Organometallic and organobimetallic complexes of platinum(II) containing 2,2′-bipyrimidyl: syntheses and spectroscopic characteristics

Preparations are described of several monometallic complexes (bipym)PtR₂ [bipym = 2,2′-bipyrimidyl; R = Me, CF₃, Ph, 1-adamantylmethyl (adme); R₂ = (CH₂)₄] and bimetallic analogues R₂Pt(μ-bipym)PtR′₂ [R = R′ = CH₃, C₆H₅, adme; R = CH₃, R′ = Ph, adme, CF₃]. IR, ¹H NMR and UV/visible spectroscopic characteristics of the two modes of bipyrimidyl coordination are discussed.     

Manganese(II) and copper(II) complexes of some nitrogenoxygen and nitrogensulphur donor ligands

Manganese(II) and copper(II) complexes of the type M(ligandH)₂ with some nitrogenoxygen and nitrogensulphur donor ligands (HL) viz. phenylpyruvic acid semicarbazone (ppysc), 4-methylphenylpyruvic acid semicarbazone (4-mppysc), phenylpyruvic acid thiosemicarbazone (ppytsc) and 4-methylphenyl pyruvic acid thiosemicarbazone (4-ppytsc), have been synthesised. All the complexes have been characterised by magnetic moment measurements, IR electronic and electron spin resonance special studies. All the ligands behave as tridentate.     

Bi- and triheteronuclear complexes of uranium and group VI transition metals

The new heterobimetallic compounds Cp₃U[OCM(CO)₂Cp′] containing uranium and group VI transition metals are synthesized from Cp₃UCl and Na[M(CO)₃Cp′] or from Cp₃UCH₃ and H[M(CO)₃Cp′] (M = Mo, W; Cp = C₅H₅; Cp′ = C₅H₅ or C₅Me₅). In a same manner, the trimetallic Cp₂U[OCMo(CO) ₂Cp]₂ is obtained starting from Cp₂U(NEt₂)₂ and H[Mo(CO)₃Cp]. All these complexes exhibit low CO stretching frequencies characteristic of isocarbonyl linkages between uranium and Mo or W atoms.     

3,6-bis(2′,-pyridyl)pyridazine dinuclear complexes: Palladium(II), platinum(II) and first row transition metal(II) mixed complexes

New Pd(II) and Pt(II) 3,6-bis(2′-pyridyl)pyridazine (dppn) mononuclear complexes of the type M(dppn)Cl₂ were prepared and characterized. From M(dppn)Cl₂, the bimetallic homonuclear complexes M(dppn)MCl₄ were prepared by reaction with Pd(PhCN)₂Cl₂ or K₂PtCl₄. Bimetallic heteronuclear species of the type M(dppn)M′Cl₄, were prepared reacting the mononuclear complexes with the stoichiometric amount of M′Cl₂ (M′ = Cu, Co, Ni). All the described reaction give product in high yield. The isolated compounds, almost completely insoluble in most organic solvents, were characterized by elemental analysis, IR, ESR, reflectance spectra, and magnetic moment measurements. On the basis of these data the geometries around the metals are discussed.     

Dioxouranium(VI) complexes of some sulphur donor ligands

Complexes of uranyl chloride and uranyl nitrate of the type UO₂X₂·2L and [UO₂X₂2L′], where X = Cl or NO₃ and L = N,N′-tetramethylthiourea (TMTU); N,N′-dimethylthiourea (DMTU); monomethylthiourea (MMTU), monoethylthiourea (METU), pyridine-2-thiol (PYT) and L′ = 4,6-dimethylpyrimidine-2-thiol (PYMT), have been prepared. The complexes were characterised on the basis of IR spectroscopy and by elemental analysis. In some cases Raman spectra are also reported.     

