The title compound, C16H17N3O3, is racemic as it crystallizes in a centrosymmetric space group (Poverline{1}), although the trans disposition of substituents about the central C—C bond is established. The five- and six-membered rings are oriented at a dihedral angle of 75.88 (8)°. In the crystal, N—H⋯N hydrogen bonds form chains of mol­ecules extending along the c-axis direction that are connected by inversion-related pairs of O—H⋯N into ribbons. The ribbons are linked by C—H⋯π(ring) inter­actions, forming layers parallel to the ab plane. A Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯H (45.9%), H⋯N/N⋯H (23.3%), H⋯C/C⋯H (16.2%) and H⋯O/O⋯H (12.3%) inter­actions. Hydrogen bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. The volume of the crystal voids and the percentage of free space were calculated to be 100.94 Å3 and 13.20%, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the electrostatic energy contributions in the title compound. Moreover, the DFT-optimized structure at the B3LYP/6–311 G(d,p) level is compared with the experimentally determined mol­ecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.

The in­do­line portion of the title mol­ecule, C16H13NO2, is planar. In the crystal, a layer structure is generated by C—H⋯O hydrogen bonds and C—H⋯π(ring), π-stacking and C=O⋯π(ring) inter­actions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (43.0%), H⋯C/C⋯H (25.0%) and H⋯O/O⋯H (22.8%) inter­actions. Hydrogen bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. The volume of the crystal voids and the percentage of free space were calculated to be 120.52 Å3 and 9.64%, respectively, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated by the dispersion energy contributions in the title compound. Moreover, the DFT-optimized structure at the B3LYP/6-311G(d,p) level is compared with the experimentally determined mol­ecular structure in the solid state.

The title compound, C27H20N4O3S, crystallizes in the monoclinic system, space group P21/n, with Z = 4. The global shape of the mol­ecule is determined by the orientation of the substituents on the central 4H-1,2,4-triazole ring. The nitro­phenyl ring, phenyl ring, and naphthalene ring system are oriented at dihedral angles of 82.95 (17), 77.14 (18) and 89.46 (15)°, respectively, with respect to the triazole ring. The crystal packing features chain formation in the b-axis direction by S⋯O inter­actions. A Hirshfeld surface analysis indicates that the highest contributions to surface contacts arise from contacts in which H atoms are involved.

In the crystal of the title compound, C6H9ClN2O, mol­ecular pairs form dimers with an R22(8) motif through N—H⋯O hydrogen bonds. These dimers are connect into ribbons parallel to the (100) plane with R44(10) motifs by N—H⋯O hydrogen bonds along the c-axis direction. In addition, π–π [centroid-to-centroid distance = 3.4635 (9) Å] and C—Cl⋯π inter­actions between the ribbons form layers parallel to the (100) plane. The three-dimensional consolidation of the crystal structure is also ensured by Cl⋯H and Cl⋯Cl inter­actions between these layers. According to a Hirshfeld surface study, H⋯H (43.3%), Cl⋯H/H⋯Cl (22.1%) and O⋯H/H⋯O (18.7%) inter­actions are the most significant contributors to the crystal packing.

The title compound [systematic name: 1-(2-nitro­phen­yl)pyrrole-2,5-dione], C10H6N2O4, crystallizes in the monoclinic system (space group P21/n) with two mol­ecules in the asymmetric unit, which are linked by C—H⋯O hydrogen bonds. Hirshfeld surface analysis showed that the most significant contributions to the crystal packing are from H⋯O/O⋯H, H⋯C/C⋯H and H⋯H inter­actions, which contribute 54.7%, 15.2% and 15.6%, respectively. A DFT study was conducted using three different levels of theory [(B3LYP/6–311+G(d,p), wB97XD/Def2TZVPP and LC-wpbe/6–311(2 d,2p)] in order to determine the stability, structural and electronic properties of the title mol­ecule with a view to its potential applications and photochemical and copolymer properties.

The title compound, [CdBr2(C6H14N2O)], was synthesized upon complexation of 4-(2-aminoethyl)morpholine and cadmium(II) bromide tetra­hydrate at 303 K. It crystallizes as a centrosymmetric dimer, with one cadmium atom, two bromine atoms and one N,N'-bidentate 4-(2-aminoethyl)morpholine ligand in the asymmetric unit. The metal atom is six-coordinated and has a distorted octa­hedral geometry. In the crystal, O⋯Cd inter­actions link the dimers into a polymeric double chain and inter­molecular C—H⋯O hydrogen bonds form R22(6) ring motifs. Further C—H⋯Br and N—H⋯Br hydrogen bonds link the components into a three-dimensional network. As the N—H⋯Br hydrogen bonds are shorter than the C—H⋯Br inter­actions, they have a larger effect on the packing. A Hirshfeld surface analysis reveals that the largest contributions to the packing are from H⋯H (46.1%) and Br⋯H/H⋯Br (38.9%) inter­actions with smaller contributions from the O⋯H/H⋯O (4.7%), Br⋯Cd/Cd⋯Br (4.4%), O⋯Cd/Cd⋯O (3.5%), Br⋯Br (1.1%), Cd⋯H/H⋯Cd (0.9%), Br⋯O/O⋯Br (0.3%) and O⋯N/N⋯O (0.1%) contacts.

