Synthesis, crystal structure and conformational analysis of an unexpected [1,5]di­thio­cine product of amino­pyridine and thio­vanillin

The synthesis of a novel N-alkyl­ated [1,5]di­thio­cine from 3-amino­pyridine and 2-mercapto-3-meth­oxy­benzaldehyde is reported, together with a structural and com­putational analysis of the unexpected product.

Inter­actions in flavanone and chalcone derivatives: Hirshfeld surface analysis, energy frameworks and global reactivity descriptors

The supra­molecular features of the crystal structures of a series of flavanones and chalcones are discussed using the Hirshfeld surface approach, together with a lattice energy analysis and electronic mol­ecular properties based on DFT global reactivity descriptors.

Structure determination of a new cocrystal of carbamazepine and DL-tartaric acid by synchrotron powder X-ray diffraction

The crystal structure of a new cocrystal of carbamazepine and DL-tartaric acid obtained by liquid-assisted grinding was solved by synchrotron powder X-ray diffraction. The starting structural model was generated by a Monte-Carlo simulated annealing method. The final structure was obtained through Rietveld refinement and an energy minimization simulation was used to estimate the H-atom positions.

Phase transition and structures of the twinned low-temperature phases of (Et₄N)[ReS₄]

The crystal structures of three phases of [(C₂H₅)₄N][ReS₄] were determined by single-crystal X-ray diffraction analysis at different temperatures.

Synthesis, crystal structures and magnetic and electrochemiluminescence properties of three manganese(II) com­plexes

Three novel manganese com­plexes have been synthesized using solvothermal methods. Two are tetra­nuclear manganese clusters, while the third has a one-dimensional network based on tetra­nuclear building units. All three com­plexes display favourable electrochemiluminescence (ECL) properties.

A new hydrate of magnesium carbonate, MgCO₃·6H₂O

The formation of a previously unknown higher hydrated magnesium carbonate, MgCO₃·6H₂O, was confirmed. Its crystal structure differs from the other known magnesium carbonates significantly, but it exhibits similarities to NiCO₃·5.5H₂O.

Solvent influence on the crystal packing of 6-amino­thio­cytosine

The same principal inter­molecular motifs, i.e. triple-hydrogen-bonded chains of an alternating sequence of two symmetry-independent mol­ecules, have been found in the structures of 6-amino­thio­cytosine and two of its solvates. In all three structures, the cytosine mol­ecule forms infinite chains along the [100] direction.

Playing around with MP, a tool for the analysis of pseudosymmetry: recurrent appearance of local pseudo-space groups in the asymmetric unit of Z′ = 4 structures

A study, performed on a reduced sampling of the whole Z′ = 4 population in the CSD (∼300 cases accounting for ∼7% of the 4861 entries in the database), showed that ∼8% of the analyzed sample (24 cases) presented in their asymmetric units pseudosymmetries which resemble, with surprising accuracy, the disposition of real symmetry elements in 3D space groups.

Characterization, crystal structure and cytotoxic activity of a rare iridoid glycoside from Lonicera saccata

A new iridoid glycoside with a rare structure having a glycosyl moiety at C-3 was obtained from Lonicera saccata, and its structure was established by spectroscopic methods and single-crystal X-ray diffraction. Its cytotoxic activity was evaluated by the MTT method.

Twist-chair conformation of the tetra­oxepane ring remains unchanged in tetra­oxa­spiro­dodecane di­amines

A seven-membered ring with two peroxide groups adopts a twist-chair conformation in three 7,8,11,12-tetra­oxa­spiro­[5.6]dodecane-9,10-di­amines. Halogen atoms and their positions have a slight effect on the geometric parameters, stereoelectronic effects and crystal packing of these com­pounds, so that the twist-chair conformation of the tetra­oxepane ring remains unchanged.

Glycosidic linkage, N-acetyl side-chain, and other structural properties of methyl 2-acetamido-2-de­oxy-β-D-gluco­pyranosyl-(1→4)-β-D-manno­pyran­oside monohydrate and related com­pounds

The crystal structure of methyl 2-acetamido-2-de­oxy-β-D-gluco­pyranosyl-(1→4)-β-D-manno­pyran­oside monohydrate was determined and com­pared with those of structurally related mono- and disaccharides. Hydrogen bonding in the N-acetyl side-chain introduces systematic changes in the N—H and C=O bond lengths that were recapitulated by density functional theory calculations.

Serendipity: Werner's argument that the `two-only forms' (green and violet) of [CoCl₂(en)₂]⁺ salts demanded his octa­hedral model was correct. True?

Chemists of the late 19th century, including Alfred Werner, prepared salts containing either green or violet cations of com­position [CoCl₂(en)₂]⁺ (en is ethyl­enedi­amine); we now refer to these as trans-di­chloro and cis-di­chloro species. We have discovered a third salt, purple in color, containing cations of the same elemental com­position and whose asymmetric unit com­position is [CoCl₂(en)₂]₂Cl₂·3H₂O.

Novel K/Mn phosphate hydrates, K₂Mn₃(H₂O)₂[P₂O₇]₂ and KMn(H₂O)₂[Al₂(PO₄)₃]: hydro­thermal synthesis and crystal chemistry

Two novel com­pounds, namely, K₂Mn₃(H₂O)₂[P₂O₇]₂ and KMn(H₂O)₂[Al₂(PO₄)₃], are members of the A₂M₃(H₂O)₂[P₂O₇]₂ and AM²⁺(H₂O)₂[M³⁺₂(PO₄)₃] morphotropic series with atoms of alkali (A) and first-row transition (M) metals. A study of the magnetic susceptibility of KMn(H₂O)₂[Al₂(PO₄)₃] revealed its paramagnetic behaviour.

Tolerance factor and phase stability of the garnet structure. Corrigendum

Corrigendum to Acta Cryst. (2019), C75, 1353–1358.