Simulation of ion transport in layered cuprates La<Subscript>2 − <Emphasis Type="Italic">x</Emphasis></Subscript>Sr<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>CuO<Subscript>4 − <Emphasis Type="Italic">δ</Emphasis></Subscript>

The processes of oxygen diffusion in La_{2 ? x} Sr _x CuO_{4 ? δ} phases have been simulated for the first time by the molecular-dynamics method. Calculations were performed for the temperature range 300–2500 K. The behavior of the radial pair correlation functions, which characterize the degree of order of O1 ions in CuO₂ layers, indicates that O^2? anions form a weakly correlated subsystem within a CuO₂ layer. To quantitatively confirm the conclusions about the predominantly two-dimensional character of ion transport and different mobilities of O1 and O2 particles in the cuprates under study, the pair oxygen diffusion coefficients in the La_{2 ? x} Sr _x CuO_{4 ? δ} lattice were calculated. It is shown that oxygen diffusion occurs through the conventional hopping mechanism mainly in CuO₂ layers; correspondingly, the diffusion coefficient for equatorial ions (O1) exceeds that for apical oxygen anions (O2) by an order of magnitude. The motion of oxygen anions was traced at the microscopic level through analysis of the particle transport trajectories. It has been proven for the first time that diffusion of O1 ions in the ab plane in a nonstoichiometric LaSrCuO_3.61 sample occurs through jumps to the nearest position or along CuO₂ layers; in a more complicated way, it may occur through unoccupied O2 lattice sites.     

Solid-state Spectroscopic and Structural Investigation of <Emphasis Type="Italic">cis</Emphasis>-(CH<Subscript>3</Subscript>)<Subscript>2</Subscript>Au(<Emphasis Type="Italic">O</Emphasis>,<Emphasis Type="Italic">O</Emphasis>′-acac)

Abstract  The structure of cis-(CH₃)₂Au(O,O′-acac) was investigated by single-crystal X-ray diffraction. It crystallizes in the orthorhombic space group Cmca with unit cell dimensions a = 6.7831(13) ?, b = 15.080(3) ?, c = 18.073(3) ? and α = β = γ = 90°. The molecule is planar but lacks a C₂ axis in the solid-state, with two Au–C bond lengths that differ by 0.078(21) ? due to crystal packing effects. The inequivalence of the crystallographic carbon positions is evident in the solid-state ¹³C CP-MAS NMR spectrum, which was recorded at low temperature due to the thermal sensitivity of the compound during magic-angle spinning. Head-to-tail stacking, which creates short intermolecular paths, was reproduced computationally in a dimer model. Graphical Abstract   Solid-state Spectroscopic and Structural Investigation of cis -(CH ₃ ) _Au 2 ( O , O ′-acac) Miyako Hisamoto • Swarup Chattopadhyay • Juergen Eckert • Guang Wu • Susannah L. Scott In the solid state, cis-(CH₃)₂Au(O,O′-acac) has no C₂ axis, two different Au–C bond lengths (1.960, 2.038 ?; Δd = 0.078(21) ?) and a close Au–C…C–Au contact; these features give rise to additional features in the ¹³C CP-MAS NMR spectrum.     

Synthesis and Crystal Structure of Bis (<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′,<Emphasis Type="Italic">N</Emphasis>′-tetramethylethylendiammonium) Octaiodo Pentachloroantimonate (III)

