Reactivity of [Ru3(μ-H)(μ-Me2pz)(CO)10] with 2,4-hexadiyne. Characterization of the first tetranuclear ynenyl complex

The tetranuclear ynenyl complex [Ru₄(μ-η²-Me₂pz)(μ₄-η⁴-MeCHCCCMe)(μ-CO)(CO)₁₀] (Me₂pz=3,5-dimethylpyrazolate) has been prepared by reaction of [Ru₃(μ-H)(μ-η²-Me₂pz)(CO)₁₀] with 2,4-hexadiyne and has been characterized by X-ray diffraction methods. It consists of an unusual broken-wing butterfly (spiked triangle) tetraruthenium framework (64-electron) with all the metal atoms bridged by a hex-2-yn-4-en-4-yl ligand (7-electron donor). This type of coordination is unprecedented for ynenyl ligands.     

Preparation of Ru(η3-2-alkenylallyl)(CO)Cl(PPh3)2 complexes via carbometallation of allenes with alkenyl ruthenium complexes

Alkenyl ruthenium complex, Ru(CHCHR)(Cl)(CO)(PPh₃)₂ 1, reacted with allenes 2 to give η³-allyl ruthenium complexes, Ru(η³-2-alkenylallyl)(Cl)(CO)(PPh₃)₂ 3, in good yields. The reaction depends on the structure of the alkenyl group. When R was phenyl or methoxycarbonyl group, the carbometallated complex 3 was yielded as a sole product. However, when R was butyl or trimethylsilyl group, besides the carbometallation product as main product, was obtained a small amount of 2-unsubstituted η³-allyl ruthenium complex which was formed via β-elimination of the alkenyl complex followed by the reaction with allene. Structure of 3 was determined by the X-ray crystal structure analysis.     

Sulfur-assisted chloride and triphenylphosphine dissociation of palladium(II) complex [Pd(PPh3)2(η1-SCNMe2)(Cl)]. X-ray structures of [Pd(PPh3)2(η1-SCNMe2)(Cl)], [Pd(PPh3)(Cl)]2(μ,η2-SCNMe2)2, and [Pd(PPh3)2(η2-SCNMe2)][PF6]

Treatment of Pd(PPh₃)₄ with Me₂NC(S)Cl in dichloromethane at −20 °C produces the complex [Pd(PPh₃)₂(η¹-SCNMe₂)(Cl)], 2. Variable temperature ¹H and ³¹P{H} NMR experiments of complex 2 shows the dissociation of either the chloride or the triphenylphosphine ligand to form complex [Pd(PPh₃)₂(η²-SCNMe₂)][Cl], 3 or the dipalladium complex [Pd(PPh₃)Cl]₂(μ,η²-SCNMe₂)₂, 4. The reaction of complex 2 with NaPF₆ affords complex [Pd(PPh₃)₂(η²-SCNMe₂)][PF₆], 5. Complexes 2, 4, and 5 are characterized by X-ray diffraction analyses.     

Luminescence of [ReI(L–L)(CO)3Cl] with L–L = lumazine and folic acid

The complexes [Re^I (L–L)(CO)₃Cl] with L–L = lumazine and folic acid were prepared and their electronic spectra were measured. The free ligands L–L, as well as both complexes, show an emission which is attributed to the fluorescence of L–L. This luminescence is apparently facilitated by excited state proton transfer.     

