Crystal and molecular structure of complex compound (C5H5)2Re(H)Cu(μ-I)2CuRe(H)(C5H5)2: A first direct proof of the formation of the Cu(I)Cu(I) bond

The structure of the bimetallic dimer complex [(η⁵-C₅H₅)₂Re(H)CuI]₂ has been investigated. The crystals are monoclinic: a = 16.070(4) Å, b = 7.788(2)Å, c = 17.439(5) Å; b = 96.62(2)°; the space group I2/a; z = 4. The bond between rhenium and copper atoms (2.60 Å) is of the donor-acceptor type; dimerization occurs by the way of formation of the double bridge CuI₂Cu and the direct inter-metal bond CuCu(2.55 Å). The hydride hydrogen atom is the terminal one. The cyclopentadienyl rings form a bent sandwich with the angle between the ring centres and rhenium atom being equal to 158°. It is suggested that the CuCu inter-metal bonding takes place on account of the transition of the non-bonding d-electrons of copper atoms to a high-spin state.     

The zero point average structure of isobutane as determined by electron diffraction and microwave spectroscopy

The molecular structure of isobutane in the gas phase was investigated by combining electron diffraction data with microwave spectroscopic rotational constants of Lide.The analysis indicated that the tertiary C-H distance (r_g = 1.122±0.006 Å) was substantially longer than the average methyl C-H distance (r_g = 1.113±0.002 Å). Other structural parameters obtained were: r_g(C-C) = 1.535±0.001 Å, ∠CCC = 110.8±0.2°, and the average ∠CCH (methyl) = 111.4±0.2°.     

Molecular structure of carbonyl fluoride as studied by gas electron diffraction and microwave data

The molecular structure of carbonyl fluoride has been determined by electron diffraction. The results have been used in conjunction with the rotational constants reported by Carpenter in a combined structure analysis. The values so obtained are r_z (C=O) = 1.1717 ± 0.0013 Å, r_z (C-F) = 1.3157 ± 0.0005 Å, and ∠_zF-C-F = 107.71 ± 0.08°. These agree with the corresponding parameters estimated by Carpenter from the rotational constants alone. The effective constants, α₃, representing the cubic anharmonicity of bond stretching vibrations have been estimated.     

Electron diffraction study on the molecular structure of hexamethylcyclotrisilazane, [(CH3)2SiNH]3

A gas electron diffraction study yielded the following geometrical parameters for hexamethylcyclotrisilazane: r(Si-N) = 1.728 ± 0.004 Å, r(Si-C) = 1.871 ± 0.004 Å, r(C-H) = 1.124 ± 0.007 Å, ∠N-Si-N = 108.4 ± 1.0°, ∠Si-N-Si = 126.8 ± 0.8°, ∠C-Si-C = 108.9 ± 2.3°, ∠H-C-H = 111.6 ± 0.9°. The (SiN)₃ ring was found to be puckered but the deviation from planarity is relatively small. Details of the ring shape could not be determined. The degree of ring puckering in six-membered rings with alternating atoms can be roughly predicted from the bond angles in analogous non-cyclic molecules.     

Spectroscopic and magnetic properties of a new class of two-dimensional bitriazole compounds: The X-ray structure of poly-bis(thiocyanato-N)-bis-μ-(4,4′-bis-1,2,4-triazole-N1,N1′)-cobalt(II) monohydrate

The synthesis of a new class of two-dimensional triazole compounds is described, including the crystal structure of [Co(NCS)₂(btr)₂]H₂O [btr stands for 4,4′-bis-1,2,4-triazole (C₄H₄N₆)]. Crystals are monoclinic, space group C2/c, a = 11.159(1) Å, b = 13.047(4) Å, c = 12.993(3) Å, β = 91.81(2)°, Z = 4. The structure has been solved by Fourier and direct methods and refined by full-matrix least squares to R = 0.0229, R_w = 0.0283. The structure consists of layers of six-coordinated cobalt atoms, each having two trans-oriented N-bonded thiocyanate groups [CoNCS 2.098(2) Å] and linked together in the equatorial plane by single bridges of btr to a two-dimensional network. The btr ligand coordinates through its N(1) and N(1′) atoms [CoN 2.128(1) and 2.142(1) Å]. The intralayer CoCo distance is 9.207(2) Å, and the inter-layer CoCo distance is 8.584(1) Å. The magnetic susceptibilities of the compound and of the isostructural nickel and iron compounds are discussed. The iron compound exhibits a high-spin-low-spin crossover at liquid-nitrogen temperatures, as shown by magnetic susceptibility.     

