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June 2019 issue
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Rare-earth-transition metal pnictides and related compounds are intriguing materials with a wide range of possible applications. Gd6FeBi2 [Zhang et al. (2019). Acta Cryst. C75, 562–567] might be useful for a plethora of applications and this article may help to initiate first efforts in that direction.
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The structure of α-D-mannopyranosyl-(1→3)-2-O-acetyl-β-D-mannopyranoside monohydrate is reported. Conformational analysis with NMR studies is discussed.
CCDC reference: 1908451
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Synthesized Cu2+-doped 3,14-diethyl-2,13-diaza-6,17-diazoniatricyclo[16.4.0.07,12]docosane bis(perchlorate) was characterized by EPR spectroscopy, single-crystal X-ray diffraction and Hirshfeld surface analysis.
CCDC reference: 1897287
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Four new thiazolidin-4-one derivatives were prepared in four steps from a natural product (β-himachalene) isolated from the essential oil of Cedrus atlantica. The crystal structure of one of them has been determined by single-crystal X-ray diffraction methods.
CCDC reference: 1911992
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The structures of seven divalent metal cation compounds of Ponceau Xylidine (PX) and five of Crystal Scarlet (CS) are presented. It is suggested that CS is a better ligand than PX for transition metals.
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Two new CdII coordination polymers based on 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole (imb) and benzenedicarboxylic acid (H2bdic) isomers have been prepared and structurally characterized. The CdII ions are linked by imb ligands in one polymer to generate a one-dimensional chain, while the CdII ions are bridged by the imb ligands and m-bdic2− anions simultaneously in the other polymer, leading to a two-dimensional network structure.
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Dibenzo[b,e]azepines and dibenzo[b,f]azocines formed concurrently by reaction of 2-allyl-N-benzylanilines with sulfuric acid are converted into key intermediates for the synthesis of bioactive polycyclic compounds. Molecular structures and supramolecular assemblies are described for two such compounds.
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Reaction of the flexible phenolic carboxylate ligand 2-(3,5-dicarboxylbenzyloxy)benzoic acid (H3L) with nickel salts in the presence of 1,2-bis(pyridin-4-yl)ethylene (bpe) leads to the generation of a mixture of two complexes under solvolthermal conditions. An interesting metal/ligand-induced crystal-to-crystal transformation was observed between the two complexes.
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For the first time, a cocrystal of the so-called calix[4]tube with a template bioactive compound belonging to the biologically relevant benzothiazole class has been observed, together with three new polymorphs of the same benzothiazole exhibiting infrequent packing polymorphism with high Z′ (one with Z′ = 8 and two with Z′ = 4).
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A probably wrong interpretation of a previously determined structure of the title compound is discussed and an alternative more convincing description is presented.
CCDC reference: 1910784
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The title compound exhibits concomitant polymorphism, giving forms in space groups Cc and Pna21. The molecules in the monoclinic polymorph are linked into a three-dimensional assembly by C—H⋯N, C—H⋯π(arene) and C—Cl⋯π(arene) interactions, but these latter interactions are absent from the orthorhombic polymorph, where the hydrogen-bonded supramolecular assembly is two-dimensional.
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A new polymorph of the title compound was discovered and its pattern of intermolecular interactions was also probed by 13C ss-NMR. Cytotoxicity against three cancer cell lines was evaluated for three symmetric bischalcones. These compounds were characterized by 1H and 13C NMR spectroscopy, mass spectrometry and IR spectroscopy.
CCDC reference: 1913498
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The crystal structure of BiGaTi4O11 was analysed by X-ray diffraction for a single crystal prepared by heating a mixture of the constituent binary oxides at 1373 K in air. The structure is a new type and Ga and Ti atoms statistically occupy distorted oxygen octahedra.
CCDC reference: 1913005
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Curvature functions at the Hirshfeld surface of metallic centres in coordination polymers are used to understand details of metal–ligand interactions.
CCDC reference: 1912697
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A five-coordinate pyridine N-oxide–5,10,15,20-tetraphenylporphyrinate–iron(III) complex was isolated and its crystal structure has been determined. The porphyrin core is moderately saddled. This complex provides a rare example of a five-coordinate iron(III) porphyrin complex that is coordinated to a neutral organic ligand through an O-monodentate binding mode.
