Showing papers in "Journal of The Chemical Society-dalton Transactions in 1975"
TL;DR: In this article, the preparation, structure, and magnetic properties of ternary oxides containing copper in oxidation states-I, -II, -III, and -IV were investigated.
Abstract: We report an investigation of the preparation, structure, and magnetic properties of ternary oxides containing copper in oxidation states-I, -II, -III, and -IV. The compounds described are: ACuO2(A = Al or Ga); AcuCo2(A = Ca, Sr, or Ba), A2Cu2O5(A = Sc, Y, Bi, or In), and A2CuO4(A = La, Al, or Ga); BaCuO2·5, ACuO3(A = Y or La); and BaCuO2·63 which is the only phase containing copper(IV) which could be obtained. X-Ray pcv.der patterns have been indexed wherever possible and magnetic-susceptibility measurements from 80 to 300 K are interpreted for all paramagnetic species.
99 citations
TL;DR: In this article, a model and procedures for the calculation of optical and e.s.r. spectra and magnetic susceptibilities of pn, dn, or fn electron systems for any basis chosen as free-ion terms and/or states relating to a molecule of any geometry are described.
Abstract: A model and procedures are described which permit the calculation of optical and e.s.r. spectra and magnetic susceptibilities of pn, dn, or fn electron systems for any basis chosen as free-ion terms and/or states relating to a molecule of any geometry. Ligand fields are parameterized within the angular-overlap model. Methods are described for calculating magnetic susceptibilities and g values in molecules whose symmetries do not predetermine the orientation of their principal molecular properties.
97 citations
TL;DR: In this article, the crystal structures of the isomorphous salts MI6[Mo7O24],4H2O (M = NH4 or K) have been refined by three-dimensional X-ray diffraction methods.
Abstract: The crystal structures of the isomorphous salts MI6[Mo7O24],4H2O (M = NH4 or K) have been refined by three-dimensional X-ray diffraction methods. Unit cell dimensions of these monoclinic compounds, space group P21/C with Z= 4, are, ammonium salt: a= 8·3934 ± 0·0008, b= 36·1703 ± 0·0045, c= 10·4715 ± 0·0011 A, β= 115·958°± 0·008°; and potassium salt: a= 8·15 ± 0·02, b= 35·68 ± 0·1, c= 10·30 ± 0·02 A, β= 115·2°± 02°.By use of multiple Weissenberg patterns, 8197 intensity data (Mo-Kα radiation) for the ammonium compound and 2178 (Cu-Kα radiation) for the potassium compound were estimated visually and used to test and refine Lindqvist's proposed structure in the space group P21/c. Lindqvist's structure was confirmed and the full matrix least-squares isotropic refinement led to R 0·076 (ammonium) 0·120 (potassium), with direct unambiguous location of the cations and water molecules in the potassium compound.
94 citations
TL;DR: In this article, it was shown that the isolated carbon atom is derived from reduction of a CO group, which leads to formation of polynuclear osmium carbonyl species based on five to eight Osmium atoms.
Abstract: Pyrolysis of [Ru3(CO)12] in a sealed evacuated tube gives [Ru6(CO)17C] thereby clearly establishing that the ‘isolated’ carbon atom is derived from reduction of a CO group. Pyrolysis of [Os3(CO)12] under similar conditions leads to formation of polynuclear osmium carbonyl species based on five to eight osmium atoms, viz. [Os5(CO)16], [Os5(CO)15C], [Os6(CO)18], [Os7(CO)21], [Os8(CO)23], and [Os8(CO)21C]. The probable structures of these polynuclear complexes are discussed.
83 citations
TL;DR: In this paper, the reactivity of olefins with [H2Os3(CO)12] without CO loss at room temperature to give vinyl derivatives of type [HOs3 (CR1:CHR2)(CO)10](R1= R2= H or Ph; R1= H, R2 = Me or Ph), alkenylene complexes [Os3, CR1:CR2), CO)10], and the phenylethynyl complex [H Os3(C2Ph)(CO), 10] were discussed.