Some mixed-ligand palladium(II) complexes and comparison of their photosensitizing ability with analogous platinum(II) complexes

Three new palladium(II) complexes of formula [Pd(bipy)(XX)] [where bipy is 2,2′-bipyridine and XX are dianions of catechol (CAT), 4-tert-butylcatechol (BCAT) and 3,4-dimercaptotoluene (DMT)] have been prepared and characterized by physical methods. A ligand-ligand charge-transfer band in each complex was observed between 16–21 kK (ε_max = 1500–2200 1 mol^?1 cm^?1) which is negatively solvochromic. These palladium(II) complexes in dimethylformamide photosensitize the formation of singlet oxygen and their ability to photosensitize triplet oxygen (³O₂) to singlet oxygen (¹O₂) are compared with analogous platinum(II) complexes. In addition, 2,2′-bipyridine-platinum(II) complex of 3,4-dimercaptotoluene also undergoes self-sensitized photooxidation.     

New biimidazole and bibenzimidazole derivatives: mono and binuclear palladium(II) or platinum(II) complexes and heterobinuclear palladium(II)-rhodium(I) or platinum(II)-rhodium(I) complexes

Novel neutral biimidazolate or bibenzimidazolate palladium(II) and platinum(II) complexes of the type M(NN)₂(dpe) [M = Pd, Pt; (NN)₂^2? = BiIm^2?, BiBzIm^2?. dpe = 1,2-bis(diphenylphosphino) ethane] have been obtained by reacting MCl₂(dpe) with TI₂(NN)₂. Complexes M(NN)₂(dpe) which are Lewis bases react with HClO₄ or [M(dpe)(Me₂CO)₂](ClO₄)₂ to yield, respectively, mononuclear cationic complexes of general formula [M{H₂(NN)₂](dpe) (M = Pd, Pt; H₂(NN)₂ = H₂BiIm, H₂BiBzIm) and homobinuclear palladium(II) or platinum(II) cationic complexes of the type [M₂{μ - (NN)₂}(dpe)₂](ClO₄)₂. Reactions of M(BiBzIm)(dpe) with [Rh(COD) (Me₂CO)_X](ClO₄) render similar heterobinuclear palladium(II)-rhodium(I) and platinum(II)-rhodium(I) cationic complexes, of general formula [(dpe)M(μ-BiBzIm)Rh(COD)](ClO₄) (M = Pd, Pt; COD = 1,5-cyclooctadiene). Di- and mono-carbonyl derivatives [(dpe)M(μ-BiBzIm)Rh(CO)L](ClO₄) (M = Pd, Pt; L = CO, PPh₃) have also been prepared. The structures of the resulting complexes have been elucidated by conductance studies and IR spectroscopy.     

Preparation and properties of some stable arsonium ylides

Stable crystalline arsonium ylides have been prepared by thermal decomposition of diazo compounds in the presence of triphenylarsine, and by condensation reactions of reactive methylene compounds with triphenylarsine oxide. The spectra of these ylides, and their reactions with benzaldehydes are discussed. Like other stabilised arsonium ylides they give alkenes rather than epoxides in Wittig reactions. They are generally more polar than their phosphonium analogues and also are more reactive in the Wittig reaction. With diphenylcyclopropenone some more reactive arsonium ylides form α-pyrones.     

Convenient syntheses of zero valent 2,2′-bipyridine and related complexes of transition metals

The neutral tris-2,2′-bipyridine(bipy) and 1,10-phenanthroline(phen)compounds Mbipy₃ and Mphen₃ can be made conveniently in high yield by sodium amalgam reduction of the chlorides of Ti, Zr, Hf, V, Nb, Ta, Cr or better, for Mo, W and Re, the respective adducts MoCl₄L, WCl₄L and ReCl₄(THF) in tetrahydrofuran containing the ligands. The Cr and Mo compounds can also be obtained from the dimeric acetates M₂(CO₂Me)₄. For vanadium, similar compounds have been obtained from 2,2′-dipyridylamine, 2,2′-dipyridyldisulfide and di-t-butyldiimine. Reduction of VCl₃ in THF containing one equivalent of 2,2′-bipyridine under CO gives the carbonyl V(CO)₄bipy. Interaction of Vbipy₃ with NO and CH₃I give respectively, V(NO)bipy₃ and [V(CH₃)I(bipy)].     

