In the title compound, C13H12O5, the mean plane of the 2H-chromene ring system (r.m.s deviation = 0.026 Å) forms a dihedral angle of 81.71 (6)° with the mean plane of ethyl 2-hydroxyacetate moiety (r.m.s deviation = 0.034 Å). In the crystal, C—H⋯O hydrogen bonds result in the formation of zigzag layers parallel to the bc plane.
In the title compound, C14H17N3O2, the mean plane of the 1,8-naphthyridine ring system (r.m.s deviation = 0.020 Å) forms a dihedral angle of 23.4 (1)° with the acetamide moiety (r.m.s deviation = 0.001 Å). The molecular structure is stabilized by an intramolecular O—H⋯N hydrogen bond, which generates an S(5) ring motif. In the crystal, molecules are linked into inversion dimers by pairs of N—H⋯O hydrogen bonds, generating 18-membered R
2(18) ring motifs.
In the title hydrate, C16H19N3O3·1.5H2O, both water molecules are disordered: one over two adjacent sites in a 0.498 (5):0.502 (5) ratio and one lying near a crystallographic twofold axis. The dihedral angle between the pyridine rings of the organic moleucle is 1.47 (6)°. In the crystal, the components are linked by N—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds, forming sheets lying parallel to the ac plane.
The asymmetric unit of the title compound, C9H7N3O2, is composed of two independent molecules. The crystal structure is stabilized by C—H⋯O and C—H⋯N hydrogen bonds, forming a three-dimensional network. The crystal structure also features pyrazine–pyrazine π–π interactions [centroid–centroid distance = 3.6994 (5) Å] and also pyridine–pyrazine π–π interactions [centroid–centroid distance = 3.6374 (5) Å].
In the title compound, C18H17N3, the dihedral angles between the central pyrimidine ring and its directly-bonded and N-bonded pendant phenyl rings are 25.48 (6) and 80.33 (6)°, respectively. The dihedral angle between the phenyl rings is 79.66 (6)°. In the crystal, inversion dimers linked by pairs of N—H⋯N hydrogen bonds generate R
2(8) loops. The crystal structure also features weak π–π [centroid–centroid separation = 3.6720 (7) Å] and C—H⋯π interactions.
In the title compound, C20H21N3, the pyrimidine ring is inclined at dihedral angles of 51.57 (4) and 2.49 (4)° to the two phenyl rings. The dihedral angle between the two terminal phenyl rings is 50.44 (4)°. In the crystal, adjacent molecules are linked via a pair of N—H⋯N hydrogen bonds, forming an inversion dimer with an R
2(8) ring motif. Furthermore, the crystal structure is stabilized by a weak π–π interaction, with a centroid–centroid distance of 3.6065 (5) Å.
In the title salt (systematic name: 6-amino-9H-purin-1-ium perchlorate), C5H6N5
−, the adeninium cation is essentially planar, with a maximum deviation of 0.038 (1) Å. The whole of the perchlorate anion is disordered over two sets of sites with an occupancy ratio of 0.589 (13):0.411 (13). In the crystal, the adeninium cations are linked by pairs of N—H⋯N hydrogen bond into inversion dimers. The dimers and the anions are further interconnected into a three-dimensional supramolecular structure via intermolecular N—H⋯O, C—H⋯O and C—H⋯N hydrogen bonds.
In the title complex, [CuBr2(C6H4N2Se)2], the CuII ion is tetracoordinated by two bromide anions and two N atoms in a distorted square-planar geometry. The two essentially planar 2,1,3-benzoselenadiazole ligands [maximum deviations = 0.012 (2) and 0.030 (2) Å] are approximately coplanar [dihedral angle = 6.14 (6)°]. In the crystal, short intermolecular Se⋯Br, Se⋯N and N⋯N interactions are observed. These short interactions and intermolecular C—H⋯Br hydrogen bonds link the complex molecules into two-dimensional arrays parallel to the ac plane.
The title compound, C18H8Cl4N4, exists in a cis configuration with respect to the bridging C=C bond. The two essentially planar quinoxaline ring systems [maximum deviations = 0.012 (1) and 0.022 (1) Å] are inclined at an angle of 59.84 (3). In the crystal, adjacent molecules are linked into chains propagating along  via intermolecular C—H⋯N hydrogen bonds. Weak intermolecular π–π [centroid–centroid distance = 3.6029 (7)°] and C—H⋯π interactions are also observed.
