Table of Contents

Abstract: Single crystals of ternary chalcogenides with the composition BaLu₂Ch₄ (Ch = S, Se and Te; orthorhombic, Pnma; a = 1211.4–1353.6, b = 395.6–438.5, c = 1427.8–1593.6 pm) could be obtained after attempts to synthesize ternary lutetium(III) nitride chalcogenides using the elements (Lu and Ch) along with BaN₃Cl as a nitrogen source. Their crystal structures are isotypic with CaFe₂O₄ containing two sorts of {[LuChCh]^8–} chains built up of edge-linked [(Lu1)(Ch2)(Ch3)₃(Ch4)₂]^9– and [(Lu2)(Ch1)₃(Ch2)₂(Ch4)]^9– octahedra, respectively. A further interconnection via the chalcogenide anions (Ch3)^2– and (Ch1)^2– leads to double chains, where either (Lu1)³⁺ or (Lu2)³⁺ coordinates these chalcogenide anions as well. The three-dimensional framework {[Lu₂Ch₄]^2–} emerges from the corner-linkage of the two kinds of double chains forming large channels apt to take up the Ba²⁺ cations. These divalent cations exhibit eight contacts to chalcogenide anions resulting in the formation of bicapped trigonal prisms [BaCh₈]^14–.

Abstract: Three new cluster compounds, Cs₂NaAs₇, Cs₄ZnAs₁₄, and Cs₄CdAs₁₄ were obtained from high temperature reactions. Their structures feature heptaarsenide [As₇]^3– anions, where the clusters in Cs₄ZnAs₁₄ and Cs₄CdAs₁₄ are dimerized by the linkers Zn and Cd, respectively. The bonding characteristics of these clusters are discussed and compared. Band structure calculation on Cs₂NaAs₇ suggests that this compound is a semiconductor with an energy gap of circa 1.6 eV, which is in consistent with the dark red color of the crystals.

Abstract: The ternary chloride Na₃MoCl₆ is obtained as red crystals from a disproportionation reaction of molybdenum dichloride, {Mo₆}Cl₁₂, in an acidic NaCl/AlCl₃ melt at 350 °C. The crystal structure (trigonal, P-31c, a = 687.1(1), c = 1225.3(2) pm, Z = 2, V = 501,0(1) 10⁶ pm³) is that of Na₃CrCl₆: within a hexagonal closest-packing of chloride ions two thirds of the octahedral voids are filled between the AB double layers with Na⁺/Mo³⁺, and between the BA layers with Na⁺.

Abstract: Investigations of the system Ba–In–Sn, with the objective to synthesize Ba₈In₁₆Sn₃₀ clathrate using Sn and In flux reactions, yielded instead the known BaSn₃ compound (P6₃/mmc; a = 7.228(2) Å, c = 5.469(3) Å) from Sn flux and its In-doped variant BaSn_2.8In_0.2(1) (a = 7.260(1) Å, c = 5.382(2) Å) from In flux. BaSn_3–xIn_x is the first, and up until now, the only ternary phase containing these elements. Its structure is isomorphic with the Ni₃Sn type (Pearson symbol hP8) and is apparently capable of sustaining small variations in the valence electron count by virtue of replacing Sn with the electron poorer In. Electrical resistivity measurements on single-crystals of both undoped and doped phases show different metallic-like behavior, suggesting that neither BaSn₃ nor BaSn_3–xIn_x are valence compounds.

Abstract: The phase and texture of a newly developed solution-processed copper phthalocyanine (CuPc) thin film have been investigated by two-dimensional grazing incidence X-ray diffraction. The results show that it has β phase crystalline structure, with crystallinity greater than 80%. The average size of the crystallites is found to be about 24 nm. There are two different arrangements of crystallites, with one dominating the diffraction pattern. Both of them have preferred orientation along the thin film normal. Based on the similarities to the vacuum deposited CuPc thin films, the new solution processing method is verified to offer a good alternative to vacuum process, for the fabrication of low cost small molecule based organic photovoltaics.