Reduction of copper (II) chloride by molybdenum and rhenium biscyclopentadienyl hydrides. Investigation of the crystal and molecular structure of [(η5-C5H5)2Re]+[CuCl2]−

The reduction of copper (II) chloride by molybdenum and rhenium biscyclopentadienyl hydrides upon their interaction in donor-type solvents has been studied by NMR, X-ray diffraction, and magnetic methods. It is established that the ionic complex [(η⁵-C₅H₅)₂Re]⁺[CuCl₂]^? forms ortho rhombic crystals with a - 13.696(2) Å, b = 7.317(1) Å, c = 5.969(1) Å, space group Pm2₁n, Z = 2. The cyclopentadienyl rings make a bent-sandwich with an angle between the ring centres and Re atom of 150.1°; the ClCuCl angle being 174.8° and the ReCu minimum distance 4.346(29) Å. The solution of [(η⁵-C⁵H₅)²Re]⁺ [CuCl₂]^? seems to activate the CH bond of the C₅H₅ rings, which results in the addition of the [(C₅H₅)(C₅H₄)ReH]⁺ hydride ion.     

Crystal structures of two 4-phenylbenzophenones

Two 4-phenylbenzophenones (I) and (II) are synthesized via Friedel-Crafts reactions. There are four crystallographically independent molecules with different conformations in the crystal structure of [1,1′-biphenyl]-4-yl(2-chlorophenyl)methanone (I). Crystals are orthorhombic, Pca2₁, C₁₉H₁₃ClO, a = 13.699(3) Å, b = 8.9385(17) Å, c = 46.836(9) Å; V = 5735(2) ų, Z = 16, d _x = 1.356 g/cm³. Torsion angles between the biphenyl rings are between 28.5° and 30.8°. Several C-H…O and C-H…Cl hydrogen bonds and weak π-π stacking contacts consolidate the crystal. Crystals of [1,1′-biphenyl]-4-yl(3-methoxyphenyl)methanone (II) are orthorhombic, Pbca, C₂₀H₁₆O₂, a = 7.8179(15) Å, b = 16.003(3) Å, c = 23.345(5) Å; V = 2920.7(10) ų, Z = 8, d _x = 1.311 g/cm³. The torsion angle between the biphenyl rings is 28.1° and C-H…O hydrogen bonds are observed in compound (II).     

The crystal structure of [Mg(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>][VO(edta)] · 3.5H<Subscript>2</Subscript>O

The crystal structure of complex [Mg(H₂O)₆][VO(edta)] · 3.5H₂O (I) was determined by X-ray diffraction study. The crystals are monoclinic, a = 6.779 Å, b = 13.373(6) Å, c = 25.054 Å, β = 96.55°, Z = 4, space group P2₁. The unit cell contains two independent [VO(edta)]^2? anions, two independent [Mg(H₂O)₆]²⁺ cations, and seven crystal-water molecules. The coordination polyhedron of each vanadium atom is formed by five donor atoms of the edta ligand (2N + 3O) (V(1)-N(1), 2.278 Å; V(1)-N(2), 2.149 Å; V(2)-N(3), 2.301 Å; V(2)-N(4), 2.165 Å; V-O(acet), 2.00 ± 0.02 Å) and the oxygen atom of the oxo group (V-O, 1.60 ± 0.01 Å). The edta ligands and the vanadium atom form three glycinate rings: two R-type rings and one G-type ring (one acetate branch remains free), as well as an E-type ring with an asymmetric gauche configuration. The [Mg(H₂O)₆] cations are slightly distorted octahedra (Mg-O, 2.013–2.132 Å, the OMgO angles are 86.6°–94.2°). The H₂O molecules form a bifurcate system of H-bonds. The crystals of compound I belong to OD-type structures with an incomplete ordering of layers.     

An electron-diffraction study of the molecular structure of gaseous perbromyl fluoride and calculation of its force field and vibrational amplitudes

The molecular structure of FBrO₃ has been studied by gas-phase electron diffraction. Least-squares refinements of the molecular geometry using fixed spectroscopic amplitudes revealed two geometrical minima. Initially, the amplitudes employed were derived from diagonal force fields obtained by spectroscopic least-squares refinements to fit observed and calculated wave numbers; for each geometry there are two spectroscopic minima. In the lowest geometrical minimum the wave number agreement is poor, however, the introduction of the ∠OBrO/∠FBrO interaction force constant removed the discrepancies; the resulting force field is F(Br-O) = 6.92 ± 0.02 mdyn Å^?1F(Br-F) = 3.22 ± 0.03 mdyn Å^?1, F(∠OBrO) = 1.06 ± 0.02 mdyn Å, F(∠FBrO) = 0.81 ± 0.03 mdyn Å, F(∠OBrO/∠FBrO) = ?0.19 ± 0.02 mdyn Å. In the corresponding geometrical minimum r_g(Br-O) = 1.582 ± 0.001 Å, r_g(Br-F) = 1.708 ± 0.003 Å, r_α(∠OBrO) = 114.9 ± 0.3°, r_α(∠FBrO) = 103.3 ± 0.3°. Perpendicular amplitude correction coefficients, calculated for each force field employed, were used throughout to relate the interatomic distances through the r_α-structure. The geometries of the r_α^o- and r_e-structures are estimated.     