Abstract: Acetylene and substituted acetylenes react with [H2Os3(CO)10] without CO loss at room temperature to give vinyl derivatives of type [HOs3(CR1:CHR2)(CO)10](R1= R2= H or Ph; R1= H, R2= Me or Ph), alkenylene complexes [Os3(CR1:CR2)(CO)10](R1= R2= H or Me; R1= H, R2= Me), and the phenylethynyl complex [HOs3(C2Ph)(CO)10], while other derivatives containing coupled alkynes are formed in low yield, if at all, at room temperature. On heating these complexes in hydrocarbon solvents, hydrogen transfer and CO loss occur to give [H2Os3(C2R2)(CO)9](R = H, Me, or Ph), [HOs3(C2R)(CO)9](R = H or Me), and [HOs3(MeC3H2)(CO)9][in two isomeric forms (A) or (B)]. The dihydrido-complexes may also be prepared by hydrogenation of [Os3-(CR1:CR2)(CO)10](R1= H or Me, R2= Me). Structures are proposed on spectroscopic evidence. The significance of these results to the reactivity of olefins with Os3(CO)12 is discussed.
77 citations
TL;DR: Tricarbonyl(η-methoxy- and tricarbonyls( η-halogeno-benzene)manganese salts have been obtained from the appropriate arenes with bromopentac-bonyl manganese and aluminium chloride.
Abstract: Tricarbonyl(η-methoxy- and tricarbonyl(η-halogeno-benzene)manganese salts have been obtained from the appropriate arenes with bromopentacarbonylmanganese and aluminium chloride. The ease of nucleophilic substitution increases sharply in the series of halogenoarene compounds linked to (OC)3Cr < (cp)Fe+ < (OC)3Mn+(cp =η-cyclopentadienyl). The high reactivity of the manganese complexes is utilised in the preparation of other functionally substituted arene complexes by reaction with amines or anionic nucleophiles. l.r. and n.m.r. study of the amino-substituted arene complexes establishes partial nitrogen to ring double bonding.
69 citations
TL;DR: In this paper, the stoicheiometry and kinetics of reaction of aqueous-ammonia (0·1-1.0M) solutions of copper(II) ions with thiosulphate ion in the presence of oxygen have been examined.
Abstract: The stoicheiometry and kinetics of reaction of aqueous-ammonia (0·1–1.0M) solutions of copper(II) ions with thiosulphate ion in the presence of oxygen have been examined. The amount of oxygen consumption and the relative amounts of the final sulphur products, namely trithionate and sulphate ions, are dependent on the initial [S2O3]2– concentration and pH. The detailed kinetics of the reaction at pH 11·2 suggest mechanisms in which O2 becomes axially associated with amminethiosulphatocopper(II) species. In this role O2 assists in electron transfer between [S2O3]2– and CuII. The most active species for [S3O6]2– formation is a tetra-amminecopper(II) complex having one axial [S2O3]2– and one axial O2 ligand. A triamminecopper(II) complex, having both axial and equatorial [S2O3]2– ligands as well as an axial O2, is suggested as the reactive intermediate for [SO4]2–formation. The role of the intermediate CuII species is one of complexing both oxidant and reductant.,in that it provides a mechanism for electron transfer and allows O2 to interact via an ionic mechanism.
67 citations
TL;DR: Variable-temperature P N.r.m. spectroscopy, coupled with lineshape analysis, has been used to derive ΔH‡ and ΔS‡ values for tertiary phosphine exchange between the complex and an excess of tertiary phosphate.
Abstract: 31 P N.m.r. spectroscopy has been used to investigate the solution structure of PdLn[L = PMe3, PMe2Ph, PMePh2, PPh3, PEt3, PBun3, P(CH2Ph)3, PPri3, P(C6H11)3, and PBut2Ph]. It is concluded that at room temperature the species existing in solution are [Pd(PMe3)4], [Pd(PMe2Ph)4], [Pd(PEt3)3], [Pd(PBun3)3], [Pd (PPh3)3], [Pd{P(CH2-Ph)3}3], [Pd(PPri3)2], [Pd{P(C6H11)3}2], and [Pd(PBut2Ph)2]. At low temperatures (–60 to –100 °C) additional species [Pd(PMePh2)4], [Pd(PPh3)4], [Pd(PEt3)4], [Pd(PBun3)4], [Pd(PPri3)3], and [Pd{P(C6H11)3}3] have been identified. Variable-temperature 31P n.m.r. spectroscopy, coupled with lineshape analysis, has been used to derive ΔH‡ and ΔS‡ values for tertiary phosphine exchange between the complex and an excess of tertiary phosphine. In order to explain the kinetics it is necessary to postulate that [Pd{P(CH2Ph)3}3] exchanges P(CH2Ph)3via dissociation to [Pd{P(CH2Ph)3}2]. Thus there is evidence for a number of formally 14-electron complexes of the type PdL2.
