Showing papers by "William Levason published in 1975"
TL;DR: In this paper, the reaction of iron(II) halides and pseudohalides with cis-1,2-bis(diphenylphosphino)ethylene (dppen) yields the complexes [Fe(dplpen)2X2] with six-coordinate, probably trans, structures.
Abstract: Reaction of iron(II) halides and pseudohalides with cis-1,2-bis(diphenylphosphino)ethylene (dppen) yields the complexes [Fe(dppen)2X2](X = Cl, Br, NCS, or N3) and [Fe(dppen)Br2]. Physical properties indicate that the [Fe(dppen)2X2] complexes have six-co-ordinate, probably trans, structures. Magnetic susceptibilities and Mossbauer spectra classify the complexes as having S= 0 (X = NCS or N3) or S= 2 (X = Br) ground states, or as existing in a temperature-dependent high-spin ⇌ low-spin equilibrium (X = Cl). The Mossbauer parameters of the complexes are discussed in terms of the bonding properties of dppen. The properties of [Fe(dppen)Br2], and of the dominant species occurring in solutions of [Fe(dppen)2X2](X = Cl or Br), are consistent with tetrahedral structures. The product of reaction of iron(III) chloride with dppen is the complex salt [Fe(dppen)2Cl2][FeCl4] in which the cation contains the metal in the S=½ state.
12 citations
TL;DR: Three open-chain quadridentate thioether ligands, 1,2-bis(o-methylthiophenylthio)ethane, 1 3-bis (o-mmethylthiobenzenethiolate)propane, and 1,4-bis-(o- methylthiophensylthiosynthetic)butane, have been prepared and their complexes with cobalt(II), nickel(II, copper(II) and rhodium(III) salts isolated and characterised as mentioned in this paper.
Abstract: Three open-chain quadridentate thioether ligands, 1,2-bis(o-methylthiophenylthio)ethane, 1,3-bis(o-methylthiophenylthio)propane, and 1,4-bis(o-methylthiophenylthio)butane, have been prepared and their complexes with cobalt(II), nickel(II), copper(II), palladium(II), platinum(II), and rhodium(III) salts isolated and characterised. These are mainly of the types six-co-ordinate [MLX2](M = Co or Ni) in which the ligand is quadridentate, four-co-ordinate [M2LX4](M = Cu, Pd, or Pt) in which the ligand is bridging quadridentate, and [Rh4L3X12]. The behaviour of these ligands is discussed in terms of normal metal co-ordination numbers and their inability to compete with halides for co-ordination positions. In NN-dimethylformamide the PdII and PtII complexes undergo complicated S-dealkylation reactions. With the former three products have been identified and contain the ligands o-methylthiobenzenethiolate and benzene-1,2-dithiolate.
8 citations
TL;DR: In this article, the square pyramidal complexes [Ni(bitas)X]BPh4(X = halide), the first examples of trivalent bismuth co-ordinated to a 3D transition metal in a positive oxidation state, and [Ni2bitas]3]4+, which contains examples of bitas functioning as a tridentate and a tetra-dentate ligand.
Abstract: Tris(o-dimethylarsinophenyl)bismuthine (bitas) forms the square pyramidal complexes [Ni(bitas)X]BPh4(X = halide), the first examples of trivalent bismuth co-ordinated to a 3d transition metal in a positive oxidation state, and [Ni2(bitas)3]4+, which contains examples of bitas functioning as a tridentate and a tetra-dentate ligand.
6 citations
TL;DR: 1,3-Bis(dimethylstibino)propane (dmsp) has been synthesized and forms stable square-pyramidal nickel(II) complexes as discussed by the authors.
Abstract: 1,3-Bis(dimethylstibino)propane (dmsp) has been synthesised and forms stable square-pyramidal nickel(II) complexes.
4 citations
TL;DR: In this article, the square pyramidal complexes [Ni(bitas)X]BPh4(X = halide), the first examples of trivalent bismuth co-ordinated to a 3D transition metal in a positive oxidation state, and [Ni2bitas]3]4+, which contains examples of bitas functioning as a tridentate and a tetra-dentate ligand.
Abstract: Tris(o-dimethylarsinophenyl)bismuthine (bitas) forms the square pyramidal complexes [Ni(bitas)X]BPh4(X = halide), the first examples of trivalent bismuth co-ordinated to a 3d transition metal in a positive oxidation state, and [Ni2(bitas)3]4+, which contains examples of bitas functioning as a tridentate and a tetra-dentate ligand.
TL;DR: In this paper, the reaction of iron(II) halides and pseudohalides with cis-1,2-bis(diphenylphosphino)ethylene (dppen) yields the complexes [Fe(dplpen)2X2] with six-coordinate, probably trans, structures.
Abstract: Reaction of iron(II) halides and pseudohalides with cis-1,2-bis(diphenylphosphino)ethylene (dppen) yields the complexes [Fe(dppen)2X2](X = Cl, Br, NCS, or N3) and [Fe(dppen)Br2]. Physical properties indicate that the [Fe(dppen)2X2] complexes have six-co-ordinate, probably trans, structures. Magnetic susceptibilities and Mossbauer spectra classify the complexes as having S= 0 (X = NCS or N3) or S= 2 (X = Br) ground states, or as existing in a temperature-dependent high-spin ⇌ low-spin equilibrium (X = Cl). The Mossbauer parameters of the complexes are discussed in terms of the bonding properties of dppen. The properties of [Fe(dppen)Br2], and of the dominant species occurring in solutions of [Fe(dppen)2X2](X = Cl or Br), are consistent with tetrahedral structures. The product of reaction of iron(III) chloride with dppen is the complex salt [Fe(dppen)2Cl2][FeCl4] in which the cation contains the metal in the S=½ state.
TL;DR: 1,3-Bis(dimethylstibino)propane (dmsp) has been synthesized and forms stable square-pyramidal nickel(II) complexes as discussed by the authors.
Abstract: 1,3-Bis(dimethylstibino)propane (dmsp) has been synthesised and forms stable square-pyramidal nickel(II) complexes.
TL;DR: In this paper, the planar thiocyanates of o-phenylenebis(diphenylarsine)(pdpa) and (o-diphensylarsinophenyl)diphosphine (padpp) were formulated, and the [M(L)2X2] complexes are predominantly five-coordinate.
Abstract: Thirty five complexes of o-phenylenebis(diphenylarsine)(pdpa) and (o-diphenylarsinophenyl)diphenylphosphine (padpp) including types [M(L)X2], [ML2][ClO4]2, [M(L)2X2](M = Pd or Pt; L = pdpa or padpp; X = Cl, Br, I, or CNS), and [Pd(pdpa)2X]ClO4 have been prepared. The planar thiocyanates are formulated [Pd(pdpa)(NCS)(SCN)] and [Pt(padpp)(NCS)(SCN)]. In dichloromethane the [Pt(pdpa)(SCN)2] complex partly isomerises to [Pt(pdpa)(NCS)(SCN)]. The five-co-ordinate [PdL2(NCS)]CNS (L = pdpa or padpp) species also isomerise in solution. The diperchlorates are planar, whilst in solution the [M(L)2X2] complexes are predominantly five-co-ordinate. On heating, the [M(L)2X2](X = Cl, Br, or I) complexes dissociate in the solid state into [M(L)X2] and free L. The tendency to five-co-ordination is Pd > Pt and pdpa > padpp. Rhodium(III) halides form adducts [Rh(pdpa)2X2]X (X = Cl, Br, or I), [Rh(padpp)2X2]X (X = Cl or Br), and [{Rh(padpp)I3}2].