X-ray structural study of fluorinated β-diketonate complexes of zirconium(IV)

Three novel complexes of zirconium(IV) are prepared and characterized by single crystal X-ray diffraction: zirconium(IV) pivaloyltrifluoroacetonate Zr(ptac)₄, zirconium(IV) trifluoroacetylacetonate Zr(tfac)₄, and zirconium(IV) hexafluoroacetylacetonate Zr(hfac)₄. Crystal data for C₃₂H₄₀F₁₂ZrO₈: a = 19.9842(6) Å, b = 11.8417(3) Å, c = 16.4831(5) Å; β = 95.2880(10)°, monoclinic, space group Cc, Z = 4, d _calc = 1.491 g/cm³, R = 0.061. Crystal data for C₂₀H₁₆F₁₂ZrO₈: a = 21.5063(15) Å, b = 7.9511(5) Å, c = 16.0510(10) Å; β = 113.736(4)°, monoclinic, space group C2/c, Z = 4, d _calc = 1.860 g/cm³, R = 0.047. Crystal data for C₂₀H₄F₂₄ZrO₈: a = 15.3533(13) Å, b = 20.2613(15) Å, c = 19.6984(17) Å; β = 95.828(2)°, monoclinic, space group P2₁/c, Z = 2, d _calc = 2.004 g/cm³, R = 0.078. All the structures are molecular and include isolated mononuclear Zr(β-dik)₄ complex molecules. Coordination environment of zirconium atom is made by eight oxygen atoms of four β-diketonates; the coordination polyhedron is an almost regular square antiprism. The Zr-O distances fall within 2.14–2.23 Å. Complexes in the structures are joined by van der Waals interactions. Using the structural data, the van der Waals energies of crystal lattices of the studied compounds are calculated by the atom-atom potential method.     

Etude cristallographique de l'arsénotellurure de zirconium quadratique

Single crystals of zirconium arsenotelluride (PbFCl type) have been prepared by direct synthesis from the elements. Chemical analysis gives: $\text{As}\text{Zr}\text{= 1.43 ± 0.02}$ and $\text{Te}\text{Zr}\text{= 0.46 ± 0.01}$, in atoms. Lattice constants are: a = 3.82 ± 0.01 Å and c = 8.17 ± 0.02Å. Experimental density is equal to 7.14 ± 0.05. Unit cell thus contains Zr_2.00As_2.86Te_0.92. The structure has been solved with 227 reflections of a single crystal recorded at room temperature. The final R factor is 0.081, excluding zero reflections. Part of the arsenic atoms fills a site and the remainder is located in a second site, the occupation of which is completed by a part of zirconium atoms. The third site is occupied, but not filled, by the tellurium atoms and the remainder of zirconium atoms.     

Steric factor in ligand displacement of zirconium alkoxides dissolved in alcohols

The present study indicates EXAFS direct structural data obtained for zirconium ethoxide, iso- and n-propoxide are alike those for zirconium n-butoxide complexes. This is evident for agreement of structural units of abovementioned alkoxides complexes. Our group developed structural model of n-butoxide earlier. Six interconnected tetramers assemble a structural unit of the alkoxides under study. The tetramers build of zirconium atoms in the highly flattened pyramid corners. Four zirconium atoms are bonded in series by double bridges through oxygen atoms of alkoxide ligands. Two of the four zirconium atoms are bias bonded by single ligand bridges. The distances between pairs of zirconium atoms inside the tetramer are 3.3 and 3.5 Å. Tetramers are linked together also by a single ligand bridges. The distance between zirconium atoms of the two neighbor tetramers is 3.9 Å. Primary particles (tetramer sextet) form aggregates in a solution. Possible shapes of the anisotropically sized aggregates is a large diameter cylinder with small height (a disk), or a small diameter cylinder with large height (a rod). Primary particles composed through ligands. The distance between the neighbor zirconium atoms of different primary particles is 4.8 or 5.1 Å depending on the coordination nature and the neighboring particles number.     

