Acta Crystallographica Section C Structural Chemistry最新文献

Reacting trimesic acid (H₃TMA, C₉H₆O₆) with CaCl₂ and MCl₂ at 110 °C under hydrothermal conditions gave the isostructural heterobimetallic coordination polymers (CPs) catena-poly[[tetraaquazinc(II)]-μ-5-carboxybenzene-1,3-dicarboxylato-[tetraaquacalcium(II)]-μ-5-carboxybenzene-1,3-dicarboxylato], [CaZn(HTMA)₂(H₂O)₈]_n, 1, and catena-poly[[tetraaquacobalt(II)]-μ-5-carboxybenzene-1,3-dicarboxylato-[tetraaquacalcium(II)]-μ-5-carboxybenzene-1,3-dicarboxylato], [CaCo(HTMA)₂(H₂O)₈]_n, 2. Compounds 1 and 2 crystallize in the monoclinic space group C2/c. The solid-state structures consist of eight-coordinate Ca^II ions and six-coordinate M^II ions. These ions are connected by a doubly deprotonated HTMA^2- ligand to create a one-dimensional (1D) zigzag chain. Poly[[decaaquabis(μ₃-benzene-1,3,5-tricarboxylato)calcium(II)dizinc(II)] dihydrate], {[CaZn₂(TMA)₂(H₂O)₁₀]·2H₂O}_n, 3, was found incidentally as a minor by-product during the synthesis of 1 at a temperature of 140 °C. It forms crystals in the orthorhombic space group Ccce. The structure of 3 consists of a two-dimensional (2D) layer composed of [Zn(TMA)] chains that are interconnected by Ca^II ions. The presence of aromatic carboxylic acid ligands and water molecules, which can form numerous hydrogen bonds and π-π interactions, increases the stability of the three-dimensional (3D) supramolecular architecture of these CPs. Compounds 1 and 2 exhibit thermal stability up to 420 °C, as indicated by the thermogravimetric analysis (TGA) curves. The powder X-ray diffraction (PXRD) data reveal the formation of unidentified phases in methanol and dimethyl sulfoxide, while 1 exhibits chemical stability in a wide range of solvents. The luminescence properties of 1 dispersed in various low molecular weight organic solvents was also examined. The results demonstrate excellent selectivity, sensitivity and recyclability for detecting acetone molecules in aqueous media. Additionally, a possible sensing mechanism is also outlined.

We report on the latest advancements in Microcrystal Electron Diffraction (3D ED/MicroED), as discussed during a symposium at the National Center for CryoEM Access and Training housed at the New York Structural Biology Center. This snapshot describes cutting-edge developments in various facets of the field and identifies potential avenues for continued progress. Key sections discuss instrumentation access, research applications for small molecules and biomacromolecules, data collection hardware and software, data reduction software, and finally reporting and validation. 3D ED/MicroED is still early in its wide adoption by the structural science community with ample opportunities for expansion, growth, and innovation.

The ternary germanide Mg_5.57Ni₁₆Ge_7.43 (cubic, space group Fm-3m, cF116) belongs to the structural family based on the Th₆Mn₂₃-type. The Ge1 and Ge2 atoms fully occupy the 4a (m-3m symmetry) and 24d (m.mm) sites, respectively. The Ni1 and Ni2 atoms both fully occupy two 32f sites (.3m symmetry). The Mg/Ge statistical mixture occupies the 24e site with 4m.m symmetry. The structure of the title compound contains a three-core-shell cluster. At (0,0,0), there is a Ge1 atom which is surrounded by eight Ni atoms at the vertices of a cube and consequently six Mg atoms at the vertices of an octahedron. These surrounded eight Ni and six Mg atoms form a [Ge1Ni₈(Mg/Ge)₆] rhombic dodecahedron with a coordination number of 14. The [GeNi₈(Mg/Ge)₆] rhombic dodecahedron is encapsulated within the [Ni₂₄] rhombicuboctahedron, which is again encapsulated within an [Ni₃₂(Mg/Ge)₂₄] pentacontatetrahedron; thus, the three-core-shell cluster [GeNi₈(Mg/Ge)₆@Ni₂₄@Ni₃₂(Mg/Ge)₂₄] results. The pentacontatetrahedron is a new representative of Pavlyuk's polyhedra group based on pentagonal, tetragonal and trigonal faces. The dominance of the metallic type of bonding between atoms in the Mg_5.57Ni₁₆Ge_7.43 structure is confirmed by the results of the electronic structure calculations. The hydrogen sorption capacity of this intermetallic at 570 K reaches 0.70 wt% H₂.

