Samuel Robinson Jebas

4-Chloro-N′-[(Z)-4-(dimethyl­amino)benzyl­idene]benzohydrazide mono­hydrate

In the title compound, C16H16ClN3O·H2O, the dihedral angle between the two aromatic rings is 44.58 (11)°. The N atom of the dimethylamino group adopts a pyramidal configuration. In the crystal structure, molecules are linked into a two-dimensional network parallel to the (001) plane by intermolecular N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds involving the water molecule and C—H⋯Cl hydrogen bonds. In addition, C—H⋯π interactions are observed.

4-(4-Bromo­benzyl­ideneamino)-1-(diphenyl­amino­meth­yl)-3-[1-(4-isobutyl­phen­yl)eth­yl]-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C34H34BrN5S, the two phenyl rings of the diphenylaminomethyl group are inclined at an angle of 73.86 (8)° and they form dihedral angles of 74.04 (8) and 48.74 (8)° with the triazole ring. Intramolecular C—H⋯S hydrogen bonds generate S(6) and S(5) ring motifs. The crystal structure is stabilized by weak C—H⋯π interactions.

N′-[(Z)-4-(Dimethyl­amino)benzyl­idene]-4-nitro­benzohydrazide mono­hydrate

In the asymmetric unit of the title compound, C16H16N4O3·H2O, there are two symmetry-independent hydrazide molecules with almost identical geometries, and two independent water molecules. The dihedral angles between the two benzene rings in the two hydrazide molecules are 0.11 (5) and 0.77 (5)°. In one molecule, an intramolecular C—H⋯O hydrogen bond generates a ring of graph-set motif S(5). Intermolecular N—H⋯O, O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds and π–π stacking interactions between the benzene rings [centroid–centroid distances in the range 3.5021 (6)–3.6403 (6) Å] are observed, together with O⋯O [2.7226 (11) Å], O⋯N [2.7072 (10) Å] and N⋯O [2.7072 (10)–2.8582 (12) Å] short contacts. The hydrazine molecules are stacked along the b axis and adjacent molecules are linked by water molecules.

4-Amino-pyridinium hydrogen succinate.

In the title salt, C5H7N2 +·C4H5O4 −, the asymmetric unit comprises an aminopyridinium cation and a hydrogen succinate anion as protonation of the aromatic N atom of the 4-aminopyridine molecule has occurred. The crystal packing is stabilized by intermolecular O—H⋯O and N—H⋯O hydrogen bonds that lead to a two-dimensional array. Short C—H⋯O contacts are also present.

3-[1-(4-Isobutyl-phen-yl)eth-yl]-6-(4-methyl-phen-yl)-1,2,4-triazolo[3,4-b][1,3,4]thia-diazole.

In the title compound, C22H24N4S, the methylphenyl and isobutylphenyl rings are inclined at an angle of 79.98 (1)° and they form dihedral angles of 4.59 (1) and 75.47 (1)°, respectively, with the triazolothiadiazole unit. An intramolecular C—H⋯S hydrogen bond generates an S(5) ring motif. The crystal structure is stabilized by intermolecular C—H⋯N hydrogen bonds and weak C—H⋯π and π–π interactions [centroid–centroid distances between the thiadiazole ring and a symmetry-related phenyl ring and between the triazole ring and the phenyl ring range from 3.5680 (8) to 3.7313 (8) Å].

Bis[1-(2-hydroxy­ethyl)-2-methyl-5-nitro-1H-imidazole-κN3]silver(I) nitrate

In the title compound, [Ag(C6H9N3O3)2]NO3, the Ag atom is bicoordinated in a distorted linear configuration by two 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole ligands through one of the N atoms. The dihedral angle between the two imidazole rings is 16.1 (2)°. The O atoms of the nitrate anion are disordered over two positions; the site occupancy factors are 0.8 and 0.2. The ions are connected by C—H⋯O interactions, while two weak intramolecular C—H⋯O interactions producing an S(6) ring motif are observed. The nitrate anion is linked to the hydroxyl groups of two neighbouring cations by O—H⋯O hydrogen bonds. The ions are packed into infinite chains along the [100] direction.

A second monoclinic polymorph of methyl 4-hydroxy­benzoate

A second monoclinic polymorph of methyl 4-hydroxybenzoate, C8H8O3, is reported. The unit-cell dimensions are different from those of the previously reported monoclinic form [Vujovic & Nassimbeni (2006 ▶). Cryst. Growth Des. 6, 1595–1597]. The asymmetric unit contains three crystallographically independent molecules, as observed in the previous form. The crystal structure is stabilized by intermolecular O—H⋯O and C—H⋯O hydrogen bonds and C—H⋯π interactions, which link the molecules into a three-dimensional network.

2-(Pyrene-1-yl)-1,3-dithiane

In the title compound, C20H16S2, the pyrene ring is planar [maximum deviation 0.0144 (15) Å] and the dithiane ring adopts a chair conformation. The crystal packing is stabilized by C—H⋯π interactions. An intramolecular C—H⋯S hydrogen bond generates an S(5) ring motif.

4,4'-Dimethoxy-benzophenone: a triclinic polymorph.

The title compound, C15H14O3, has been found to crystallize as a new triclinic polymorph. The asymmetric unit of the present structure, as in the previously reported monoclinic structure [Norment & Karle (1962 ▶). Acta Cryst. 15, 873–878], contains two independent molecules, which differ slightly in the orientations of the two benzene rings. The crystal packing of the triclinic polymorph is stabilized by intermolecular C—H⋯O hydrogen bonds and C—H⋯π interactions.

Tetra­kis(4-amino­pyridine-κN1)dichlorido­copper(II) monohydrate

The asymmetric unit of the title compound, [CuCl2(C5H6N2)4]·H2O, contains two crystallographically independent complex molecules and two water molecules. The CuII ion in each molecule is six-coordinated in an elongated octahedral geometry, with the equatorial plane defined by four pyridine N atoms of four aminopyridine ligands and the axial positions occupied by two Cl atoms. In the crystal structure, molecules are linked into a three-dimensional framework by C—H⋯Cl, O—H⋯Cl, N—H⋯O, N—H⋯Cl and N—H⋯N hydrogen bonds and C/N—H⋯π interactions involving the pyridine rings.