Acta Crystallographica Section C Structural Chemistry最新文献

The crystal structure of magnesium nickel tetraboride, MgNiB₄, was solved and refined based on single-crystal X-ray diffraction data. MgNiB₄ crystallizes in the Pbam space group [a = 5.8791 (2), b = 11.2982 (5) and c = 3.2771 (1) Å] and is isostructural with the YCrB₄ type. The MgNiB₄ and YCrB₄ structures both belong to the AlB₂-type structural family, for which the formation of 6₃-nets by B atoms is typical. In MgNiB₄, B atoms form five- and seven-membered ring nets, which result from a rearrangement of the 6₃-nets. Strong covalent B-B interactions are established according to electronic structure calculations using the tight-binding linear muffin-tin orbital atomic spheres approximation (TB-LMTO-ASA) method. The maximum hydrogen absorption by the MgNiB₄ alloy reached 3.75 wt% H₂.

The crystal structure of the sodium aluminium difluorosulfate NaAl(SO₄)F₂ has been determined from laboratory powder diffraction data. Its characterization allows for improving the monitoring of aluminium industrial production starting from cryolite. It is characterized by a perovskite single layer formed by the fluorine corner-sharing of [AlF₄O₂] octahedra with SO₄ groups, and sodium as the interlayer content. This could be the n = 1 member of a possible new family of 2D perovskite materials AM_n(SO₄)F_3n-1 (A⁺ = Na, Li; M³⁺ = Al, Fe, V, Cr), which remains to be confirmed.

The pyrazole-based Schiff base (E)-3-tert-butyl-N-[(2-nitrophenyl)methylidene]-1-phenyl-1H-pyrazol-5-amine, C₂₀H₂₀N₄O₂, was synthesized in a straightforward manner via a solventless maceration technique, and its structure elucidated through spectroscopic characterization and single-crystal X-ray diffraction analysis. The compound exhibits a degree of coplanarity, influenced by the ortho-nitro group on a phenyl ring. Crystal structure analysis, complemented by Hirshfeld surface analysis and QTAIM-C calculations, reveals that the crystal packing is mainly stabilized by a network of π-stacking and dispersion interactions. Notably, H...C π-stacking interactions, particularly those between ortho- and para-C-H atoms of phenyl groups, play a significant role in the packing motif. The Hirshfeld surface also reveals a 5.8% contribution from H...N contacts, involving aliphatic H atoms interacting with a pyrazole N atom. CE-B3LYP calculations highlight the dominance of dispersion forces in the crystal, with the strongest interaction energy calculated to be -58.9 kJ mol^-1 between the central molecule and the molecular pair related by the identity symmetry operation (x, y, z). These findings provide insights into the structure-property relationships of this compound and contribute to understanding crystal engineering principles for designing new materials.

As a new generation of multi-functional materials, crystalline coordination polymers have attracted widespread attention due to their fascinating framework structures, interesting topologies and potential applications. Two new coordination polymers, namely, poly[[μ₂-trans-1,2-bis(pyridin-3-yl)ethylene-κ²N:N']bis(μ₃-terephthalato-κ³O:O':O'')dizinc(II)], [Zn₂(C₈H₄O₄)₂(C₁₂H₁₀N₂)]_n or [Zn₂(tp)₂(3,3'-dpe)]_n, (I), and poly[diaqua[μ₂-trans-1,2-bis(pyridin-3-yl)-ethylene-κ²N:N']bis(μ₂-furan-2,5-dicarboxylate-κ²O:O')dizinc(II)], [Zn₂(C₆H₂O₅)₂(C₁₂H₁₀N₂)(H₂O)₂]_n or [Zn₂(fdc)₂(3,3'-dpe)(H₂O)₂]_n, (II), have been prepared by the hydrothermal reactions between Zn(NO₃)₂·6H₂O and trans-1,2-bis(pyridin-3-yl)ethylene (3,3'-dpe) with two similar dicarboxylic acids, i.e. terephthalic acid (H₂tp) and furan-2,5-dicarboxylic acid (H₂fdc), respectively. The coordination framework of (I) is a 3D pcu net with the point symbol 4¹²6³. The void space of the single framework in (I) is filled by the mutual interpenetration of two crystallographically equivalent networks, forming a threefold interpenetrating 3D architecture. Compound (II) is a 2D 3-connected coordination network parallel to the bc plane with the Schläfli symbol 6³. Neighbouring 2D coordination networks are further connected to each other via hydrogen-bonding interactions to produce a 3D supramolecular framework. The thermal stability and photoluminescence properties of these two coordination polymers have also been investigated.