Zirconiumphthalocyanine: Darstellung und Eigenschaften chloridhaltiger Phthalocyanine des drei- und vierwertigen Zirconiums; Kristallstruktur von cis-Di(triphenylphosphin)iminium-tri(chloro)phthalocyaninato(2–)zirconat(IV)-di(dichlormethan)

Zirconiumphthalocyanines: Synthesis and Properties of Chloride Ligated Phthalocyanines of Ter- and Quadrivalent Zirconium; Crystal Structure of cis-Di(triphenylphosphine)iminium-tri(chloro)phthalocyaninato(2–)zirconate(IV)-di(dichloromethane) cis-Di(chloro)phthalocyaninato(2–)zirconium(IV) is obtained by the reaction of ZrCl₄ with phthalodinitrile in 1-chloronaphthaline at 230°C. It reacts with molten di(triphenylphosphine)iminiumchloride ((PNP)Cl) yielding cis-di(triphenylphosphine)iminium-tri(chloro)phthalocyaninato(2-)zirconate(IV), cis-(PNP)[ZrCl₃Pc^2?]. This crystallizes with two molecules of dichloromethane in the monoclinic space group P2₁/n with the lattice constants a = 15.219(4) Å, b = 20.262(10) Å, c = 20.719(4) Å, b? = 93.46(2)°, Z = 4. The seven coordinated Zr atom is situated in a “square base-trigonal cap” polyhedron. The plane of the three chlorine atoms runs parallel to the plane of the four isoindole nitrogen atoms N_iso. The Zr–Cl distances range from 2.49 to 2.55 Å, the Zr? N_iso distances from 2.26 to 2.29 Å. Due to ion packing effects the Pc^2? ligand shows an asymmetrical convex distortion. The PNP cation adopts the bent conformation. The P? N? P angle is 139°, the P? N distance 1.58 Å. As confirmed by the cyclovoltammograms cis-(PNP)[ZrCl₃Pc^2?] is oxidized (anodically or chemically by Cl₂) to yield cis-tri(chloro)phthalocyaninato(1–)zirconium(IV) and reduced (cathodically or chemically by [BH₄]^?) yielding chlorophthalocyaninato(2–)zirconium(III) and cis-di(triphenylphosphine)iminium-di(chloro)phthalocyaninato(2–)zirconate(III). The optical spectra show the typical π–π*-transitions of the Pc^2? resp. Pc^? ligand not much affected by the different states of oxidation and coordination of zirconium. The same is true for the vibrational spectra of the Pc^2? resp. Pc^? ligand. In the f.i.r. spectra between 350 and 150 cm^?1 the asym. and sym. Zr? Cl stretching and Cl? Zr? Cl deformation vibration as well as the asym. Zr? N stretching vibration of the [ZrCl_xN₄] skeleton (x = 1–3) is assigned.     

Volatile zirconium complexes with sterically hindered β-diketonates: Structure and thermal properties

The structure and thermal properties of a novel zirconium(IV) complex with a methoxy substituted β-diketonate ligand tetrakis-(2-methoxy-2,6,6-trimethylheptane-3,5-dionato)zirconium are described. The complex sublimes without decomposition under low pressure (10^–2 Torr) at 200 °C. The crystal structure of the complex is molecular and is composed of two structural Zr(zis)₄ isomers in a 1:1 ratio. The crystallographic data are as follows: C₈₈H₁₅₂F₂₄O₂₄Zr₂, P-1, a = 12.1350(7) Å, b = 19.7733(10) Å, c = 21.0526(12) Å, α = 83.338(2)°, β = 89.571(2)°, γ = 73.515(2)°, V = 4809.5(5) ų, Z = 2, d = 1.227 g/cm³. The coordination environment of the zirconium atom consists of eight oxygen atoms from four β-diketonate ligands; the coordination polyhedron is a square antiprism. The Zr–O distances are in a range 2.127-2.202 Å. The thermal properties of the complex are studied by TG–DTA. The effect of the crystal structure (molecular packing) on the volatility and thermal properties is compared for the new complex and two other analogous zirconium complexes with β-diketonate ligands containing bulky terminal substituents. The results of the mass spectrometric study of thermal behavior of the complexes on programmed heating of vapor under the conditions similar to those in a hot wall CVD reactor under low pressure, including the decomposition in the presence of oxygen, are discussed.     