Poly-stoichiometry of hydrated phases is relatively uncommon for organic materials and extended libraries of such species adopting different aqua-to-substrate ratios are still rare. The kinetically controlled higher hydrates could be particularly interesting for their structural relationships, which presumably may imprint some features of the substrate/substrate and aqua/substrate bonding in solutions, and provide insights into the nucleation stage. Two metastable high hydrates are prepared by crash crystallization. The crystal structures of 3,3',5,5'-tetranitro-4,4'-bipyrazole tetrahydrate, C₆H₂N₈O₈·4H₂O, (1), and 3,3',5,5'-tetranitro-4,4'-bipyrazole pentahydrate, C₆H₂N₈O₈·5H₂O, (2), are intrinsically related to the previously reported anhydrate and monohydrate, while displaying natural evolution of the patterns upon progressive watering. The accumulation of the water molecules causes their clustering, with the generation of one-dimensional tapes and two-dimensional layers in the genuine channel hydrates (1) and (2), respectively, versus the pocket hydrate structure of C₆H₂N₈O₈·H₂O. The hydration primarily affects the pyrazole sites. It conditions the emergence of N-H...O and O-H...N hydrogen bonds, which is a destructive factor for pyrazole/pyrazole N-H...N hydrogen bonding. At the same time, extensive noncovalent interactions of the organic molecules, namely, lone pair-π-hole O...N interactions of the NO₂/NO₂ and NO₂/pyrazole types, are more competitive to the hydrogen bonding and the motifs of mutual organic/organic stacks remain intact with the increase in hydration. These trends agree with the results of Hirshfeld surface analysis. The contributions of the contacts involving H atoms are increased in line with the growing number of water molecules, while the fraction of O...N/N...O (NO₂) contacts is nearly invariant. One may postulate the significance of the lone pair-π-hole interactions to the aggregation of nitro species in solutions and their relevance for the sebsequent development of the solid-state patterns through nucleation.

Six new pyrimidin-2-yl-substituted triaryltriazoles, namely, 4-(4-R-phenyl)-3-(pyridin-2-yl)-5-(pyrimidin-2-yl)-1,2,4-triazoles [L¹: R = methoxy (OCH₃); L²: R = methyl (CH₃); L³: R = nil (H); L⁴: R = bromo (Br); L⁵: R = chloro (Cl); L⁶: R = fluoro (F)] have been successfully synthesized with yields in the range 68.3-81.7%. Compounds L^1-6 have been characterized by UV-Vis, FT-IR, ¹H NMR and ESI-MS spectroscopy, and elemental analysis. In addition, the structures of L^2-6 and the ethanol monosolvate of L² (L²·C₂H₅OH) have been determined by single-crystal X-ray diffraction. A combination of intermolecular O-H...N, C-H...O, C-H...N and C-H...π hydrogen bonds connects the components of L²·C₂H₅OH into a three-dimensional (3D) framework. A combination of three intermolecular C-H...N hydrogen bonds links the molecules of L² or L³ into two different 3D networks. Both L⁴ and L⁵ show a similar 3D net structure through two intermolecular C-H...N hydrogen bonds and one kind of C-H...π interaction. However, L⁶ displays a more complicated 3D net structure via three intermolecular C-H...N hydrogen bonds and one kind of C-H...π interaction. Notably, an interaction between the π-electrons and the lone-pair p-electrons of a halogen atom (Br, Cl and F) is observed in L^4-6, which will further stabilize the 3D networks. The intermolecular interactions in L²·C₂H₅OH and L^2-6 were further investigated by 3D Hirshfeld surface analyses and 2D fingerprint plots to show that the prominent interactions are H...H, N...H/H...N and C...H/H...C contacts.