Metal complexes of some asymmetric diaminodiamide ligands—II. Stabilities of complexes of nickel(II) in aqueous solution

Equilibria between a series of asymmetric diaminodiamides and Ni(II) in aqueous solution have been studied by potentiometric and spectrophotometric methods. The ligands were S,R,S- and S,S,S-N,N′-dialanylpropylenediamine (DAPN), S,S-N,N′-dialanylethylenediamine (DAEN), R-N,N′-diglycylpropylenediamine (DGPN), and N,N′-diglycylethylenediamine (DGEN). At lower values of pH the complexes NiL²⁺ and in some cases NiL²⁺₂ were formed. Spectral data indicated that both of these were octahedral. At higher pH the two amide protons were lost and square planar complexes were formed. The diastereomeric DAPN ligands showed stereoselectivity in the equilibrium constants for deprotonation and formation of the square planar complexes. Comparison of optical rotatory dispersion curves and absorption spectra for the various complexes permits partial assignment of structures.     

Four- and five-coordinate copper(II) complexes containing mixed ligands

New copper(II) complexes of general formula, Cu(ONS)B (ONS = the di-negatively charged Schiff base, S-benzyl-β-N-(2-hydroxyphenyl) methylendithiocarbazate; B = pyridine, 2,2′-dipyridyl or 1,10-phenanthroline) have been synthesized and characterised by magnetic and spectroscopic measurements. The complex, Cu(ONS)py is four-coordinate and square-planar. Magnetic and spectroscopic data support a five-coordinate, presumably, a trigonal-bipyramidal structure for the [Cu(ONS)dipy] and (Cu(ONS)phen] complexes     

S-alkyl and S-alkylaryl cysteine complexes with platinum(II) and their interactions with nucleosides

The reactions of K₂PtCl₄ with the aminoacids, S-methyl-L-cysteine, S-ethyl-L-cysteine, S-benzyl-L-cysteine, S-para-nitro-benzyl-L-cysteine, S-diphenyl-methyl-L-cysteine, S-tribenzyl-L-cysteine and S-4′,4′-dimethoxy-diphenylmethyl-L-cysteine were studied in neutral or acidic aqueous solutions. Complexes of the formulae PtLCl₂, [PtL₂]Cl₂ and Pt(L-H⁺)₂, where L = aminoacid, were isolated in the solid state and their structures investigated with elemental analysis, conductivity measurements, IR, ¹H NMR and ¹³CNMR spectra. The results show that the coordination sites of Pt(II) with the amino-acids are the N and S atoms, producing two diastereoisomers around the chiral sulphur atom, which were identified in the ¹H NMR and ¹³CNMR spectra. The complexes PtLCl₂ further react with the nucleosides guanosine and inosine. The complexes [PtL(nucl)₂]Cl₂ were isolated from these reactions and studied with the same methods. They showed a PtN₇ bonding with the nucleosides and retained the N, S bondings with the aminoacids. As a result of the higher trans influence of S than N, the nucleoside molecule coordinated to the metal through N₇ and trans to S has a weaker bond strength than the other, as it is revealed from the ¹H NMR and ¹³C NMR spectra of these complexes.     

Organometallic oxime and allied derivatives II. Synthesis and properties of some tri-n-butylgermanium oximates

Tributylgermanium oximates have been prepared by reactions (a) of tributylgermanium chloride with (i) oximes in the presence of a base, (ii) sodium oximates, and (iii) organotin oximates, as well as (b) of tributylgermanium ethoxide and oxide with oximes.The derivatives have been characterised by elemental analyses, molecular weight measurements and IR spectra. Their reactions have been studied in detail.     

