G. K. Nagaraja

4-Chloro-benzaldehyde (1-isobutyl-1H-imidazo[4,5-c]quinolin-4-yl)hydrazone monohydrate.

In the title compound, C21H20ClN5·H2O, the 1H-imidazo[4,5-c]quinoline ring is approximately planar, with a maximum deviation of 0.0795u2005(7)u2005Å, and it forms a dihedral angle of 7.65u2005(3)° with the chlorophenyl ring. In the crystal, the components are linked into chains along the a axis via intermolecular N—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds. One of the H atoms of the water molecule is disordered over two positions with a site-occupancy ratio of 0.80u2005(4):0.20u2005(4).

4-Hydrazinyl-1-isobutyl-1H-imidazo[4,5-c]quinoline.

In the title compound, C14H17N5, the 1H-imidazo[4,5-c]quinoline ring system is essentially planar, with a maximum deviation of 0.0325u2005(7)u2005Å. In the crystal, a pair of intermolecular N—H⋯N hydrogen bonds link neighbouring molecules, forming an inversion dimer and generate an R 2 2(10) ring motif. These dimers are further connected into a chain along the b axis via intermolecular C—H⋯N hydrogen bonds, resulting in an R 2 2(14) ring motif.

2-[(E)-(2,4,6-Trichloro-phen-yl)imino-meth-yl]phenol.

The title molecule, C13H8Cl3NO, exists in a trans configuration with respect to the C=N bond [1.278u2005(2)u2005Å]. The benzene rings form a dihedral angle of 24.64u2005(11)°. The molecular structure is stabilized by an intramolecular O—H⋯N hydrogen bond, which generates an S(6) ring motif. In the crystal, π–π stacking interactions [centroid–centroid distances = 3.6893u2005(14)u2005Å] are observed.

2-[(E)-(2,4-Dimethyl­phen­yl)imino­meth­yl]phenol

The asymmetric unit of the title compound, C15H15NO, contains two independent molecules, both of which exist in trans configurations with respect to the C=N bonds [1.278u2005(2) and 1.279u2005(2)u2005Å]. In each molecule, intramolecular O—H⋯N hydrogen bonds generate S(6) ring motifs. In one molecule, the benzene rings form a dihedral angle of 13.38u2005(9)°, while in the other molecule the dihedral angle is 30.60u2005(10)°. In the crystal, the two independent molecules are linked via weak intermolecular C—H⋯O hydrogen bonds.

6-(4-Chloro­phen­yl)-2-isobutyl­imidazo[2,1-b][1,3,4]thia­diazole

In the title compound, C14H14ClN3S, the imidazo[2,1-b][1,3,4]thiadiazole system is essentially planar, with a maximum deviation of 0.006u2005(2)u2005Å. The dihedral angle between the imidazo[2,1-b][1,3,4]thiadiazole and chlorophenyl rings is 5.07u2005(8)°. In the crystal, there are no classical hydrogen bonds but stabilization is provided by weak π–π [centroid–centroid distance = 3.5697u2005(11)u2005Å] and C—H⋯π interactions.

1-Isobutyl-N,N-dimethyl-1H-imidazo[4,5-c]quinolin-4-amine.

In the title compound, C(16)H(20)N(4), the 1H-imidazo[4,5-c]quinoline ring system is approximately planar, with a maximum deviation of 0.0719u2005(15)u2005Å. An intra-molecular C-H⋯N hydrogen bond contributes to the stabilization of the mol-ecule, forming an S(6) ring motif. In the crystal, the mol-ecules are stacked along the b axis through weak aromatic π-π inter-actions between benzene and imidazole and benzene and pyridine rings [centroid-centroid distances = 3.6055u2005(10) and 3.5342u2005(10)u2005Å, respectively].

3-[(1-Isobutyl-1H-imidazo[4,5-c]quinolin-4-yl)amino]­benzoic acid

In the title compound, C21H20N4O2, the statistically planar 1H-limidazole ring [maximum deviation = 0.003u2005(1)u2005Å] makes dihedral angles of 1.33u2005(9) and 8.23u2005(7)°, respectively, with the essentially planar fused pyridine ring [maximum devation = 0.018u2005(1)u2005Å] and the pendant benzene ring, which is attached to the pyridine ring by an —NH— group. An intramolecular C—H⋯N interaction, which generates an S(6) ring, helps to estalish the molecular conformation. In the crystal, the molecules are linked by N—H⋯O, C—H⋯O and O—H—N hydrogen bonds, which generate bifurcated R 1 2(6) and R 2 2(9) ring motifs, resulting in supramolecular [001] chains. The crystal structure also features weak π–π stacking [centroid–centroid distance = 3.5943u2005(9)u2005Å] and C—H⋯π interactions.

2-Azido-1-(3,6-dichloro-9H-fluoren-1-yl)ethanone.

In the title compound, C15H9Cl2N3O, an intramolecular C—H⋯O interaction generates an S(7) ring motif. The cyclopenta-1,3-diene ring forms dihedral angles of 1.93u2005(6) and 2.78u2005(6)° with its attached benzene rings. In the crystal, molecules are linked by C—H⋯N and C—H⋯O hydrogen bonds, thereby forming layers lying parallel to the ac plane. The crystal also features a π–π interaction with a centroid–centroid distance of 3.5612u2005(6)u2005Å.

N'-(4-Fluoro-benzyl-idene)-2-(4-fluoro-phen-yl)acetohydrazide.

In the title compound, C15H12F2N2O, the dihedral angle between the two benzene rings is 48.73u2005(8)°. The hydrazine group is twisted slightly, with a C—N—N—C torsion angle of 172.48u2005(12)°. In the crystal, molecules are connected by strong N—H⋯O and weak C—H⋯O hydrogen bonds, forming supramolecular chains along the c axis. The structure is consolidated by π–π [centroid–centroid separation = 3.6579u2005(10)u2005Å] and C—H⋯π interactions.

1-(tert-But-oxy-carbon-yl)piperidine-4-carb-oxy-lic acid.

In the title compound, C11H19NO4, the piperidine ring adopts a chair conformation. In the crystal, molecules are linked by intermolecular O—H⋯O and C—H⋯O hydrogen bonds, forming a layer parallel to the bc plane.