Abstract  

The synthesis and Crystal structure are given for the bis (N,N,N′,N′-tetramethylethylendiammonium) octaiodo pentachloroantimonate (III) salt. An X-ray investigation has shown that the title compound crystallizes in a monoclinic system, space group P2₁/m with the following lattice parameters a = 9.786(2) Ǻ, b = 14.024(5) Ǻ, c = 14.336(3) Ǻ, β = 91.35(2)° and Z = 2. The structure was solved from 3085 independent reflections with R ₁ = 0.0402 and wR ₂ = 0.0952 and refined with 152 parameters. The structure shows a layer arrangement perpendicular to the [(b)\vec] \vec{b} -axis: planes of [SbCl₅]²⁻, I₃ ⁻ and I₅ ⁻ anions alternate with planes of [(CH₂)₂(NH(CH₃)₂)₂]²⁺ cations. The [SbCl₅]²⁻ square pyramids present an active lone electron pair (LEP) on the Sb atoms and they are interconnected by means of N–H···Cl hydrogen bond originating from [(CH₂)₂(NH(CH₃)₂)₂]²⁺ entities. The polyiodides (I₃ ⁻ and I₅ ⁻) anions form a planer zigzag polymeric chains via I···I linking interactions. These chains are linked to the [SbCl₅]²⁻ anions by a long range contact.     

Dimorphism of <Emphasis Type="Italic">R</Emphasis>F<Subscript>3</Subscript> (<Emphasis Type="Italic">R</Emphasis> = La–Nd) crystals based on the data of X-ray diffraction studies

The ratio of two forms of tysonite in nominally pure single crystals of RF₃ (R = La–Nd) obtained from melts under identical conditions (the as-grown state) is studied for the first time by X-ray diffraction. Crystals of RF₃ with R = La–Nd belong to the β-LaF₃ structural type (space group \(P\bar 3c1\), Z = 6) and form twins. Samples 0.2–0.4 in diameter contain inclusions of the high-temperature a form (space group P6₃/mmc, Z = 2). It is shown that twinning and dimorphism of the RF₃ crystals (R = La–Nd) have a common structural basis.     

X-ray Structure of <Emphasis Type="Italic">mer</Emphasis>-[Mo(CO)<Subscript>3</Subscript>(PPh<Subscript>3</Subscript>)(<Emphasis Type="Italic">κ</Emphasis><Superscript>2</Superscript>-dppm)]

Abstract  

Treatment of [Mo(CO)₃(NCMe)₃] with bis(diphenylphosphino)methane (dppm) and triphenylphosphine (PPh₃) at 50 °C afforded mer-[Mo(CO)₃(PPh₃)(κ ²-dppm)] (1) in 55% yield which has been characterized by single crystal X-ray diffraction studies and spectroscopic measurements. Compound 1 crystallizes in the triclinic space group P−1 with a = 10.3449(6), b = 11.1570(6), c = 17.8961(10) ?, β = 80.8400(10)°, Z = 2 and V = 1959.8(2) ?³.     

Cationic transport mechanism in α-Ag<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Cu<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>I(0 < <Emphasis Type="Italic">x</Emphasis> < 0.25): Molecular-dynamics simulation

The structural and transport characteristics of an Ag_{1 ? x} Cu _x I(0 < x < 0.25) solid solution have been simulated by the molecular-dynamics method. It is found that the cation diffusion coefficient decreases with increasing copper concentration; this correlation is in agreement with the experimentally observed decrease in ionic conductivity. It is shown that the cationic transport in disordered Ag_{1 ? x} Cu _x I phases is mainly due to the migration of silver cations, whereas the mobility of copper cations is much lower. Cu⁺ cations are found to reside in the 8c positions in a bcc cell; this finding suggests the existence of nanoscale α-CuI regions.     

Crystal structure of Сu<Subscript>2–<Emphasis Type="Italic">m</Emphasis></Subscript>Te (<Emphasis Type="Italic">m</Emphasis> = 0.25)

The Сu₂Te compound has been synthesized by alloying Сu and Te taken in stoichiometric ratios. A Сu₂Te sample has been homogenized by annealing at 773 K for 100 h. A pure copper phase in the form of thin filaments is found to segregate from the synthesized product (4 g) by the end of annealing. It is established by X-ray diffraction analysis that the copper-deficient sample is crystallized into the trigonal system with lattice parameters а = 8.328(1) Å, с = 7.196(1) Å, V = 432.2(1) ų, sp. gr. \(P\overline 3 m1\), Z = 8. The crystal structure is determined and the sample composition Сu_2–m Te (m = 0.25) is refined by the Rietveld method. The three independent copper atoms in the lattice are found to have different coordination numbers: 3, 4, and 5.     