The title acetamide compound, C8H9BrN2O, crystallizes with three crystallographically independent molecules (A, B and C) in the asymmetric unit. In molecule A, the mean plane through the acetamide unit is inclined at a dihedral angle of 4.40 (11)° with respect to the pyridine ring [10.31 (12) and 2.27 (11)°, respectively, for molecules B and C]. In the crystal structure, molecules are interconnected into sheets parallel to the ac plane by N—H⋯O, C—H⋯Br, C—H⋯O and C—H⋯N hydrogen bonds. The structure is further stabilized by weak intermolecular C—H⋯π interactions.
The title compound, C22H30N4O2, lies about a crystallographic inversion center. The whole molecule is disordered over two positions with a refined occupancy ratio of 0.636 (10):0.364 (10). The pyridine rings are approximately planar, with maximum deviations of 0.033 (10) and 0.063 (17) Å for the major and minor components, respectively. The mean planes of the pyridine rings form dihedral angles of 17 (2)° in the major component and 18 (2)° in the minor component with the respective formamide groups attached to them. In the crystal packing, intermolecular N—H⋯O and C—H⋯O hydrogen bonds link the molecules into two-dimensional networks parallel to the ab plane.
The asymmetric unit of the title compound, C12H8N2·0.5C2H4N2S2, contains one 1,10-phenanthroline molecule and a half-molecule of dithiooxamide, which lies across a crystallographic inversion center. The 1,10-phenanthroline unit is not strictly planar, with dihedral angles between the central benzene ring and the pyridine rings of 1.42 (10) and 1.40 (10)°. In the crystal structure, two 1,10-phenanthroline molecules are linked together by one dithiooxamide via intermolecular N—H⋯N hydrogen bonds.
In the title compound, C15H19N3, the pyrimidine ring is approximately planar [maximum deviation = 0.007 (1) Å] and forms a dihedral angle of 3.15 (6)° with the benzene ring. In the crystal packing, intermolecular N—H⋯N hydrogen bonds link pairs of neighbouring molecules into dimers with R
2(8) ring motifs. These dimers are stacked along the b axis.
The complete molecule of the title compound, C10H4Cl6N2, is generated by crystallographic twofold symmetry, with two C atoms lying on the rotation axis; the 1,8-naphthyridine ring is almost planar with an r.m.s. deviation of 0.0002 Å. In the crystal structure, the molecules are stacked in an antiparallel manner along . Short Cl⋯Cl [3.3502 (4)] and Cl⋯N [3.2004 (11)–3.2220 (10) Å] contacts are observed in the crystal structure.
In the title compound, guanidinium chloridotrioxidochromate(VI), (CH6N3)[CrClO3], both the cation and anion are generated by crystallographic mirror symmetry, with one O and one N atom and the Cr, Cl and C atoms lying on the mirror plane. The bond lengths in the guanidinium cation are intermediate between normal C—N and C=N bond lengths, indicating significant delocalization in this species. In the crystal structure, intermolecular N—H⋯Cl interactions generate R
1(6) ring motifs. These ring motifs are further interconnected by intermolecular N—H⋯O hydrogen bonds into infinite chains along .
The asymmetric unit of the title compound, C14H6Cl6N2, contains two crystallographically independent molecules, each of which is slightly twisted from planarity. The dihedral angles between the central ring and the two outer rings are 3.81 (7) and 4.30 (7)° in one molecule, and 4.13 (8) and 4.10 (7)° in the other. In the crystal structure, molecules are interlinked by C—Cl⋯Cl interactions into sheets parallel to the ac plane. These sheets are stacked along the b axis in such a way that the molecules are antiparallel; they are further connected into a supramolecular network. There are no classical hydrogen bonds. C⋯Cl [3.637 (2) Å], Cl⋯Cl [3.5639 (5)–3.6807 (8) Å] and Cl⋯N [3.3802 (15)–3.4093 (15) Å] short contacts and π–π interactions, with centroid–centroid distances in the range 3.5868 (9)–3.7844 (9) Å, are observed.
In the title compound, C9H5N3, the quinoxaline ring is essentially planar, with a maximum deviation of 0.012 (1) Å. Short intermolecular distances between the centroids of the 2,3-dihydropyrazine and benzene rings [3.6490 (5) Å] indicate the existence of π⋯π interactions. In the crystal packing, the molecules are linked via two pairs of intermolecular C—H⋯N interactions, forming R
2 (8) and R
2 (10) ring motifs; these molecules are further linked into a two-dimensional network parallel to (1 0 2) via another C–H⋯N interaction.
