The complete anion of the title hydrated mol­ecular salt, 2C5H8N3 +·C8H4O4 −·2H2O, is generated by a crystallographic twofold axis. In the crystal, the cations, anions and water mol­ecules are connected by N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network. The crystal structure also features C—H⋯π inter­actions.

In the title mol­ecular salt–adduct, C5H8N3 +·C6H7O2 −·C6H8O2, the 2,3-diamino­pyridinium cation is essentially planar, with a maximum deviation of 0.013 (2) Å, and is protanated at its pyridine N atom. The sorbate anion and sorbic acid mol­ecules exist in extended conformations. In the crystal, the protonated N atom and one of the two amino-group H atoms are hydrogen bonded to the sorbate anion through a pair of N—H⋯O hydrogen bonds, forming an R 1 2(6) ring motif. The carboxyl groups of the sorbic acid mol­ecules and the carboxyl­ate groups of the sorbate anions are connected via O—H⋯O hydrogen bonds. Furthermore, the ion pairs and neutral mol­ecules are connected via inter­molecular N—H⋯O hydrogen bonds, forming sheets lying parallel to (100).

The asymmetric unit of the title compound, C5H8N3 +·C7H4ClO2 −·C7H5ClO2, contains an ion pair and a 3-chloro­benzoic acid mol­ecule. In the cation, the pyridine N atom is protonated. In the crystal, the components are connected via N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, thereby forming sheets lying parallel to (100).

In the title mol­ecular salt, C5H8N3 +·C7H5O3 −, the 2,3-diamino­pyridinium cation is essentially planar, with a maximum deviation of 0.006 (2) Å. In the crystal, adjacent cations and anions are linked by pairs of N—H⋯O hydrogen bonds, generating R 2 2(8) loops. These dimers are linked by further N—H⋯O hydrogen bonds and C—H⋯O inter­actions to form sheets lying parallel to (001). A typical intra­molecular O—H⋯O hydrogen bond is also observed in the salicylate (2-hy­droxy­benzoate) anion, which generates an S(6) ring. The crystal structure also features π–π stacking inter­actions between the pyridinium rings of the cations, with a centroid–centroid distance of 3.5896 (15) Å.

In the title hydrated mol­ecular salt, C5H8N3 +·C7H5O6S−·H2O, the ion pairs and water mol­ecules are connected by N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, thereby forming a three-dimensional network. There is an intra­molecular O—H⋯O hydrogen bond in the 3-carb­oxy-4-hy­droxy­benzene­sulfonate anion, which generates an S(6) ring motif.

In the title mol­ecular salt, C5H8N3 +·C5H7O4 −, the 2,3-diamino­pyridine mol­ecule is protonated at the pyridine N atom. The cation is essentially planar, with a maximum deviation of 0.015 (2) Å, and the anion adopts an extended conformation. In the crystal, the hydrogen glutarate (4-carb­oxy­butano­ate) anions are self-assembled through O—H⋯O hydrogen bonds, forming chains. The cations are connected to the anion chains via N—H⋯O hydrogen bonds, forming a three-dimensional network. The crystal structure also features aromatic π–π inter­actions between the pyridinium cations, with a centroid–centroid distance of 3.4464 (10) Å.

In the title salt (systematic name: 6-amino-9H-purin-1-ium perchlorate), C5H6N5 +·ClO4 −, 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 [001] 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.

In the title compound, C15H11NO3, the two essentially planar benzaldehyde groups [maximum deviations = 0.0487 (12) and 0.0205 (10) Å] are inclined at a dihedral angle of 72.64 (6)° with respect to each other. The bridging C—C—N—C torsion angle is 22.58 (18)°. In the crystal, inter­molecular bifurcated acceptor N—H⋯O and C—H⋯O hydrogen bonds link inversion-related mol­ecules into dimers incorporating R 1 2(7) and R 2 2(8) ring motifs. The crystal structure is further stabilized by weak inter­molecular C—H⋯π inter­actions.

In the title pyrrolidine compound, C30H24Br2N2O3, the two fused pyrrolidine rings adopt envelope and twisted conformations, whereas the piperidine ring adopts an envelope conformation. The essentially planar 2,3-dihydro­indanone unit [maximum deviation = −0.0163 (19) Å] is inclined at inter­planar angles of 14.29 (9) and 61.07 (9)° to the two benzene rings. In the crystal, adjacent mol­ecules are linked into dimers by inter­molecular O—H⋯N and C—H⋯O hydrogen bonds. Short inter­molecular Br⋯Br inter­actions [3.5140 (6) Å] further inter­connect these dimers into double dimeric columns along the b axis.