C–H⋅<Emphasis Type="Italic">s</Emphasis>O hydrogen bond networks in <Emphasis Type="Italic">E</Emphasis>- and Z-unsaturated esters of C-glycosides

Methyl E(Z)-4,7 anhydro-5-benzamido-6,8-di-O-benzoyl-2,3,5-trideoxy-d-allo-oct-2-enoate have been synthesized like intermediates and isolated as single crystals during the synthesis of pyrazole-related C nucleosides as synthetic product with cytotoxic activity.¹ Crystal structures of E(Z) isomers were determined by X-ray analysis. E isomer crystallizes in the triclinic crystal system, space group P1, a = 5.319(1) Å, b = 10.758(2) Å, c = 12.229(2) Å, α = 72.38(2)^∘, β = 89.97(2)^∘, γ = 87.07(2)^∘, D_x = 1.320 Mgm⁻³ and Z isomer in the orthorhombic crystal system, space group P2₁2₁2₁, a = 5.1297(13) Å, b = 19.667(5) Å, c = 25.871(6) Å, D_x = 1.348 Mgm⁻³. The molecular structure was solved by direct method on the basis of 2609 and 2727 unique reflections recorded at the temperature 293 K (E-isomer) and 173 K (Z-isomer) up to the final R-factor 0.0378 and 0.0435, respectively. C–H⋅sO contact networks were analyzed and the correlation established between the existence of the weak C–H⋅sO hydrogen bonds and the melting point of the single crystals.     

Unclassical hydrogen bonds of C—H⋅<Emphasis Type="Italic">s</Emphasis>O and C—H⋅<Emphasis Type="Italic">s</Emphasis>N in the crystals of 2-amino-3-cyano-4-(3,4-dichlorophenyl)-5-oxo-1,4,5,6-tetrahydro-4H-pyrano[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidine

The 2-amino-3-cyano-4-(3,4-dichlorophenyl)-5-oxo-1,4,5,6-tetrahydro-4H-pyrano[2,3-d] pyrimidine (1, C₁₇H₁₅Cl₂N₅O₃) was synthesized and characterized by IR,¹H NMR and elemental analysis. The molecular structure of1 was further studied by using X-ray crystallography. The crystals of compound1 are triclinic, space groupP-1,a = 6.0090(4) Å,b = 10.4056(7) Å,c = 15.6021(11) Å, α = 70.983(4), β = 84.056(6), γ = 84.611(6),Z = 2,V = 915.47(11) ų. Two types of unclassical hydrogen bonds C–H?sO and C–H?sN were presented in the crystals. In addition, there were classical hydrogen bonds in the crystal structure.     

Synthesis and crystal structure of <Emphasis Type="Italic">N</Emphasis>-(6methoxylbenzothiazol-2-yl)-1-(4-fluorophenyl)<Emphasis Type="Italic">O</Emphasis>,<Emphasis Type="Italic">O</Emphasis>-dipropyl-<Emphasis Type="Italic">α</Emphasis>-aminophosphonate

Molecular and crystal structure of N-(6-methoxybenzothiazol-2-yl)-1-(4-fluorophenyl)-O,O-dipropyl-α-aminophosphonate, C₂₁H₂₆FN₂O₄PS, have been determined by single-crystal X-ray diffraction study. The title compound is tetragonal, with a = 21.35(3) Å, c = 20.16(5) Å, Z = 16, D _x = 1.308 Mg/m³, μ(MoKα) = 0.247 mm^?1, and space group is I4₁/a. The structure was solved by direct method and refined to a final R = 0.0687 for 2370 reflections with I > 2σ(I). The compound shows a fully delocalized benzothiazole system with a sp² hybridization of the N(2). There is a strong intermolecular hydrogen bond between P=O and NH. The crystal structure is stabilized by a strong intermolecular N–H?sO hydrogen bond.     