64 citations
TL;DR: In this article, the preparation and properties of [Nb(CN)8]n−n−4−5 (n= 4 or 5) cyanoniobates are described.
Abstract: The preparation and properties of salts of [Nb(CN)8]n–(n= 4 or 5) are described. E.p.r. spectra of [Nb(CN)8]4– salts indicate a change in configuration from D2d in the solid state to D4d in solution. The vibrational and electronic spectra of these cyanoniobates are reported and support these structural changes. E.p.r. and vibrational spectra of [M(CN)8]3–(M = Mo or W) salts in the solid state and in solution are also given.
58 citations
TL;DR: In the presence of oxygen, RuH(CO)2(η-C5H5)], (II; M = Ru), has been isolated and shown to be a direct precursor of (II) as discussed by the authors.
Abstract: Both Ru3(CO)12 and [H4Ru4(CO)12] react rapidly with cyclopentadiene in the absence of oxygen to yield [RuH(CO)2(η-C5H5)], (II; M = Ru), quantitatively, characterised in part via high-yield conversion into [RuH(CO)(PPh3)(η-C5H5)]. In the presence of oxygen [{Ru(CO)2(η-C5H5)}2], (III; M = Ru), is obtained in ca. 70% yield. The complex [Ru(CO)3(η-C5H6)], (I; M = Ru), has been isolated and shown to be a direct precursor of (II). Treatment of (I; M = Ru) with [Ph3C][BF4] gives [Ru(CO)3(η-C5H5)][BF4], while triphenyl-phosphine displaces C5H6 forming [Ru(CO)3(PPh3)2]. Carbonylation (100 atm) of [RuH(CO)(PPh3)(η-C5H5)] in the presence of Et2O·BF3 gives [Ru(CO)2(PPh3)(η-C5H5)][BF4] in high yield. A minor product of the reaction of Ru3(CO)12 and C5H6 is tentatively identified as [Ru3H(CO)9(η3-C5H5)], (IV); a related fluxional osmium complex, [Os3H2(CO)9(η2-C5H4)], is obtained on treating [H2Os3(CO)10] with C5H6. Low-yield formation of (I; M = Os) and (II; M = Os) from reaction of Os3(CO)12, [H2Os3(CO)10], or [H2Os(CO)4] with C5H6 is described.
57 citations
TL;DR: The crystal structure of the title compound has been determined by single-crystal X-ray diffraction photography, and refined isotropically by the method of least squares to R 0·11 6, based on 552 independent reflections as discussed by the authors.
Abstract: The crystal structure of the title compound has been determined by single-crystal X-ray diffraction photography, and refined isotropically by the method of least squares to R 0·11 6, based on 552 independent reflections There are two molecules in a hexagonal unit cell, space group P63, with a= 10·43(3) and c= 22·79(5)A The structure consists of cations [Fe3O(piv)6(MeOH)3]+(piv = CMe3·CO2) lying on the three-fold axes, with chloride ions on the screw axes The cation is analogous to that in the chromium(III) and iron(III) basic acetates, except for the rigorous three-fold symmetry and the fact that the central oxygen atom is displaced 0·24 A from the Fe3 plane The mass spectrum is unusual in showing peaks due to ions containing more than three iron atoms, eg Fe4O(piv)6+ which appears in greater abundance than any trinuciear ion
TL;DR: In this article, the electron transfer reactions of binary metal carbonyls at a Pt electrode in aprotic solvents have been investigated and the mechanisms of these electrode reactions have been studied.
Abstract: The electron-transfer reactions of several binary metal carbonyls at a Pt electrode in aprotic solvents have been investigated. In tetrahydrofuran, cathodic reduction of the carbonyls M(CO)n leads to the anions [M2(CO)2n– 2]2–(M = Cr, Mo, W, and Fe) and [M(CO)n]–(M = V), while reduction of the binuclear carbonyls M2(CO)10(M = Mn and Re) gives the anions [M(CO)5]–. Of the anodic reactions, of particular interest are the oxidations of Cr(CO)6 and M2(CO)10(M = Mn and Re) which, in acetonitrile, produce the cations [Cr(CO)6]+ and [M(CO)5(NCMe)]+ respectively. The mechanisms of these electrode reactions have been studied.