The whole mol­ecule of the title coumarin derivative, C11H10O3, is approximately planar, with a maximum deviation of 0.116 (3) Å from the least-squares plane defined by all non-H atoms. In the crystal, adjacent mol­ecules are linked into chains along [011] via inter­molecular C—H⋯O hydrogen bonds.

The title complex, [Sn4(C4H9)8(C7H3ClNO4)4O2], is a cluster formed by a crystallographic inversion center around the central Sn2O2 ring. Both of the two independent Sn atoms are five-coordinated, with distorted trigonal–bipyramidal SnC2O3 geometries. One Sn atom is coordinated by two butyl groups, one O atom of the benzoate anion and two bridging O atoms, whereas the other Sn atom is coordinated by two butyl groups, two O atoms of the benzoate anions and a bridging O atom. The O atoms of the bridging benzoate anion are disordered over two sites with an occupancy ratio of 0.862 (12):0.138 (12). One of the butyl groups coordinated to the Sn2O2 ring is disordered over two sites with an occupancy ratio of 0.780 (8):0.220 (8), whereas both of the two butyl groups coordinated to the other Sn atom are disordered over two sites with occupancy ratios of 0.788 (5):0.212 (5) and 0.827 (10):0.173 (10). All the butyl groups are equatorial with respect to the SnO3 trigonal plane. In the crystal, complex mol­ecules are stacked down [010] with weak inter­molecular C—H⋯π inter­actions stabilizing the crystal structure.

In the title sydnone compound [systematic name: 3-(4-meth­oxy­phen­yl)-1,2,3-oxadiazol-3-ium-5-olate], C9H8N2O3, the essentially planar oxadiazole ring [maximum deviation = 0.005 (1) Å] is inclined at a dihedral angle of 30.32 (8)° with respect to the benzene ring. In the crystal, adjacent mol­ecules are inter­connected by inter­molecular C—H⋯O hydrogen bonds into sheets lying parallel to (100). Weak inter­molecular π–π inter­actions [centroid–centroid distance = 3.5812 (8) Å] further stabilize the crystal packing.

In the title compound, C14H8F2N2O, the amide plane is inclined at dihedral angles of 28.12 (12) and 32.89 (12)° with respect to the two benzene rings; the dihedral angle between the two rings is 5.58 (5)°. In the crystal, inter­molecular N—H⋯O and C—H⋯F hydrogen bonds link adjacent mol­ecules into a double-chain structure along the b axis.

In the title coumarin derivative, C13H12O4, the 2H-chromene ring system is essentially planar [maximum deviation = 0.047 (1) Å]. An intra­molecular hydrogen bond is observed between the hy­droxy and the ketonic O atoms. In the crystal, pairs of inter­molecular C—H⋯O hydrogen bonds link inversion-related mol­ecules into dimers. Additional inter­molecular C—H⋯O hydrogen bonds further inter­connect these dimers into two-dimensional arrays incorporating R 2 2(9) ring motifs.

In the title compound, C16H14N2O3, the essentially planar 1,3,4-oxadiazole ring [maximum deviation = 0.0021 (11) Å] is inclined at dihedral angles of 8.06 (6) and 11.21 (6)° with respect to the two benzene rings; the dihedral angle between the latter rings is 11.66 (5)°. In the crystal, short inter­molecular C⋯O inter­actions [2.9968 (15) Å] connect adjacent mol­ecules into chains propagating in [203]. The crystal structure is further stabilized by weak inter­molecular C—H⋯π inter­actions.

In the title isoniazid derivative, C13H11N3O4·2H2O, the Schiff base mol­ecule exists in an E configuration with respect to the acyclic C=N bond. An intra­molecular O—H⋯N hydrogen bond forms a six-membered ring, producing an S(6) ring motif. The essentially planar pyridine ring [maximum deviation = 0.0119 (8) Å] is inclined at a dihedral angle of 7.30 (4)° with respect to the benzene ring. In the crystal, inter­molecular O—H⋯N, O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into two-dimensional arrays lying parallel to the (10) plane. These arrays are further inter­connected into a three-dimensional extended network via O—H⋯O and C—H⋯O hydrogen bonds. A weak inter­molecular π–π inter­action [centroid-to-centroid distance = 3.5627 (5) Å] is also observed.

