Oxidative coupling of phosphinomethanides at a metal centre: P-P vs. C-C bond formation and the molecular structure of the novel bis-ylide (Me 3Si)2C=PMe2-PMe2=C(SiMe 3)2
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Metal induced coupling of [CH2PMe2]- leads to Me2PCH2CH2PMe2, whereas coupling of [C(X)(SiMe3)(PMe2)]- (X=SiMe3 or PMe2) results in P-P bond formation affording [(X)(SiMe 3)C=PMe2-]2, with a central P-P bond of length 2.278(1) A.
- Karsch, Hans H.,Deubelly, Brigitte,Mueller, Gerhard
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p. 517 - 518
(2007/10/02)
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- FUNKTIONELLE TRIMETHYLPHOSPHANDERIVATE. XIX. PHOSPHINOMETHYLSUBSTITUIERTE ZIRCONIUMVERBINDUNGEN ALS NUCLEOPHILE: SYNTHESE, REAKTION MIT CO UND MOLEKUELSTRUKTUR VON 2Ni
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The organozirconium-substituted phosphines Cp2Zr(X)CH2PMe2 (Cp = η5-C5H5; X = Cl, CH2PMe2) have been prepared from Cp2ZrCl2 and LiCH2PMe2.In these compounds, the phosphinomethyl group acts as a monohapto (η1-) ligand.On reaction with CO, the bis(phosphinomethyl)zirconium complex forms a red complex, which by means of NMR spectroscopy is shown to contain a novel zircona heterocycle.With Ni(COD)2, Cp2Zr(CH2PMe2)2 forms the 2:1 complex 2Ni.Crystals (from tetrahydrofuran) are triclinic, space group P, with parameters a 13.433(5), b 18.062(3), c 19.505(2) Angstroem, α 64.35(2), β 76.82(1), γ 71.28(2) deg, V 4018.12 Angstroem3, dx 1.445 g cm-3 for Z = 4, μ(Mo-Kα) 11.5 cm-1, T 21 deg C.Refinement of 743 parameters on 8826 reflections converged at R = 0.055.The molecular structure consists of monomeric units with two bidentate Cp2Zr(CH2PMe2)2 molecules acting as chelating ligands to a tetrahedral Ni0 centre.The six-membered Zr(CH2PMe2)2Ni rings adopt a chair conformation.Steric strain by interaction of the axial cyclopentadienyl and methyl ligands at Zr and P, respectively, causes these rings to be considerably flattened.
- Karsch, Hans H.,Mueller, Gerhard,Krueger, Carl
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p. 195 - 212
(2007/10/02)
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