TL;DR: In this article, the effects of substituents on the aryl halides and of the halide as leaving group have been investigated by competitive measurements, and the mechanistic implications of these results are discussed.
Abstract: The oxidative addition of aryl halides, RC6H4X, to tris(triphenylphosphine)nickel(0) has been studied (R = H, m- or p-Me, -Cl, -CN, and -OPh, p-OMe, -COMe, and -COPh, and m-CO2Me; X = Cl, Br, or I). The effects of substituents on the aryl halides and of the halide as leaving group have been investigated by competitive measurements. The reactions of p-chloroanisole and p- and m-dichlorobenzene display first-order kinetics with respect to the aryl halides and the nickel complex. Triphenylphosphine decreases the reaction rate. The mechanistic implications of these results are discussed.
TL;DR: In this paper, an overall mechanism for the rearrangement reactions of all tertiary phosphine complexes of type [RuX2L3 or 4] is proposed and the results indicate that similar compounds are formed from [RuBr2(PPh3)4].
Abstract: The reactions of [RuCl2(PPh3)4] with several tertiary phosphine ligands in various solvents have been examined. Whereas prolonged reaction in ethanol or dichloromethane leads to the well known ionic dimers [Ru2Cl3L6]Cl(L = PEtPh2, PEt2Ph, or PMe2Ph), reaction in non-polar solvents such as hexane or light petroleum (b.p. 60–80 °C) produces neutral complexes. For L = PEtPh2, [RuCl2(PEtPh2)3] has been isolated although this readily converts to the triple chloride-bridged dimer [(Ph2EtP)3RuCl3RuCl(PEtPh2)2] in non-polar and [Ru2Cl3(PEtPh2)3]Cl in polar media. For L = PEt2Ph and PClPh2, only [L3RuCl3RuClL2] can be isolated although 31P n.m.r. studies indicate the presence of [RuCl2(PEt2Ph)3] in the reaction mixture. For L = PMe2Ph, cis-[RuCl22(PMe2Ph)4] is formed although this very readily rearranges to [Ru2Cl3(PMe2Ph)6]Cl. Preliminary studies indicate that similar compounds are formed from [RuBr2(PPh3)4]. All these compounds {including [RuCl2(PPh3)3 and 4]} have been extensively studied by variable-temperature 31P n.m.r. spectroscopy and an overall mechanism for the rearrangement reactions of all tertiary phosphine complexes of type [RuX2L3 or 4] is proposed.
TL;DR: In this article, a computer program, PSEUDOPLOT, is described as an alternative to the normalised-curves approach for selecting a set of formation constants necessary to define a system of competing equilibria.
Abstract: A computer program, PSEUDOPLOT, is reported as an alternative to the normalised-curves approach for selecting a set of formation constants necessary to define a system of competing equilibria. The selection of constants to describe the zinc(II) and lead(II) complexes of glycinate, glycylglycinate, and glycylglycylglycinate are reported as examples of the use of PSEUDOPLOT. Protonated and hydroxo-complexes have been identified.
TL;DR: In this article, a number of perfluorocarboxylic acid derivatives were derived from RFCO2H (RF= CF3, C2F5, or C6F5) or low-oxidation-state triphenylphosphine complexes of the platinum-group metals.
