In the title mol­ecule, C17H18F2N2, the dihedral angle between the benzene rings is 73.40 (3)°. The piperazine ring is close to an ideal chair conformation and the N—H hydrogen is in an equatorial position. In the crystal, molecules are linked via weak C—H⋯F hydrogen bonds.

In the title mol­ecule, C25H23N3O2, two terminal phenyl rings are twisted by 50.20 (6) and 71.26 (5)° from the mean plane (r.m.s. deviation = 0.032 Å) of the central benzyl­idene–amino–pyrazolone fragment. The N atoms of the pyrazole ring have a pyramidal environment, the sums of the valence angles around them being 353.5 (2) and 347.3 (2)°. The crystal structure is stabilized by C—H⋯O interactions.

In the title compound (systematic name: (R)-dimeth­yl{2-[1-phenyl-1-(pyridin-2-yl)eth­oxy]eth­yl}aza­nium (R,R)-3-carb­oxy-2,3-dihy­droxy­propano­ate), C17H23N2O+·C4H5O6 −, the doxylaminium cation is protonated at the N atom. The tartrate monoanions are linked by short, almost linear O—H⋯O hydrogen bonds into chains extended along [100]. These chains are inter­linked by anion–pyridine O—H⋯N hydrogen bonds into a two-dimensional grid structure. WeakC—H⋯O inter­actions also play a role in the crystal packing. An intra­molecular hy­droxy–carboxyl­ate O—H⋯O hydrogen bond influences the conformation of the anion: the hydrogen-bonded fragment is almost planar, the maximum deviation from the mean plane being 0.059 (14) Å. In the cation, the aromatic rings are almost perpendicular [dihedral angle = 84.94 (8)°] and the conformation of the O—C—C—N chain is gauche(−), the dihedral angle is −76.6 (2)°. The absolute configuration was assigned on the basis of known chirality of the parent compound.

In the title compound, C17H16ClNO2, the N=C—O—C—C fragment is planar within 0.029 (1) Å, and makes dihedral angles of 66.71 (8) and 59.61 (8)° with the planes of the chloro­phenyl and benzoyl rings, respectively. The carbonyl C=O bond is not coplanar with either of the aromatic rings; it makes angles of 42.5 and 23.5° with the normals to the ring planes. In the crystal, very weak C—H⋯O, C—H⋯Cl, C—H⋯π and π–π [inter­planar distance = 3.53 (1) Å] inter­actions are observed.

In the title salt {systematic name: [2-hy­droxy-3-(3-meth­oxy­phen­yl)cyclo­hexyl­meth­yl]dimethyl­aza­nium 2,4,6-trinitro­phenol­ate}, C16H26NO2 +·C6H2N3O7 −, the cation is protonated at the N atom. The cyclo­hexane ring adopts a chair conformation with the hy­droxy substituent in an axial position. In the crystal, O—H⋯O and N—H⋯O hydrogen bonds link the cations and anions into supra­molecular chains along [100].

In the title compound, [Zn2(C8H7N3OS)2(C5H5N)2], the Zn2O2 ring has a flattened roof shape, with the roof angle equal to 10.10 (6)°. The thio­semicarbazones act as tridentate ligands to one ZnII atom, with the O atoms additionally in bridging positions to the second ZnII atom. Both ZnII atoms are five-coordinated; the coordination polyhedra are close to square pyramids, with the pyridine N atoms at apical positions. Two inter­molecular N—H⋯N and one relatively weak N—H⋯S hydrogen bond, together with C—H⋯S weak inter­actions, connect the mol­ecules into a three-dimensional network.

In the title compound, [U(C18H15N3O3S)O2(C2H5OH)]·C2H5OH, the UVI ion is in a distorted penta­gonal–bipyramidal coordination geometry, with two oxide O atoms in axial sites. Two N and two O atoms of the tetra­dentate ligand and an O atom of an ethanol ligand form the equatorial plane. The dihedral angle between the mean planes of the two benzene rings is 34.8 (3)°. In the crystal, relatively strong O—H⋯O hydrogen bonds connect the complex and ethanol solvent mol­ecules into alternating centrosymmetric R 2 2(8) and R 4 4(16) ring motifs, forming chains along [100]. Weak inter­molecular C—H⋯O hydrogen bonds are also present.