The title mol­ecule, [Fe2(C5H5)2(C23H17ClN2)]·C3H7NO, is twisted end to end and the central N/C/N unit is disordered. In the crystal, several C—H⋯π(ring) inter­actions lead to the formation of layers, which are connected by further C—H⋯π(ring) inter­actions. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (60.2%) and H⋯C/C⋯H (27.0%) inter­actions. Hydrogen bonding, C—H⋯π(ring) inter­actions and van der Waals inter­actions dominate the crystal packing.

The crystal structures and Hirshfeld surface analyses of three similar compounds are reported. Methyl 4-[4-(di­fluoro­meth­oxy)phen­yl]-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa­hydro­quinoline-3-carboxyl­ate, (C21H23F2NO4), (I), crystallizes in the monoclinic space group C2/c with Z = 8, while isopropyl 4-[4-(di­fluoro­meth­oxy)phen­yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa­hydro­quinoline-3-carb­oxyl­ate, (C23H27F2NO4), (II) and tert-butyl 4-[4-(di­fluoro­meth­oxy)phen­yl]-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexa­hydro­quinoline-3-carboxyl­ate, (C24H29F2NO4), (III) crystallize in the ortho­rhom­bic space group Pbca with Z = 8. In the crystal structure of (I), mol­ecules are linked by N—H⋯O and C—H⋯O inter­actions, forming a tri-periodic network, while mol­ecules of (II) and (III) are linked by N—H⋯O, C—H⋯F and C—H⋯π inter­actions, forming layers parallel to (002). The cohesion of the mol­ecular packing is ensured by van der Waals forces between these layers. In (I), the atoms of the 4-di­fluoro­meth­oxy­phenyl group are disordered over two sets of sites in a 0.647 (3): 0.353 (3) ratio. In (III), the atoms of the dimethyl group attached to the cyclo­hexane ring, and the two carbon atoms of the cyclo­hexane ring are disordered over two sets of sites in a 0.646 (3):0.354 (3) ratio.

In the title compound, C31H24N4O2, the quinoxaline units are distinctly non-planar and twisted end-to-end. In the crystal, C—H⋯O and C—H⋯N hydrogen bonds link the mol­ecules into chains extending along the a-axis direction. The chains are linked through π-stacking inter­actions between inversion-related quinoxaline moieties.

The title compound, C14H12N2O4, was obtained from 2-acetyl-6-amino­naphthalene through two-step reactions of acetyl­ation and nitration. The mol­ecule comprises the naphthalene ring system consisting of functional systems bearing a acetyl group (C-2), a nitro group (C-5), and an acetyl­amino group (C-6). In the crystal, the mol­ecules are assembled into two-dimensional sheet-like structures by inter­molecular N—H⋯O and C—H⋯O hydrogen-bonding inter­actions. Hirshfeld surface analysis illustrates that the most important contributions to the crystal packing are from O⋯H/H⋯O (43.7%), H⋯H (31.0%), and C⋯H/H⋯C (8.5%) contacts.

In the title compound, C21H15N5OS2, mol­ecular pairs are linked by N—H⋯N hydrogen bonds along the c-axis direction and C—H⋯S and C—H⋯O hydrogen bonds along the b-axis direction, with R22(12) and R22(16) motifs, respectively, thus forming layers parallel to the (10overline{4}) plane. In addition, C=S⋯π and C≡N⋯π inter­actions between the layers ensure crystal cohesion. The Hirshfeld surface analysis indicates that the major contributions to the crystal packing are H⋯H (43.0%), C⋯H/H⋯C (16.9%), N⋯H/H⋯N (11.3%) and S⋯H/H⋯S (10.9%) inter­actions.

The asymmetric unit of the title compound, 2C31H28N2O4S·C2H6O, contains a parent mol­ecule and a half mol­ecule of ethanol solvent. The main compound stabilizes its mol­ecular conformation by forming a ring with an R12(7) motif with the ethanol solvent mol­ecule. In the crystal, mol­ecules are connected by C—H⋯O and O—H⋯O hydrogen bonds, forming a three-dimensional network. In addition, C—H⋯π inter­actions also strengthen the mol­ecular packing.

