Computational study of ethene hydroarylation at [Ir(κ(2)-OAc)(PMe3)Cp]+

Density functional theory calculations have been employed to model ethene hydroarylation using an [Ir(κ(2)-OAc)(PMe(3))Cp](+) catalyst, 1. The reaction proceeds via: (i) an acetate-assisted C-H activation of benzene via an AMLA-6 transition state; (ii) rate-limiting insertion of ethene into the Ir-Ph bond; and (iii) protonolysis of the β-phenylethyl species by HOAc. A range of competing processes are assessed, the most important of which are the C-H activation of ethene at 1 and trapping of the β-phenylethyl intermediate with ethene. The former process gives rise to Ir-vinyl species which can then access further ethene insertion to give stable allyl by-products. A comparison with other ethene hydroarylation catalysts reported in the literature is presented.     

Darstellung und Eigenschaften von Heteropolykationenverbindungen,IV: Darstellung und Struktur von Natriumdodekaaluminogalliumsulfat-Ikosihydrat,Na[GaO4Al12(OH)24(H2O)12](SO4)4 ·xH2O mitx∼20

Summary A chemical analyses of Na[GaO₄(Al₁₂(OH)₂₄(H₂O)₁₂](SO₄)₄ ·xH₂O withx20 [a=17.861 (4) Å; F 3 m-T _d ² ;Z=4] in connection with a crystal structure investigation confirmed the tetrahedral coordination of the gallium atom by oxygen atoms, as well as the far extending statistical distribution of the crystal water in the structure. The syntheses was done by neutralization of a satured aqueous aluminium chloride solution, mixed with metallic gallium and sodium sulfate, by an aqueous sodiumhydroxide solution.

     

X-ray crystal structure of [VO(DPA)(H2O)2]·2H2O (DPA=Dipicolinate dianion)

The X-ray crystal structure of the trans-diaqua complex [VO(DPA)(H2O2)]·2H2O (1) (DPA=dipicolinate dianion) has been determined. Comparison with the known structure of [VO(DPA)(o-phen)]·3H2O (2), obtained from (1) by displacement of the two coordinated aqua molecules, shows that the coordination sphere around vanadium is reorganised during this reaction.     

Synthese von Cp(CO)2 MnTCNE aus [Cp(CO)2MnXPh]n (X = S,Se, Te; n = 1,2); Festkörperstruktur und Magnetismus

Cp(CO)₂MnTCNE (1) which was first reported by M. Herberhold et al., has been obtained from the reaction of [Cp(CO)₂MnXPh]_n (X = S, n = 1; X = Se, Te, n = 2) with TCNE. The synthesis of the relevant organometallic sulfur, selenium and tellurium derivatives is described. An X-ray diffraction study of the TCNE compound reveals that two Cp(CO)₂MnNCC(CN)C(CN)₂ (1) molecules form centrosymmetric dimers containing a coordinated centrosymmetric (TCNE)₂^x− pair. The bond lenghts, the v(CN) spectra and a solid state magnetism of μ_eff = 1.1 μ_B (293 K) are all consistent with this structural finding.     

Ein beitrag zur hydrolyse von titanocendichlorid: Darstellung,struktur und eigenschaften des dreikernigen,Sauerstoff-zentrierten,basischen carboxylatokomplexes [Ti3(μ3-O)(μ2-OH)3(μ2-HCOO)3(η5-C5H5)3]+ HCOO− · 2HCOOH

On hydrolysis of dicyclopentadienyltitanium dichloride in water at pH > 5 one cyclopentadienyl group is removed. Reaction of the product with formic acid gives the ionic crystalline trinuclear complex [Ti₃(μ₃-O)(μ₂-OH)₃(μ₂-HCOO)₃(η⁵-C₅H₅)₃]⁺ HCOO⁻ · 2HCOOH whose structure was determined by X-ray analysis. The complex cation is oxygen centered. The TiOTi angles (106.9(2) to 107.6(2)°) at the central oxygen atom are close to the tetrahedral angle. Each pair of Ti atoms is bridged by a formiato and an hydroxo ligand. The coordination octahedra around each Ti atom are completed by an η⁵-bonded C₅H₅ group.     