Synthesis and crystal structure of 1D 2,3-naphtho 15-crown-5 complex [Na(N15C5)]<Subscript>2</Subscript>[Ni(i-mnt)<Subscript>2</Subscript>] containing S⋅<Emphasis Type="Italic">s</Emphasis>C and S⋅<Emphasis Type="Italic">s</Emphasis>π interactions

The reaction of 2,3-naphtho-15-crown-5 (N15C5) with Na₂[Ni(i-mnt)₂] [i-mn = 1,1-dicyanoethylene-2,2-dithiolate] affords the title complex [Na(N15C5)]₂[Ni(i-mnt)₂] (1), which is characterized by elemental analysis, FT-IR, UV-visible spectra and single crystal X-ray diffraction. 1 crystallizes in the triclinic, space group P with a = 8.291(4), b = 12.833(7), c = 12.913(6) Å, = 115.732 (7), = 105.030(7), = 90.912(8), V = 1182.2(10) ų, Z = 1 and R₁(wR₂) = 0.0422(0.1001). The single crystal X-ray analysis shows that the [Na(N15C5)]⁺ complex cations act as the bridges linking the [Ni(i-mnt)₂]^2– anions into a 1D infinite chain through Na–N interactions and SsC and Ss interactions are observed in the chain with the shortest SsC distance of 3.433 Å.     

3-[4-Bromo-α(<Emphasis Type="Italic">R</Emphasis>*)-methoxybenzyl]-6-chloro-3(<Emphasis Type="Italic">S</Emphasis>*),4(<Emphasis Type="Italic">S</Emphasis>*)-dihydroxychroman: X-ray and DFT Studies

Sodium borohydride reduction of E-3-benzylidenechromanone epoxides in dry methanol has afforded 3(S*), 4(S*)-dihydroxy-3-[α(R*)-methoxybenzyl]chromans as an interesting class of products, the structures of which have been assigned mainly from spectral data and consideration of the mechanistic aspects. X-ray diffraction study of one of them, 3-[4-bromo-α(R*)-methoxybenzyl]-6-chloro-3(S*),4(S*)- dihydroxychroman, is performed. The title compound crystallizes in the monoclinic sp. gr. P2₁/n, with a = 13.336(6) Å, b = 10.866(5) Å, c = 27.166(11) Å, β = 95.193(6)°, V = 3920(3) ų, and Z = 8. Supramolecular construction of the compound involves O–H···O intermolecular hydrogen bonds as well as three other types of non-covalent interactions which are responsible for crystal packing. Density functional theory was applied for geometry optimization, molecular orbital calculations, and prediction of UV spectral features. The geometric parameters (bond lengths, bond angles, and dihedral angles) for the representative compound obtained from density functional theory with B3LY6-31G basis set were in good agreement with experimental values.     

Synthesis and Crystal Structure of <Emphasis Type="Italic">Tris</Emphasis>-(<Emphasis Type="Italic">N</Emphasis>–<Emphasis Type="Italic">N</Emphasis> dimethyl benzylammonium)-hexachlorobismuthate(III)

Abstract  The salt tris-(N–N dimethyl benzylammonium)-hexachlorobismuthate(III) crystallizes in the triclinic system P1 with unit cell parameters: a = 9.0300(12), b = 9.9220(3), c = 19.575(2) ?, α = 79.955(5), β = 89.952(2), γ = 88.108(6)°, V = 1726.0(3) ?³, Z = 2. The examination of the structure shows an alternate stacking of inorganic layers of hexachlorobismuthate(III) anions and organic layers of [C₆H₅CH₂NH(CH₃)₂]⁺ cations parallel to the a-axis. The cohesion forces of the packing of N–N dimethyl benzylammonium units in the layer and between two adjacent layers are provided by hydrogen bonds (N–H⋯Cl) and van der Waals contacts. Index Abstract  The examination of the structure shows a layer arrangement parallel to the a-axis: planes of octahedral anions [BiCl₆]³⁻ alternate with planes of [C₆H₅CH₂NH(CH₃)₂]⁺ cations (Fig. 3). The cohesion forces of the packing of the N–N dimethyl benzylammonium units in the layer and between two adjacent layers are provided by hydrogen bonds (N–H⋯Cl) and van der Waals contacts. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Growth and dielectric properties of KTiOPO<Subscript>4</Subscript> and K<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Rb<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>TiOPO<Subscript>4</Subscript> crystals