In the crystal of the title compound, C18H14O10·2H2O, the arene rings of the biphenyl moiety are tilted at an angle of 24.3 (1)°, while the planes passing through the carboxyl groups are rotated at angles of 8.6 (1) and 7.7 (1)° out of the plane of the benzene ring to which they are attached. The crystal structure is essentially stabilized by O—H⋯O bonds. Here, the carboxyl groups of neighbouring host mol­ecules are connected by cyclic R22(8) synthons, leading to the formation of a three-dimensional network. The water mol­ecules in turn form helical supra­molecular strands running in the direction of the crystallographic c-axis (chain-like water clusters). The second H atom of each water mol­ecule provides a link to a meth­oxy O atom of the host mol­ecule. A Hirshfeld surface analysis was performed to qu­antify the contributions of the different inter­molecular inter­actions, indicating that the most important contributions to the crystal packing are from H⋯O/O⋯H (37.0%), H⋯H (26.3%), H⋯C/C⋯H (18.5%) and C⋯O/O⋯C (9.5%) inter­actions.

In the title mol­ecule, C21H23N3O3, the imidazolidine ring slightly deviates from planarity and the morpholine ring exhibits the chair conformation. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds form helical chains of mol­ecules extending parallel to the c axis that are connected by C—H⋯π(ring) inter­actions. A Hirshfeld surface analysis reveals that the most important contributions for the crystal packing are from H⋯H (55.2%), H⋯C/C⋯H (22.6%) and H⋯O/O⋯H (20.5%) inter­actions. The volume of the crystal voids and the percentage of free space were calculated to be 236.78 Å3 and 12.71%, respectively. Evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the nearly equal electrostatic and dispersion energy contributions. The DFT-optimized mol­ecular structure at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined mol­ecular structure in the solid state. Moreover, the HOMO–LUMO behaviour was elucidated to determine the energy gap.

In the ten-membered 1,3,4,6-tetra­hydro-2H-pyrido[1,2-a]pyrimidine ring system of the title compound, C17H15N5, the 1,2-di­hydro­pyridine ring is essentially planar (r.m.s. deviation = 0.001 Å), while the 1,3-diazinane ring has a distorted twist-boat conformation. In the crystal, mol­ecules are linked by N—H⋯N and C—H⋯N hydrogen bonds, forming a three-dimensional network. In addition, C—H⋯π inter­actions form layers parallel to the (100) plane. Thus, crystal-structure cohesion is ensured. According to a Hirshfeld surface study, H⋯H (40.4%), N⋯H/H⋯N (28.6%) and C⋯H/H⋯C (24.1%) inter­actions are the most important contributors to the crystal packing.

In the title compound, C17H12N2O, the quinoxaline moiety shows deviations of 0.0288 (7) to −0.0370 (7) Å from the mean plane (r.m.s. deviation of fitted atoms = 0.0223 Å). In the crystal, corrugated layers two mol­ecules thick are formed by C—H⋯N hydrogen bonds and π-stacking inter­actions.

The quinoxaline moiety in the title mol­ecule, C13H13ClN2O3, is almost planar (r.m.s. deviation of the fitted atoms = 0.033 Å). In the crystal, C—H⋯O hydrogen bonds plus slipped π-stacking and C—H⋯π(ring) inter­actions generate chains of mol­ecules extending along the b-axis direction. The chains are connected by additional C—H⋯O hydrogen bonds. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (37.6%), H⋯O/O⋯H (22.7%) and H⋯Cl/Cl⋯H (13.1%) inter­actions.

A novel cationic complex, bromido­tetra­kis­[5-(prop-2-en-1-ylsulfan­yl)-1,3,4-thia­diazol-2-amine-κN3]copper(II) bromide, [CuBr](C5H7N3S2)4Br, was synthesized. The complex crystallizes with fourfold mol­ecular symmetry in the tetra­gonal space group P4/n. The CuII atom exhibits a square-pyramidal coord­ination geometry. The Cu atom is located centrally within the complex, being coordinated by four nitro­gen atoms from four AAT mol­ecules, while a bromine anion is located at the apex of the pyramid. The amino H atoms of AAT inter­act with bromine from the inner and outer spheres, forming a two-dimensional network in the [100] and [010] directions. Hirshfeld surface analysis reveals that 33.7% of the inter­mol­ecular inter­actions are from H⋯H contacts, 21.2% are from S⋯H/H⋯S contacts, 13.4% are from S⋯S contacts and 11.0% are from C⋯H/H⋯C, while other contributions are from Br⋯H/H⋯Br and N⋯H/H⋯N contacts.