In the title compound, C16H12BrFO2, the dihedral angle between the aromatic rings is 23.75 (12)° and the dihedral angle between the prop-2-en-1-one fragment and the fluorobenzene ring is 20.9 (2)°. In the crystal, only van der Waals interactions occur.

The overall shape of the mol­ecule of the title compound, C17H15BrO2, can be described by the dihedral angles between three planar fragments: 1-bromo-2-meth­oxy­phenyl ring [maximum deviation = 0.003 (2) Å], the central prop-2-en-1-one chain [maximum deviation = 0.005 (2) Å], and the methyl­phenyl ring [maximum deviation = 0.004 (2) Å]. The terminal planes are twisted by 10.37 (12)°, while the central plane is almost coplanar with the methyl­phenyl ring [3.30 (13)°], but the dihedral angle with the other phenyl ring is significantly larger [8.76 (16)°]. In the crystal, mol­ecules are linked into chains along [001] by three C—H⋯O hydrogen bonds. These chains inter­act with each other by means of weak π–π contacts [centroid–centroid distances = 3.73 (1) and 3.44 (1) Å]. An inter­molecular C—H⋯Br inter­action also occurs.

There are two symmetry-independent mol­ecules in the asymmetric unit of the title compound, C21H17Cl2FO3. Both these mol­ecules are very similar: the normal probability plots for bond lengths, angles and even for torsion angles show that the differences are of a statistical nature. A pseudocentre of symmetry is located between the symmetry-independent mol­ecules at [0.245 (1), 0.535 (19), 0.909 (1)]. The cyclo­hexene rings have slightly distorted sofa conformations in both mol­ecules and the two benzene rings are inclined by dihedral angles of 61.33 (14) and 62.85 (14)°. In the crystal, relatively short inter­molecular C—H⋯O inter­actions join mol­ecules into homomolecular (i.e. ⋯AAA⋯ and ⋯BBB⋯) chains along the b axis. These chains are inter­connected by further heteromolecular C—H⋯O inter­actions.

In the crystal structure of the title compound [systematic name: 1-methyl­piperazine-1,4-diium bis­(2,4,6-trinitro­phen­ol­ate)], C5H14N2 2+·2C6H2N3O7 −, the ionic components are connected by relatively strong N—H⋯O hydrogen bonds into centrosymmetric six-membered conglomerates, which comprise two dications and four anions. Besides Coulombic inter­actions, only weak C—H⋯O inter­actions and some stacking between picrates (separation between the planes of ca. 3.4 Å but only a small overlapping) can be identified between these ‘building blocks’ of the crystal structure. The piperazine ring adopts a chair conformation with the methyl substituent in the equatorial position. In the picrate anions, the twist angles of the nitro groups depend on their positions relative to the phenolate O atom: it is much smaller for the NO2 groups para to the C—O− group [15.23 (9)and 3.92 (14)°] than for the groups in the ortho positions [28.76 (13)–39.84 (11)°].

In the crystal structure of the title compound, C21H18F2O3, the cyclo­hexene ring has a slightly distorted sofa conformation; the two benzene rings are inclined by 76.27 (8)° and their planes make dihedral angles of 16.65 (10) and 67.53 (7)° with the approximately planar part of the cyclo­hexenone ring [maximum deviation 0.044 (2) Å, while the sixth atom is displaced by 0.648 (3) Å from this plane]. In the crystal, weak inter­molecular C—H⋯O, C—H⋯F and C—H⋯π inter­actions join mol­ecules into a three-dimensional structure.

In the crystal structure of the title compound, C21H18ClFO3·0.5C7H8, the toluene solvent mol­ecules occupy special positions on centres of symmetry, and consequently are disordered across this site. The cyclo­hexene ring has a slightly distorted sofa conformation; the two benzene rings are inclined by 72.90 (7)° and their planes make dihedral angles of 30.09 (10) (chloro­phen­yl) and 88.13 (6)° (fluoro­phen­yl) with the approximately planar part of the cyclo­hexenone ring [maximum deviation from plane through five atoms is 0.030 (2) Å, the sixth atom is 0.672 (3)Å out of this plane]. Weak inter­molecular C—H⋯O and C—H⋯X (X = F, Cl) inter­actions join mol­ecules into a three-dimensional structure. Also, a relatively short and directional C—Cl⋯F—C contact is observed [Cl⋯F = 3.119 (2) Å, C—Cl⋯F = 157.5 (2)° and C—F⋯Cl 108.3 (2)°]. The solvent mol­ecules fill the voids in the crystal structure and are kept there by relatively short and directional C—H⋯π inter­actions.