Abstract: Perfluorocarboxylic acids, RFCO2H (RF= CF3, C2F5, or C6F5), react with hydrido(triphenylphoshine) or low-oxidation-state triphenylphosphine complexes of the platinum-group metals to yield a wide range of perfluorocarboxylato-derivatives. Products which have been prepared in this manner include [RuCl(OCOCF3)(CO)(PPh3)2], [Ru(OCORF)2(CO)(PPh3)2], [Ru(OCORF)2(CO)2(PPh3)2], [RuH(OCOCF3)(PPh3)3], [OsCl(OCORF)(CO)(PPh3)3], [OsH(OCORF)(CO)(PPh3)3], [Os(OCORF)2(CO)(PPh3)2], [OsH(OCORF)(CO)2(PPh3)2], [Os(OCORF)2(CO)2(PPh3)2], [OsH(OCOCF3)(PPh3)3], [Rh(OCORF)(PPh3)3], [Rh(OCORF)(CO)(PPh3)2], [IrH(OCORF)2(CO)(PPh3)2], and [Ir(H)2(OCORF)(PPh3)3]. The new complexes have been characterised and, where possible, their stereochemistry has been determined by i.r. and n.m.r. spectroscopy. The occurrence of a rapid intramolecular exchange between uni- and bi-dentate perfluorocarboxylate ligands in the complexes [M(OCORF)2(CO)(PPh3)2](M = Ru or Os) has been established by observation of temperature-dependent 19F n.m.r. spectra for the trifluoroacetate derivatives. Mechanisms involving oxidative addition of perfluorocarboxylic acids to the precursors, and subsequent reductive elimination of dihydrogen, are proposed for the reactions discussed. The tendency for unidentate perfluorocarboxylate ligands situated trans to strong σ-donor ligands to undergo alcoholysis is reported.
TL;DR: In this article, an apparatus for the generation of metal vapours and their reactions with potential ligand precursors is described, and a symmetry sandwich structure is proposed for these compounds on the basis of 1H n.m.r, mass, and photoelectron spectroscopy.
Abstract: An apparatus for generation of metal vapours and their reactions with potential ligand precursors are described. Co-condensation of titanium atoms with benzene, toluene, or mesitylene gives the compounds [(H6C6)2Ti], [(MeC6H5)2Ti], and [(mes)2Ti], respectively. Symmetrical sandwich structures are proposed for these compounds on the basis of 1H n.m.r., i.r., mass, and photoelectron spectroscopy.
TL;DR: In this paper, high-energy photoelectron (p.e.) spectra have been obtained for a number of compounds of antimony and the binding energies range from 542.9, 533.3 eV for [Et4N][SbF6] to 538.6, 529.0eV for Bun3Sb, but there is little correlation with the formal oxidation state.
Abstract: High-energy photoelectron (p.e.) spectra have been obtained for a number of compounds of antimony. The antimony 3d(,5//2) binding energies range from 542.9, 533.3 eV for [Et4N][SbF6] to 538.6, 529.0 eV for Bun3Sb, but there is little correlation with the formal oxidation state. Assignment of the oxidation state of antimony on the basis of X-ray p.e. data alone is not possible with certainty and even gross structural differences may remain undetected by this method.
TL;DR: Aqueous stability constants for complex formation of dibenzo-18crown-6 (dbc) with a series of metal ions have been determined spectrophotometrically by the solubility technique.
Abstract: Aqueous stability constants for complex formation of dibenzo-18-crown-6 (dbc) with a series of metal ions have been determined spectrophotometrically by the solubility technique (Mn+= Na+, K+, Rb+, Cs+, Ag+, Tl+, [NH4]+, Sr2+, Ba2+, Pb2+, and La3+). The stability of the complexes is affected by changes in the ionic strength of the solutions and thermodynamic constants have been obtained by extrapolating the experimental values to infinite dilution. The monodissociated ion pairs [BaCl]+ and [SrCl]+ complex more strongly with dbc than the free ions Ba2+ and Sr2+. The behaviour of dbc with bivalent metal ions is much more sensitive to their ionic size than in the case of univalent ions. This is explained on the basis of electrostatic considerations.
TL;DR: In this paper, the title complexes of Au(dmp)Cl3 and Br3 have been synthesized and their crystal and molecular structures determined from three-dimensional X-ray data obtained by counter methods.
Abstract: The title complexes [(4) Au(dmp)Cl3 and (5) Au(dmp)Br3, dmp = 2,9-dimethyl-1,10-phenanthroline] have been synthesised and their crystal and molecular structures determined from three-dimensional X-ray data obtained by counter methods. Crystals of (4) and (5) are not isomorphous though both are monoclinic, space group P21/C, with Z= 4 in unit cells of dimensions: (4)a= 7.343(1), b= 18.712(3), c= 12.143(3)A, β= 112.29(2)°;(5), a= 8.046(1), b= 10.478(3), c= 20.079(5)A, β= 92.65(2)°. The structures were solved by the heavy-atom method and refined by full-matrix least-squares to R 0.035 [(4) 904 reflections] and 0.060 [(5) 1122 reflections].The compounds consist of discrete, diamagnetic five-co-ordinate molecules in both the solid state and in solution in aprotic solvents. The distribution of the ligands about the metal is approximately square pyramidal with the axial ligand displaced from the vertical, and at a relatively great distance from the metal, so that they may also be described as strongly distorted square planar. The direction of the distortion is such as to reduce the energy of the high-spin (triplet) state, but the magnitude is too low to produce a high-spin ground-state.