In the title compound, C20H17BrO5S, mol­ecules are connected by inter­molecular C—H⋯S hydrogen bonds with R22(10) ring motifs, forming ribbons along the b-axis direction. C—H⋯π inter­actions consolidate the ribbon structure while van der Waals forces between the ribbons ensure the cohesion of the crystal structure. According to a Hirshfeld surface analysis, H⋯H (40.5%), O⋯H/H⋯O (27.0%), C⋯H/H⋯C (13.9%) and Br⋯H/H⋯Br (11.7%) inter­actions are the most significant contributors to the crystal packing. The thio­phene ring and its adjacent di­carboxyl­ate group and the three adjacent carbon atoms of the central hexene ring to which they are attached were refined as disordered over two sets of sites having occupancies of 0.8378 (15) and 0.1622 (15). The thio­phene group is disordered by a rotation of 180° around one bond.

Carb­oxy­hydrazides are widely used in medicinal chemistry because of their medicinal properties and many drugs have been developed containing this functional group. A suitable inter­mediate to obtain potential hydrazide drug candidates is the title compound 5-hy­droxy­penta­nehydrazide, C5H12N2O2 (1). The aliphatic compound can react both via the hydroxyl and hydrazide moieties forming derivatives, which can inhibit Mycobacterium tuberculosis catalase-peroxidase (KatG) and consequently causes death of the pathogen. In this work, the hydrazide was obtained via a reaction of a lactone with hydrazine hydrate. The colourless prismatic single crystals belong to the ortho­rhom­bic space group Pca21. Regarding supra­molecular inter­actions, the compound shows classic medium to strong inter­molecular hydrogen bonds involving the hydroxyl and hydrazide groups. Besides, the three-dimensional packing also shows weak H⋯H and C⋯H contacts, as investigated by Hirshfeld surface analysis (HS) and fingerprint plots (FP).

The asymmetric unit of the title compound, C25H18N6·H2O, comproses two mol­ecules (I and II), together with a water mol­ecule. The terminal phenyl groups attached to the methyl groups of the mol­ecules I and II do not overlap completely, but are approximately perpendicular. In the crystal, the mol­ecules are connected by N—H⋯N, C—H⋯N, O—H⋯N and N—H⋯O hydrogen bonds with each other directly and through water mol­ecules, forming layers parallel to the (001) plane. C—H⋯π inter­actions between these layers ensure the cohesion of the crystal structure. A Hirshfeld surface analysis indicates that H⋯H (39.1% for mol­ecule I; 40.0% for mol­ecule II), C⋯H/H⋯C (26.6% for mol­ecule I and 25.8% for mol­ecule II) and N⋯H/H⋯N (24.3% for mol­ecules I and II) inter­actions are the most important contributors to the crystal packing.

The title copper(II) complex, [Cu(C18H19N3O3)(C3H4N2)], consists of a tridentate ligand synthesized from l-leucine and azo­benzene-salicyl­aldehyde. One imidazole mol­ecule is additionally coordinated to the copper(II) ion in the equatorial plane. The crystal structure features N—H⋯O hydrogen bonds. A Hirshfeld surface analysis indicates that the most important contributions to the packing are from H⋯H (52.0%) and C⋯H/H⋯C (17.9%) contacts.

The title compound, C12H15N3O2S, adopts an E configuration with respect to the C=N bond. The propionate group adopts an anti­periplanar (ap) conformation. There are short intra­molecular N—H⋯N and C—H⋯O contacts, forming S(5) and S(6) ring motifs, respectively. In the crystal, mol­ecules are connected into ribbons extending parallel to [010] by pairs of N—H⋯S inter­actions, forming rings with R22(8) graph-set motifs, and by pairs of C—H⋯S inter­actions, where rings with the graph-set motif R21(7) are observed. The O atom of the carbonyl group is disordered over two positions, with a refined occupancy ratio of 0.27 (2):0.73 (2). The studied crystal consisted of two domains.

In the title compound, C24H21NO3S, the cyclopentene ring adopts an envelope conformation. In the crystal, mol­ecules are linked by C—H⋯π inter­actions, forming ribbons along the a axis. Inter­molecular C—H⋯O hydrogen bonds connect these ribbons to each other, forming layers parallel to the (0overline{1}1) plane. The mol­ecular packing is strengthened by van der Waals inter­actions between the layers. The inter­molecular contacts were qu­anti­fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H⋯H 46.0%, C⋯H/H⋯C 21.1%, O⋯H/H⋯O 20.6% and S⋯H/H⋯S 9.0%.