Die Struktur der Komplexnitride NbCrN und Ta1−x Cr1+x N

The crystal structure of the isotypic compounds NbCrN and Ta_1?x Cr_1+x N has been determined from X-ray powder patterns. The tetragonal unit cell contains 12 atoms and belongs to the space group P4bm. The lattice parameters are for NbCrN:a=4.283 Å,c=7.360 Å, for Ta_0.8Cr_1.2Na=4.249 Å,c=7.334 Å. The structure is characterized by relatively close packed double layers of Nb(Ta)-atoms and Cr-atoms parallel to the base plane. The nitrogen atoms are within the octahedral interstitial sites of the niobium(tantalum) double layer.     

A hierarchic structure in zirconium butoxide complexes in <Emphasis Type="Italic">n</Emphasis>-butanol solutions

The structure of particles in zirconium n-butoxide solutions in n-butyl alcohol is determined by means of EXAFS, SAXS, and molecular mechanics modeling. Zirconium atoms are found to be bonded to each other via the oxygen atom and to form large anisotropic particles in the solution. Primary particles have a shape close to spherical; their diameter together with the solvate shell is 28.9 Å. These particles then aggregate into anisotropic structures. During solution aging under normal conditions without contact with the atmosphere, the particle anisotropy increases because of the aggregation of complexes. When the solution concentration decreases, the particles are divided into primary spherical particles with a characteristic size of 28.9 Å. The described changes are confirmed by a decrease in the number of Zr-Zr distances of 4.8 Å and 5.1 Å, which according to the EXAFS data, correspond to the bonds between the primary particles. The characteristic maximum sizes of particles in solutions with concentrations from 0.1 g to 0.003 g ZrO₂/ml are 160–80 Å.     

The crystal and molecular structure of copper(I) trifluoromethanesulphonate cyclohexene complex

The first crystal structure of a copper(I) trifluoromethanesulphonate (cyclo)olefin complex, viz. copper(I) triflate-cyclohexene, CuOSO₂CF₃ · C₆H₁₀, is presented. The compound crystallises in the space group P$\text{1}$ with a 10.288(1), b 10.412(1), c 11.059(1) Å, α 65.81(1), β 81.25(1), γ 70.45(1)° and Z = 4. The structure has been solved by Patterson and Fourier methods and refined to a final R = 0.062. The compound consists of tetrameric units which are interconnected by CuOCu bridges to give an infinite chain. The tetramer has S_i symmetry. Both Cu ions are four-coordinated with a geometry that is intermediate between trigonal pyramidal and tetrahedral. The copper ions in the tetramer are joined together by oxygen—sulphur—oxygen bridges of the triflate anion.     

The crystal and molecular structure of bis-dimethylaminotitanium difluoride tetramer

The crystal structure of [(Me₂N)₂TiF₂₄ has been determined by single-crystal X-ray diffraction. The crystals are tetragonal, I$\text{4}$, a = b = 11.313(5), c = 12.862(4) Å, Z = 2. The titanium atoms display a distorted octahedral coordination and are linked by TiFTi and TiNMe₂Ti bridges to form a tetramer, which possesses a crystallographic inverse tetrad axis at its centre. One fluorine and one dimethylamino group do not participate in the bridging. The principal bond lenghts are TiF(bridging) 2.00(2) and 2.06(2), TiF (terminal) 1.77(2), TiN(bridging) 2.14(3) and 2.19(3), TiN(terminal) 1.99(30) Å. The structure has been refined to R = 0.077 for 231 visually estimated unique reflections.     