Methods of growth of KTiOPO₄ and K_{1 ? x} Rb _x TiOPO₄ crystals of high optical quality have been optimized. The dielectric properties (permittivity and conductivity) of the crystals grown have been investigated at frequencies from 10² to 10⁶ Hz in the temperature range from 100 to 350 K, along the [001] crystallographic direction. It is established that partial substitution of K⁺ ions with Rb⁺ ions leads to a decrease in the permittivity and conductivity.     

Refinement of the composition and structure of YBaCo<Subscript>4−<Emphasis Type="Italic">x</Emphasis></Subscript>Al<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript>7+δ</Subscript> crystals

YBa(Co_{4 ? x} Al _x )O_{7 + δ} (114Y) crystals have been grown in the Y-Ba-Co-O system by spontaneous crystallization from a slowly cooled nonstoichiometric melt. To change the oxygen content, the crystals were isothermally annealed in air in the range of 280–490°C. The crystals grown were characterized by scanning electron microscopy and powder X-ray diffraction. According to the data of an X-ray spectroscopic quantitative microprobe analysis, the average compositions of “as-grown” and oxygen-saturated crystals were Y_1.04Ba₁Co_3.54Al_0.50O_7.8 and Y_1.02Ba₁Co_3.55Al_0.51O_8.4, respectively. The refinement of the crystal structure after saturation on an automatic Bruker X8APEX diffractometer with a CCD detector (MoKα radiation, graphite monochromator, θ_max = 32.54°, sp. gr. P6₃ mc, a = 6.2746(9), c = 10.257(3) Å, V = 349.71(13) ų, Z = 2, d _calcd = 5.220 g/cm³) reveals the location of Al in two independent positions of Co atoms and yields the general formula of the compound as YBaCo_3.26Al_0.74O₇. Problems related to the difference in the compositions obtained by different methods are discussed.     

Synthesis and Characterization of the Osmium Compound <Emphasis Type="Italic">cis</Emphasis>(CO)<Emphasis Type="Italic">–</Emphasis>ClOs(CO)<Subscript>2</Subscript>(bpcd)[C(O)Et]

Photochemical activation of the triosmium cluster Os₃(CO)₁₂ in CH₂Cl₂ solvent and ethylene, followed by treatment with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd), furnishes the new octahedral compound cis(CO)–ClOs(CO)₂(bpcd)[C(O)Et] in low yield. The title compound has been isolated and characterized in solution by IR and ¹H NMR spectroscopies, with the solid-state structure of cis(CO)–ClOs(CO)₂(bpcd)[C(O)Et] determined by X-ray diffraction analysis. cis(CO)–ClOs(CO)₂(bpcd)[C(O)Et] crystallizes in the triclinic space group P-1, a = 10.043(2), b = 11.455(2), c = 16.221(3) Å, α = 74.900(3)°, β = 76.150(3)°, γ = 76.221(2)°, V = 1718.2(5) ų, Z = 2, D _cacl = 1.717 Mg/m³; R = 0.0453, R _w = 0.0778 for 6703 observed reflections with I > 2σ(I). The presence of the chlorine and propanioyl groups in cis(CO)–ClOs(CO)₂(bpcd)[C(O)Et] is structurally confirmed, and the origin of the these groups from the reaction solvent and ethylene is discussed.     

