organic compounds
Open access
In the title compound, C12H9BrN4O, the N′-methylidenepyrazine-2-carbohydrazide and 4-bromobenzene groups are oriented at a dihedral angle of 10.57 (7)°. The hydrazide N—H group is involved in intramolecular N—HN interaction, which generates an S(5) motif. A short C—HO interaction is formed between the methylidene H atom and the carbonyl O atom. It connects molecules into chains extending along [100]. In addition, molecules are arranged into stacks extending along [010] via π–π interactions between pyrazine and benzene rings, with centroid–centroid distances of 3.837 (2) and 3.860 (2) Å.
organic compounds
Open access
The title compound, C13H12N4O2, crystallized with two independent molecules (A and B) in the asymmetric unit. Molecule B is planar to within 0.044 (3) Å for all non-H atoms, while molecule A is slightly twisted, with a dihedral angle of 6.29 (4)° between the mean planes of the pyrazine-2-carbohydrazide and 1-(2-hydroxyphenyl)ethanone moieties (r.m.s. deviations = 0.0348 and 0.0428 Å, respectively). S(5) and S(6) ring motifs are formed in both molecules due to the presence of intramolecular O—HN and N—HN hydrogen bonds. In the crystal, molecules A and B are linked by a C—HO hydrogen bond. They stack along the a-axis direction, forming columns with π–π interactions involving inversion-related pyrazine and benzene rings [centroid–centroid distances = 3.5489 (13)–3.8513 (16) Å].
organic compounds
Open access
In the title compound, C12H9BrN4O, the dihedral angle between the aromatic rings is 12.16 (12)°. An intramolecular N—HN hydrogen bond closes an S(5) ring. In the crystal, C—HO hydrogen bonds link the molecules into C(6) chains propagating in [010]. Very weak aromatic π–π stacking [centroid–centroid separations = 3.9189 (15) and 3.9357 (15) Å] is also observed.