A new binuclear germanium(IV) and copper(II) complex with 1,3-diamino-2-propanoltetraacetic acid: Crystal and molecular structure of [(H2O)(OH)Ge(μ-Hpdta)Cu(H2O)] · 3H2O

A heteronuclear germanium(IV) and copper(II) complex with 1,3-diamino-2-propanoltetraacetic acid (H₅Hpdta) has been synthesized for the first time. The compound has been characterized by elemental analysis, X-ray diffraction, thermogravimetry, and IR spectroscopy. The structure of the complex [(H₂O)(OH)Ge(μ-Hpdta)Cu(H₂O)] · 3H₂O (I) has been determined by single-crystal X-ray diffraction. The crystals of I are monoclinic, a = 1 5.327(4) Å, b = 11.626(3) Å, c =21.058(3) Å, β = 96.35(2)°, V = 3729.2(2) ų, Z = 8, space group C2/c, R1 = 0.0551 on 3090 reflections with I > 2σ(I). The structural units of the crystal of I are binuclear complex molecules [(H₂O)(OH)Ge(μ-Hpdta)Cu(H₂O)] and crystal water molecules. The germanium and copper atoms are linked by the bridging oxygen atom of the deprotonated isopropanol group of the Hpdta^5? ligand (Ge-O, 1.843(3) Å; Cu-O, 2.221(3) Å). The coordination spheres of the Ge and Cu atoms contain each one nitrogen atom (Ge-N, 2.090(4) Å; Cu-N, 2.000(4) Å) and two carboxyl oxygen atoms from four acetate arms of the heptadentate Hpdta^5? ligand (av. Ge-O, 1.909(3) Å; Cu-O, 1.948(3) Å). The coordination polyhedron of the Ge atom is completed to a distorted octahedron by the oxygen atoms of the terminal hydroxy group (Ge-O, 1.786(3) Å) and a water molecule (Ge-O, 1.904(3)Å). The coordination polyhedron of the copper atom is completed to a prolate tetragonal pyramid (4 + 1) by the oxygen atom of a water molecule in the equatorial position (Cu-O, 1.955(4) Å) and the bridging O(11) atom (Hpdta^5?) in the apical position. Binuclear molecules are linked pairwise in a head-to-head manner via double Cu-O(2) bridges to form the centrosymmetric tetranuclear supramolecule {[(H₂O)(OH)Ge(μ-Hpdta)Cu(H₂O)]}₂. The coordination of the Cu atom is completed by the weak Cu-O(2A) contact (3.303 Å) to an asymmetrically elongated tetragonal bipyramid (4 + 1 +1). In the crystal, the complex molecules and crystal water molecules are combined by a system of hydrogen bonds into a three-dimensional framework.     

Die Kristallstruktur von CuBr · (C2H5)4P2

The crystal structure of CuBr · (C₂H₅)₄P₂ has been determined by single crystal X-ray methods. The crystals are triclinic (space group P 1 ) with two formula units per unit cell (a) = 9,29, b = 9,92, c = 7,57 Å, α = 85,3°, β = 106,6°, γ = 109,1°. The copper atoms are tetrahedrally coordinated by two bromine and two phosphorus atoms (of different biphosphine molecules). The structure has continuous chains running parallel c, in which the copper atoms are linked together by alternating double bridges consisting of two biphosphine molecules and two bromine atoms, respectively.     

