Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II)

Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II) of the type M(pnp)(CONHR)Cl (pnp = 2,6-bis(diphenylphosphinomethyl)pyridine; M Pd, R  C₆H₅, p-CH₃C₆H₄, p-CH₃OC₆H₄, C₆H₁₁, t-Bu; M  Pt, R  C₆H₅), Pd(pnp)[CON(Pr)₂]Cl (Pr = propyl), M(pnp)(COOR)Cl (M  Pd, R  C₆H₅, CH₃; M  Pt, R  CH₃), Pd(pnp)(COOCH₃)₂ result from reaction of M(pnp)Cl₂ with carbon monoxide and amines or alkoxides at room temperature and atmospheric pressure.The carbamoyl complexes react with bases to give urethane or diphenylurea depending upon the experimental conditions.     

Mechanism of reductive elimination of benzonitrile in cyanophenyl complexes of nickel(II) : II. Reactions of [cyano(phenyl)bis(tricyclohexylphosphine)nickel(II)]

The thermal decomposition of the complex Ni(CN)(C₆H₅)(PCy₃)₂ (Cy = cyclohexyl) in decalin has been examined. The complex reacts with P(OC₂H₅)₃ to give C₆H₅CN in quantitative yield. The mechanism of this reaction has been investigated and compared with that of the similar reaction shown by Ni(CN)(C₆H₅)(PEt₃)₂. The results indicate that the easiest path for the reaction involves a bimolecular attack of P(OC₂H₅)₃ at the metal atom before reductive elimination of C₆H₅CN.     

Some reactions of di-π-cyclopentadienyllead(II)

(C₅H₅)₂Pb reacts with HX to give (C₅H₅)PbX or PbX₂, X = Cl,Br,CH₃CO₂, with BF₃·Et₂O to give (C₅H₅)₂PbBF₃ and with TCNE to give (C₅H₅)₂Pb·O·5TCNE or (C₅H₅)₂Pb·TCNE.     

Reinvestigation of a transmetallation synthesis of bis(cyclopentadienyl)samarium(II) and formation of a new soluble cyclopentadienylsamarium(II) compound

The transmetallation reaction between (C₅H₅)₂Hg and activated samarium metal in tetrahydrofuran (thf)/ether did not give (C₅H₅)₂Sm(thf)₂ but (C₅H₅)₃Sm(thf), whilst reduction of the last compound with potassium in thf gave KSm(C₅H₅)₃, a soluble organosamarium(II) complex.     

Polythiolated complexes. Part 2(1). Palladium(II) and platinum(II) derivatives of polyfluorophenylthiolates

Summary The preparation and characterization of the new thiolate complexes [M(SR)₂(SEt₂)₂] (M=Pt, R=C₆F₅ orp-C₆HF₄) and [M(SR)₂]_n (M=Pd, R=C₆F₅,p-C₆HF₄ orp-C₆H₄F; M=Pt, R=p-C₆H₄F) is discussed. The tendency to form polymeric, rather than monomeric species, varies as follows: Pd>Pt; C₆H₄F>C₆HF₄> C₆F₅. [Pt(SC₆F₅)₂(SEt₂)₂] has atrans square planar coordination.     

Seven-coordinate complexes of molybdenum(II) and tungsten(II) containing pyrazole as a ligand

Summary Equimolar quantities of [MI₂(CO)₃(NCMe)₂] (M = Mo or W) and C₃H₄N² (pyrazole) react in CH₂C1₂ at room temperature to give the iodo-bridged dimers [M(μ-I) (CO)₃(C₃H₄N²)]₂ (1) and (2). Two equivalents of C₃H₄N² react with [MI₂(CO)₃(NCMe)₂] (M = Mo or W) to give the bis(pyrazole) complexes [MI₂(CO)₃(C₃H₄N²)₂] (3) and (4) in good yield. Three and four equivalents of pyrazole react with [MoI₂(CO)₃(NCMe)₂] to give the cationic complexes [MoI(CO)₃(C₃H₄N²)₃]I (5) and [MoI(CO)₂(C₃H₄N²)₄]I (6), respectively. The mixed ligand complexes [MI₂(CO)₃(C₃H₄N²)L] (M = Mo or W; L = PPh₃, AsPh₃ or SbPh₃) (7)-(12) are prepared by reacting equimolar amounts of [MI₂(CO)₃(NCMe)₂] and L in CH₂C1₂ at room temperature, followed by an in situ reaction with one equivalent of C₃H₄N². The MoSnCl₃ complex [MoCl(SnCl₃)(CO)₃(C₃H₄N²)₂] (13) is prepared in an analogous manner using acetone as the solvent, whilst the mixed ligand compound [MoCl(SnQ₃)(CO) ₃(C₃H₄N²)(PPh₃)] (14) was prepared by treating the dimeric complex [Mo(μ-Cl)(SnCl₃)(CO)₃(PPh₃)]₂ with two equivalents of C₃H₄N². All the new complexes were characterised by elemental analysis (carbon, hydrogen and nitrogen), i.r. and ¹H n.m.r. spectroscopy.     

