Understanding of magnetic ordering in Gd-rich compounds

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.

Conformational analysis of the disaccharide methyl α-D-manno­pyranosyl-(1→3)-2-O-acetyl-β-D-manno­pyran­oside monohydrate

The structure of α-D-manno­pyranosyl-(1→3)-2-O-acetyl-β-D-manno­pyran­oside monohydrate is reported. Conformational analysis with NMR studies is discussed.

Synthesis, structural characterization, EPR spectros­copy and Hirshfeld surface analysis of a novel Cu²⁺-doped 3,14-di­ethyl-2,13-di­aza-6,17-diazo­niatri­cyclo­[16.4.0.0^7,12]do­cosane bis­(perchlorate)

Synthesized Cu²⁺-doped 3,14-diethyl-2,13-di­aza-6,17-diazo­niatri­cyclo­[16.4.0.0^7,12]docosane bis­(perchlorate) was characterized by EPR spectroscopy, single-crystal X-ray diffraction and Hirshfeld surface analysis.

Hemisynthesis, crystal structure and inhibitory effect of sesquiterpenic thio­semicarbazones and thia­zolidin-4-ones on the corrosion behaviour of stainless steel in 1 M H₂SO₄ solution

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.

Di­sulfonated azo dyes: metal coordination and ion-pair separation in twelve M^II compounds of Ponceau Xylidine and Crystal Scarlet

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.

Effects of two benzene­dicarb­oxy­lic acids on the construction of Cd^II coordination polymers incorporating a flexible N-donor ligand

Two new Cd^II 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 Cd^II ions are linked by imb ligands in one polymer to generate a one-dimensional chain, while the Cd^II ions are bridged by the imb ligands and m-bdic²⁻ anions simultaneously in the other polymer, leading to a two-dimensional network structure.

A concise and efficient concurrent synthesis of 6,11-di­hydro­dibenzo[b,e]azepines and 5,6,11,12-tetra­hydro­dibenzo[b,f]azocines and their conversion to 4-oxo-8,13-di­hydro-4H-benzo[5,6]azepino[3,2,1-ij]quinoline-5-carboxyl­ates and N-acetyl-5,6,11,12-tetra­hydro­dibenzo[b,f]azocines: synthetic sequence, spectroscopic characterization and the structures of two products

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.

Killing two birds with one stone: 2D+2D→3D parallel stacking and 3D self-penetrating structures in one reaction and their crystal-to-crystal transformation

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.

Exploring the structural landscape of 2-(thio­phen-2-yl)-1,3-benzo­thia­zole: high-Z′ packing polymorphism and cocrystallization with calix[4]tube

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).

HBr or not HBr? That is the question: crystal structure of 6-hy­droxy-1,4-diazepane-1,4-diium dibromide redetermined

A probably wrong inter­pretation of a previously determined structure of the title compound is discussed and an alternative more convincing description is presented.

Monoclinic and ortho­rhom­bic forms of (RS)-(E)-4-[2-(4-chloro­benzyl­idene)hydrazin­yl]-6,11-di­methyl-6,11-di­hydro-5H-benzo[b]pyrimido[5,4-f]azepine: synthesis, concomitant polymorphism and supra­molecular assembly mediated by C—H⋯N, C—H⋯π(arene) and C—Cl⋯π(arene) inter­actions

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.

ss-NMR and single-crystal X-ray diffraction in the elucidation of a new polymorph of bis­chalcone (1E,4E)-1,5-bis­(4-fluoro­phen­yl)penta-1,4-dien-3-one

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.

Synthesis, crystal structure and properties of a quaternary oxide with a new structure type, BiGaTi₄O₁₁

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.

Understanding metal–ligand inter­actions in coordination polymers using Hirshfeld surface analysis

Curvature functions at the Hirshfeld surface of metallic centres in coordination polymers are used to understand details of metal–ligand inter­actions.

A five-coordinate iron(III) porphyrin complex including a neutral axial pyridine N-oxide ligand

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.

Synthesis and characterization of two isostructural 3d–4f coordination compounds based on pyridine-2,6-di­carb­oxy­lic acid and 4,4′-bi­pyridine

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 Eu^III and Tb^III cations adopt nine-coordinated trigonal–prismatic geometries.

Three new quinuclidine-based structures: second harmonic generation response for 1,2-bis­(1-azoniabi­cyclo­[2.2.2]octan-3-yl­idene)hydrazine dichloride

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.

Crystal structure and DFT analyses of a penta­coordinated PCP pincer nickel(II) complex

The synthesis and X-ray structure of a new penta­coordinated cationic NHC-pincer Ni^II complex is reported. Density functional theory calculations provided an insight into the bonding

Characteristic features of polytypism in compounds with the La₁₈W₁₀O₅₇-type structure

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.

Investigation of the effect of the N-oxidation process on the inter­action of selected pyridine compounds with biomacromolecules: structural, spectral, theoretical and docking studies

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.

Thermally activated delayed fluorescent (TADF) coordination polymer with the generation of singlet oxygen

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%.

Conversion of substituted 5-aryl­oxypyrazole­carbaldehydes into reduced 3,4′-bi­pyrazoles: synthesis and characterization, and the structures of four precursors and two products, and their supra­molecular assembly in zero, one and two dimensions

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.

Magnetic properties of a new cobalt hydrogen vanadate with a dumortierite-like structure: Co_13.5(OH)₆(H_0.5VO_3.5)₂(VO₄)₆

Single crystals of a novel hydrogen vanadate were prepared by a simple hydro­thermal method. DC magnetic investigation revealed an anti­ferromagnetic behaviour.

A new crystal form of the NSAID dexketoprofen

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.

Tautomeric polymorphism of the neuroactive inhibitor kynurenic acid

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.

Adsorption behaviour of a Cd^II–triazole MOF for butan-2-one in a single-crystal-to-single-crystal (SCSC) fashion: the role of hydrogen bonding and C—H⋯π inter­actions

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.

Construction of SnS₂–SnO₂ heterojunctions decorated on graphene nanosheets with enhanced visible-light photocatalytic performance

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.

Three polymorphs of 3-(3-phenyl-1H-1,2,4-triazol-5-yl)-2H-1-benzo­pyran-2-one formed from different solvents

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.