The structure of (dichloro) (DI-μ-acetato)(bis-triphenyl phosphine) dimolybdenum(II)

The title compound was obtained in crystalline form suitable for X-ray structure determination. It forms crystals in the monoclinic space group P2₁/c with two centrosymmetric molecules in a unit cell of dimensions, a = 10.888(1) Å, b = 10.182(2) Å, c = 17.929(4) Å, β = 104.33(1)°. The central Mo₂Cl₂(O₂C)₂P₂ core has effectively C_2h-symmetry with the following principal dimensions: MoMo = 2.091(1) Å, MoCl = 2.405 Å, MoP = 2.566(2) Å, MoO(av.) = 2.103[4] Å, MoMoP = 104.38(7)°, and MoMoCl = 116.23(8)°.     

Molecular structures of propene and 3,3,3-trifluoropropene determined by gas electron diffraction

The structures of propene and 3,3,3-trifluoropropene have been studied by electron diffraction intensities measured in the present study and rotational constants reported in the literature. The following average structures have been determined: For propene, r_g(CC) = 1.342 ± 0.002 Å, r_g(C-C) = 1.506 ± 0.003 Å, r_g(C-H)_vinyl = 1.104 ± 0.010 Å, r_g(C-H)_methyl = 1.117 ± 0.008 Å, ∠(C-CC) = 124.3 ± 0.4°, ∠(CC-H) = 121.3 ± 1.4°, and ∠(C-C-H) = 110.7 ± 0.9°; for trifluoropropene, r_g(CC) = 1.318 ± 0.008 Å, r_g(C-C) = 1.495 ± 0.006 Å, r_g(C-H)= 1.100 ± 0.018 Å, r_g(C-F) = 1.347 ± 0.003 Å, ∠(C-CC) = 125.8 + 1.1°, ∠(C-C-F) = 112.0 ± 0.2°, where the valence angles refer to the r_av structure, and the uncertainties represent estimated limits of experimental error. A simple set of quadratic force constants for each molecule has been estimated. Regular trends have been observed in the CC and C-C bond distances and the C-CC angles in these and related molecules. Significant differences between the CC, C-C and C-F distances and the C-C-F angle in trifluoropropene and in hexafluoroisobutene reported by Hilderbrandt et al. have been indicated.     

Synthesis,structure, and configuration of new spirooxyndol compound

Structure of a new spirooxyndol compound, [indoline-3,2′(3′H)-[3′-acetyl-2′-acetamide-[1,3,4]-thiodiazoline]-1-benzyl]-2, has been determined by X-ray diffraction analysis. Crystal is monoclinic, unit cell parameters are: a = 12.097(1) Å, b = 10.172(1) Å, c = 32.987(1) Å; β = 97.731(3)°, space group P2₁/n, Z = 4, compound C₄₂H₄₄N₈O₇S₂. Independent part of the unit cell is formed by two crystallographically independent molecules, practically equal in composition and configuration. Two independent molecules are united by the exosphere molecule of ethanol. Phenyl and pyrol rings are located virtually in one plane, dihedral angle formed by mean-square planes of these rings vary within 1.5(2)–3.3(2)°. In both molecules thiodiazoline and pyrol rings are spiro-joint over carbon atom, the dihedral angle formed by the latter is 89.1(1)° and 88.5(1)°, sulfur and nitrogen atoms in the molecules A and B being on different sides of pyrol ring keeping identical configuration of carbon node. Crystal structure is composed due to branched system of intermolecular hydrogen bonds.     

