A reappraisal of the nature of the product from the reaction of bis(methylcyclopentadieny)tin(II) with tungsten(cyclopentadienyl) (tricarbonyl) hydride

The nature of the product obtained from the title reaction has been reexamined, and identified as ClSn[W(CO)₃C₅H₅)]₃.     

The preparation and crystal structure of bis(bis(diphenyl-phosphino)ethane)carbonylformylosmium(II) hexafluoroantimonatedichloromethane (1/1)

Reaction of trans[Os(CO)₂(dppe)₂]²⁺ with [KHB(OPrⁱ)₃] gives the formyl complex trans[Os(CHO)(CO)(dppe)₂][SbF₆] which is thermally very stable; the crystal structure shows it to have trans stereochemistry and a long Os-C bond.     

Coordination,oligomerisation and transfer hydrogenation of acetylenes by some ruthenium and osmium carboxylates: Crystal and molecular structures of bis(trifluoroacetato)carbonyl-(methanol) bis(triphenylphosphine)ruthenium(II) and (1,4-diphenylbut-1-en-3-yn-2-yl)trifluoroacetato-(carbonyl) bis(triphenylphosphine)ruthenium(II)

The hydrides [MH(O₂CCF₃)(CO)(PPh₃)₂] (M = Ru or Os) react with disubstituted acetylenes PhCCPh and PhCCMe to afford vinylic products [M{C(Ph)CHPh}(O₂CCF₃)(CO)(PPh₃)₂] and [M{C(Ph)CHMe}(O₂CCF₃)(CO) (PPh₃)₂]/[M{C(Me)CHPh}(O₂CCF₃)(CO)(PPh₃)₂] respectively. Acidolysis of these products with trifluoroacetic acid in cold ethanol liberates cis-stilbene and cis-PhHCCHMe respectively thus establishing the cis-stereochemistry of the vinylic ligands. The complexes [M(O₂CCF₃)₂(CO)(PPh₃)₂] formed during the acidolysis step undergo facile alcoholysis followed by β-elimination of aldehyde to regenerate the parent hydrides [MH(O₂CCF₃)(CO)(PPh₃)₂] and thereby complete a catalytic cycle for the transfer hydrogenation of acetylenes. The molecular structure of the methanol-adduct intermediate, [Ru(O₂CCF₃)₂(MeOH)(CO)(PPh₃)₂] has been determined by X-ray methods and shows that the coordinated methanol is involved in H-bonding with the monodentate trifluoroacetate ligand [MEO-H---OC(O)CF₃; O...O = 2.54 Å]. The hydrides [MH(O₂CCF₃)(CO) (PPh₃)₂]react with 1,4-diphenylbutadiyne to afford the complexes [M{C(CCPh)CHPh} (O₂CCF₃)(CO)(PPh₃)₂]. The ruthenium product, which has also been obtained by treatment of [RuH(O₂CCF₃)(CO)(PPh₃)₂] with phenylacetylene, has been shown by X-ray diffraction methods to contain a 1,4-diphenylbut-1-en-3-yn-2-yl ligand. The osmium complexes [Os(O₂CCF₃)₂(CO)(PPh₃)₂], [OsH(O₂CCF₃)(CO)(PPh₃)₂] and [Os{C(CCPh)CHPh}(O₂CCF₃)(CO)(PPh₃)₂] all serve as catalysts for the oligomerisation of phenylacetylene. Acetylene reacts with [Ru(O₂CCF₃)₂(CO)(PPh₃)₂] in ethanol to afford the vinyl complex [Ru(CHCH₂)(O₂CCF₃)(CO)(PPh₃)₂].     