Intermolecular Hydrogen Bonds and the Supramolecular Structure of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-Bis(<Emphasis Type="Italic">p</Emphasis>-tolylsulfonyl)diethylenetriamine

Abstract  The title compound N,N′-bis(p-tolylsulfonyl)diethylenetriamine (1) was synthesized and its crystal structure determined by X-ray diffraction. Adjacent molecules of 1, symmetrically related through a c-glide, are linked by alternating hydrogen bonds that form molecular chains along [0 0 1]. Two molecular chains occur in each unit cell and pack to form alternating layers in a three-dimensional supramolecular structure. The compound crystallizes in the Pca2₁ space group stabilized by the inclusion of solvent dichloromethane molecules in structural voids between molecules of 1. The dichloromethane molecules are related through a twofold screw rotation axis and are not disordered. Index Abstract  Intermolecular hydrogen bonds involving sulfonamide moieties of title compound afford a supramoleular structure that accommodates the inclusion of dichloromethane in alternating layers.      

Crystal structure of [<Emphasis Type="Italic">N</Emphasis>-(2-aminoethyl)iminodiacetato](1,10-phenanthroline)copper(II) tetrahydrate, [Cu(<Emphasis Type="Italic">Aeida</Emphasis>)(<Emphasis Type="Italic">Phen</Emphasis>)] · 4H<Subscript>2</Subscript>O

Crystals of [N-(2-aminoethyl)iminodiacetato](1,10-phenanthroline)copper(II) tetrahydrate, [Cu(Aeida)(Phen)] · 4H₂O (I), are obtained, and their structure is determined. Crystals I are triclinic, and the unit cell parameters are as follows: a = 8.341(1) Å, b = 9.424(1) Å, c = 13.864(2) Å, α = 74.23(1)°, β = 79.25(1)°, γ = 82.67(1)°, Z = 2, and space group P1. The structural units of the crystal are [Cu(Aeida)(Phen)] molecular complexes and crystallization water molecules. The coordination polyhedron of the copper atom is a tetragonal bipyramid with four nitrogen atoms in the equatorial plane (mean Cu-N, 2.05 Å) and two oxygen atoms of the acetate groups in axial positions (Cu-O, 2.264 and 2.426 Å; O-Cu-O angle, 148.8°). The Aeida and Phen ligands fulfill the tetradentate (2N + 2O) chelate and bidentate (2N) chelate functions, respectively. The complexes are joined into dimer associates in which the interplanar spacing between Phen molecules is equal to 3.54 Å and the Cu?Cu distance is 7.02 Å.     

Growth of ZnSe<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>S<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> solid solution crystals from vapor phase

Partially faceted ZnSe_{1 − x} S _x solid solution crystals have been grown from a vapor phase in a closed stationary horizontal system. The growth has been performed in cylindrical quartz ampoules—∼10 mm in diameter and evacuated to a residual pressure of less than ∼10⁻³ Pa-at a temperature of 1050°C and a temperature drop between the source and growth zones of 10–16°C. The crystal structure, optical absorption, and composition inhomogeneity along the ingot length have been investigated by X-ray diffractometry and optical spectroscopy in the wavelength range of 300–3000 nm. The solid-solution composition range corresponding to cubic polymorphs is determined. The concentration dependences of the lattice parameter and band gap are presented.     

Crystal and molecular structures of [Co(<Emphasis Type="Italic">D</Emphasis>H)(<Emphasis Type="Italic">o-phen</Emphasis>)<Subscript>2</Subscript>][BF<Subscript>4</Subscript>]<Subscript>2</Subscript> · 2H<Subscript>2</Subscript>O

The crystal structure of a new mixed-ligand complex [Co(DH)(o-phen)₂][BF₄]₂ · 2H₂O is determined by X-ray diffraction. The crystal is monoclinic, a = 12.2081(11) Å, b = 14.3474(9) Å, c = 17.7393(16) Å, β = 104.95(1)°, and space group P2₁/c. The coordination octahedron of Co³⁺ is formed by two nitrogen atoms of the dimethylglyoxime molecule and four nitrogen atoms of o-phenanthroline molecules. The dimethylglyoxime molecule is singly deprotonated and acts as DH^?. The mean Co-N distances for dioxime and o-phenanthroline are 1.911 and 1.964 Å, respectively. The key role in the formation of the crystal structure is played by [BF₄]^? outer-sphere anions and crystallization water molecules, which form an extended hydrogen-bond system.