The asymmetric unit of the title compound, C10H10N2, contains one half-molecule with the two shared C atoms lying on a twofold rotation axis. The 1,8-naphthyridine is almost planar with a dihedral angle of 0.42 (3)° between the fused pyridine rings. In the crystal, molecules are linked into infinite chains along the c axis by intermolecular C—H⋯N hydrogen bonds, generating R
2(8) ring motifs. In addition, the crystal structure is further stabilized by C—H⋯π interactions.
The asymmetric unit of the title compound, C14H23N5O3·2H2O, contains two crystallographically independent 6-amino-2,5-bis(pivaloylamino)pyrimidin-4(3H)-one molecules (A and B) with similar geometry and four water molecules. In both independent molecules, one of the amide groups is almost coplanar with the pyrimidine ring [dihedral angle of 12.85 (9) in A and 12.30 (10)° in B], whereas the other amide group is significantly twisted away from it [dihedral angle is 72.18 (7) in A and 71.29 (7)° in B]. In each independent molecule, an intramolecular N—H⋯O hydrogen bond generates an S(6) ring motif. Molecules A and B are linked into chains along the a axis by N—H⋯O and C—H⋯O hydrogen bonds. Adjacent chains are linked into a two-dimensional network parallel to the ac plane by water molecules via N—H⋯O and O—H⋯O hydrogen bonds.
The asymmetric unit of the title compound, C20H17N3, contains two crystallographically independent molecules (A and B). In molecule A, the two benzene rings form dihedral angles of 74.12 (7) and 7.83 (7)° with the pyridine ring, while in molecule B these angles are 77.48 (7) and 21.50 (7)°. The seven-membered heterocyclic ring adopts a boat conformation in both molecules. In the crystal structure, each of the independent molecules forms a centrosymmetric R
2(8) dimer linked by paired N—H⋯N hydrogen bonds. The crystal structure is further stabilized by intermolecular C—H⋯N hydrogen bonds and C—H⋯π interactions.
In the molecular structure of the title compound, C11H14Br2N2O, the dimethylpropionamide substituent is twisted slightly with respect to the pyridine ring, the interplanar angle being 12.3 (2)°. The dibromomethyl group is orientated in such a way that the two Br atoms are tilted away from the pyridine ring. In the crystal structure, molecules are associated into supramolecular chains by weak C—H⋯O interactions. The crystal is further stabilized by weak N—H⋯Br and C—H⋯N interactions.
The title compound, C20H14N2, comprises two crystallographically independent centrosymmetric molecules (A and B) with different conformations due to the disorder of molecule B. The whole of molecule B is disordered over two sets of positions, corresponding to a 180° rotation of the molecule, with a site-occupancy ratio of 0.780 (6):0.220 (6). The minor component of the disordered part in B has the same configuration as molecule A, but the major component is different. The dihedral angle between the planes of molecule A and molecule B (major component) is 63.22 (3)°. The crystal structure is stabilized by intermolecular C—H⋯π interactions.
The nitro group in the title compound, C10H11NO2S2, is almost coplanar with the benzene ring, making a dihedral angle of 3.42 (8)°. The 1,3-dithiane ring adopts a chair conformation. The crystal structure is stabilized by intermolecular C—H⋯O and C—H⋯π [C⋯Cg = 3.4972 (10) Å] interactions.
The asymmetric unit of the title compound, C14H18N3O+·Cl−·H2O, comprises a substituted amido–naphthyridine cation, a chloride anion and a water molecule of crystallization. Intramolecular C—H⋯O hydrogen bonds generate six-membered rings, producing an S(6) ring motif. The amido group is twisted from the naphthyridine ring, making a dihedral angle of 17.65 (7)°. The crystal structure is stabilized by intermolecular N—H⋯O, N—H⋯Cl, O—H⋯Cl (× 2), and C—H⋯O (× 2) hydrogen bonds. These interactions linked neighbouring molecules into chains along the a and b axes of the crystal, thus forming molecular sheets parallel to the (001) plane.
In the title compound, C13H15NO2S2, the nitro group is coplanar with the benzene ring to which it is attached, forming a dihedral angle of 1.07 (14)°. The dithiane ring adopts a chair conformation. In the crystal structure, molecules are linked through C—H⋯O and C—H⋯π [C⋯Cg = 3.7164 (15) Å] interactions. The crystal studied was an inversion twin with an 0.134 (5):0.866 (5) domain ratio.