Ru/12SrO–7Al2O3 (S12A7) catalyst prepared by physical mixing with Ru (PPh3)3Cl2 for steam reforming of toluene

Steam reforming of toluene as a model of aromatics was performed over various Ru/12SrO–7Al₂O₃ (S12A7) catalysts, and the effects of Ru precursor, calcination and pre-treatment conditions on the catalytic activity and durability of Ru/S12A7catalysts were investigated. The catalytic activity of prepared Ru/S12A7 catalysts exhibited higher than that of a commercial Ru/Al₂O₃ (RA), despite low Ru loading. The catalysts prepared by the physical mixing of Ru (PPh₃)₃Cl₂ and S12A7 (PPH) had higher catalytic activities than the catalysts prepared by the impregnation with RuCl₃ nH₂O (CL). It is interesting that the N₂ pre-treated PPH and CL catalysts especially had higher catalytic activities than the H₂ pre-treated PPH and CL catalysts. In their catalysts, there was a linear relationship between the catalytic activity and the Ru dispersion estimated by CO chemisorption. The catalytic activity of the N₂ pre-treated PPH catalyst has little decreased with time on stream, whereas the catalytic activities of the N₂ pre-treated CL catalyst and H₂ pre-treated PPH catalyst gradually decreased with time on stream.     

The formation of [RuCl(p-cymene)(Me2HPz)(PPh2OR)]Cl (Me2HPz=3, 5-dimethylpyrazole; R=H,Me and p-Tol) complexes from the cleavage of the P–N bond of a P-coordinated P(Me2Pz)Ph2 ligand by ROH molecules in a ruthenium(II) complex. Crystal structure of [RuCl(p-cymene)(Me2HPz)(PPh2OH)]Cl

The complex [RuCl₂(p-cymene)]₂ reacts with 1-(3,5-dimethyl)pyrazolyldiphenylphosphine (P(Me₂Pz)Ph₂) to give the complex RuCl₂(p-cymene)(P(Me₂Pz)Ph₂). This compound reacts with ROH molecules (R=H, Me and p-Tol) to give [RuCl(p-cymene)(Me₂HPz)(PPh₂OR)]Cl (R=H, Me and p-Tol) complexes, which contain both Me₂HPz and PPh₂OR coordinated molecules.     

Phosphorus–carbon bond cleavage of Ph2PCH2PPh2 at a triruthenium center: synthesis and structural characterization of [Ru3(μ-CO)(CO)6(μ-PPh2)2(μ3-CH2PPh)]

The reaction of Ph₂PH with [Ru₃(CO)₁₀(μ-dppm)] (1) at 98°C gave [Ru₃(μ-CO)(CO)₆(μ-PPh₂)₂(μ₃-CH₂PPh)] (7) in 20% yield. Compound 7 was characterized by elemental analysis, ¹H and ³¹P{¹H} NMR and mass spectroscopic data and also by a single crystal structure determination. The compound is shown to consist of a triruthenium cluster with an unusual example of a triply bridging CH₂PPh ligand and two doubly bridging PPh₂ ligands.     

An unusual o-metallated pyridyl dirhodium(II) complex: [Rh2{μ-(C5H3N)NH(C5H4N)}2{η2-(C5H4N)NH(C5H4N}2]Cl2·CH3OH

Reaction of Rh₂(O₂CMe)₄ and bis(2-pyridyl)amine, Hdpa, followed by addition of CH₂Cl₂ led to replacement of the acetate groups by Hdpa and orthometallation of two Hdpa pyridyl groups. The isolated complex, [Rh₂{μ-(C₅H₃N)NH(C₅H₄N)}₂{η²-(C₅H₄N)NH(C₅H₄N}₂]Cl₂ (1), has been characterized by X-ray crystallography, showing that the complex has two equatorially bound Hdpa groups and two bridging orthometallated dpa anions.     

A copper–cyclen coordination complex associated with a polyoxometalate anion: Synthesis,crystal structure and electrochemistry of [Cu(cyclen)(MeCN)][W6O19]

The reaction between Cu(NO₃)₂·3H₂O and a tetra-aza macrocycle, more specifically, cyclen in 1:1 MeCN–MeOH solvent mixture forms a Cu²⁺–cyclen coordination complex in situ, that has been reacted with an isopolyanion [W₆O₁₉]^2? in a slow diffusion technique, resulting in the isolation of an ion-pair solid [Cu(cyclen)(MeCN)][W₆O₁₉] (1). Single crystal structural investigation on 1 shows a square pyramidal geometry around the metal centre (copper ion) with an axially bound MeCN solvent molecule. The title compound 1 is the first crystallographically characterized ion-pair compound, in which a transition metal coordination complex of a tetra-aza-crown ether (cyclen) has been associated with a polyoxometalate cluster anion. This communication deals with synthesis, spectroscopic, structural and electrochemical analyses of compound 1.     