Abstract: An unsymmetrical trinickel metal complex, [Ni₃(dpa)₄(4-sb)(H₂O)]×3H₂O (1), where dpa is a 2,2’-dipyridylamine anion and 4-sb is 4-sulfobenzoate dianion, was synthesized and characterized by X-ray crystallography, IR, elemental analysis, fluorescence, and cyclic voltammetry. The molecular structure of 1 is a cluster with a linear trimer. The extended structure is a 3D architecture assembled by hydrogen bonds. The 4-sulfobenzoate axial replacement leads to the change of Ni-Ni distances, the shift of the fluorescence emission, and the reversible one-electron reduction process without oxidation process.

Abstract: In China, Korea, and Japan, Umbilicaria esculenta is considered as both food and medicinal resources from lichen. In the current study, a prismatic crystal was first isolated from edible lichen U. esculenta via solvent fractionation. The structure of the crystalline compound was elucidated as allantoin using single-crystal X-ray crystallographic and spectroscopic techniques. In light of the wide use of synthesized allantoin in cosmetic industry as a skin protectant, the biological origin of the allantoin isolated from natural food stuff edible lichen has great potential to be developed into functional cosmetics. Current findings also provided useful information for ecologists to further explore the role of lichen and allantoin in nitrogen metabolism.

Abstract: When crystallized from ethanol, 7,7-dimethyl-2-pyridin-4-yl-6,7-dihydro-1,2,4-triazolo[1,5-a][1,3,5]triazin-5-amine forms crystals which have monoclinic (P2₁/n) symmetry with unit cell dimensions a = 7.3326(5) Å, b = 19.4897(14) Å, c = 8.6586(6) Å, α = 90°, β = 106.069(2)°, γ = 90°, V = 1189.06(14) ų, Z = 4. The triazine ring in the molecule has a flattened boat conformation with gem-dimethyl groups as flagpole and bowsprit at the bow. The puckering parameters for the ring are: Q = 0.2996(14) Å, θ = 111.7(3)° and φ = 124.1(3)°. In the crystal, molecules are arranged in the three types of chains generated by the intermolecular NH···N hydrogen bonds. The extended chains with the C(11) graph-set motif running along a [010] axis are formed by the amino group hydrogen atom and the pyridine nitrogen atom of another molecule. The C(4)C(6) chains with the R²₂(8) binary graph-set motif running along a [101] direction are formed by linking the amino group hydrogen atom and the hydrogen atom at the triazine nitrogen atom with the triazole and triazine nitrogen atoms of another molecule, respectively. The centrosymmetric inverted dimers are formed via the C-H···π interactions between the methyl group hydrogen and the pyridine ring of the pair molecule.

Abstract: Systematic syntheses in the Ba–Ga–Sn system confirmed the existence of a new ternary phase BaGa_1.79Sn_4.21(2) (EuGa₂Ge₄ structure type; orthorhombic space group Cmcm, Pearson symbol oS28) with lattice parameters a = 4.5383(6) Å, b = 12.2486(16) Å, c = 14.3747(19) Å. The structure is best viewed as an open-framework based on tetrahedrally coordinated Sn/Ga atoms with Ba atoms enclosed in the voids within it. The new phase co-precipitates with two other compounds with very similar compositions—Ba₈Ga_14.5Sn_31.5(4) (K₄Si₂₃ structure type; cubic space group , Pearson symbol cP54; a = 11.6800(12) Å), and Ba₈Ga_13.2Sn_32.8(3), (Eu₄Ga₈Ge₁₅ structure type; cubic space group , Pearson symbol cI54; a = 11.5843(7) Å). Detailed discussion on how syntheses affect the crystal chemistry, and the temperature dependence of the atomic displacement parameters, obtained from single-crystal structure refinements, are also reported in this article.