Synthesis of divalent aryloxy- and diorganoamido-lanthanides from bis(pentafluorophenyl)lanthanide(II) complexes

The complexes M(OR)₂(thf)₃ (M = Yb or Eu, R = 2,6-Bu^t₂-4-MeC₆H₂; M = Yb, R = 2,4,6-Bu^t₃C₆H₂ or 2,6-Bu^t₂C₆H₃; thf = tetrahydrofuran) and M(NR₂)₂(thf)₄ (M = Yb or Eu, R₂N = carbazol-9-yl; M = Yb, R₂N = 2-phenylindol-1-yl) have been prepared by reactions of (C₆F₅)₂M (M = Yb or Eu) with substituted phenols, carbazole, or 2-phenylindole.     

Synthesis and structural characterization of ruthenium(II) and iron(II) complexes containing 1,2-di-(2-thienyl)-ethene derived ligands as chromophores

A new family of three-legged piano stool structured organometallic compounds containing the η⁵-cyclopentadienylruthenium(II)/iron(II) fragments {M(η⁵-C₅H₅) (DPPE)}⁺, {Ru(η⁵-C₅H₅)(PPh₃)₂}⁺ and {Ru(η⁵-C₅H₅)(TMEDA)}⁺ with coordinated thiophene based chromophores, namely 5-(2-thiophen-2-yl-vinyl)-thiophene-2-carbonitrile (L1) and 5-[2-(5-Nitro-thiophen-2-yl)-vinyl]-thiophene-2-carbonitrile (L2) has been synthesized and fully characterized by ¹H, ¹³C, ³¹P NMR, IR and UV-Vis spectroscopies. Also, electrochemical studies were carried out by cyclic voltammetry and all experimental data are interpreted and compared with related compounds under the scope of NLO properties. Compounds [Ru(η⁵-C₅H₅)(DPPE)(NC(C₄H₂S)C(H)C(H)(C₄H₃S))][CF₃SO₃] (1′Ru) [Fe(η⁵-C₅H₅)(DPPE)(NC(C₄H₂S)C(H)C(H)(C₄H₃S))] [PF₆] (1Fe) and [Ru(η⁵-C₅H₅)(DPPE)(NC(C₄H₂S)C(H)C(H)(C₄H₂S)NO₂)][CF₃SO₃] (4′Ru) were also crystallographically characterized.     

Kinetische untersuchungen an carbonyl(diorganyldithiophosphinato)-komplexen des mangans und rheniums

The substitution reactions of monomeric dithiophosphinato complexes R₂ PS₂ M(CO)₄ (R = C₂ H₅, C₆H₅; M = Mn, Re) with monodentate ligands P(C₆H₅)₃, As(C₆H₅)₃ and pyridine are examined kinetically. The reactions with P(C₆H₅)₃ and pyridine follow first-order and those with As(C₆H₅)₃ second-order kinetics. The rate constants as well as activation parameters are calculated and discussed in detail together with the reaction mechanism.     

Pd(II) and Pt(II) Complexes of 2-Phenyl- and 2-Benzyl-imidazoline: Synthesis,Structural Characterization,DNA Modification and in vitro Antileukaemic Activity

In this paper we describe the synthesis and chemical characterization of three new Pd(II)–imidazoline complexes: [PdCl₂ (C₆H₅–CH₂–C₃H₅N₂)₂] (2), [PdCl(SEt₂) (C₆H₄-C₃H₅N₂)] (5) and [Pd(C₆H₄-C₃H₅N₂) (μ-Br)]₂ (6). We have also analyzed the DNA modifications and in vitro antileukaemic activity of these compounds and of their previously reported analogs [Pd Cl₂ (C₆H₅–C₃H₅N₂)₂] (1), [Pd (C₆H₄–C₃H₅N₂) (μ-OAc)]₂ (3), [Pd (C₆H₄–C₃H₅N₂) (μ-Cl)]₂ (4) and [Pt(C₆H₄–C₃H₅N₂)(μ-Cl] (7). All these compounds modify the DNA secondary structure since they alter the melting temperature (T_m) of the DNA. Circular dichroism spectra indicated, moreover, that compounds 3, 5 and 6 induced higher modification on the double helix than compounds 1, 2 and 4. While compounds 1, 2 and 5 seem to induce slight changes in the electrophoretic mobility of the open and covalently closed circular forms of pUC8 DNA at high r_i (input molar ratio of Pd or Pt to nucleotides), compounds 3, 6 and 7 do not modify at any r_i the tertiary structure of the plasmid DNA. Antileukaemic tests suggest that compounds 1, 4 and 7 exhibit important cytotoxic activity since their IC₅₀ values against HL-60 human leukaemic cells were below 10 μg ml⁻¹. © 1997 John Wiley & Sons, Ltd.     