Isolierung und struktur eines Cp2TiIV-komplexes mit dem dianion des bis(ethoxythiophosphorsäure)disulfids als chelatligand: Cp2Ti(P2S4O2(OEt)2)

Ethanolysis of P₄S₁₀ in the presence of Cp₂TiCl₂ and some H₂O produces the red air-stable complex Cp₂Ti(P₂S₄O₂(OEt)₂) (A) in which the dianion of bis(ethoxythiophosphoric acid)-disulfide acts as chelating ligand, bonded via two oxygen atoms to Ti. The molecular structure of A has been determined by X-ray diffraction. A crystallizes in the orthorhombic space group Pca2₁ with a 15.559(4), b 9.622(3), c 14.326(4) Å and Z = 4.     

[Cp2Nb(CH3)2]+ [AsF6]− und [Cp2Mo(CH3)2]2+ [AsF6]2−, die ersten Niobocen- und Molybdänocendimethyl-Komplexe mit den Zentralmetallatomen in ihrer maximalen Oxidationsstufe

The preparation of the first niobium(V) and molybdenum(VI) dimethylmetallocene cations is reported. [Cp₂Nb(CH₃)₂]⁺[AsF₆]⁻ (1) and [Cp₂Mo(CH₃)₂]²⁺ [AsF₆]₂⁻ (2) (Cp = η⁵-C₅H₅) are prepared by oxidation of Cp₂Nb(CH₃)₂ and Cp₂Mo(CH₃)₂ with AsF₅ in liquid sulfur dioxide. IR investigations confirm the ionic structure of 1 and 2, and that the AsF₆⁻ is not coordinated to the metal centre.     

Syntheses and structures of seven-coordinate K3[Cd(Dtpa)], K2[Cd(H2O)4][Cd(Edta)(H2O)]2 · 2H2O, and Na2[Cd(H2O)4][Cd(Edta)(H2O)]2 · 2H2O complexes

The title complexes, K₃[Cd(Dtpa)] (H₅Dtpa = diethylenetriamine-N,N,N,N′,N′-pentaacetic acid, (I)), K₂[Cd(H₂O)₄][Cd(Edta)(H₂O)]₂ · 2H₂O (H₄Edta = ethylenediamine-N,N,N′,N′-tetraacetic acid, (II)), and Na₂[Cd(H₂O)₄][Cd(Edta)(H₂O)]₂ · 2H₂O (III), were prepared, and their compositions and structures were determined by elemental analyses, IR spectra, and single-crystal X-ray diffraction techniques, respectively. In complex I, the Cd is seven-coordinated by one Dtpa ligand yielding a pseudo-monocapped trigonal prism conformation, and the complex crystallizes in the triclinic crystal system with the Pi space group. The crystal data are as follows: a = 8.7300(17), b = 9.1200(18), c = 15.110(3) Å, α = 95.52(3)°, β = 96.59(3)°, γ = 99.63(3)°, V = 1170.0(4) ų, Z = 2, ρ = 1.754 g/cm³, μ = 1.519 mm^?1, F(000) = 616, R = 0.0644 and wR = 0.1712 for 3842 observed reflections with I ≥ 2σ(I). For complex II, in the [Cd(Edta)(H₂O)]^2? complex anion the Cd²⁺ ion is seven-coordinated by one Edta ligand and one water molecule, yielding a pseudo-pentagonal bipyramid conformation. In the [Cd(H₂O)₄]²⁺ cation, the bridged Cd is six-coordinated, yielding an almost standard octahedral conformation. The complex crystallizes in the monoclinic system with P2₁/n space group. The crystal data are as follows: a = 9.098(3), b = 16.442(6), c = 12.023(4) Å, β = 91.053(6)°, V = 1798.3(12) ų, Z = 2, ρ = 2.098 g/cm³, μ = 2.086 mm^?1, F(000) =1124, R = 0.0406 and wR = 0.1152 for 3680 observed reflections with I ≥ 2σ(I). In complex III, the conformations of Cd²⁺ ions are similar to those of the potassium salt complex, and the complex also crystallizes in the monoclinic crystal system with the P2₁/n space group. The crystal data are as follows: a = 9.134(7), b = 16.500(13), c = 12.075(10) Å, β = 91.054(12)°, V = 1820(2) ų, Z = 2, ρ = 2.015 g/cm³, μ = 1.856 mm^?1, F(000) = 1092, R = 0.0363 and wR = 0.0879 for 3707 observed reflections with I ≥ 2σ(I).     