Abstract: Large crystals of the methyl ester of the N-a-benzyloxycarbonyl protected Ala-Phe dipeptide (Z-AF-OMe) were obtained after the very slow evaporation of a solution of the corresponding carboxylic acid (Z-AF-OH) in methanol containing an excess of HCl. The structure was confirmed by single crystal X-ray diffraction data. It crystallizes in the orthorhombic space group P2₁2₁2₁ with unit cell dimensions a = 5.0655(6) Å, b = 8.4614(8) Å, c = 46.856(5) Å, V = 2008.3(4) ų, Z = 4. In the crystal, the molecules form hydrogen bonded chains running along the a axis of the unit cell. Other secondary interactions are also discussed.

Abstract: Synthesis of the title compound from 4-methoxyaniline was accomplished in three steps. The structure was supported by spectroscopic data and unambiguously confirmed by single crystal X-ray diffraction data. It crystallizes in the monoclinic space group P2₁ with unit cell dimensions α = 9.9349(8), b = 6.3377(5), c = 10.5783(10) Å, β = 97.752(3)°, V = 659.97(10) ų, Z = 2.

Abstract: Despite the simple chemical formula, [Ni(1,10-phenanthroline)₂(H₂O)₂](NO₃)₂, crystallizes with a remarkably complicated 3-D hydrogen bonding supramolecular assembly. The title compound crystallizes in the monoclinic space group P2₁/c, with an unusually long b axis and a large cell volume. A huge asymmetric unit has been identified, containing six discrete [Ni(1,10-phen)₂(H₂O)₂]²⁺ cations and twelve nitrate anions. Detailed analyses of the crystal structure and O-H×××O and C-H×××O hydrogen bonding interactions are reported and discussed. In this way the anion-directed assembly of the 3-D structure is illustrated. The thermal and spectroscopic properties of the compound are described. Upon heating to 308 K, the crystal undergoes a phase change to a much simpler structure with a single [Ni(1,10-phen)₂(H₂O)₂]²⁺ cation within the asymmetric unit and unit cell volume one sixth of that at low temperature. Although the crystal decomposed during data collection, it was possible to establish the molecular packing in the high temperature form and relate it to that at low temperature.

Abstract: Recently we showed how crystallization in microemulsions could lead directly to the most stable polymorph, thereby leapfrogging Ostwald’s rule of stages. Here we consider in more details the crystallization of mefenamic acid from dimethylformamide microemulsions. Crystallization of mefenamic acid from bulk DMF has previously been shown to produce only the metastable Form II irrespective of the supersaturation or temperature. In contrast, we show that stable Form I can be produced from DMF microemulsions provided the lowest supersaturations that can achieve crystallization are used; these correspond to initial supersaturations that are significantly higher than those commonly used in bulk solution crystallizations, owing to the large decrease in supersaturation that occurs when a nuclei grows in a 3D-nanoconfined droplet. Increasing the supersaturation above the minimum required for crystallization leads to increasing proportions of metastable Form II crystals. In compositions crystallizing a mixture of Form I and Form II crystals, the Form I crystals can nevertheless be obtained exclusively by slowly heating the microemulsions.

Abstract: Synthesis and single-crystal X-ray structure determination of the new antimonide oxide, Ba₅Cd₂Sb₄O₂ are reported. Ba₅Cd₂Sb₄O₂ crystallizes in the monoclinic space group C2/m (No. 12) with unit cell parameters: a = 17.247(7) Å, b = 4.9279(18) Å, c = 12.240(5) Å, and β = 132.558(4)°; Z = 2. Its crystal structure can be described as a polyanionic [Cd₂Sb₄]^6– sub-lattice made up of fused CdSb₄ tetrahedra, stacked between puckered slabs of oxo-anions, O^2–, and Ba²⁺ cations. This structure can also be described as a “double-salt”, i.e., a structure composed of fragments from the Zintl phase Ba₃Cd₂Sb₄ intercalated by two BaO-like moieties. The topological similarities between the structures of these compounds are discussed.