In the title mol­ecule, C21H17N3O2, the five-membered ring is slightly ruffled and dihedral angles between the pendant six-membered rings and the central, five-membered ring vary between 50.78 (4) and 86.78 (10)°. The exocyclic nitro­gen lone pair is involved in conjugated π bonding to the five-membered ring. In the crystal, a layered structure is generated by O—H⋯N and N—H⋯O hydrogen bonds plus C—H⋯π(ring) and weak π-stacking inter­actions.

The title compound, C12H10N2O3, was obtained by the de­acetyl­ation reaction of 1-(6-amino-5-nitro­naphthalen-2-yl)ethanone in a concentrated sulfuric acid methanol solution. The mol­ecule comprises a naphthalene ring system bearing an acetyl group (C-3), an amino group (C-7), and a nitro group (C-8). In the crystal, the mol­ecules are assembled into a two-dimensional network by N⋯H/H⋯N and O⋯H/H⋯O hydrogen-bonding inter­actions. n–π and π–π stacking inter­actions are the dominant inter­actions in the three-dimensional crystal packing. Hirshfeld surface analysis indicates that the most important contributions are from O⋯H/H⋯O (34.9%), H⋯H (33.7%), and C⋯H/H⋯C (11.0%) contacts. The energies of the frontier mol­ecular orbitals were computed using density functional theory (DFT) calculations at the B3LYP-D3BJ/def2-TZVP level of theory and the LUMO–HOMO energy gap of the mol­ecule is 3.765 eV.

In the title compound, C15H13NO3S, the mol­ecular conformation is stable with the intra­molecular O—H⋯O hydrogen bond forming a S(7) ring motif. In the crystal, mol­ecules are connected by C—H⋯O hydrogen bonds, forming C(8) chains running along the a-axis direction. Cohesion of the packing is provided by weak van der Waals inter­actions between the chains. A Hirshfeld surface analysis was undertaken to investigate and qu­antify the inter­molecular inter­actions. The thio­phene ring is disordered in a 0.9466 (17):0.0534 (17) ratio over two positions rotated by 180°.

The benzimidazole entity of the title mol­ecule, C17H21N5O, is almost planar (r.m.s. deviation = 0.0262 Å). In the crystal, bifurcated C—H⋯O hydrogen bonds link individual mol­ecules into layers extending parallel to the ac plane. Two weak C—H⋯π(ring) inter­actions may also be effective in the stabilization of the crystal structure. Hirshfeld surface analysis of the crystal structure reveals that the most important contributions for the crystal packing are from H⋯H (57.9%), H⋯C/C⋯H (18.1%) and H⋯O/O⋯H (14.9%) inter­actions. Hydrogen bonding and van der Waals inter­actions are the most dominant forces in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization of the title compound is dominated via dispersion energy contributions. The mol­ecular structure optimized by density functional theory (DFT) at the B3LYP/6–311 G(d,p) level is compared with the experimentally determined mol­ecular structure in the solid state.

In the title compound, C6H4BrF3N4O2, the oxa­diazole ring is essentially planar with a maximum deviation of 0.003 (2) Å. In the crystal, mol­ecular pairs are connected by N—H⋯N hydrogen bonds, forming dimers with an R22(8) motif. The dimers are linked into layers parallel to the (10overline{4}) plane by N—H⋯O hydrogen bonds. In addition, C—O⋯π and C—Br⋯π inter­actions connect the mol­ecules, forming a three-dimensional network. The F atoms of the tri­fluoro­methyl group are disordered over two sites in a 0.515 (6): 0.485 (6) ratio. The inter­molecular inter­actions in the crystal structure were investigated and qu­anti­fied using Hirshfeld surface analysis.

The reaction of copper(II) oxalate and hexa­methyl­ene­tetra­mine in a deep eutectic solvent made of urea and choline chloride produced crystals of penta­amine­copper(II) dichloride–urea (1/1), [Cu(NH3)5]Cl2·CO(NH2)2, which was characterized by single-crystal X-ray diffraction. The complex contains discrete penta­amine­copper(II) units in a square-based pyramidal geometry. The overall structure of the multi-component crystal is dictated by hydrogen bonding between urea mol­ecules and amine H atoms with chloride anions.

The title mol­ecule, C18H26O4, consists of two symmetrical halves related by the inversion centre at the mid-point of the central –C—C– bond. The hexene ring adopts an envelope conformation. In the crystal, the mol­ecules are connected into dimers by C—H⋯O hydrogen bonds with R22(8) ring motifs, forming zigzag ribbons along the b-axis direction. According to a Hirshfeld surface analysis, H⋯H (68.2%) and O⋯H/H⋯O (25.9%) inter­actions are the most significant contributors to the crystal packing. The contribution of some disordered solvent to the scattering was removed using the SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9–18] in PLATON. The solvent contribution was not included in the reported mol­ecular weight and density.