TL;DR: In this paper, a single-crystal X-ray diffractometry of L-cysteine with methylmercury hydroxide or chloride in basic solution is described.
Abstract: The title complex has been prepared from the reaction of L-cysteine with methylmercury hydroxide or chloride in basic solution and characterised by single-crystal X-ray diffractometry. Crystals are orthorhombic, space group P212121, with unit cell dimensions a= 6·386(6), b= 26·026(13), c= 5·282(4)A and Z= 4. The structure was solved by Patterson and Fourier techniques and refined by full-matrix least-squares methods to a final R of 0·065 for 980 independent observed reflections measured on an automatic diffractometer. The amino-acid is co-ordinated to Hg via a deprotonated sulphydryl group [Hg–S 2·352(12)A]. A weak intramolecular Hg ⋯ O interaction [2·85(2)A] to a carboxylate group is present. Individual molecules of the complex are linked by hydrogen bonds to solvent water molecules. The vibrational spectra of the complex are discussed [ν(Hg–S) 326 cm–1].
TL;DR: Pyridine reacts with Os3(CO)12 to give a series of bridging 2-pyridyl complexes: [HOs3(NC5H4)(CO)10] and [Os2(NC 5H4)2(CO]6], isomers (A) and (B).
Abstract: Pyridine reacts with Os3(CO)12 to give a series of bridging 2-pyridyl complexes: [HOs3(NC5H4)(CO)10]; [HOs3(NC5H4)(CO)9(py)], isomers (A) and (B); [H2Os3(NC5H4)2(CO)8]; and [Os2(NC5H4)2(CO)6], isomers (A) and (B). Several of the corresponding derivatives of 4-methyl- and 4-benzyl-pyridine are also described. Evidence is given for successive and reversible reactions in which loss of CO from the cluster is accompanied either by co-ordination of an extra py or by hydrogen transfer from co-ordinated py to the metal. Quinoline and isoquinoline with Os3(CO)12 give the isomers [HOs3(NC9H6)(CO)10] in which quin has been metallated exclusively at the 2-position whereas iquin gives isomers metallated at the 1- and 3-positions respectively.
TL;DR: The ruthenium compound is monoclinic, a= 8.939(3), b= 18.045(7), c= 11.363(3)A, β= 91.52(2)°, Z= 4, space group P21/n as mentioned in this paper, the structure was determined by Patterson and Fourier syntheses and refined by full-matrix least squares procedures to a final R of 0.041 for 2 720 independent reflections measured by diffractometer.
Abstract: Crystals of the title compound are monoclinic, a= 8.939(3), b= 18.045(7), c= 11.363(3)A, β= 91.52(2)°, Z= 4, space group P21/n. The structure was determined by Patterson and Fourier syntheses and refined by full-matrix least-squares procedures to a final R of 0.041 for 2 720 independent reflections measured by diffractometer. The co-ordination geometry about the ruthenium atom is essentially octahedral with cis-chlorine atoms. Of the four dimethyl sulphoxide ligands three are S- and one is O-bonded, the O-bonded ligand being trans to a S-bonded ligand. Important mean bond distances are : Ru–Cl 2.435(1), Ru–S 2.277(1)(trans to Cl), 2.252(1)(trans to O), Ru–O 2.142(3), S–O 1.484(5)(S-bonded), and 1.557(4)A(O-bonded).
TL;DR: In this paper, the crystal structure of the title compound has been determined by the heavy-atom method from diffractometer data and refined by least-squares to R 0·082 for 3449 reflections.