Synthesis and structure of an infinite-chain form of ZrI2 (α)

The synthesis of a second polymorph of ZrI₂ has been achieved by a transport reaction between ZrI₄ and zirconium metal under a $\text{750}\text{850}\text{°}\text{C}$ gradient in a sealed tantalum tube. The black lath-like crystals produced in the 775°C region occur in space group $\text{P2}{}_1\text{m}$ with a = 6.821(2) Å, b = 3.741(1) Å, c = 14.937(3) Å, β = 95.66(3)°, Z = 4. A total of 669 independent reflections with 2θ ≤ 50° and I > 3σ(I) were measured at room temperature on a four-circle automated diffractometer with monochromatized MoKα radiation and were corrected for absorption (μ = 190 cm^?1). The structure was solved by direct methods and full-matrix least-squares refinement of all atoms with anisotropic thermal parameters to give final residuals R = 0.064 and R_w = 0.079. This phase is isoelectronic and isostructural with β-MoTe₂, a distorted CdI₂-type structure in which the zirconium atoms are displaced 0.440 Å from the octahedral centers along a to form infinite zigzag metal chains (d_ZrZr = 3.182(3) Å) parallel to b. The phase is a diamagnetic semiconductor at room temperature (E_g ～ 0.1 eV).     

Antiferromagnetic complexes involving metalmetal bonds : I. Synthesis and molecular structure of an antiferromagnetic dimer with a CrCr bond

The binuclear complex (C₅H₅)₂Cr₂(S)(SCMe₃)₂ was prepared by refluxing a solution of chromocene and t-butylmercaptane in heptane. The structure of the product was determined by single crystal X-ray diffraction. The chronium atoms are linked by a sulphide bridge (SCr 2.24 Å;, <CrSCr 74.1° and two SCMe₃ bridges (CrS 2.38 Å;, <CrSCr 68.3–69.3°). The two cyclopentadienyl ligands (CC 1.41 Å;, CrC 2.23 Å;) are in apical positions, their ring planes being parallel to each other. The complex is an antiferromagnet (?2J cm^?1) despite the small CrSCr angles and short chromiumchromium distance (2.689 Å;) indicative of strong CrCr bonding.     

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.     

catena‐Poly­[[bis­(quinoxaline‐κN)cobalt(II)]‐di‐μ‐dicyan­amido‐κ2N1:N5] and catena‐poly­[[bis(quinoxaline‐κN)copper(II)]‐di‐μ‐dicyan­amido‐κ2N1:N5]

Two new complexes, [Co(C₂N₃)₂(C₈H₆N₂)₂], (I), and [Cu(C₂N₃)₂(C₈H₆N₂)₂], (II), are reported. They are essentially isomorphous. Complex (I) displays distorted octahedral geometry, with the Co atom coordinated by four dicyan­amide nitrile N atoms [Co—N = 2.098 (3) and 2.104 (3) Å] in the basal plane, along with two monodentate quinoxaline N atoms [Co—N = 2.257 (2) Å] in the apical positions. In complex (II), the Cu atom is surrounded by four dicyan­amide nitrile N atoms [Cu—N = 2.003 (3) and 2.005 (3) Å] in the equatorial plane and two monodentate quinoxaline N atoms [Cu—N = 2.479 (3) Å] in the axial sites, to form a distorted tetragonal–bipyramidal geometry. The metal atoms reside on twofold axes of rotation. Neighbouring metal atoms are connected via double dicyan­amide bridges to form one‐dimensional infinite chains. Adjacent chains are then linked by π–π stacking interactions of the quinoxaline mol­ecules, resulting in the formation of a three‐dimensional structure.     

Synthesis and crystal chemistry of NH3(MoO3)3

NH₃(MoO₃)₃ crystallizes with hexagonal symmetry, space group $\text{P6}{}_3\text{m}$, lattice constants a = 10.568 Å, c = 3.726 Å, and Z = 2. The crystal structure has been determined by Patterson synthesis and refined assuming isotropic temperature factors to a final conventional R value of 0.085. The structure shows a three-dimensional arrangement built up of double chains of distorted MoO₆ octahedra, parallel to the [001] direction. The octahedral double chains are linked among each other through common oxygen atoms. In addition to the shared oxygen atoms, each molybdenum is coordinated to one terminal oxygen. MoO distances range from 1.645 to 2.378 Å and OMoO angles from 74.3 to 114.3°. These results are consistent with the fact that molybdenum in high-valence states shows octahedral coordination with terminal oxygens.     