[Cu(bpp)2(bpdc)(H2O)2]×2H2O and [Cu(bpp)2](tdc)×7.5H2O的合成、晶体结构和热稳定性

在室温下, 由Cu(NO3)2 、1,3 -二（4 -吡啶基）丙烷(bpp)、4,4 ’ -联苯二甲酸(H2bpdc)和2,5-噻吩二甲酸(H2tdc)制备出两种新型铜( II)配位聚合物[Cu(bpp)2(bpdc)(H2O)2]n·2nH2O, 1 和[Cu(bpp)2]n·n(tdc) 7.5nH2O, 2。两个配位聚合物均为一维线型结构,铜原子均采取变形的八面体结构,在轴线方向上的两个水分子与铜原子存在较弱的配位作用。在配合物1中,两个bpdc羧酸根离子与铜原子配位,而2中的tdc羧酸离子没有与铜原子键合,只是作为反离子平衡电荷。在两个产物中, 配体bpp具有不同的构象。热重分析表明配合物1与2分别在110°C和160°C以下是稳定的。     

Gas phase reactions of Cl2O with X−(D2O)n=0–4 (X = O,OD, O2, DO2, and O3)

The reactions of Cl₂O with the cluster ions X⁻(D₂O)_n=0–4 (X = O, OD, O₂, DO₂, and O₃) were studied in a He buffer gas at temperatures within the range 171–298 K and pressures of 0.27–0.51 Torr, using a flow-tube apparatus. All ions were found to react with Cl₂O at rates slower than predicted by the collision rate and the charge center was transferred from X⁻ to Cl⁻ or ClO⁻. The primary product ions Cl⁻(DOCl) and ClO⁻(DOCl) were observed to react further to produce the ions Cl₃O⁻ and Cl₃O₂⁻. The rate constants for the observed reactions are reported and the role that thermodynamics plays in determining possible reaction channels is discussed.     

炔烃与[Cp*Ru(H2O)(NBD)]BF4的[2+2+2]Diels-Alder反应

过渡金属催化的[2 2 2]环加成反应由于没有原子损失和较高的立体选择性,在合成不饱和多环化合物中已经被广泛应用[1].但一般反应时间较长,反应时常需要加热.我们发现金属有机化合物[Cp*Ru(H2O)(NBD)]BF4(Cp*是五甲基环戊二烯基,NBD是降冰片二烯)中的NBD与甲基苯基乙炔在室温就可发生[2 2 2]Diels-Alder反应[2].进一步研究发现,在室温下,炔烃PhC三CR(R=H,COOEt,Ph)和双炔烃HC三CC6H4C6H4C三CH与[Cp*Ru(H2O)-(NBD)]BF4中的NBD也能进行Diels-Alder反应,30 min即以较高产率生成[2 2 2]环加成产物.     

The structure of gas-phase [Al·nH2O]+: hydrated monovalent aluminium Al+ (H2O)n or hydride-hydroxide HAlOH+ (H2O)(n-1)?