Synthesis and structure of a binuclear ruthenium 4-chlorobenzamidato complex

The compound Ru₂Cl(4-Cl-C₆H₄CONH)₄ was prepared by reaction of Ru₂Cl(O₂CCH₃)₄ with 4-Cl-C₆H₄CONH₂ at 180°C. Crystals of the composition Ru₂Cl(4-Cl-C₆H₄CONH)₄CH₃OH were obtained by slow diffusion of CH₃OH containing Et₄NCl into a Me₂SO solution of the compound. The structure of the crystalline product, which loses solvent of crystallization on removal from the mother liquor, was solved by X-ray crystallography by mounting a single crystal in a capillary containing the mother liquor. The crystals belong to the space group P1? (triclinic crystal system) with a = 12.731(3) Å, b = 14.389(3) Å, c = 12.604(3) Å, α = 103.41(2)°, β = 106.43(2)°, γ = 64.90(2)°, V = 1988.6(8) ų and Z = 2. There are two half ruthenium dimers linked by a Cl atom and an uncoordinated solvent CH₃OH molecule per asymmetric unit. The ruthenium dimers lie on two centers of inversion at 0, 0, 0 and 1/2, 0, 0. The chloride ions bridge dinuclear cations in the crystal, forming infinite zigzag chains. The average Ru-Ru distance is 2.296[1] Å and each ruthenium atom has a RuClN₂O₂ coordination sphere where the average Ru′-Ru-Cl angle is virtually linear (175.68[6]°). The metal oxidation states in the complex are + 2 and + 3, giving an average value of + 2.5. The arrangement of four bridging 4-Cl-benzamidato ligands is of the 2 : 2 type. The average Ru-N, Ru-O, Ru-Cl distances and Ru(1)-Cl(1)-Ru(2) angle are 2.036[6] Å, 2.044[5] Å, 2.583[2] Å and 117.26(8)°, respectively. The IR spectrum of the compound shows two N-H stretches at 3380 and 3340 cm^?1. The electronic spectrum of the compound in Me₂SO exhibits bands at 558 nm (ε = 340 M^?1 cm^?1), 425 nm (1000) and 320 nm (22,700).     

Synthesis and crystal structure of a second polymorph of N,N′-bis(salicylidene)-3,5,3′,5′-tetramethyl-biphenyl-4,4′-diamine

The Schiff base compound N,N′-bis(salicylidene)-3,5,3′,5′-tetramethyl-biphenyl-4,4′-diamine was synthesized and crystal structure was determined by single-crystal X-ray diffractometry. The result shows that there is another polymorphic form (B) in structure besides published one (A) [1]. In structure B, there are four aromatic rings. The dihedral angles between the phenol rings and the adjacent dimethylbenzene rings are distinctly larger than that formed by the dimethylbenzene rings, possibly as a result of the steric hindrance of the methyl groups and the presence of intramolecular O-H…N hydrogen bonds. The remarkable defference between A and B lies in the angles of C1–C6 ring and C25–C30 ring, which are 51.64(13)° and 7.40(7)° in B and A, respectively. Crystal data for the title compolex C₃₀H₂₇N₂O₂: Monoclinic, P2(1)/c, a = 14.346(3) Å, b = 12.258(2) Å, c = 14.265(3) Å; β = 99.515(4)°, V = 2474.1(7) ų, Z = 4.     

Metal-phenoxyalkanoic acid interactions—12: The crystal and molecular structure of μ-aqua-di-μ-[(2-chlorophenoxy)ethanoato-(O,O′)]-bis[(2-chlorophenoxy)-ethanoato-bis(pyridine)nickel(II)]-water (1/1)

The crystal structure of the pyridine adduct of nickel (2-chlorophenoxy)-ethanote, {[Ni₂(2-CPA)₄(py)₄(H₂O)] · H₂O}, has been determined from three dimensional X-ray data at 293 K. Crystals of the complex are triclinic, space group P$\text{1}$, with two dimers in a unit cell of dimensions a = 21.740(5), b = 14.312(7), c = 9.044(2)Å, α = 96.69(4), β = 84.99(4), γ = 101.20(3)°. The structure was solved by direct methods and refined to 0.059 for 2682 ‘observed’ reflections. The dimer consists of two face-to-face NiO₄N₂ octahedra joined at their apical positions by a bridging water molecule [Ni(1)-Ow; 2.14(1)Å; Ni(2)-Ow, 2.10(1)Å; Ni(1)-Ôw-Ni(2), 116.9(4)°]. Two bidentate carboxyl groups of the 2-CPA molecules bridge the other two corners of the triangular face while the other two 2-CPA ligands are unidentate [Ni-O, 2.05(1)Å (mean)]. The coordination about each Ni is completed by two cis-related pyridine nitrogens [Ni-N; 2.11(1)Å (mean)]     

Crystal and molecular structure of [Au(C<Subscript>14</Subscript>H<Subscript>24</Subscript>N<Subscript>4</Subscript>)][H<Subscript>3</Subscript>O](ClO<Subscript>4</Subscript>)<Subscript>4</Subscript>