X-ray crystal structure of the clathrate compound tetrakis[(benzonitrile)(triphenylphosphorane)nickel(0)] · 2 toluene · ~1 n-hexane · ~1 cycloocta-1,5-diene

The preparation and the chemical properties of the clathrate compound tetrakis[(benzonitrile)(triphenylphosphorane)nickel(0)] · 2 toluene · ~1 n-hexane · ~1 cycloocta-1,5-diene are described. The crystal and molecular structure of this compound were determined from X-ray diffractometer data. The structure was solved by direct and Fourier methods and refined by least-squares techniques to R = 0.117 for 3441 independent reflections. The crystals are monoclinic, space group P2₁, with Z = 2, in a unit cell of dimensions a 14.680(7), b 28.198(18), c 15.482(8) Å, β = 118.43(8)°. Eight (NiP(C₆H₅)₃ · NCC₆H₅) formula units are present as two tetrameric molecules in the unit cell. Each Ni atom of the tetramer is linked by σ bonds to a P and N atom and by π bonds to the NC group of another benzonitrile molecule. The coordination of the nickel atoms is roughly trigonal. The nickel and N atoms form an eight-membered ring with a boat conformation. The NCC groups of the benzonitrile residues are bent and the NC distances indicate a high degree of double bond character for all these bonds. The triphenylphosphorane groups adopt a “propeller”-like conformation. Four solvent molecules 2 toluene, 1 n-hexane, and ~1 cycloocta-1,5-diene per asymmetric unit are present in the unit cell.     

Double helix of the coordination polymer of silver with 1,3-bis(4-pyridyl)propane: Synthesis and crystal structure of [Ag(C<Subscript>13</Subscript>H<Subscript>14</Subscript>N<Subscript>2</Subscript>)](CF<Subscript>3</Subscript>CO<Subscript>2</Subscript>)

The [Ag(Bpp)](CF₃CO₂) complex (Bpp is 1,3-bis(4-pyridyl)propane, C₁₃H₁₄N₂) is synthesized, and its structure is determined. The crystals are monoclinic, space group C2/c, a = 26.169(5), b = 10.521(2), c = 12.906(3) Å, β = 117.99(3)°, V = 3137.7(11) ų, ρ_calcd = 1.775 g/cm³, Z = 8. The structure contains double helices of-Ag-Bpp-Ag-Bpp-cationic chains with a helix period of 21.042 Å. The Ag…Ag distance between a pair of silver atoms from different chains in the helix is 3.201 Å, and the distance between the adjacent helices is 3.279 Å. The silver atom is linked with two bridging nitrogen atoms of two Bpp ligands in an almost linear coordination: Ag-N_avg 2.142 Å; NagN, 171.3(4)°. The CF₃C ₂ ^? anion has a weak contact with the silver ion (Ag…O 2.62(2) Å).     

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.     

Exchange interaction via hydrogen bridges in dimeric copper(II) complexes. A theoretical analysis

The singlet—triplet splitting (E_ST=2J₁₂) is calculated in dimeric [Cu(H₂O)(NH₃)₂(OH)]⁺ where the copper atoms are joined by two O-H…O bridges. This molecule acts as a model for a well investigated copper(II) complex (O…O 2.32(2) Å) which shows an antiferromagnetic spin coupling (2J₁₂ = −94 cm⁻¹). Calculations with different oxygen-oxygen distances (2.34–2.84 Å) show a nearly linear dependence of the singlet-triplet splitting which is far from being negligible even for the greater O-O distances (2.64–2.84 Å).