Synthesis and characterization of cobalt(II), nickel(II) and copper(II) perchlorate complexes with bis [(diphenylphosphinyl)methyl] phenylphosphine oxide,bis [(disphenylphosphinyl)methyl]ethyl phosphinate,and bis [(diphenylphosphinyl)methyl] phosphinic acid

The synthesis and characterization of cobalt(II), nickel(II) and copper(II) perchlorate complexes containing bis [(diphenylphosphinyl)methyl] [phenylphosphine oxide (RPPH), bis [(diphenylphosphinyl)methyl] ethyl phosphinate (RPOEt), and bis [(diphenylphosphinyl)methyl] phosphinic acid (RPOH) have been studied. The substituent at the central phosphorus atom of the ligand is responsible for the types of complexes formed. The new complexes [M(RPPh)₂(ClO₄)₂.nH₂O, [M(RPPh)₃](ClO₄)₂.4H₂O, [M(RPOEt)₂](ClO₄)₂.2H₂O, and [M(RPOH)₃] (ClO₄)₂.nH₂O are characterized as high spin and most of them have an octahedral or distorted octahedral geometry [M = Co(II), Ni(II), or Cu(II); n = 2?5]. The coordination of two P = O groups from one ligand to the metal has been proposed for most of the complexes formed. The coordination of all three P = O groups has been assumed for complexes [M(RPPh)₂](ClO₄)₂.nH₂O and [M(RPOEt)₂](ClO₄)₂.2H₂O.     

Kinetic study on the reaction of cis-dioxo-(N-(5-X-salicylidene)-2-aminobenzenethiolato) molybdenum(VI) with ethyldiphenylphosphine

The reactions of ethyldiphenylphosphine with a number of cis-dioxomolybdenum(VI) Schiff base coordination complexes are described. These molybdenum complexes incorporate tridentate Schiff base ligands obtained from the condensation of 5-X-salicylaldehyde (X = Cl, Br, H, CH₃O) with o-aminobenzenethiol. Oxomolybdenum(IV) Schiff base complexes were observed as products of the reaction of these Mo(VI) complexes with PEtPh₂. The kinetics for these reactions were followed spectrophotometrically and the applicable rate law is ? d[MoO₂L]/dt = k₁[MoO₂L][PEtPh₂]. The k₁'s were shown to vary systematically as the X-substituent on the ligand was changed. For MoO₂(5-X-SSP), the specific rate constants at 30°C span the range from 19.6 × 10^?4 M^?1 sec^?1 (X = Br) to 8.4 × 10^?4 M^?1 sec^?1 (X = CH₃O). It was also observed that a correlation exists between the cathodic reduction potentials (E_pc) and the k₁'s within the series. The rate of reaction of MoO₂(5-X-SSP) with PEtPh₂ was altered and systematically controlled through ligand design.     

Studies on extraction of copper(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone

The extraction of Cu(II) with 1-phenyl-3-methyl-4-acyl-5-pyrazolone (HA), in different organic solvents has been studied. The extraction mechanism of Cu(II) and the composition of the extracted species has been determined. Cu(II) was extracted as CuA₂, or in the presence of TOPO, as CuA₂TOPO. The extraction constants do not change regularly with increasing the length of acyl chain in the 1-phenyl-3-methyl-4-acyl-5-pyrazolone derivatives. The effect of the temperature on the extraction of Cu(II) has also been investigated.     

Kinetics of the reaction of Di-μ-acetatodi-μ-oxalatodiaquodiruthenium(II,III) anion with N-(2-hydroxyethyl)-ethylenediaminetriacetatoaquotitanium(III)

Reduction of [Ru₂(CH₃COO)₂(C₂O₄)₂(H₂O)₂]^? by N-(2-hydroxyethyl)-ethylenediaminetriacetatoaquotitanium(III) [Ti(HEDTA)] involves several distinct stages. The first stage has a half-time of less than 1 ms, and is interpreted as a substitution reaction leading to a multinuclear intermediate. The second stage has a second-order rate constant of 5 x 10₃M^?1s^?1 [25°C, μ = 0.1 m (LiCF₃SO₃)]. The rate-limiting process for the second stage is electron transfer within the assembled multinuclear complex. Subsequent slower stages correspond to breakup of the multinuclear Ru(II)₂-Ti(IV) complex formed by electron transfer. The overall rate of reduction of this oxidant by Ti(HEDTA) is less than the corresponding rate for the reaction in which Ti³⁺ acts as reductant, mainly because the stability of the binuclear complex is reduced by the presence of the aminoacid ligand. The data are consistent with the conclusion that the ligand increases the rate of intramolecular ET, probably by reducing geometric change associated with oxidation of Ti(III) to Ti(IV).     