In the title compound, C31H24N4O2, the di­hydro­quinoxaline units are both essentially planar with the dihedral angle between their mean planes being 64.82 (4)°. The attached phenyl rings differ significantly in their rotational orientations with respect to the di­hydro­quinoxaline planes. In the crystal, one set of C—H⋯O hydrogen bonds form chains along the b-axis direction, which are connected in pairs by a second set of C—H⋯O hydrogen bonds. Two sets of π-stacking inter­actions and C—H⋯π(ring) inter­actions join the double chains into the final three-dimensional structure.

In the title compound, C19H17NO5S, the cyclo­hexene ring adopts nearly an envelope conformation. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, forming a three-dimensional network. In addition, C—H⋯π inter­actions connect the mol­ecules by forming layers parallel to the (010) plane. According to the Hirshfeld surface analysis, H⋯H (36.9%), O⋯H/H⋯O (31.0%), C⋯H/H⋯C (18.9%) and S⋯H/H⋯S (7.9%) inter­actions are the most significant contributors to the crystal packing.

Three new 1H-indole derivatives, namely, 2-(bromo­meth­yl)-3-methyl-1-(phenyl­sulfon­yl)-1H-indole, C16H14BrNO2S, (I), 2-[(E)-2-(2-bromo-5-meth­oxy­phen­yl)ethen­yl]-3-methyl-1-(phenyl­sulfon­yl)-1H-indole, C24H20BrNO3S, (II), and 2-[(E)-2-(2-bromo­phen­yl)ethen­yl]-3-methyl-1-(phenyl­sulfon­yl)-1H-indole, C23H18BrNO2S, (III), exhibit nearly orthogonal orientations of their indole ring systems and sulfonyl-bound phenyl rings. Such conformations are favourable for inter­molecular bonding involving sets of slipped π–π inter­actions between the indole systems and mutual C—H⋯π hydrogen bonds, with the generation of two-dimensional monoperiodic patterns. The latter are found in all three structures, in the form of supra­molecular columns with every pair of successive mol­ecules related by inversion. The crystal packing of the compounds is additionally stabilized by weaker slipped π–π inter­actions between the outer phenyl rings (in II and III) and by weak C—H⋯O, C—H⋯Br and C—H⋯π hydrogen bonds. The structural significance of the different kinds of inter­actions agree with the results of a Hirshfeld surface analysis and the calculated inter­action energies. In particular, the largest inter­action energies (up to −60.8 kJ mol−1) are associated with pairing of anti­parallel indole systems, while the energetics of weak hydrogen bonds and phenyl π–π inter­actions are comparable and account for 13–34 kJ mol−1.

In the title mol­ecular salt, (C12H14N2)[CoCl4], the dihedral angle between the pyridine rings of the cation is 52.46 (9)° and the N—C—C—N torsion angle is −128.78 (14)°, indicating that the ring nitro­gen atoms are in anti-clinal conformation. The Cl—Co—Cl bond angles in the anion span the range 105.46 (3)–117.91 (2)°. In the extended structure, the cations and anions are linked by cation-to-anion N—H⋯Cl and C—H⋯Cl inter­actions, facilitating the formation of R44(18) and R44(20) ring motifs. Furthermore, the crystal structure features weak anion-to-cation Cl⋯π inter­actions [Cl⋯π = 3.4891 (12) and 3.5465 (12) Å]. Hirshfeld two-dimensional fingerprint plots revealed that the most significant inter­actions are Cl⋯H/H⋯Cl (45.5%), H⋯H (29.0%), Cl⋯C/C⋯Cl (7.8%), Cl⋯N/N⋯Cl (3.5%), Cl⋯Cl (1.4) and Co⋯H (1%) contacts.

This study presents the synthesis, characterization and Hirshfeld surface analysis of a small organic ammonium salt, C2H7BrN+·Br−. Small cations like the one in the title compound are considered promising components of hybrid perovskites, crucial for optoelectronic and photovoltaic applications. While the incorporation of this organic cation into various hybrid perovskite structures has been explored, its halide salt counterpart remains largely uninvestigated. The obtained structural results are valuable for the synthesis and phase analysis of hybrid perovskites. The title compound crystallizes in the solvent-free form in the centrosymmetric monoclinic space group P21/c, featuring one organic cation and one bromide anion in its asymmetric unit, with a torsion angle of −64.8 (2)° between the ammonium group and the bromine substituent, positioned in a gauche conformation. The crystal packing is predominantly governed by Br⋯H inter­actions, which constitute 62.6% of the overall close atom contacts.

