In the title compound, C12H9BrN4O, the N'-methyl-idene-pyrazine-2-carbohydrazide and 4-bromobenzene groups are oriented at a dihedral angle of 10.57 (7)°. The hydrazide N-H group is involved in intra-molecular N-H⋯N inter-action, which generates an S(5) motif. A short C-H⋯O inter-action is formed between the methyl-idene H atom and the carbonyl O atom. It connects mol-ecules into chains extendi...

In the title compound, C(13)H(13)N(3)O, the phenyl and pyrrole rings are inclined at 47.45 (8)°. In the crystal, inter-molecular N-H⋯O and C-H⋯O hydrogen bonds form R(2) (1)(6) ring motifs. Mol-ecules connected through these hydrogen bonds are arranged into polymeric chains extending along the c axis.

The title compound, C(7)H(5)ClN(4), is almost planar (r.m.s. deviation = 0.022 Å). The dihedral angle between the aromatic rings is 2.82 (5)°. The packing results in polymeric chains extending along the a axis. In the crystal, mol-ecules are connected to each other through inter-molecular C-H⋯N hydrogen bonds, resulting in R(2) (2)(10) ring motifs.

In the title compound, C16H17N3OS, the dihedral angle between the planes of the benzene and pyridine rings is 71.33 (15)°. An intra-molecular N-H⋯O hydrogen bond is present. In the crystal, weak aromatic C-H⋯O hydrogen bonds link the mol-ecules into chains extending along a.

In the cation of the title compound, C(6)H(6)N(5) (+)·ClO(4) (-), the pyridinium and tetra-zole rings form a dihedral angle of 23.6 (1)°. In the crystal structure, weak inter-molecular N-H⋯O and N-H⋯N hydrogen bonds link cations and anions into chains extending along the b axis.

In the title compound, C15H22N2O·H2O, the dihedral angle between the planes of the piperidine and benzene rings is 31.63 (1)°. The piperidine ring adopts a chair conformation. The water solvent mol-ecule is involved in inter-species O-H⋯O, O-H⋯N, N-H⋯O and weak C-H⋯O hydrogen-bonding inter-actions, giving rise to chains extending along [010].

This paper presents some interesting results of numerical analysis of the Extended Blaschke functions, which are constructed by extending Blaschke product. On the complex plane, the convergent domains of the functions form fractal patterns of constrained Herman rings with limited-layered structures, which demonstrate skip-symmetry, symmetry broken, chaos, and degeneracy in conjunction with para...

In the title mol-ecule, C(17)H(16)N(4)O, the triazole ring makes dihedral angles of 29.00 (1) and 77.74 (1)°, respectively, with the phenyl and benzene rings. In the crystal structure, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains extending along the c axis.

In the title compound, C(33)H(26)Cl(3)N(3)OS, the oxadiazole, piperidine and benzothia-pezine rings adopt envelope, chair and twist-boat conformations, respectively. In the crystal, the mol-ecular aggregation is characterized by chains of centrosymmetrically related pairs connected through Cl⋯Cl inter-actions [3.533 (2) Å], extending parallel to (202).

In the title compound, C6H3ClN2SSe, the selenadiazole and chloro-thio-phene rings are almost coplanar [dihedral angle = 5.24 (15)°]. In the crystal, C-H⋯N inter-actions link the mol-ecules into chains extending along the b-axis direction. C-H⋯π inter-actions also occur.