Complexes of 1-methyl-4-mercaptopiperidine with zinc(II), cadmium(II) and mercury(II) halides

The preparation of a series of complexes formed by 1-methyl-4-mercaptopiperidine (AH) and divalent zinc, cadmium and mercury halides is reported together with some spectral and physical properties. The results of a crystallographic study allows to establish the structure of those of formula [M₂(AH)₂X₄]H₂O (M = Zn, Cd, Hg; X = Br, I) consisting of dimers and involving tetrahedral environment with sulphur-bridges for the metal atoms. Polymeric structures are proposed for the complexes of formulae Cd(AH)Cl₂ and Hg₂Cl₄(AH).     

Carbonyl-organocobalt(I) and -(II) complexes

Passage of CO through solutions of complexes (C₆F₅)₂CoL₂ gives carbonyl derivatives (C₆F₅)₂CoL₂(CO) (L₂ = 2 PEt₃, 2 P-n-Bu₃, 2 PPh₃, Ph₂PCH₂CH₃PPh₂). The properties of these compounds are described.The compounds are also produced by treating solutions of (C₆F₅)₂Co-(dioxane)₂ with CO, but a simultaneous reduction to (C₆F₅)Co(CO)₄ takes place. Treatment of the latter complex with monodentate ligands gives substitution products (C₆F₅)Co(CO)₃L (L = PEt₃, P-n-Bu₃, PPh₃) all of which are monomeric, whereas the addition of Ph₂PCH₂CH₂PPh₂ gives the dimer (C₆F₅)(CO)₂CoLLCo(CO)₂(C₆F₅). The properties of these compounds are discussed.     

Studies on the thermal decomposition of salicylhydroxamic acid and its metal complexes with Ni(II), Co(II), Fe(II), Mn(II) and Zn(II)

The thermal decomposition of salicylhydroxamic acid and its metal complexes with Ni(II), Co(II), Fe(II), Mn(II) and Zn(II) has been studied by TG, DTG, DTA and IR spectroscopy. All the compounds investigated decompose to yield intermediate N-hydroxylactams.Decomposition schemes have been proposed and reaction enthalpies and kinetic parameters have been calculated.     

Metal-(phenylthio)acetic acid interactions—VI. The crystal and molecular structures of diaquabis[(phenylsulfinyl) acetato[bis(pyridine)copper(II) and bis[(benzylthio) acetato]bis(pyridine)copper(II)

The crystal structures of diaquabis[(phenylsulfinyl) acetato]bis(pyridine)-copper(II), (1), and bis[(benzylthio) acetato]bis(pyridine)copper(II) (2) have been determined using X-ray diffraction. In (1), the copper atom is at the centre of a distorted octahedron with the equatorial sites occupied in a trans configuration by two unidentate (phenylsulfinyl)acetate oxygens [Cu-O, 1.97(2),2.01(2)Å] and two pyridine nitrogens [Cu-N, 1.99(2),2.05(2) Å] with water molecules completing the polyhedron [Cu-O, 2.51(2),2.58(2) Å]. The copper atom in (2) is at the inversion centre of a distorted octahedron having in the equatorial sites, trans-related pyridine nitrogens [Cu-N, 1.993(3) Å] and four oxygens from two asymmetric bidentate (benzylthio)acetate ligands [Cu-O, 2.012(3), 2.510(5) Å].     

Kinetics of the reaction of aluminum EDTA and cobalt(II) EDTA with calmagite

The reaction of aluminum EDTA with calmagite was found to be first-order in calmagite, half-order in aluminum EDTA, and zero-order in excess EDTA. The three-halves-order apparent rate constant at pH 9.48 and 20°C with ionic strength 0.30 was 0.232 ± 0.0141^{$\text{1}\text{2}$} · mol^{$\text{1}\text{2}$} · s^?1. The activation energy was 3.2 ± 0.3 kcal/mol. The pH dependence was complex between 8 and 10. The mechanism proposed is a rapid dissociation of a dimer of aluminum EDTA to a monomer followed by a rate-determining displacement of the EDTA by calmagite. The reaction of Co(II) EDTA with calmagite was confirmed to be first-order in Co(II) EDTA and first-order in calmagite with an activation energy of 7.5 ± 0.6 kcal/mol.     

