Twinned L-aspartic acid

The natural amino acid L-aspartic acid contains two carboxylic acid groups, and the crystal structures are characterized by strong intermolecular hydrogen bonds between these groups. Data quality and proper handling of the twinning are essential for the analysis of the protonation states.

Synthesis and crystal structure of bis­(levofloxacindiium) di­aqua­tetra-μ-chlorido-penta­chlorido­tricopper(II) chloride

A trinuclear copper(II)–levofloxacin complex, (C₁₈H₂₂FN₃O₄)₂[Cu₃Cl₉(H₂O)₂]Cl, was synthesized and its crystal structure determined. It features five-coordinated Cu^II centres with Jahn–Teller distortion and a three-dimensional hydrogen-bonded supra­molecular network.

Cyanidotris(1,3,5-tri­aza-7-phosphaadamantane)silver(I) tetra­hydrate

The compound is a neutral discrete complex where the silver(I) center is coordinated by three phospho­rus atoms from three distinct PTA ligands and one carbon atom from the nitrile ion, resulting in a distorted tetra­hedral geometry around the Ag centre.

2-Fluoro­benzyl (Z)-2-(5-chloro-2-oxoindolin-3-yl­idene)hydrazine-1-carbodi­thio­ate di­methyl sulfoxide monosolvate

The packing of the title solvate features hetero-halogen⋯halogen (Cl⋯F), and chalcogen (S⋯O) bonding, as well as non-standard offset π–π stacking.

Monoclinic polymorph of 2-aza­niumylmethyl-1H-benzimidazol-3-ium dichloride monohydrate

The title hydrated salt, a new monoclinic polymorph, crystallizes in space group P2₁/c. The components pack in sheets in the ab plane and these sheets are hydrogen bonded to their neighbours, generating a three-dimensional network.

(1R*,2R*,5R*,6S*)-6-Bromo-9-oxabi­cyclo­[3.3.1]nonan-2-ol

Both six-membered rings in the title bi­cyclo­[3.3.1] system, adopt a chair conformation. Hydrogen bonds from the hy­droxy group to the ether bridge connect the mol­ecules into zigzag chains: single-enantiomer chains propagating along the b-axis direction form the crystal.

2-Phenyl-4,5-di-p-tolyl-1H-imidazol-3-ium picrate

The title mol­ecular salt, C₂₃H₂₁N₂⁺·C₆H₂N₃O₇⁻, featuring discrete ion pairs, crystallizes from ethanol through slow solvent evaporation. In the crystal, the imidazolium cation and the picrate anion are linked by N—H⋯O hydrogen bonds as a result of proton transfer from picric acid to the pyrimidine-type nitro­gen atom of the imidazole ring.

2-Chloro-4-hy­droxy­anilinium chloride

The title compound crystallizes in ortho­rhom­bic space group Pnma with both cations and anions lying on a mirror plane in the crystal. Parallel mol­ecules form stacks with inter­planar spacing 3.1473 (2) Å, but slipped by 1.97 Å.

4,5,6,7-Tetra­hydro­benzo[d]thia­zol-2-amine

In the title compound, the six-membered ring is disordered over two half-chair orientations. In the crystal, infinite [001] chains linked by N—H⋯N hydrogen bonds occur.

1,2-Bis[di­(benzo­furan-2-yl)phosphan­yl]ethane

A new electron-rich, bidentate phosphine, 1,2-bis­[di­(benzo­furan-2-yl)phosphan­yl]ethane, was synthesized and structurally characterized by single-crystal X-ray diffraction.

N′-[(E)-5-Oxopyrrolidin-2-yl­idene]pyridine-2-carbohydrazide

In the title compound, the dihedral angle between the planes of the pyridine and oxo­pyrroli­dine rings is 6.9 (2)°. In the crystal, inversion dimers linked by pairwise N—H⋯O hydrogen bonds generate R₂²(14) loops.

N′-(2,6-Di­methyl­phen­yl)-N-phenyl­methanimidamide

The extended structure of the title compound features strong N—H⋯N hydrogen bonds forming infinite C(4) chains propagating along the c-axis direction.

2-Oxo-2H-chromen-7-yl penta­noate

In the title compound, C₁₄H₁₄O₄, the dihedral angle between the coumarin nucleus and the penta­noate moiety is 84.6 (9)°. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds into centrosymmetric dimers with an R₂²(8) graph-set motif, and π–π inter­actions are also observed.

4-Methyl-N-[2-(2-phenyl­ethyn­yl)phen­yl]-N-(prop-2-yn-1-yl)benzene-1-sulfonamide

The title compound, C₂₄H₁₉NO₂S, was prepared by propargylation of the sulfonamide. The tolyl group points to the planar tolane unit. In the extended structure, two inter­molecular hydrogen bridges connect the mol­ecules to form chains.

4,4′-(Acridine-2,7-di­yl)bis­(2-methyl­but-3-yn-2-ol)

The title acridine derivative, which has two 2-methyl­but-3-yn-2-ol moieties at the 2,7-positions, was synthesized by Sonogashira coupling reaction. In crystal, a columnar structure is formed by the π–π stacking of acridine units. The 2-methyl­but-3-yn-2-ol moieties form inter­molecular hydrogen bonds.