A convenient method for the synthesis of [Pd{[(η5-C5H3)–CHN–(CH2)2–NMe2]Fe(η5-C5H5)}Cl] and the study of its reactivity with diphosphines

A one-pot method for the preparation of [Pd{[(η⁵-C₅H₃)–CHN–(CH₂)₂–NMe₂]Fe(η⁵-C₅H₅)}Cl] is described. Its X-ray crystal structure and its reactions with the diphosphines Ph₂P–(CH₂)_n–PPh₂ {with n=1 (ddpm) or 2 (dppe)} are also reported.     

Copolymerizations of ethylene with 1–decene over various ansa–metallocene complexes combined with Al( i-Bu) 3/ [CPh 3] [B(C 6F 5) 4] cocatalyst

Copolymerizations of ethylene with 1-decene were carried out with a series of stereospecific metallocene compounds, rac–(EBI)Zr(NMe₂)₂ [ 1, EBI = ethylene–1,2–bis( 1–indenyl)], rac–(EBI)Hf(NMe₂ (2), rac–Me₂Si( 1–C₅H₂–2–Me–4– ^t Bu)₂Zr(NMe₂)₂ (3), ethylidene(cyclopentadienyl)(9-fluorenyl)ZrMe2 [4, Et(Flu)(Cp)ZrMe2] and isopropylidene(cyclopentadienyl)(9–fluorenyl)ZrMe₂ [5, iPr(Flu)(Cp)ZrMe₂], combined with Al(i–Bu)₃/[CPh₃] [B(C₆F₅)₄] cocatalyst. All catalyst systems showed very high copolymerization rates and the 1–decene reactivity decreased in the order of 2 > 5 > 1 4 > 3. The reactivity product of ethylene and 1–decene (r _E x r _D) was below 1 except 3 catalyst, corresponding to random copolymer structures with an alternating character. The melting point (T_m), crystallinity (X_C), intrinsic viscosity ([] and density of the 1–decene/ethylene copolymers decreased markedly with an increase in the 1–decene content, regardless of the type of catalytic system.     

An inorganic–organic hybrid material with a novel oxometallic framework: Hydrothermal synthesis and characterization of [Zn3O3(C13H14N2)3]V6O15

A new hybrid material [Zn₃O₃(C₁₃H₁₄N₂)₃]V₆O₁₅ (1) with extended framework structure has been synthesized hydrothermally and characterized by vibrational spectroscopy, thermogravimetry and complete single crystal X-ray diffraction analysis. The compound has a complex three-dimensional covalent framework structure. It exhibits a fully oxidized novel oxometallic framework containing 10-membered {V₄ZnO₅} oxometalate rings and 4,4′-trimethylene dipyridine ligands (C₁₃H₁₄N₂) that connect pairs of crystallographically equivalent zinc atoms. The extended structure of 1 may also be viewed as containing a framework of corner-sharing {VO₄} and {ZnO₂N₂} polyhedra together with 4,4’-trimethylene dipyridine ligands linking zinc centers. The hybrid material is thermally stable up to 323 °C. It contains metal centers and coordination geometry that make it a potentially attractive model compound for investigating the structures of metallo-organic biomolecules by use of solid state NMR spectroscopic techniques. Crystal data for C₃₉H₄₂N₆O₁₈V₆Zn₃: monoclinicic P2₁, a = 10.9894(9) Å, b = 18.1493 (15) Å, c = 13.0903 (11) Å, β = 109.8880(10)°, V = 2455.1(4) Å³, Z = 2, D_calc. = 1.873 Mg/m³.     