Darstellung von Acetatoblei(IV)- und Acetatozinn(IV)- manganpentacarbonylen durch Acidolyse von (C6H5)4–n−M[Mn(CO)5]n (M  Sn,Pb; n = 1, 2) mit Essigsäure

Preparation of Acetatolead(1V) and Acetatotin(1V) Manganese Pentacarbonyls by Acidolysis of (C₆H₅)_4?n M[Mn(CO)₅]_n (M ? Sn, Pb; n = 1, 2) with Acetic Acid By acidolysis of (C₆H₅)_4?nM[Mn(CO)₅]_n (M ? Sn, Pb; n = 1, 2) with acetic acid no M? Mn bonds are broken, but M? C bonds. In this reaction (CH₃COO)₂M[Mn(CO)₅]₂ is formed from (C₆H₅)₂M[Mn(CO)₅]₂, and (CH₃COO)₃SnMn(CO)₅ and (CH₃COO)₂C₆H₅PbMn(CO)₅ from (C₆H₅)₃MMn-(CO)₅. (CH₃COO)₂C₆H₅SnMn(CO)₅ is prepared from Cl₂C₆H₅SnMn(CO)₅ and AgCH₃COO. According to IR spectroscopic data the acetato ligands of the diacetato complexes are bidentate, while in (CH₃COO)₃SnMn(CO)₅ bi- and monodentate carboxylate groups are present. For the central atoms Sn and Pb octahedral coordination is proposed.     

Coordination compounds of cobalt(II), nickel(II), and copper(II) with 4-(3-hydroxyphenyl)-1,2,4-triazole: Synthesis and study

New Co(II), Ni(II), and Cu(II) complexes with 4-(3-hydroxyphenyl)-1,2,4-triazole (L) with the compositions [Co₃L₆(H₂O)₅(C₂H₅OH)](NO₃)₆ · 2H₂O · C₂H₅OH (I), [Ni₃L₆(H₂O)₆](NO₃)₆ · 2H₂O (II), and [M₃L₆(H₂O)₆](ClO₄)₆ · nH₂O (M = Co2⁺, n = 2 (III); Ni²⁺, n = 2 (IV); Cu²⁺, n = 0 (V)) are synthesized. The complexes are studied by X-ray structure analysis, X-ray diffraction analysis, UV and IR spectroscopy, and the statistical magnetic susceptibility method. All compounds have the linear trinuclear structure. Ligand L is coordinated to the metal ions by the N(1) and N(2) atoms of the heterocycle according to the bidentate bridging mode. In all compounds the coordination polyhedron of the metal atom is a distorted octahedron. The molecular and crystal structures of compound I, [Co₃L₆(H₂O)₆](ClO₄)₆ · 8C₂H₅OH (IIIa), and [Ni₃L₆(H₂O)₆](ClO₄)₆ · 8C₂H₅OH (IVa) are determined.     

DECARBONYLATION OF ACYLCHLOROBIS-(TRIPHENYLPHOSPHINE) PLATINUM(II) COMPLEXES PROMOTED BY TIN(II) CHLORIDE

Abstract

While it might be expected that the availability of vacant coordination sites in the four coordinate acyl complexes trans[Pt(PPh₃)₂ (RCO)Cl] provides low energy pathways for alkyl and aryl migration and subsequent decarbonylation, the decarbonylation has been previously achieved only at elevated temperatures. The addition of SnCl₂ greatly facilitates decarbonylation of [Pt(PPh₃)₂ (RCO)Cl] where R is CH₃, C₂ H₅, Y[sbnd]C₆ H₄. Compounds of the type [Pt(PPh₃)₂ (RCO)SnCl₃] and [Pt(PPh₃)₂ R(SnCl₃)] have been isolated. The removal of SnCl₂ from these compounds has been achieved with ethanol. A kinetic study of the decarbonylation of [Pt(PPh₃)₂ (RCO)SnCl₃] (where R is CH₃, C₂ H₅, Y[sbnd]C₆ H₄ for Y=H, CH₃, CH₃ O, NO₂, Cl) is reported. The role of 3 and 5 coordinate intermediates in alkyl-aryl migrations in Pt(II) systems is discussed.     