The title compound, C8H11PS, which melts below room temperature, was crystallized at low temperature. The P—S bond length is 1.9623 (5) Å and the major contributors to the Hirshfeld surface are H⋯H (58.1%), S⋯H/H⋯S (13.4%) and C⋯H/H⋯C contacts (11.7%).

The crystal structure of the title 2:1 mol­ecular complex between 2-(allyl­thio)­pyridine and 1,2,4,5-tetra­fluoro-3,6-di­iodo­benzene, C6F4I2·2C8H9NS, at 100 K has been determined in the monoclinic space group P21/c. The most noteworthy characteristic of the complex is the halogen bond between iodine and the pyridine ring with a short N⋯I contact [2.8628 (12) Å]. The Hirshfeld surface analysis shows that the hydrogen⋯hydrogen contacts dominate the crystal packing with a contribution of 32.1%.

In the title compound, C19H18BrFN2O, the pyrrolidine ring adopts an envelope conformation. In the crystal, mol­ecules are linked by inter­molecular N—H⋯O, C—H⋯O, C—H⋯F and C—H⋯Br hydrogen bonds, forming a three-dimensional network. In addition, C—H⋯π inter­actions connect mol­ecules into ribbons along the b-axis direction, consolidating the mol­ecular packing. The inter­molecular inter­actions in the crystal structure were qu­anti­fied and analysed using Hirshfeld surface analysis.

In the title compound, C14H14O4, the dihedral angle between the coumarin ring system (r.m.s deviation = 0.016 Å) and the penta­noate ring is 36.26 (8)°. A short intra­molecular C—H⋯O contact of 2.40 Å is observed. Hirshfeld surface analysis reveals that 46.1% of the inter­molecular inter­actions are from H⋯H contacts, 28.6% are from H⋯O/O⋯H contacts and 14.7% are from H⋯C/C⋯H.

The pyrazolo­pyrimidine moiety in the title mol­ecule, C13H12N4S, is planar with the methyl­sulfanyl substituent lying essentially in the same plane. The benzyl group is rotated well out of this plane by 73.64 (6)°, giving the mol­ecule an approximate L shape. In the crystal, C—H⋯π(ring) inter­actions and C—H⋯S hydrogen bonds form tubes extending along the a axis. Furthermore, there are π–π inter­actions between parallel phenyl rings with centroid-to-centroid distances of 3.8418 (12) Å. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (47.0%), H⋯N/N⋯H (17.6%) and H⋯C/C⋯H (17.0%) inter­actions. The volume of the crystal voids and the percentage of free space were calculated to be 76.45 Å3 and 6.39%, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the cohesion of the crystal structure is dominated by the dispersion energy contributions.

Reaction of thorium(IV) nitrate with 2-[(4-phenyl-1H-1,2,3-triazol-1-yl)meth­yl]pyridine (L) yielded (LH)2[Th(NO3)6] or (C14H13N4)2[Th(NO3)6] (1), instead of the expected mixed-ligand complex [Th(NO3)4L2], which was detected in the mass spectrum of 1. In the structure, the [Th(NO3)6]2− anions display an icosa­hedral coordination geometry and are connected by LH+ cations through C—H⋯O hydrogen bonds. The LH+ cations inter­act via N—H⋯N hydrogen bonds. Hirshfeld surface analysis indicates that the most important inter­actions are O⋯H/H⋯O hydrogen-bonding inter­actions, which represent a 55.2% contribution.

Two new [1-(phenyl­sulfon­yl)-1H-indol-2-yl]methanamine derivatives, namely, N-(3-meth­oxy­phen­yl)-N-{[1-(phenyl­sulfon­yl)-1H-indol-2-yl]meth­yl}acetamide, C24H22N2O4S, (I), and N-(2,5-di­meth­oxy­phen­yl)-N-{[1-(phenyl­sulfon­yl)-1H-indol-2-yl]meth­yl}benzene­sulfonamide, C29H26N2O6S2, (II), reveal a nearly orthogonal orientation of their indole ring systems and sulfonyl-bound phenyl rings. The sulfonyl moieties adopt the anti-periplanar conformation. For both compounds, the crystal packing is dominated by C—H⋯O bonding [C⋯O = 3.312 (4)–3.788 (8) Å], with the structure of II exhibiting a larger number, but weaker bonds of this type. Slipped π–π inter­actions of anti­parallel indole systems are specific for I, whereas the structure of II delivers two kinds of C—H⋯π inter­actions at both axial sides of the indole moiety. These findings agree with the results of Hirshfeld surface analysis. The primary contributions to the surface areas are associated with the contacts involving H atoms. Although II manifests a larger fraction of the O⋯H/H⋯O contacts (25.8 versus 22.4%), most of them are relatively distal and agree with the corresponding van der Waals separations.