Metal–metal interaction through CH2–CN bridge: synthesis and characterization of [CpM(L2)NCCH2Fc]PF6 complexes (Fc=ferrocenyl; L=1/2 dppe,PPh3; M=Fe,Ru)

The new complexes [CpM(L₂)NCCH₂Fc]PF₆ (M=Fe 1, Ru 2; Fc=ferrocenyl), have been prepared from reaction of CpM(L₂)X and the ligand Fc–CH₂CN 3 in methanol and in the presence of NH₄PF₆. The compounds were characterized by elemental analysis as well as spectroscopic methods. Electrochemical as well as near-IR measurements suggest a weak metal–metal interaction for the Fe(II)–Fe(III) complex. Hush parameters for this mixed-valence complex suggest a class II Robin–Day type with a moderate metal–metal interaction similar to that observed in the related pyridine bridged systems (η⁵-C₅H₅)Fe-η⁵-C₅H₄–C₅H₄N–ML_n. The unusual electron transfer through a insulating CH₂ group is the first such example for an asymmetric binuclear system.     

Synthesis and characterization of dinuclear copper(II) complexes, [Cu2([20]-DCHDC)(La)2] (La = N3−, NCS− or S2O32−) with tetraazadiphenol macrocyclic ligand having cyclohexane rings

The chiral dinuclear tetraazadiphenol macrocyclic copper(II) complexes [Cu₂([20]-DCHDC)(L_a)₂] {H₂[20]-DCHDC = 14,29-dimethyl-3,10,18,25-tetraazapentacyclo-[25,3,1,0^4,9,1^12,16,0^19,24]ditriacontane-2,10,12,14,16(32),17,27(31),28,30-decane-31,32-diol; L_a = N₃^? (II), NCS^? (IV) or S₂O₃^2? (V)} has been synthesized and structurally characterized by elemental analysis, conductance, electronic and IR spectra as well as FAB-MS method. Crystal structure of [Cu₂([20]-DCHDC)(N₃)₂]·2CH₃OH (III) determined by X-ray crystallography reveal the two square pyramidal copper centers bridged by the two phenoxide oxygen atoms, with large Cu–O–Cu angles {100.88(10)°}.     

A novel hexagonal honeycomb K–Cr-oxalate anionic network with layers separated by a five-coordinated Cu(II)–pypn complex (pypn = N,N′-bis(2-pyridylmethyl)-1,3-propanediamine). Synthesis,characterisation, spectroscopy and crystal structure of {[KCr(C2O4)3][Cu(pypn)(H2O)](H2O)4}

A novel hexagonal-based honeycomb compound with overall formula {[KCr(C₂O₄)₃][Cu(pypn)(H₂O)](H₂O)₄} is reported in which pypn is with the tetradentate ligand (N,N′-bis(2-pyridylmethyl)-1,3-propanediamine). The [KCr(C₂O₄)₃]^2? moiety forms a hexagonal honeycomb structure, while the five-coordinated [Cu(pypn)(H₂O)]²⁺ moiety is located in between the layers, partly filling the holes in the cavities. The synthesis, X-ray crystal structure and some spectroscopic properties are presented. The coordination of Cr(III) is octahedral, with a CrO₆ chromophore, and the K⁺ ion is in a KO₆ environment (K–O distances vary from 2.36 to 2.48 ?). The [KCr(C₂O₄)₃]^2? layers have the K⁺ ions in a Λ conformation, while the Cr(III) ions in the Δ conformation. The geometry around the Cu(II) is five-coordinated with four nitrogens from the chelating pypn ligand in a plane and the apical position being occupied by the oxygen atom of the coordinating water molecule. The packing of the cationic and the anionic layers appears to be of special interest.