CCDC reference: 1906085
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Two new isostructural 3d–4f coordination compounds based on pyridine-2,6-dicarboxylic acid and 4,4′-bipyridine have been synthesized under hydrothermal conditions. Both have a trinuclear molecular structure in which the EuIII and TbIII cations adopt nine-coordinated trigonal–prismatic geometries.
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The crystal structures of three quinuclidine-based compounds, synthesized through a catalyst-free route, are reported. Analysis of the hydrogen-bond interactions allows us to understand the symmetry properties of the crystal structures.
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The synthesis and X-ray structure of a new pentacoordinated cationic NHC-pincer NiII complex is reported. Density functional theory calculations provided an insight into the bonding
CCDC reference: 1911358
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Crystals with the La18W10O57-type structure were obtained by the self-flux method from high-temperature solutions in the Li2O–La2O3–WO3 system. The co-existence of two phases was revealed in one crystal (6H and 5H polytypes), with the space groups P2c and P321, which were different with respect to the character of the superstructure ordering.
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Two new N-oxide compounds, glycinium 2-carboxy-1-(λ1-oxidaneyl)-1λ4-pyridine-6-carboxylate–glycine–water (1/1/1) and methyl 6-carboxy-1-(λ1-oxidaneyl)-1λ4-pyridine-2-carboxylate, were prepared and identified by elemental analysis, FT–IR, Raman spectroscopy and single-crystal X-ray diffraction.
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4,4′-{9,9′-Spirobi[10H-acridine]-10,10′-diyl}dibenzoic acid was designed and synthesized as a new donor–acceptor motif molecule and applied as a ligand with Cd as a metal connector to form a one-dimensional coordination polymer. Both the ligand and the polymer present a sky-blue TADF emission, together with a photoluminescence quantum yield of 40%.
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5-Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde readily undergoes nucleophilic substitution to form the corresponding 5-aryloxy derivatives which can be converted in two further steps to reduced 3,4′-bipyrazoles. Different combinations of C—H⋯N, C—H⋯O and C—H⋯π hydrogen bonds lead to supramolecular assemblies in zero, one and two dimensions.
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Single crystals of a novel hydrogen vanadate were prepared by a simple hydrothermal method. DC magnetic investigation revealed an antiferromagnetic behaviour.
CCDC reference: 1916824
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A new crystal form of dexketoprofen, the S-enantiomer of ketoprofen, has been characterized in the solid state by SCXRD, DSC and computational methods. A comparison with the already known α form of dexketoprofen is also presented. The thermal behaviour of both polymorphs has been investigated by means of variable-temperature single-crystal and microcrystalline powder X-ray diffraction.
CCDC reference: 1914726
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Six new solid-state forms of the endogenous N-methyl-D-aspartate (NMDA) receptor antagonist kynurenic acid (KYN), one of which is a new polymorph of KYN monohydrate, have been synthesized and studied with respect to their structural and thermal properties. KYN adopts three different conformations and appears as the enol and keto tautomers and as the zwitterion.
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A new host–guest system C4H8O@Cd-MOF that encapsulates butan-2-one molecules was obtained via a single-crystal-to-single-crystal transformation and characterized by single-crystal X-ray diffraction, 1H NMR, IR, TGA and powder X-ray diffraction analysis. The specific binding sites for butan-2-one in the host were determined.
CCDC reference: 1915526
SnS2–SnO2 heterojunctions assembled on graphene nanosheets were prepared by a two-step hydrothermal method. Due to the enhanced visible-light absorption, efficient separation of photo-generated holes and electrons, and the excellent electron accepting and transporting properties of graphene, the as-synthesized SnS2–SnO2/RGO nanocomposites with an optimized hydrothermal reaction time displayed an excellent photodegradation rate of RhB under visible-light irradiation.
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Three 3-(3-phenyl-1H-1,2,4-triazol-5-yl)-2H-1-benzopyran-2-one polymorphic modifications have been studied. The differences between the crystals were analyzed using a method based on a comparison of the pairwise interaction energies between neighbouring molecules in the crystal phase.