A primary amine, n-hexylamine (HA, C₆H₁₅N), has been studied at high pressure by single-crystal X-ray diffraction. The structure of this compound has been determined, at ambient temperature, from the freezing pressure up to 1.40 GPa. HA at high pressure crystallizes in the space group Pca2₁, which was already found at ambient pressure and low temperature. The compressibility of the N-H...N hydrogen bonds has been compared with that of the shortest C-H...N and H...H intermolecular distances, revealing that the H...H distances exhibit the highest degree of compressibility among them.

Seven dinuclear metal complexes and one trinuclear metal complex have been synthesized using the redox-active diphenyl-substituted tetraoxolene 2,5-dihydroxy-3,6-diphenyl-1,4-benzoquinone (H₂Ph₂dhbq, C₁₈H₁₂O₄) as a bridging ligand and tris[(pyridin-2-yl)methyl]amine (TPA, C₁₈H₁₈N₄) as a tetradentate terminal ligand. Single-crystal X-ray diffraction data confirm the final redox states of all components, revealing both expected and unexpected redox behavior across the eight reported complexes. Metal complexes with the formula [M^II₂(Ph₂dhbq^2-)(TPA)₂]²⁺ can be synthesized from Mn, Fe, Co, Ni, Zn, and Ru, using either the oxidized ligand H₂Ph₂dhbq or a combination of the reduced ligand H₄Ph₂dhbq and an in-situ oxidant. Additionally, switching to Group 13 elements, such as Ga, facilitates the formation of the related [M^III₂(Ph₂dhbq^4-)(TPA)₂]²⁺ complex, wherein the ligand remains in its initial reduced state.

Aminocarb [4-(dimethylamino)-3-methylphenyl N-methylcarbamate, C₁₁H₁₆N₂O₂], a synthetic pesticide, was crystallized and characterized by single-crystal and powder X-ray diffraction. In the solid state, the molecules have a strong chain N-H...O hydrogen bond with a strength of -29.37 kJ mol^-1 and a short C-H...π contact that build a wave-like three-dimensional structure. The structural stability and intermolecular interaction of Aminocarb were investigated using differential scanning calorimetry (DSC) and density functional theory (DFT). The results show that the compound is chemically stable, and the two dominating interactions are electrostatic and dispersion energies. An electrostatic potential map reveals the binding sites of the molecules for reactivity. The understanding of the structural stability and interactions in Aminocarb provided in this study could be used to design new compounds with improved solubility and bioavailability. The dimethylamino group and the methyl group on the carbamate could be modified with other alkyl groups, which might reduce the Aminocarb toxicity, thereby leading to the development of safe, efficient and cost-effective compounds.

The crystal structure of the calcium bis(tetrafluoroborate) hydrate Ca(BF₄)₂·xH₂O has been determined from laboratory powder diffraction data. The water molecules all belong to [CaO₄F₄] square antiprisms sharing F corners with [BF₄] tetrahedra, forming a mono-dimensional structure of infinite ribbons interconnected by H...F and H...O hydrogen bonds. No place is found for interstitial water molecules, so that the compound has to be reformulated as Ca(H₂O)₄(BF₄)₂, which is isostructural with calcium perchlorate tetrahydrate, Ca(ClO₄)₂·4H₂O.

The salts 2-amino-4-methoxy-6-methylpyrimidinium N-methylsulfamate, C₆H₁₀N₃O⁺·CH₄NO₃S^-, I, and 2-amino-4-methoxy-6-methylpyrimidinium 4-hydroxybenzoate, C₆H₁₀N₃O⁺·C₇H₅O₃^-, II, have been synthesized and characterized by single-crystal X-ray diffraction. The protonation process takes place in both salts from acid to base. In both salts, the ring and amine N atoms, and the sulfoxide and carboxylate O atoms form eight-membered R₂²(8) ring motifs. The nature of the different types of interactions present in the crystals have been explored using Hirshfeld surface analysis. The percentage contributions of the different interactions in the crystal structures have been calculated using 2D fingerprint plots. The volumes of the voids present in salts I and II are 233.25 and 398.48 ų, respectively. The band gap energies (ΔE) of salts I and II are 3.2022 and 3.5357 eV, respectively, as calculated by frontier molecular orbital (FMO) analysis. In Bader's quantum theory of atoms in molecules (QTAIM) analysis, the values of the electron density [ρ(r_cp)] and the Laplacian of the electron density [∇²ρ(r_cp)] at the protonated region of salt I are 0.261 e Å^-3 and 2.889 e Å^-5, respectively, and for salt II are 0.357 e Å^-3 and 3.2 e Å^-5. The pharmacokinetic properties and drug-like nature of the salts were confirmed by in-silico ADME (Absorption, Distribution, Metabolism and Excretion) prediction.