Photochemical reaction between cyclohexyl isocyanide and π-cyclopentadienyldicarbonyltrimethylsilyliron(II)

The photoreaction between C₅H₅Fe(CO)₂Si(CH₃)₃ (I) and cyclohexyl isocyanide leads to the sequential replacement of both carbonyl groups by the isocyanide. Both the racemic monosubstituted product, C₅H₅Fe(CO)(C₆H₁₁NC)Si(CH₃)₃ (II) and the disubstituted product, C₅H₅Fe(C₆H₁₁NC)₂Si(CH₃)₃ (III) have been isolated and characterized. Photoreaction between the disubstituted product III and C₅H₅Fe(CO)₂Si(CH₃)₃ in a sealed tube gives the monosubstituted product, II. Thermal initiation of the above reactions failed. The disubstituted product III is stable under both the thermal and photochemical conditions used; thus, insertion of isocyanide into FeSi bond was observed not to occur.     

Facile synthesis of new polyolefinic ruthenium(0) complexes from ruthenium(II) precursors

The new ruthenium(II) complex [(C₈H₁₀)RuCl₂]_n (1) (C₈H₁₀ = 1,3,5-cyclooctatriene; n ⩾ 2) has been obtained from the reaction of RuCl₃·xH₂O with 1,3,5,7-cyclooctatetraene in refluxing ethanol. Reduction of [(C₈H₁₀)RuCl₂]_n and [(C₇H₈)RuCl₂]₂ (2) (C₇H₈ = 1,3,5-cyclooctatriene) by Na/Hg amalgam in the presence of isoprene (C₅H₈) gives the novel ruthenium(O) complexes [(η⁶-C₈H₁₀)Ru(η⁴-C₅H₈)] (3) and [(η⁶-C₇H₈)Ru(η⁴-C₅H₈)] (4). [(η⁶-C₇H₈Ru(η⁴-C₅H₈)] reacts with CO and HBF₄ to give [(η⁶-C₇H₈)Ru(η³-C₅H₉)(CO)][BF₄] (C₅H₉ = trans-1,2-dimethylallyl (5a); 1,1-dimethylallyl (5b)).     

Lead(II) and cadmium(II) compounds with 2,4-dichlorophenoxyacetic acid (2,4D) and 2-(2,4-dichlorophenoxy)-propionic acid (2,4DP): Synthesis and properties

The paper presents the conditions under which compounds of the commercial herbicides, 2,4-dichlorophenoxyacetic acid (2,4D; C₈H₆O₃Cl₂) and 2-(2,4-dichlorophenoxy)-propionic acid (2,4DP; C₉H₈O₃Cl₂), with lead(II) and cadmium(II) are formed and the results of the examination of their properties.On the basis of the elemental analysis and Pb and Cd determination, the following molecular formulae for the obtained compounds were proposed: Pb(C₈H₅O₃Cl₂)₂.H₂O, Cd(C₈H₅O₃Cl₂)₂.₂H₂O, Pb(C₉H₇O₃Cl₂)2·H₂O and Cd(C₉H₇O₃Cl₂)₂·H₂O. Water solubility of the synthesized complexes at room temperature was examined. X-ray powder analysis was carried out. The discussion of IR spectra and conductivity data is presented. Thermal decomposition of these compounds in air was studied by TG/MS methods.This revised version was published online in November 2005 with corrections to the Cover Date.     