Metal complexes of 2-(2′-carboxymethylthio-phenylazo)-5-nitrotoluene—II. Complex formation equilibria with copper(II) ion in several dioxane—water solvent mixtures

Stability constants of copper(II) complexes formed by 2-(2′-carboxymethyl-thiophenylazo)-5-nitrotoluene in dioxane—water solvent mixtures of several different compositions [50, 60 and 75% dioxane (v/v)] were determined from EMF measurements, at 25°C and 0.1 mol dm^?3 NAClO₄ ionic medium. Graphical treatment of experimental data gives for the equilibria nA^?+Cu²⁺ = CuA_n^(2-n)+ (n = 1 or 2), in a solvent with X% (v/v) dioxane, the following values of log β₁, and log β₂ (given here successively). X = 50:2.41, 6.77; X = 60:3.36, 7.45; X = 75:4.33, 7.64. The relation between solvent composition and the values found for the stability constants is discussed. From EMF measurements made with the copper(II) ion-selective electrode, at constant pH, the nature of the effective donor groups in this potentially terdentate ligand is inferred.     

Synthesis and spectral properties of a new binuclear iron complex: The ion tetracyano(4-cyanopyridine) ferrate(II)-μ-cyano-pentacyanoferrate(II)

A new cyano-bridged binuclear complex of Fe(II) can be prepared by mixing pentacyano(ammine)ferrate(II) with 4-cyanopyridine at a mole ratio 2:1. IR and UV-VIS spectra, together with kinetic data on ligand substitution, point to the following structure; (NC)₅Fe-NC-Fe(CN)₄(N

-CN)^6?, both in solid state and in aqueous solution, thus demonstrating that cyanide forms a bridge between two iron atoms which is much more stable than that formed by 4-cyanopyridine.     

Carbonylierung von bis(triphenylphosphin)-platin(II)- und -palladium(II)-komplexen in gegenwart von aminen und α-aminosäureestern

The crystal structure of (C₅H₅)₃Pr·CNC₆H₁₁ was determined from single-crystal X-ray diffraction data. The monoclinic unit cell of dimensions a = 8.298(3), b = 21.66(1), c = 11.943(4) Å, and β = 104.98(3)° contains four molecules in general positions of space group P2₁/c. Each molecule is composed of three C₅H₅ rings in a nearly exact trigonal array, η⁵-bonded to the Pr atom at a distance of 2.53 Å to the centroid of each ring, plus a single CNC₆H₁₁ adduct attached to the Pr atom along the trigonal axis at 2.65 Å. The presence of a CN triple bond in the isonitrile moiety and the nearly linear CNC configuration add credence to the previous proposal that there is a pure donor bond from the isonitrile carbon to the metal atom.     

Metal complexes of anti-inflammatory drugs—I. Complexes of iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) with 4-hydroxy-3-(5-methyl-3-is

The preparation, spectroscopic and magnetic properties are reported for complexes of iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) with th     

Variable-temperature and solvent NMR study of bis(μ2-methanethiolato)-bis(dinitrosyliron) and bis(μ2-methaneselenolato)-bis(dinitrosyliron)

The ¹H NMR spectrum of Fe₂(SMe)₂(NO)₄ has been measured in a total of 22 solvents, and the activation barrier ΔG^≠ for the C_2h?C_2v isomerisation in nine of these solvents. In aromatic solvents, the solvent-induced shifts are consistent with the formation of charge-transfer complexes, either 1:1 or 1:n; in non-aromatic, non-halogenated solvents of high dipolarity/polarizability the solvent-induced shifts follow the variation of the solvatochromic parameter, π*. The behaviour of Fe₂(SeMe)₂(NO)₄ in a limited range of solvents is similar. The activation barrier ΔG^≠ in Fe₂(SMe)₂(NO)₄ is ca 78 kJ mol^?1 in the majority of solvents, but that for Fe₂(SeMe)₂(NO)₄ is significantly higher.     