In both ionic components of the title salt, C4H7N2 +·C6H2N3O7 −, the rings are approximately planar; the maximum deviation from the mean plane is an order of magnitude larger in the picrate ring [0.0289 (10) Å] than in the imidazolium ring [0.0028 (10) Å. The nitro groups are twisted with respect to the six-atom ring plane; the NO2 groups next to the oxide O atom, at the 2- and 6-positions, are twisted more [by 53.59 (9) and 18.46 (12)°] than the NO2 group at the 4-postition, for which the twist angle is 7.28 (16)°. In the crystal, N—H⋯O hydrogen bonds, in which the hydroxyl O atom acts as a double acceptor and one of the O atoms from a nitro group acts as an additional acceptor, connect mol­ecules into chains along the c-axis direction. Relatively short C—H⋯O contacts and π–π inter­actions between symmetry-related six-membered rings [centroid–centroid distances = 3.5938 (10) and 3.6223 (10) Å] also occur.

In the mononuclear title complex, [Co(C18H18N2O2)(C4H9N)2]ClO4·0.5C8H10, the CoIII ion has a slightly distorted octa­hedral coordination geometry. In the Me–salen ligand, the benzene rings are almost parallel, making a dihedral angle of 0.48 (13)°, but the torsion angle along the central C—C bond is 41.1 (2)°·The pyrrolidine rings are in slightly distorted chair conformations. The N atoms of the pyrrolidine axial ligands are involved in N—H⋯O hydrogen bonds with the perchlorate anions, and these hydrogen bonds connect the ionic species into infinite chains along the b axis. Some relatively short C—H⋯π inter­actions are also present in the crystal structure and C—H⋯O inter­actions occur. The guest solvent p-xylene mol­ecule lies on a special position at the inversion centre.

The title compound, C13H13F2N6O+·C6H2N3O7 −, is the first structurally characterized salt of the cation of fluconazole [systematic name 2-(2,4-difluorophenyl)-1,3-bis(1H-1,2,4-triazol-1-yl)propan-2-ol], a synthetic anti­fungal agent. In the crystal, the components are linked by O—H⋯O hydrogen bonding between the hy­droxy group of the fluconazolium cation and the C=O(−) group of the picrate anion. This complex is additionally stabilized by secondary, but relatively short, C—H⋯O inter­actions. The dimers thus formed are connected by N—H⋯N cation–cation hydrogen bonds into helices running along [010]. Neighboring helices of opposite handedness are joined by weak anion–anion C—H⋯O(nitro) inter­actions. In the cation, the mean planes of the three rings are approximately, within ca 25°, parallel to the central C—O bond. In the picrate anion two nitro groups, in turn, are almost coplanar with the ring plane [forming dihedral angles of 6.5 (2) and 3.8 (2)°] while the third nitro group is significantly twisted [by 46.79 (13)°].

The title compound, C15H10BrFO, is isostructural with (2E)-1-(4-chloro­phen­yl)-3-(4-fluoro­phen­yl)prop-2-en-1-one [Qiu et al. (2006 ▶). Acta Cryst. E62, o3525–o3526], but the structures of other dihalogen analogues, without fluorine, are different, although they are also isostructural within the series. The mol­ecule is approximately flat, the dihedral angle between the ring planes being 8.49 (13)°. In the crystal structure, inter­molecular C—H⋯O, C—H⋯F and C—H⋯Br hydrogen bonds link mol­ecules into V-shaped ribbons running parallel to [101] and stacked with an inter­planar distance of approximately 3.53 Å (centroid–vcentroid distance = 3.857 Å)..

In the title compound, C15H13Cl2NOS, the benzene and thio­phene rings make a dihedral angle of 10.8 (1)°. The dimethyl­amino substituent and the α,β-unsaturated carbonyl group are almost coplanar with respect to the aromatic ring, forming dihedral angles of 4.73 (3)° and 5.0 (2)°, respectively. In the crystal structure, mol­ecules are connected into two-dimensional layers by weak C—H⋯Cl hydrogen bonds and C—Cl⋯O [Cl⋯O = 3.073 (2) Å] inter­actions. These layers are stacked with short C(meth­yl)–H⋯π contacts betweeen the layers.