A newly synthesized N,N'-dipropyl-substituted isoindigo derivative, namely, 1-propyl-3-(1-propyl-1,2-dihydro-2-oxo-3H-indol-3-ylidene)-1,3-dihydro-2H-indol-2-one, C₂₂H₂₂N₂O₂, was found to have three polymorphic forms (denoted Forms I, II and III) under various crystallization conditions. Crystal structure analysis indicated that Form III had a significantly different molecular conformation from the other two polymorphs. Their different packing arrangements were correlated with differences in the intermolecular interactions. Thermal measurements revealed that Forms I and II are enantiotropically related, and Form II exhibits thermally dynamic behaviour.

A novel Zn^II coordination polymer, namely, poly[{μ₂-bis[4-(2-methyl-1H-imidazol-1-yl)phenyl]methanone-κ²N³:N^3'}(μ₂-5-bromobenzene-1,3-dicarboxylato-κ²O¹:O³)zinc(II)], [Zn(C₈H₃BrO₄)(C₂₁H₁₈N₄O)]_n or [Zn(Br-BDC)(MIPMO)]_n, (I), has been synthesized by the solvothermal method using 5-bromoisophthalic acid (Br-H₂BDC), bis[4-(2-methyl-1H-imidazol-1-yl)phenyl]methanone (MIPMO) and Zn(NO₃)₂·6H₂O. Structure analysis showed that compound (I) displays twofold parallel interwoven sql nets. Fluorescence experiments confirmed that the compound can sensitively and selectively detect nitrofurantoin (NFT) in aqueous medium. In addition, the possible fluorescence quenching mechanisms of compound (I) toward NFT are investigated.

A confiscated package of street drugs was characterized by the usual mass spectral (MS) and FT-IR analyses. The confiscated powder material was highly crystalline and was found to consist of two very different species, accidentally of sizes convenient for X-ray diffraction. Thus, one each was selected and redundant complete sets of data were collected at 100 K using Cu Kα radiation. The selected crystals contained: (a) 1,2-diphenyl-2-(pyrrolidin-1-yl)ethanone hydrochloride hemihydrate or 1-(2-oxo-1,2-diphenylethyl)pyrrolidin-1-ium chloride hemihydrate, C₁₈H₂₀NO⁺·Cl^-·0.5H₂O, (I), a synthetic cathinone called `α-D2PV', and (b) the sugar myo-inositol, C₆H₁₂O₆, (II), probably the only instance in which the drug and its diluent have been fully characterized from a single confiscated sample. Moreover, the structural details of both are rather attractive showing: (i) interesting hydrogen bonding observed in pairwise interactions by the drug molecules, mediated by the chloride counter-anions and the waters of crystallization, and (ii) π-π interactions in the case of the phenyl rings of the drug which are of two different types, namely, π-π stacking and edge-to-π. Finally, the inositol crystallizes with Z' = 2 and the resulting diastereoisomers were examined by overlay techniques.

Silver nitrate reacts with 6-methylmercaptopurine riboside (6-MMPR) in aqueous solution containing methanol and dimethyl sulfoxide at room temperature to give a colourless crystalline complex, namely, bis(6-methylmercaptopurine riboside-κN⁷)(nitrato-κ²O,O')silver(I) 2.32-hydrate, [Ag(NO₃)(C₁₁H₁₄N₄O₄S)₂]·2.32H₂O. The crystal structure, determined from synchrotron diffraction data, shows a central Ag^I ion on a crystallographic twofold rotation axis, coordinated in an almost linear fashion by two 6-MMPR ligands via atom N7 (purine numbering), with the nitrate counter-ion loosely coordinated as a bidentate ligand, forming a discrete molecular complex as an approximate dihydrate. The complex and water molecules are connected in a three-dimensional network by hydrogen bonding.