4-(4-Methyl-phen-yl)-2-(prop-2-yn-1-yl)phthalazin-1(2H)-one.

In the title compound, C18H14N2O, the dihedral angle between the methyl-phenyl ring and the phthalazone ring system (r.m.s. deviation = 0.034 Å) is 53.93 (9)°. In the crystal, mol-ecules are connected by C-H⋯O hydrogen bonds, forming chains along [101]. The chains are linked by π-π inter-actions [centroid-centroid distance 3.6990 (12) Å], forming layers parallel to (10-1).

(E)-N'-[4-(Di-methyl-amino)-benzyl-idene]-2-(4-methyl-phen-oxy)acetohydrazide.

In the title compound, C18H21N3O2, the dihedral angle between the benzene rings is 68.85 (11)°. In the crystal, the mol-ecules are linked by C-H⋯O and N-H⋯O hydrogen bonds, as well as weak C-H⋯π contacts, forming a three-dimensional supra-molecular architecture.

4-Cyano-3-fluoro-phenyl 4-(hexa-dec-yl-oxy)benzoate.

In the title compound, C30H40FNO3, the dihedral angle between the benzene rings is 57.76 (7)°. The alkyl chain adopts an all-trans conformation. In the crystal, mol-ecules are linked by pairs of C-H⋯O hydrogen bonds, forming inversion dimers.

5-(4-Chloro-phen-oxy)-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde.

In the title compound, C17H13ClN2O2, the phenyl and chloro-benzene rings are inclined to the central pyrazole ring at 40.84 (9) and 65.30 (9)°, respectively. In the crystal, pairs of C-H⋯π inter-actions link the mol-ecules into inversion dimers and C-H⋯O hydrogen bonds link these dimers into columns extended in [010]. The crystal packing exhibits short inter-molecular O⋯Cl contacts of 3.0913 (16) Å.

Dimethyl 2-[2-(2,4,6-tri-chloro-phen-yl)hydrazin-1-yl-idene]butane-dioate.

In the title compound, C12H11Cl3N2O4, the dihedral angle between the aromatic ring and the hydrazine (NH-N=C) grouping is 52.2 (3)°. The butanedioate groups exhibit planar conformations. An intra-molecular N-H⋯O hydrogen bond links the N-H group of the hydrazine to one of the meth-oxy groups of the butane-dioate moiety. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds and π-π inter-actions are also observed [centroid-centroid separation = 3.535 (1) Å].

N'-Benzyl-idene-2-chloro-N-(4-chloro-phen-yl)acetohydrazide.

In the title compound, C15H12Cl2N2O, the atoms not making up the chloro-benzene ring are approximately coplanar (r.m.s. deviation = 0.073 Å). The dihedral angle between these 13 atoms and the chloro-benzene ring is 67.37 (10)°. The C=O and Csp (2)-Cl groups are almost eclipsed [Cl-C-C=O = -6.5 (3)°]. In the crystal, C(6) chains linked by C-H⋯O hydrogen bonds result in [100] chains.

1-[5-Methyl-1-(4-nitro-phen-yl)-1H-1,2,3-triazol-4-yl]ethanone.

The asymmetric unit of the title compound, C11H10N4O3, contains two independent mol-ecules in which the benzene rings make dihedral angles of 38.3 (2) and 87.1 (2)° with respect to the triazole rings. In the crystal, the mol-ecules are linked by C-H⋯O hydrogen bonds, forming chains along [021]. Further, weak C-O⋯π [3.865 (5) Å, 83.8 (3)°] and N-O⋯π [3.275 (5) and 3.240 (6) Å, 141.8 (4) and 102.8 (3)°] inter-actions are observed.

5-(5'-Fluoro-2'-meth-oxy-biphenyl-3-yl)-1,3,4-oxa-diazol-2-amine.

In the title compound, C15H12FN3O2, the dihedral angles between the central benzene ring and the pendant benzene and oxa-diazole rings are 45.05 (13) and 15.60 (14)°, respectively. The C atom of the meth-oxy group is roughly coplanar with its attached ring [displacement = 0.178 (4) Å]. In the crystal, N-H⋯N hydrogen bonds link the mol-ecules into [010] chains. Weak C-H⋯π inter-actions are also observed.

1-{3-(4-Methyl-phen-yl)-5-[5-(2-nitro-phen-yl)furan-2-yl]-4,5-di-hydro-1H-pyrazol-1-yl}ethanone.

In the title compound, C22H19N3O4, the dihedral angle between the furan and pyrazole rings is 82.73 (19)° while the dihedral angles between the furan and pyrazole rings and their attached benzene rings are 31.93 (18) and 1.88 (18)°, respectively. In the crystal, inversion dimers linked by pairs of C-H⋯O hydrogen bonds generate R 2 (2)(16) loops. In addition, weak C-H⋯π and aromatic π-π stacking [minimum centroid-centroid distance = 3.5374 (17) Å] inter-actions are observed.

5-[(2-Methyl-4-nitro-1H-imidazol-1-yl)meth-yl]-1,3,4-thia-diazol-2-amine.

In the title compound, C7H8N6O2S, the dihedral angle between the imidazole and thia-diazole rings is 70.86 (15)°. In the crystal, mol-ecules are linked into [10-1] chains by N-H⋯N hydrogen bonds, which incorporate centrosymmetric R 2 (2)(8) and R 2 (2)(18) loops. The chains are linked by C-H⋯O and C-H⋯N inter-actions, generating a three-dimensional network. Very weak π-π stacking [centroid-centroid distance = 3.901 (17) Å] is also observed.

Ethyl 2-[4-(2-chloro-benzo-yl)-2,6-di-methyl-phen-oxy]ethano-ate.

The asymmetric unit of the title compound, C(19)H(19)ClO(4), contains two independent mol-ecules. The dihedral angles between the benzene rings are 63.41 (8) and 61.41 (9)°. Adjacent mol-ecules of different types are inter-connected in pairs through π-π inter-actions between their central benzene rings [centroid-centroid separation = 3.801 (2) Å, inter-planar spacing = 3.605 (2) Å, centroid shift = 1.204 (2) Å]. Finally, C-H⋯O hydrogen bonds link these dimers into bilayers parallel to (100).

2-Methylxanthen-9-one.

In the title compound, C(14)H(10)O(2), the tricycle is not planar, being bent with a dihedral angle of 4.7 (1)° between the two benzene rings. In the crystal, π-π inter-actions between the six-membered rings of neighbouring mol-ecules [centroid-centroid distances = 3.580 (3) and 3.605 (3) Å] form stacks propagating along [101].