The tetranuclear molecules of the title compound, [Sn4(C4H9)8(C7H5N2O4)4O2], reside on a crystallographic inversion center. Both the two independent Sn atoms are five-coordinate, with distorted trigonal–bipyramidal geometries. One Sn atom is coordinated by two O atoms of the carboxyl­ate anions, one bridging O atom and two butyl groups and the other Sn atom is coordinated by an O atom of the carboxyl­ate anion, two bridging O atoms and two butyl groups. All the butyl groups are equatorial with respect to the SnO3 trigonal plane. The mol­ecular structure is stabilized by intra­molecular N—H⋯O hydrogen bonds. In the crystal, pairs of inter­molecular bifurcated acceptor N—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into chains along [10]. Weak inter­molecular C—H⋯π and π–π inter­actions [centroid–centroid distance = 3.713 (2) Å] 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 asymmetric unit of the title compound, C14H17N3O3·0.25H2O, comprises two independent organic mol­ecules and a water mol­ecule lying on a crystallographic twofold rotation axis with 50% site occupancy. In both independent mol­ecules, the cyclo­hexene rings adopt envelope conformations but superposition of the two molecules shows that the flap atoms point in opposite directions. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds inter­connect adjacent mol­ecules into a three-dimensional network. Weak inter­molecular π–π aromatic stacking inter­actions [centroid–centroid distances = 3.4985 (9) and 3.6630 (9) Å] are also observed.

The asymmetric unit of the title compound, C20H22N2O4, comprises two crystallographically independent mol­ecules (A and B) with slightly different geometries. The dihedral angle between the two terminal phenyl rings is 61.7 (1)° in mol­ecule A and 29.6 (1)° in B. The cyclo­hexane rings adopt chair conformations. In the crystal packing, inter­molecular N—H⋯O hydrogen bonds inter­connect adjacent mol­ecules into a ladder-like structure along the c axis incorporating R 2 2(20) ring motifs. The crystal packing is further stabilized by weak inter­molecular C—H⋯π inter­actions.

In the title indoline compound, C19H14N2O3S, the pyrrolidine ring adopts an envelope conformation with the four-connected (spiro) C atom as the flap [displacement = 0.148 (3) Å]. The mean plane formed through the indoline unit is inclined at dihedral angles of 89.92 (16) and 59.54 (12)° with the thia­zole and phenyl rings, respectively; the dihedral angle between the latter rings is 9.55 (14)°. In the crystal, pairs of inter­molecular C—H⋯O hydrogen bonds link neighbouring mol­ecules into inversion dimers, producing R 2 2(6) hydrogen-bond ring motifs. Weak inter­molecular C—H⋯π as well as π–π inter­actions [centroid–centroid distance = 3.4041 (15) Å] further consolidate the crystal structure.

The title compound, C23H16N2O3, exists in a Z configuration with respect to the acyclic C=C bond. The pyridine and phenyl rings are oriented at dihedral angles of 72.97 (4) and 45.05 (4)°, respectively, with respect to the almost planar indoline ring system [maximum deviation 0.080 (1) Å]. The pyridine and phenyl rings are oriented almost perpendicular to each other [dihedral angle 88.93 (5)°]. In the crystal, mol­ecules are inter­connected into a three-dimensional framework via inter­molecular C—H⋯O and C—H⋯N hydrogen bonds and weak π–π inter­actions [centroid–centroid distance = 3.681 (1) Å].

In the title compound, C19H15NO3S, the dihydro­phenanthrene unit is not planar, its central ring being distorted towards a sofa conformation. The essentially planar thia­zole ring [maximum deviation = 0.005 (1) Å] is inclined at a dihedral angle of 85.29 (5)° with respect to the mean plane formed through the dihydro­phenanthrene unit. In the crystal structure, pairs of inter­molecular C—H⋯O hydrogen bonds link adjacent mol­ecules into inversion dimers. Inter­molecular O—H⋯N hydrogen bonds further inter­connect these dimers into chains along the a axis. The crystal structure is further stabilized by weak inter­molecular C—H⋯π inter­actions involving the thia­zole ring.