Investigations on organotin,organolead, lead(IV), and lead(II) dithiolates

Bis(triorganometal) 1,2-dithiolates (R₃M)₂S₂R′ [(HS)₂R′ = C₇H₈S₂ for toluene-dithiol-3,4 (H₂TDT); M = Sn, Pb; R = Ph; or (HS)₂R′ = C₁₀H₁₄S₂ for 1,2-dimethyl-4,5-bis(mercaptomethyl)benzene (H₂DBB); M = Sn, R = CH₃, C₆H₅; M = Pb, R = C₆H₅], diorganometal 1,2-dithiolates R₂MS₂R′ [(HS)₂R′ = C₆H₆S₂ for 1,2-dimercaptobenzene (H₂DMB); M = Pb, R = CH₃, C₂H₅, C₆H₅; or (HS)₂R′ = H₂TDT; M = Sn, R = CH₃, C₆H₅; M = Pb, R = C₆H₅; or (HS)₂R′ = H₂DBB; M = Sn, R = CH₃, C₆H₅; M = Pb, R = CH₃, C₂H₂, C₆H₅; or (HS)₂R′ = C₈H₆N₂S₂ for 2,3-dimercaptoquinoxaline (H₂QDT); M = Pb, R = C₆H₅] and some lead(IV) and lead(II) dithiolates Pb(S₂R′)_n [(HS)₂R′ = H₂DMB, n = 2; (HS)₂R′ = H₂TDT, n = 2; (HS)₂R′ = H₂DBB, n = 1 or 2] have been prepared. Vibrational, ¹H NMR, and Mössbauer spectroscopic data are consistent with pentacoordination of tin in R₂SnTDT and with tetracoordination of tin in R₂SnS₂R′ and (R₃Sn)₂S₂R′ in the solid state. The soluble compounds are monomeric in solution. Coupling constants for the methyltin compounds indicate tetracoordination in solution.     

Stability constants of phthalate complexes of copper (II), nickel (II), zinc (II), cobalt (II), uranyl (II) and throium (IV) by paper electrophoresis

Summary Stoichiometric stability constants of Cu(II), Ni(II), Zn(II), Co(II), UO₂(II) and Th(VI) phthalate have been determined by paper electrophoresis. Phthalic acid (0.005 mol dm⁻³) was added to the background electrolyte: 0.1 mol dm⁻³ HClO₄. The proportions of C₆H₅C₂O ₄ ⁻ and C₆H₄C₂O ₄ ⁼ were varied by changing the pH of the electrolyte. These anions yielded the complexes, Cu C₆H₅C₂O ₄ ⁺ , Cu C₆H₄C₂O₄, Zn C₆H₅C₂O ₄ ⁺ , Co C₆H₅C₂O ₄ ⁺ , Ni C₆H₅C₂O ₄ ⁺ , UO₂ C₆H₅C₂O ₄ ⁺ , UO₂ (C₆H₄C₂O₄) ₂ ⁼ and Th (C₆H₄C₂O₄)₂ whose stability constants are found to be 10^3.0, 10^4.7, 10^2.6, 10^2.5, 10^2.3, 10^3.5, 10^12.6 and 10^13.4 respectively (μ=0.1, temp 40°C).     

Ni(II) and Co(II) complexes with 2,4-dichlorophenoxyacetic acid and 2-(2,4-dichlorophenoxy)-propionic acid

Nickel(II) and cobalt(II) complexes with the commercial herbicides 2,4-dichlorophenoxyacetic acid (2,4D; C₈H₆O₃Cl₂) and 2-(2,4-dichlorophenoxy)-propionic acid (2,4DP; C₉H₈O₃Cl₂) were prepared and characterized. On the basis of the results of elemental analysis and Ni and Co determination, the following molecular formulae were proposed for the obtained compounds: Ni(C₈H₅O₃Cl₂)₂·6H₂O, Co(C₈H₅O₃Cl₂)₂·6H₂O, Ni(C₉H₇O₃Cl₂)₂·2H₂O and Co(C₉H₇O₃Cl₂)₂·2H₂O. X-ray powder analysis was carried out. The IR, electronic (VIS) spectra and conductivity data were discussed. Water solubility of the synthesized complexes at room temperature was examined. Thermal decomposition of the compounds was studied. Dehydration processes occur during heating in air. The anhydrous compounds decompose via different intermediate products to oxides. TG/MS studies indicate formation of gaseous mass fragments of decomposition including H₂O⁺, OH⁺, CO₂ ⁺, HCl⁺, Cl₂ ⁺, CH₃Cl⁺, CH₂O⁺, C₆H₆ ⁺ and other. This revised version was published online in August 2006 with corrections to the Cover Date.     

Photoelectron spectroscopy of f-element organometallic compounds II. Tricyclopentadienyl derivatives of uranium(IV) and thorium(IV)

The photoelectron spectra of some cyclopentadienyI derivatives of uranium(IV) and thorium(IV), namely (C₅H₅)₃ ThCl, (C₅H₅)₃ UCl, (C₅ H₄ CH₃)₃ ThCl, (C₅ H₄ CH₃)₃ UCl, (C₅ H₄ CH₃)₃ UBr and (C₅ H₄ CH₃ )₃ UBH₄, are reported the metal 5f ionization has been detected in all the uranium derivative spectra and a simple molecular orbital scheme qualitatively accounts for the number and position of the observed low energy bands.