(E)-N'-(3,4-Di-meth-oxy-benzyl-idene)nicotinohydrazide monohydrate.

In the title hydrated compound, C15H15N3O3·H2O, the nicotinohydrazide mol-ecule adopts a trans conformation with respect to the C=N double bond. The dihedral angle between the benzene and pyridine rings is 5.10 (14)°. In the crystal, the solvent water mol-ecule acts as an acceptor, forming an N-H⋯O hydrogen bond supported by two C-H⋯O contacts. It also acts as a donor, forming bifurcated O-H⋯(O,O) and O-H⋯N hydrogen bonds that combine with the former contacts to form zigzag chains of mol-ecules along the c-axis direction. An additional O-H⋯O donor contact completes a set of six hydrogen bonds to and from the water mol-ecule and connects it to a third nicotinohydrazide mol-ecule. This latter contact combines with weaker C-H⋯O hydrogen bonds supported by a C-H⋯π contact to stack mol-ecules along b in a three-dimensional network.

N-(4,4'-Dibromo-[1,1'-biphen-yl]-2-yl)benzamide.

In the title compound, C(19)H(13)Br(2)NO, the dihedral angle between the rings of the biphenyl group is 53.59 (14)°. The ring of the benzamide group is inclined to the phenyl rings of the biphenyl group by 23.87 (15) and 75.89 (15)°. There are no significant inter-molecular inter-actions in the crystal structure.

(E)-N'-(4-Meth-oxy-benzyl-idene)pyridine-3-carbohydrazide dihydrate.

In the title compound, C14H13N3O2·2H2O, the hydrazone mol-ecule adopts an E conformation with respect to the C=N bond. The dihedral angle between the benzene and pyridine rings is 8.55 (10)°. The methyl-idene-hydrazide [-C(=O)-N-N=C-] fragment is essentially planar, with a maximum deviation of 0.0375 (13) Å. The mean planes of the benzene and pyridine rings make dihedral angles of 2.71 (14) and 11.25 (13)°, respectively, with mean plane of the methyl-idene-hydrazide fragment. In the crystal, the benzohydrazide and water mol-ecules are linked by N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds into a three-dimensional network.

7-[(Morpholin-4-yl)(phen-yl)meth-yl]quinolin-8-ol.

In the title compound, C20H20N2O2, the quinoline ring system makes dihedral angles of 81.05 (4) and 61.16 (5)° with the mean planes of the benzene and morpholine rings, respectively; the mean planes of the latter two rings make a dihedral angle of 83.59 (4)°. In the crystal, pairs of O-H⋯N hydrogen bonds link neighbouring mol-ecules related by a twofold rotation axis, generating R2(2)(10) motifs.

12-(4-Meth-oxy-benzo-yl)-2-methyl-benzo[f]pyrido[1,2-a]indole-6,11-dione.

In the title compound, C(25)H(17)NO(4), the indolizine fused naphthaquinone unit is approximately planar [r.m.s deviation = 0.0678 Å] and makes a dihedral angle of 57.82 (5)° with the benzene ring of the meth-oxy-benzene group. The naphtho-quinone O atoms deviate, in the same sense, from the mean plane of the fused six-membered rings by 0.2001 (14) and 0.0516 (14) Å. In the crystal there is π-π stacking of inversion-related pairs of mol-ecules [inter-planar spacing = 3.514 (2) Å].

2,3,6,7-Tetra-bromo-9-butyl-9H-carbazole.

In he title compound, C(16)H(13)Br(4)N, the carbazole skeleton is nearly planar [maximum deviation = 0.026 (4) Å] and makes a dihedral angle of 73.8 (4)° with the butyl chain. The butyl chain adopts a trans conformation. In the crystal, mol-ecules are linked by π-π stacking inter-actions [centroid-centroid distance = 3.559 (2) Å].

2,2'-Bithio-phene-3,3'-dicarbonitrile.

The complete mol-ecule of the title compound, C(10)H(4)N(2)S(2), is generated by an inversion center situated at the mid-point of the bridging C-C bond. The bithio-phene ring system is planar [maximum deviation = 0.003 (2) Å] and the central C-C bond length is 1.450 (2) Å. There are no significant inter-molecular inter-actions in the crystal structure, which is stabilized by van der Waals inter-actions.

4,4'-Dibromo-2-nitro-biphen-yl.

The title compound, C(12)H(7)Br(2)NO(2), a biphenyl derivative, displays a twisted conformation with the two benzene rings making a dihedral angle of 55.34 (14)°. The dihedral angle between the nitro group and its parent benzene ring is 26.8 (2)°. The crystal structure is stabilized by inter-molecular C-H⋯Br and C-H⋯O inter-actions, which lead to the formation of chains propagating along the c-axis direction.

Crystal structure of (E)-3-{[2-(2,4-di-chloro-benzyl-idene)hydrazin-1-yl]carbon-yl}pyridinium chloride trihydrate.

In the title hydrated salt, C13H10Cl2N3O(+)·Cl(-)·3H2O, the organic cation exhibits a dihedral angle of 8.26 (14)° between the mean planes of the pyridinium and benzene rings, and dihedral angles of 8.70 (15) and 15.93 (5)° between the mean planes of the hydrazide group and the benzene and pyridinium rings, respectively. In the crystal, N-H⋯O, N-H⋯Cl, C-H⋯O, C-H⋯Cl, O-H⋯O, O-H⋯N and O-H⋯Cl hydrogen bonds link the complex cations, chloride anions and solvent water mol-ecules into a three-dimensional network.

Crystal structure of ethyl 6-chloro-methyl-2-oxo-4-(2,3,4-tri-meth-oxy-phen-yl)-1,2,3,4-tetra-hydro-pyrimidine-5-carboxyl-ate.

In the title compound, C17H21ClN2O6, the di-hydro-pyrimidine ring adopts a flattened envelope conformation, with the sp (3)-hybridized C atom forming the flap. The dihedral angle between the least-squares planes of the benzene and di-hydro-pyrimidine rings is 88.09 (6)°. An intra-molecular C-H⋯O hydrogen bond generates an S(6) ring. In the crystal, mol-ecules are linked via pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R 2 (2)(8) ring motif, and the dimers are linked via further pairs of N-H⋯O hydrogen bonds, forming R 2 (2)(14) rings and chains of mol-ecules along [111]. Pairs of inversion-related chains are linked via weak C-H⋯π inter-actions.

Crystal structure of ethyl 6-methyl-2-sulfanyl-idene-4-(thio-phen-2-yl)-1,2,3,4-tetra-hydro-pyrimidine-5-carboxyl-ate.

In the title compound, C12H14N2O2S2, the di-hydro-pyrimidine ring adopts a sofa conformation, with the C atom bearing the thienyl ring lying above the plane of the five remaining approximately coplanar (r.m.s. deviation = 0.0405 Å) atoms of the ring. The dihedral angle between the five near coplanar atoms of the ring and the thienyl ring is 89.78 (11)°. In the crystal, mol-ecules are linked into a supra-molecular chain along [100] via N-H⋯O(carbon-yl) hydrogen bonds. Inversion-related chains are linked into double chains via N-H⋯S(thione) hydrogen bonds. The three-dimensional architecture also features meth-yl-thienyl C-H⋯π inter-actions.