De-Hong Wu

Bis(benzyl­trimethyl­ammonium) tetra­bromidocuprate(II)

In the title molecular salt, (C10H16N)2[CuBr4], the CuII ion adopts a squashed tetrahedral geometry with Br—Cu—Br angles varying between 99.29 (3) and 132.53 (3)°. In the crystal, the components are linked by C—H⋯Br interactions, thereby generating a three-dimensional network.

4-Ethyl­anilinium 2-carb­oxy­acetate

In the crystal structure of the title compound, C8H12N+·C3H3O4 −, the hydrogen malonate anions are linked into infinite chains parallel to the b axis by intermolecular O—H⋯O hydrogen bonds of the type COO−⋯HO2C in a head-to-tail fashion. The 4-ethylanilinium cations link adjacent anion chains by intermolecular N—H⋯O hydrogen bonds into a two-dimensional network parallel to the b and c axes.

4-Cyano-benzaldehyde thio-semi-carbazone.

The molecule of the title compound, C9H8N4S, adopts an E configuration about both the C=N and C—NH bonds. In the crystal structure, adjacent molecules are linked by intermolecular N—H⋯S hydrogen-bonding interactions, forming chains running parallel to the b axis.

4-Ethyl­anilinium perchlorate–18-crown-6 (1/1)

The asymmetric unit of the title compound, C8H12N+·ClO4 −.C12H24O6, contains one half of the cationic [(C2H5—C6H4—NH3)(18-crown-6)]+ moiety and one half of the ClO4 − anion. Two O atoms of the crown ether, four C atoms and the N atom of the ethylanilinium unit and the Cl and two O atoms of the anion lie on a mirror plane. In the crystal structure, the –NH3 + group lies in the 18-crown-6 ring, forming a supramolecular rotator–stator-like structure linked by intramolecular N—H⋯O hydrogen bonds. The six O atoms of the crown ether lie approximately in a plane, the mean deviation being 0.1771 (3) Å; the N atom lies approximately 0.855 (3) Å from the centroid of the crown ether ring.

Ammonium hexa-fluorido-phosphate-18-crown-6 (1/1).

In the crystal structure of the title compound, NH4 +·PF6 −·C12H24O6, the cation is situated in the 18-crown-6 ring, forming a supramolecular rotator-stator-like structure held by N—H⋯O hydrogen bonds. The six O atoms of the crown ether lie approximately in a plane [mean deviation 0.2129 (3) Å]; the N atom is displaced by 0.864 (3)Å from the centroid of the 18-crown-6 ring. The slightly distorted tetrahedral cations further interact with the slightly distorted octahedral anions via intermolecular N—H⋯F hydrogen bonds.

N,N′-Bis[(E)-4-cyano­benzyl­idene]urea

The molecule of the title compound, C17H10N4O, has crystallographically imposed C 2 symmetry. The urea group and the benzene ring are nearly coplanar, the dihedral angle between them being 4.15 (7)°. The crystal packing is stabilized by aromatic π–π stacking interactions, with a centroid-to-centroid separation of 3.833 (4) Å.

Ethyl 4-(4-cyano­phen­yl)-6-methyl-2-thioxo-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate

The asymmetric unit of the title compound, C15H15N3O2S, contains two independent molecules corresponding to the R and S enantiomers. The dihydropyrimidinone rings adopt a flattened boat conformation. One of the ethyl groups is disordered over two orientations with occupancy factors of 0.700 (7) and 0.300 (7). In the crystal structure, molecules are linked by intermolecular N—H⋯O hydrogen-bonding interactions into one-dimensional chains along the c-axis direction. The chains are further connected by N—H⋯S hydrogen bonds, forming a three-dimensional network.

1,4-Bis(benzimidazol-2-yl)benzene dimethyl­formamide disolvate

The aromatic molecule of the title compound, C20H14N4·2C3H7NO, occupies a special position on an inversion center. The benzimidazole unit (planar to within 0.008 Å) forms a dihedral angle of 9.1 (2)° with the central benzene ring. The benzimidazole H atom participates in a hydrogen bond with the dimethylformamide solvent molecule, thus giving rise to the title 1:2 aggregate. These aggregates are further linked in the crystal structure by aromatic π–π stacking interactions [centroid–centroid distance = 6.356 (2) Å].

4-Ethyl­anilinium 4-methyl­benzene­sulfonate

In the crystal structure of the title molecular salt, C8H12N+·C7H7O3S−, the 4-ethylanilinium cations and 4-methylbenzenesulfonate anions are linked into chains parallel to the b axis by intermolecular N—H⋯O hydrogen bonds.

3,5-Bis(ethoxy­carbon­yl)-2,6-dimethyl-1,4-dihydro­pyridine-4-carboxylic acid

The title molecule, C14H19NO6, was synthesized by the reaction of glyoxylic acid, ethyl acetoacetate and NH4HCO3. In the crystal structure, the dihydropyridine ring adopts an asymmetric boat-type conformation with the C atom bearing the carboxyl group showing a signficantly larger deviation [0.325 (2) Å] from the base plane then the N atom [0.137 (2) Å]. One of the ethyl groups is disordered over two positions with occupancies of 0.741 (10) and 0.259 (10). The crystal is stabilized by strong intermolecular hydrogen bonds. N—H⋯O interactions form infinite chains in the a direction. O—H⋯O hydrogen bonds form typical carboxylic acid dimers, which link the N—H⋯O chains into a ladder-type double chain.