- The synthesis of triangulo-trimetal complexes containing both iron(II) and vanadium(II)
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Reactions between a variety of vanadium(II) and iron(II) starting materials in tetrahydrofuran (thf) solution afforded di-, tri-, and tetra-nuclear complexes containing thf or N,N,N′,N′-tetramethylethylenediamine (tmen) as ligands. Most products were ionic and contained the two metals in different structural units, cation or anion. Trinuclear clusters formulated as [V3-x-FexCl5(tmen)3][BPh 4](x = 0-3) were obtained and characterised by C, H, N and metal analyses, 1H NMR, M?ssbauer, and positive ion FAB and electrospray mass spectroscopies, and magnetic moment measurements in solution. We characterised fully by low-temperature single-crystal X-ray diffraction analysis the mixed-metal triangulo-complex salt [V2Fe(μ-Cl)3(μ3-Cl)2(tmen) 3][BPh4].
- Evans, David J.,Hitchcock, Peter B.,Leigh,Nicholson, Brian K.,Niedwieski, Antonio C.,Nunes, Fábio S.,Soares, Jaísa F.
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- The synthesis, molecular and electronic structure of cyanovinylidene complexes
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Reaction of the readily available metal acetylide complexes Ru(CCC 6H4R-4)(PPh3)2Cp (R = OMe, Me, H, CN, CO2Me), Ru(CCFc)(PPh3)2Cp and Fe(CCC 6H4R-4)(dppe)C
- Long, Ella M.,Brown, Neil J.,Man, Wing Y.,Fox, Mark A.,Yufit, Dmitry S.,Howard, Judith A.K.,Low, Paul J.
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p. 358 - 371
(2012/03/13)
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- Square planar vs tetrahedral geometry in four coordinate iron(II) complexes
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The geometric preferences of a family of four coordinate, iron(II) d 6 complexes of the general form L2FeX2 have been systematically evaluated. Treatment of Fe2(Mes)4 (Mes = 2,4,6-Me3C6H2) with monodentate phosphine and phosphite ligands furnished square planar trans-P2Fe(Mes) 2 derivatives. Identification of the geometry has been accomplished by a combination of solution and solid-state magnetometry and, in two cases (P = PMe3, PEt2Ph), X-ray diffraction. In contrast, both tetrahedral and square planar coordination has been observed upon complexation of chelating phosphine ligands. A combination of crystallographic and magnetic susceptibility data for (depe)Fe-(Mes)2 (depe = 1,2- bis(diethylphosphino)ethane) established a tetrahedral molecular geometry whereas SQUID magnetometry and Moessbauer spectroscopy on samples of (dppe)Fe(Mes)2 (dppe = 1,2-bis(diphenylphosphino)-ethane) indicated a planar molecule. When dissolved in chlorinated solvents, the latter compound promotes chlorine atom abstraction, forming tetrahedral (dppe)Fe(Mes)Cl and (dppe)FeCl2. Ligand substitution reactions have been studied for both structural types and are rapid on the NMR time scale at ambient temperature.
- Hawrelak, Eric J.,Bernskoetter, Wesley H.,Lobkovsky, Emil,Yee, Gordon T.,Bill, Eckhard,Chirik, Paul J.
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p. 3103 - 3111
(2008/10/09)
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- Moessbauer and preparative studies of some iron(II) complexes of diphosphines
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Analytical and Moessbauer spectral data show that Ph2PCH2CH2PPh2 (dppe) forms adducts [FeCl2(dppe)] and [FeI2(dppe)], and that [FeCl2(dppe)2] does not exist. The phosphine 1,2-C6H4(PPh2)2 (opdp) forms adducts FeX2(opdp)2, which exists in one form (high-spin, trans octahedral) for X = Cl, and in two isomeric forms for X = Br or I. One isomer for X = I is high-spin, trans octahedral, and the other is ionic low-spin, and five-co-ordinate. A comparison is made of these structures and of their Moessbauer spectra with those of derivatives of Me2PCH2CH2PMe2, Et2PCH2CH2PEt2, Pri2PCH2CH2Pri 2, and Ph2PCH2PPh2.
- Barclay, J. Elaine,Leigh, G. Jeffery,Houlton, Andrew,Silver, Jack
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p. 2865 - 2870
(2007/10/02)
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- Mechanistic Studies on Iron Phosphine Complexes. Part 1. Protonation and Substitution of trans- (X=Cl or Br, diphosphine=Et2PCH2CH2PEt2 or Ph2PCH2CH2PPh2)
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The mechanisms of protonation and substitution of trans- have been investigated in tetrahydrofuran at I=0.1 mol dm-3(n4>) and 25 deg C.In the presence of acid, HX, loss of phosphine and formation of occurs by a variety of pathways dependent upon the nature of the phosphine.When diphosphine=dppe rapid ring opening of the chelate from trans- allows protonation of the pendant phosphorus atom.Subsequent dissociation of the phosphine ligand, and protonation of the metal, with release of dihydrogen, results in the formation of .When diphosphine=depe a further pathway involving initial protonation of the metal is identifiable.In contrast, substitution of trans- by L=CO, MeCN, or PhCN to yield trans-+ has to await the slow dissociation of halide.
- Henderson, Richard A.
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p. 509 - 514
(2007/10/02)
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- The Electro-Syntheses of Anhydrous Metal Chloride Complexes of Iron, Cobalt, and Nickel
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The electro-syntheses of the anhydrous metal(II) chlorides od Fe, Co, and Ni are described.The appropriate metal is present in the form of a sacrificial anode and the reaction is carried out in an undivided cell with ethanolic solutions of hydrogen chloride.The primary products, MCl2 . n EtOH (1 - 3), are obtained in yields of 83 - 100percent based upon the current consumed and are converted into 4 - 6 upon reaction with THF, into 7 - 12 upon reaction with triorganophosphanes and into the tetrachlorometallate(II) complexes 13 - 15 upon reaction with Cl.Electrochemical reduction of nickel(II) chloride and triphenylphosphane (1 : 3) in THF leads to the formation of chlorotris(triphenylphosphane)nickel(I) (18) in 65percent yield.
- Lehmkuhl, Herbert,Mehler, Klaus,Hauschild, Gerlinde
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p. 438 - 444
(2007/10/02)
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