Zinc(II), cadmium(II) and mercury(II) complexes of 4,6-dimethyl-pyrimidine-2(1H)-one

The following zinc(II), cadmium(II) and mercury(II) complexes of 4,6-dimethylpyrimidine-2(1H)-one (L) have been prepared and investigated by conductometric,IR and Raman methods: MX₂L₂ (M = Zn, X = Cl, Br(CHCl₃, I(CHCl₃, CF₃COO; M = Cd, X = Cl, Br CF₃COO; M = Hg, X = Cl, CF₃COO), Cd₂I₄L₃, Hg₃X₆L₂ (X = Cl, Br), Hg₃X₆L₄(X = Br, I), MX₂L₄·6H₂O (M = Zn, Cd, X = CIO₄, BF₄; M = Hg, X = CIO₄. The ligand is principally bonded through the unprotonated nitrogen atom and in some complexes also through the carbonylic oxygen atom. The zinc halide complexes are tetrahedrally coordinated, the trifluoroacetate ion is coordinated as a monodentate ligand.     

Synthesis,spectroscopic properties and crystal structure of the eight-coordinated lead complex bis[thiocyanato]-1,4,7,10,13-pentaoxacyclopentadecano lead(II)

The complex [Pbc[15]crown-5](SCN)₂ was synthesized and characterized spectroscopically (IR and FIR range) and the crystal structure was determined by X-ray diffraction on a single crystal (orthorhombic space group Pmc2₁). The structure was solved by Patterson synthesis with least-square refinement. The final R-value is 0.0328. Two Pb-atoms and two unidentical halves of the ligand were found in the asymmetric unit. For each complexed lead cation and each half of the crown ether there exists a plane of reflexion, whereby C18 and C28 are disordered. There is, however, no centre of inversion between these unidentical halves. The elementary cell comprises four units and two different types of two centrally coordinated Pb cations. Both lead cations are eight-coordinated. In the case of Pb1 the eight donor centres are the five O-atoms of the ligand and three N-atoms of the thiocyanates. For Pb2 these are five oxygens of the ligand, one nitrogen and two sulphurs of the three thiocyanates. In this complex the thiocyanate ligands occur in both ionic and covalent states. The complexation of the crown ether and the two different species of thiocyanate anions are indicated too by typical shifted absorption bands in the IR spectra. The vibrations in the FIR region can be assigned to the interactions between lead and the donor groups.     

Group IB organometallic chemistry: XXXV. Crystal and molecular structure of [Cu4(4-MeC6H4)-MeC-C(C6H4NMe2-2)2(C6H4NMe2-2)2], a tetranuclear organocopper compound containing bridging alkenyl and aryl groups

The crystal and molecular structure of the title compound has been determined by a single crystal X-ray diffraction study using standard Patterson and Fourier methods. The structure was refined by a block-diagonal least-square procedure to a finalR value of 0.16 for 3454 reflections. Crystals are monoclinic, space groupP2₁/c, witha 14.007(5), b 12.224(5), c 28.358(8)A?, β 99.60(1)°, andZ - 4.The molecule consists of a central rhombus-type core of copper atoms to which the alkenyl and aryl groups are bound in a bridging fashion (two electron-three center bonding). The two alkenyl and the two aryl groups each occupy adjoining edges of the Cu₄ core. The dimethylamino groups of the alkenyl ligand coordinate to copper, whereas those of the bridging aryl ligand are free. As a result the copper core is made up of copper atoms which are alternatingly two- and three-coordinate.The structure is discussed in terms of structural information now available for organocopper compounds. The geometry of the Cu₂C (bridge) moiety in organocopper cluster compounds as expected varies little with the nature of the bridging one-electron organo ligand (alkyl, alkenyl, alkynyl or aryl).