In the title compound, C19H13F3N2O·H2O, the phenyl and pyrroloquinoline ring system are close to coplanar [dihedral angle = 10.94 (4)°]. The meth­oxy group also is almost coplanar with the phenyl ring [5.4 (1)°]. In the crystal structure N—H⋯O(water) and water–quinoline O—H⋯N hydrogen bonds build up a supra­molecular chain-like arrangement along [001]. The remaining H atom of the water mol­ecule does not take part in classical hydrogen bonds. Instead, this O—H bond points toward the center of the phenyl ring of a neighbouring mol­ecule. Weak C—H⋯O and C—H⋯π inter­actions are also present.

In the title compound, C19H16F3N3, the dihedral angle between the naphthalene and quinoline ring systems is 14.58 (8)°. The hydrazone C—N—N=C—C chain is in an extended conformation and its mean plane is nearly coplanar with the quinoline plane [dihedral angle = 3.45 (9)°]. The bond angles within the phenyl ring show the almost additive influence of the two para substituents. In the crystal, weak π–π [centroid–centroid distances = 3.779 (2) and 3.718 (1) Å] and C—H⋯F directional inter­actions join the mol­ecules into centrosymmetric dimers, which are further connected into infinite zigzag chains propagating along a.

In the title compound, C24H21BrO3, the central bromo­methoxy­benzene ring forms dihedral angles of 63.6 (1) and 60.3 (1)° with the terminal phenyl rings, while the angle between the two phenyl rings is 25.8 (1)°. The crystal structure is stabilized by weak C—H⋯Br and C—H⋯O hydrogen bonds, and C—H⋯π and π–π stacking [centroid–centroid distance = 3.910 (3) Å] inter­actions.

In the title compound, C11H14ClNO, the piperidine ring adopts a chair conformation: the hydroxyl substituent and the N-bound H atom occupy the axial positions, while the benzene ring occupies the equatorial position. In the crystal, the mol­ecules are linked into a centrosymmetric tetra­mer through strong O—H⋯N and weak N—H⋯O hydrogen bonds; the N and O atoms act as both donor and acceptor for these inter­actions. The tetra­mers are further joined by hydrogen bonds into a layer parallel to (100).

The crystal structure of chloranilic acid, C6H2Cl2O4, was first described by Andersen in 1967 [Andersen, E. K. (1967). Acta Cryst. 22, 188–191] at room temperature using visually estimated intensities. Taking into account the importance of the title compound, we have redetermined the structure at 100 (1) K. The approximately planar mol­ecule [the maximum deviation from the mean plane through the ring is 0.0014 (9) Å for the ring atoms and 0.029 (3) Å for the other atoms] occupies a special position, lying across the center of symmetry. In the crystal structure, a two-dimensional hydrogen-bonded network sustained by O—H⋯O inter­actions runs approximately parallel to [101]. The two-dimensional layers are further packed in a parallel fashion, stabilized by Cl⋯Cl inter­actions [Cl⋯Cl = 3.2838 (8) Å, C—Cl⋯Cl = 152.96 (6)°].

In the title compound, C15H10Cl3NO2, an intra­molecular N—H⋯O hydrogen bond forms a six-membered ring and enforces an almost coplanar conformation for the acetamido group, the central benzene ring and the bridging carbonyl C—C(=O)—C group: the dihedral angles between the benzene ring and the acetamide and carbonyl C—C(=O)—C planes are 7.06 (11) and 7.17 (12)°, respectively. The dihedral angle between the two benzene rings is 67.43 (9)°. Because a strong hydrogen-bond donor is involved in the intra­molecular inter­action, the crystal packing is determined by weak C—H⋯O and C—H⋯Cl inter­actions.

In the title compound (systematic name: 1-benz­yloxy-3-methyl-1-oxobutan-2-aminium chloride), C12H18NO2 +·Cl−, the ester group is approximately planar, with a maximum deviation of 0.040 (2) Å from the least-squares plane, and makes a dihedral angle of 28.92 (16)° with the phenyl ring. The crystal structure is organized by N—H⋯Cl hydrogen bonds which join the two components into a chain along the b axis. Pairs of chains arranged anti­parallel are inter­connected by further N—H⋯Cl hydrogen bonds, forming eight-membered rings. Similar packing modes have been observed in a number of amino acid ester halides with a short unit-cell parameter of ca 5.5 Å along the direction in which the chains run.