The crystal and molecular structure of doubly protonated tetraazamacrocyclic complex of gold(III) [Au(C₁₄H₂₄N₄)][H₃O](ClO₄)₄ has been determined. The crystals are monoclinic: a = 11.158(2) Å, b = 8.243(1) Å, c = 14.756(2) Å; β = 98.65(1)°, V = 1341.8(3) ų, Z = 2, ρ(calc) = 1.134 g/cm³, space group P2₁/n. The structure is built of almost flat centrosymmetrical Au(C₁₄H₂₄N₄)]³⁺ and [H₃O]⁺ cations and [ClO₄]^? anions. The gold atom is coordinated with four nitrogen atoms of the ligand forming a flat square. The coordinated ligand is protonated at its γ-carbon atoms of the two six-membered chelate rings. The Au-N bond lengths are almost identical (the mean value is 1.994 Å). The six-membered rings of the complex contain C=N diimine bonds. The [H₃O]⁺ oxonium ion has H-bonds with the oxygen atoms of perchlorate ions.     

Crystal structure of 6-ferrocenyl-3-phenyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole

A new compound of 6-ferrocenyl-3-phenyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole is synthesized and its single crystal structure is determined by X-ray diffraction method. The compound belongs to the monoclinic P2₁/c space group with cell parameters: a = 10.5523(12) Å, b = 13.8414(16) Å, c = 11.4303(13) Å, V = 1603.5(3) ų.     

Synthetic and structural studies on some 1,3-diselena- and 1,3-dithia-[3]ferrocenophanes of germanium and tin. crystal and molecular structure of 1,3-diselena-2,2- dichlorogermyl-[3]ferrocenophane

A series of [3]ferrocenophanes of general formula Fe(C₅H₄X)₂YCl₂ and the spiro compounds [Fe(C₅H₄X)₂]₂Ge (X = S, Se; Y = Ge, Sn) have been prepared by the reaction of ferrocene 1,1′-dithiol and ferrocene 1,1′-diselenol with tetrahalides of germanium and tin. Spectroscopic properties of the compounds are reported. In solution, the compounds are fluxional by a bridge reversal process. The crystal structure of 1,3-diselena-2,2-dichlorogermyl-[3]ferrocenophane at 163 K. has been determined by X-ray diffraction methods. At that temperature, crystals have space group P2₁/n with a 6.222(3), b 16.156(13), c 12.968(4) Å, β 97.53(1)° and Z = 4. Least-squares refinement gave R = 0.033 for 2834 unique significant reflections whose intensities were measured by counter diffractometry. The two SeGe bond lengths are 2.323 and 2.325(1) Å, with GeCl 2.148 and 2.161(1) Å. The SeGeSe bond angle is 118.2(1)°, ClGeCl 104.7(1)°, and SeGeCl angles range from 106.2 to 109.8(1)°. The SeC bond lengths are 1.901 and 1.904(5) Å, with CSeGe angles of 95.8 and 96.5(2)°. The cyclopentadienyl rings are in an eclipsed conformation with a mean twist angle of 2.7°, and are inclined to one another at 6.1°. The Se atoms are displaced from the ring planes by 0.17 and 0.20 Å yielding a non-bonded intramolecular Se…Se contact of 3.99 Å.     

Molecular structure of bis(acetylacetonato)nickel(II) in the gas phase as determined from electron diffraction data

The molecular structure of bis(acetylacetonato)nickel(II) has been determined by a sector-microphotometer gaseous electron-diffraction method. The experimental data were found to be consistent with a monomeric square-planar structure. The structural parameters of the chelate were determined as follows: ∠ ONiO = 93.6 ± 1.1°, r_g(Ni-O) = 1.876±0.005A Å, r_g(C-0) = 1.273± 0.007 Å, r_g(C-C_ring) = 1.401 ± 0.010 Å, r_g(C-C_methyl) = 1.504 ± 0.013 Å. The mean amplitudes of vibration and the shrinkage effects were calculated from normal-vibration treatment using the Urey-Bradley force field.     

Structure cristalline de SrFeF5

The crystal structure of SrFeF₅ has been determined by single crystal X-ray diffraction methods.The unit cell is monoclinic (space group $\text{P2}{}_1\text{c}$) with a = 7.062 ± 0.001 Å, b = 7.289 ± 0.001 Å, c = 14.704 ± 0.001 Å, β = 95.40 ± 0.01° and Z = 8.The lattice is built up of spiral chains of octahedra parallel to the Oy axis. These chains are formed by (FeF₆)^3? octahedra sharing corners of the same edge. The strontium atoms bridge three neighbouring chains. The SrTiF₅, SrVF₅, SrCoF₅, and BaInF₅ phases are isostructural with SrFeF₅.