Abstract: The crystal structure of the title compound has been determined by the heavy-atom method from diffractometer data and refined by least-squares to R 0·082 for 3449 reflections. Crystals are monoclinic, space group A2/a, a= 23·252(6), b= 18·342(4), c= 17·824(5)A, β= 92·45(2)°, Z= 8. The iron atom is surrounded by three bidentate ligands, the six Fe–N distances being equal (mean 1·973 A). The geometries of two of the perchlorate ions are as expected but the third ion is badly disordered, and there may be additional partial occupancy of the lattice by further water molecules. The e.s.r. spectrum has been determined at ca. 85 K and the principal g values are found to be along the molecular pseudo-trigonal axis (g1 1·459(5)) and in the plane normal to it [g2, g3 2·615(10), 2·727(10)]. The splitting of the 2T2g ground term of the Fe3+ ion (ΔAggca. 800 cm–1) is deduced to be opposite in sign to that predicted by crystal-field theory.
TL;DR: The crystal structures of cis-and trans-dichlorobispyridineplatinum(II)[(I) and (II)] have been determined by heavy-atom techniques from 1 000 and 1 032 (II) observed intensities, measured by diffractometer, and refined by least-squares methods to R 0.041 and 0.068 (II).
Abstract: The crystal structures of cis- and trans-dichlorobispyridineplatinum(II)[(I) and (II)] have been determined. Crystals of (I) are monoclinic, space group C2/c, with a= 9.408(5), b= 17.110(14), c= 15.270(7)A, β= 98.53(4)°, Z= 8; crystals of (II) are triclinic, space group P, with a= 7.695(6), b= 7.091 (5), c= 5.542(5)A, α= 87.6(1), β= 83.7(1), γ= 79.3(1)°, Z= 1. The structures were solved by heavy-atom techniques from 1 000 (I) and 1 032 (II) observed intensities, measured by diffractometer, and refined by least-squares methods to R 0.041 (I) and 0.068 (II).Both complexes consist of discrete molecules with platinum showing the usual square-planar co-ordination. Shortest mean Pt ⋯ Pt distances are 4.967 (I) and 5.542 A(II). Molecules of (I) pack in a manner similar to that of cis-[Pt(NH3)2Cl2], but the large Pt ⋯ Pt distances preclude any metal–metal interaction.
TL;DR: In this article, the molecular structure of the palladium complex has been determined from a single-crystal X-ray diffraction study and refined to R= 0.042 for 3 319 independent observed reflections.
Abstract: Reaction of [Ni(cod)(ButNC)2], [Pd(ButNC)2], and [Pt(trans-stilbene)(PEt3)2] with [Me4N]+[closo-CB10H11]–and closo-2-NMe3-2-CB10H10 affords the closo-metallacarbaboranes [Me4N]+[1,1-L2-1,2-MCBl0H11]– and [1,1-L2-2-NMe3-1,2-MCBl0Hl0](M = Ni or Pd, L = ButNC; M = Pt, L = PEt3). The molecular structure of the palladium complex has been determined from a single-crystal X-ray diffraction study and refined to R= 0.042 for 3 319 independent observed reflections. Crystals are monoclinic, space group P21/n. with cell dimensions of a= 10.947(3), b= 15.194(4), c= 15.804(4)A, β= 103.45(2)°. The 12-atom polyhedron has a very distorted icosahedral geometry, marked by an extremely weak metal-carbon interaction with Pd–C(cage) at 2.600(6)A. The metal to carbaborane bonding is described in terms of approximately square planar co-ordination.
TL;DR: In this article, cyclohexadienyl and 6-exo-methyl- or -phenyl-cyclohexadianyl complexes bearing halogeno-, alkoxy-, or dialkyl-amino-substituents in the 1- or 2-positions are obtained by reaction of lithium tetrahydridoaluminate or methyl-or phenyl-lithium with the appropriately substituted (η-arene)tricarbonylmanganese salt.
Abstract: Cyclohexadienyl and 6-exo-methyl- or -phenyl-cyclohexadienyl complexes bearing halogeno-, alkoxy-, or dialkyl-amino-substituents in the 1- or 2-positions are obtained by reaction of lithium tetrahydridoaluminate or methyl-or phenyl-lithium with the appropriately substituted (η-arene)tricarbonylmanganese salt. Directive effects in these nucleophilic additions are compared with those observed for arene complexes of iron and chromium.