Theoretical studies predict that [Al·nH(2)O](+) clusters are present as hydride-hydroxide species HAlOH(+)(H(2)O)(n-1) in gas-phase experiments, energetically favoured by 200 kJ mol(-1) over Al(+)(H(2)O)(n). After collisions with D(2)O, however, no H/D scrambling occurs between H(2)O and D(2)O in clusters with n > 38, indicating that large clusters are present as the higher-energy isomers Al(+)(H(2)O)(n).     

Syntheses and structures of mononuclear eight-coordinate Na[ErIII(Cydta)(H2O2]·5H2O (Cydta = trans-1,2-cyclohexanediaminetetraacetic acid) and binuclear nine-coordinate Na2[SmIII(Cydta)][SmIII(Cydta)(H2O)3] · 11H2O

The title complexes, Na[Er^III(Cydta)(H₂O)₂] · 5H₂O (I) and Na₂[Sm^III(Cydta)][Sm^III(Cydta)(H₂O)₃] · 11H₂O (II) (Cydta is trans-1,2-cyclohexanediaminetetraacetic acid), are prepared and characterized using IR, elemental analyses, and single-crystal X-ray diffraction techniques. Crystal I belongs to triclinic system (space group P1), which has a mononuclear eight-coordinate slightly distorted square antiprismatic conformation. The crystal data are as follows: a = 8.371(12) Å, b = 9.952(14) Å, c = 14.74(2) Å, α = 88.32(2)°, β = 76.30(2)°, γ = 87.87(2)°, V = 1192(3) ų, Z = 1, ρ = 1.835 g/cm³, μ = 3.612 mm^?1, F(000) = 658, R = 0.0194, and wR = 0.0520 for 4130 observed reflections with I≥2σ(I). Crystal II belongs to monoclinic system (space group P2₁/n), which has the binuclear nine-coordinate structure with tricapped trigonal prismatic conformation for Sm(1) and the pseudomonocapped square antiprismatic conformation for Sm(2). The crystal data are as follows: a = 12.283(6) Å, b = 15.626(7) Å, c = 25.875(12) Å, β = 97.962(7)°, V = 4919(4) ų, Z = 4, ρ = 1.717 g/cm³, μ = 2.476 mm^?1, F(000) = 2536, R = 0.0781, and wR = 0.1745 for 8554 observed reflections with I ≥ 2σ(I).     

Crystal Structure and Interaction with DNA of [Ni(phen)(mal)(H2O)2]·3H2O

A new complex [Ni(phen)(mal)(H2O)2]·3H2O (phen = 1,10-phenanthroline,mal2-= malonic acid) has been synthesized by the reaction of nickel nitrate,phen and malonic acid.EA,IR spectra and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure of the title complex.Crystal data:monoclinic system,space group P2/c,a =8.937(3),b = 12.163(5),c = 9.725(3)(A),β = 119.36°,C15H19N2O9Ni,Mr= 430.03,Z = 2,F(000) =446,V = 921.3 (A)3,Dc = 1.550 g/cm3,μ = 1.104 mm-1,-10≤h≤ 10,-12≤k≤ 14,-11 ≤l≤7,R =0.0261 and wR = 0.0609 for 4376 (Rint = 0.0203) independent reflections and 1631 observed ones (I＞ 2σ(I)).Ni(Ⅱ) exhibits an octahedral coordination geometry,with hydrogen bonds and π-π interactions stabilizing the whole structure.UV spectrum of the complex interacting with protamine DNA indicates that the title compound interacts with DNA via insertion mode with bonding constant Kb of 1.11 × 104.     

Ti-Verbindungen mit fulvalenbrücken: Die struktur von [CpTiMe2]2(C10H8)

X-ray analysis for the orange-yellow thermally unstable crystalline compound [CpTiMe₂]₂(C₁₀H₈) (3(Me)), which results from methylation of [CpTiCl₂]₂(C₁₀H₈), confirms the presence of a fulvalene bridge. The two CpTiMe₂ fragments in 3(Me) are trans with respect to the fulvalene group.