Reactions involving transition metals : XIX. Some reactions of perfluoronorbornadiene with low valent transition metal complexes

Perfluoronorbornadiene reacts with the compounds [M(PPh₃)₄] (M = Pt, Pd) and [IrCl(CO)(PMePh₂)₂] to give the adducts [(C₇F₈)M(PPh₃)₂] and [(C₇F₈)IrCl(CO)(PMePh₂)₂] in which one of the double bonds is coordinated to the metal atom. The platinum complex reacts further with [Pt(PPh₃)₄] to give [(C₇F₈){Pt(PPh₃)₂}₂] having both double bonds coordinated to a Pt atom. The carbonylmetal anions [M^?] react to form the mono-substitution products [(C₇F₇)M] (M = Mn(CO)₅, Re(CO)₅, Ir(CO)₂(PPh₃)₂, Rh(CO)₂(PPh₃)₂), but the use of an excess of [Fe(CO)₂(η-C₅H₆)]^? leads to substitution of one fluorine atom on each of the double bonds. The complex having M = Mn(CO)₅ reacts with [Pt(PPh₃)₄] to afford the derivative [(C₇F₇){Mn(CO)₄(PPh₃)}{Pt(PPh₃)₂}], and the compound where M = Ir(CO)₂(PPh₃)₂ undergoes an oxidative addition reaction with acetyl chloride. Oxidative coupling products have been isolated on UV irradiation of a mixture of perfluoronorbornadiene and [Fe(η⁴-CH₂CRCHCH₂)(CO)₃] (R = H, Me), and under similar conditions the reaction with Fe(CO)₅ affords [(C₇F₈)Fe(CO)₄] in very low yield.     

Preparation and complexation properties of polystyrene resins containing diethylenetriamine derivatives

Styrene-divinylbenzene copolymer resins containing a series of diethylenetriamine derivatives have been prepared and characterized. The multidentate ligands are covalently bound to the polymer matrix without causing inter- and intrastrand bridging structures. The properties of the present chelating resins have been examined with respect to the uptake of transition metal ions.     

Palladium(II) malonato complexes with some heterocyclic ligands

Palladium(II) malonato complexes with heterocyclic ligands have been synthesized and characterized by spectroscopic and biological studies. The compoun     

Synthesis and spectroscopic studies of dimeric copper(II) complexes containing imidazoles and dipeptides

Six dimeric copper(II) complexes of the type Na[Cu₂(D)(L)], where D = glycylglycinate dianion, and HL = imidazole and 2-methylimidazole; D = glycyl-L-tyrosinate dianion, HL = imidazole and benzimidazole; D = glycyl-L-phenylalaninate dianion, and HL = imidazole; and D = glycyl-L-tryptophenate dianion, and HL = benzimidazole, have been prepared. They were characterized by IR, visible absorption, and EPR spectroscopy. The EPR data indicated their complete dimeric behaviour in basic solution with two Cu(II) ions in close proximity of <7Å with imidazolate, 2-methyl-imidazolate, and benzimidazolate bridges.     

3,3′-Dicarbomethoxy-2,2′-bipyridyl complexes of palladium(II), platinum(II) and rhodium(III)

3,3′-Dicarbomethoxy-2,2′-bipyridyl(DCMB)reacts with K₂MCl₄(M = Pd,Pt) to give M(DCMB)Cl₂ and with RhCl₃ to give the cis-[Rh(DCMB)₂Cl₂]⁺ ion. Attempts to prepare the tris (DCMB) complex with Rh(III) and analogous Co(III) complexes were unsuccessful.     

Preparation of novel polymer ligands containing tetraaza macrocyclic schiff base as a highly selective extractant for copper(II)

Three types of the novel polymer ligands in which 6,8,15,17-tetramethyl-dibenzo-5,9,14,18-tetraaza-cyclotetradecene (L) is present as an integral part of the polymer backbone have been prepared. These polymer ligands are oligomers whose polymerization degree may be about five. Their complexing abilities and extractabilities for copper(II) and nickel(II) have been investigated. Among the polymer ligands, Poly-L3, which contains triethyleneglycol bis(p-phenylene) group as a linkage group, was found to be an excellent extractant for copper(II).     

Preparation and characterization of tetrahalodimolybdenum(II) complexes with alkyl-substituted pyridines

The preparation and characterization of new tetrahalodimolybdenum(II) complexes with alkyl-substituted pyridines is described. IR and visible data are used to infer structural information with respect to previously prepared complexes of this type.