TL;DR: The crystal structure of the title complex has been determined by direct methods from X-ray diffractometer data as discussed by the authors, and the crystal is monoclinic, space group C2/c, a= 19.629(11), b= 10.755(6), c= 17.425(31)A, β= 90.21(6)°.
Abstract: The crystal structure of the title complex has been determined by direct methods from X-ray diffractometer data. Crystals are monoclinic, space group C2/c, a= 19.629(11), b= 10.755(6), c= 17.425(31)A, β= 90.21(6)°. Z= 4. Refinement of atomic parameters by full-matrix least-squares methods gave R 0.084 for 1 894 reflections.The two halves of the complex are related by a two-fold symmetry axis which passes through a pair of aliphatic C–C bonds on opposite sides of the crown ring. The polyether ring folds around the pair of sodium ions. Each cation interacts with three oxygen atoms of the ligand; each of the fourth pair of oxygen atoms is 2.965 A from a cation, not directed towards the cation, and not involved in co-ordination. Torsion angles in the crown ring differ considerably from normal; about the two-fold axis, the torsion angle of one C–C bond (where there is slight site disorder) is 117°, an eclipsed arrangement, and of the other bond is 139°.An o-nitrophenolate anion on each side of the crown ring completes the six-fold co-ordination of the cations. Each anion chelates a cation and the phenolate oxygen (carrying most of the anionic charge) bridges the pair of cations. Molecular dimensions are as expected. Packing in the crystal is by van der Waals' interactions, including the parallel arrangement of benzene rings of crown ligands about a centre of symmetry.
TL;DR: In this paper, the signs and magnitudes of the spin-coupling constants between tin and the directly bound elements boron, nitrogen, silicon, tin, tellurium, and tungsten in some trimethylstannyl derivatives are compared with the corresponding couplings involving carbon.
Abstract: Heteronuclear double-resonance experiments are used to determine the signs and magnitudes of the spin-coupling constants between tin and the directly bound elements boron, nitrogen, silicon, tin, tellurium, and tungsten in some trimethylstannyl derivatives These and other coupling constants involving tin are compared with the corresponding couplings involving carbon and it is found that for X = H, B, C, F, Si, Sn, Te, and W, 1K(Sn–X) is approximately nine times 1K(C–X) whereas for X = N, PIII, Pv, and Se this is not so For X = N and Pv the reduced couplings to carbon and tin are of opposite sign The results are consistent with a molecular orbital theory which does not use the mean excitation energy approximation and, in general, it is concluded that the s-overlap integral βSn – X is smaller than βC – X which leads to larger negative contributions to the mutual polarizability in the case of tin compounds
TL;DR: A series of new five-coordinate complexes, R3SnL [R = Me.m., n.m.], has been prepared and characterized by i.r. and Mossbauer spectroscopy as mentioned in this paper.
Abstract: A series of new five-co-ordinate complexes, R3SnL [R = Me. (I)–(III) or Ph, (IV)–(VI); L = anions of acetylacetone (acac), benzoylacetone (bzac), or dibenzoylmethane (bzbz)], has been prepared and characterized by i.r., n.m.r. and Mossbauer spectroscopy. Compounds (I)–(III) have large quadrupole splittings (3·69–3·86 mm s–1), while those of (IV)–(VI) are much smaller (1·38–2·25 mm s–1). By use of partial quadrupole splittings these splittings are shown to be consistent with the mer-structure for compounds (I)–(III), and the all-cis-structure for (IV)–(VI). The all-cis-structure has been confirmed for (VI), [Ph3Sn(bzbz)], by a single-crystal X-ray diffraction study. Crystals are monoclinic, space group P21/c, with Z= 4 in a unit cell of dimensions: a= 13·216(5), b= 9·443(4), c= 22·344(9)A, and β= 109·42(2)°. The structure was solved by the heavy-atom method from intensity data collected by diffractometric methods, and refined by full-matrix least-squares methods to R 0·051 for 2328 observed reflections. The co-ordination about the Sn atom is essentially a distorted trigonal bipyramid. The phenyl groups occupy one axial and two equatorial co-ordination sites with the chelating ligand bonded to one equatorial and one axial site. Sn–C(eq) Bond lengths are 2·149(7) and 2·181(6), and Sn–C(ax) 2·180(6)A. The Sn–O(ax) distance [2·276(7)A] is significantly longer than Sn–O(eq)[2·094(7)A].