The di­hydro­imidazole ring in the title mol­ecule, C20H20N2O3S, is slightly distorted and the lone pair on the tri-coordinate nitro­gen atom is involved in intra-ring π bonding. The methyl­sulfanyl substituent lies nearly in the plane of the five-membered ring while the ester substituent is rotated well out of that plane. In the crystal, C—H⋯O hydrogen bonds form inversion dimers, which are connected along the a- and c-axis directions by additional C—H⋯O hydrogen bonds, forming layers parallel to the ac plane. The major contributors to the Hirshfeld surface are C⋯H/H⋯C, O⋯H/H⋯O and S⋯H/H⋯S contacts at 20.5%, 14.7% and 4.9%, respectively.

The title compound, C17H13BrN4O5, was synthesized by a Cu2Br2-catalysed Meldal–Sharpless reaction between 4-nitro­phen­oxy­acetic acid propargyl ether and para-bromo­phenyl­azide, and characterized by X-ray structure determination and 1H NMR spectroscopy. The mol­ecules, with a near-perpendicular orientation of the bromo­phenyl-triazole and nitro­phen­oxy­acetate fragments, are connected into a three-dimensional network by inter­molecular C—H⋯O and C—H⋯N hydrogen bonds (confirmed by Hirshfeld surface analysis), π–π and Br–π inter­actions.

In the title mol­ecule, C25H29N5O, the di­hydro­quinoxaline unit is not quite planar (r.m.s. deviation = 0.030 Å) as there is a dihedral angle of 2.69 (3)° between the mean planes of the constituent rings and the mol­ecule adopts a hairpin conformation. In the crystal, the polar portions of the mol­ecules are associated through C—H⋯O and C—H⋯N hydrogen bonds and C—H⋯π(ring) and C=O⋯π(ring) inter­actions, forming thick layers parallel to the bc plane and with the n-octyl groups on the outside surfaces.

This study presents the synthesis, characterization and Hirshfeld surface analysis of the title mononuclear complex, [PdCl2(C12H14N4)]·C3H7NO. The compound crystalizes in the P21/c space group of the monoclinic system. The asymmetric unit contains one neutral complex Pd(HLc-Pe)Cl2 [HLc-Pe is 2-(3-cyclo­pentyl-1,2,4-triazol-5-yl)pyridine] and one mol­ecule of DMF as a solvate. The Pd atom has a square-planar coordination. In the crystal, mol­ecules are linked by inter­molecular N—H⋯O and C—H⋯N hydrogen bonds, forming layers parallel to the bc plane. A Hirshfeld surface analysis showed that the H⋯H contacts dominate the crystal packing with a contribution of 41.4%. The contribution of the N⋯H/H⋯N and H⋯O/O⋯H inter­actions is somewhat smaller, amounting to 12.4% and 5%, respectively.

The present study focuses on the synthesis and structural characterization of a novel dinuclear CuII complex, [tri­chlorido­copper(II)]-μ-chlorido-{bis­[2-hy­droxy-N'-(propan-2-yl­idene)benzohydrazide]copper(II)} monohydrate, [Cu2Cl4(C10H12N2O2)2]·H2O or [Cu(H2L)2(μ-Cl)CuCl3]·H2O [H2L = 2-hy­droxy-N'-(propan-2-yl­idene)benzohydrazide]. The complex crystallizes in the monoclinic space group P21/n with one mol­ecule of water, which forms inter­actions with the ligands. The first copper ion is penta-coordinated to two benzohydrazine-derived ligands via two nitro­gen and two oxygen atoms, and one bridging chloride, which is also coordinated by the second copper ion alongside three terminal chlorines in a distorted tetra­hedral geometry. The arrangement around the first copper ion exhibits a distorted geometry inter­mediate between trigonal bipyramidal and square pyramidal. In the crystal, chains are formed via inter­molecular inter­actions along the a-axis direction, with subsequent layers constructed through hydrogen-bonding inter­actions parallel to the ac plane, and through slipped π–π stacking inter­actions parallel to the ab plane, resulting in a three-dimensional network. The inter­molecular inter­actions in the crystal structure were qu­anti­fied and analysed using Hirshfeld surface analysis. Residual electron density from disordered methanol mol­ecules in the void space could not be reasonably modelled, thus a solvent mask was applied.

This study presents the synthesis, characterization and Hirshfeld surface analysis of 1-[6-bromo-2-(3-bromo­phen­yl)-1,2,3,4-tetra­hydro­quinolin-4-yl]pyrrolidin-2-one, C19H18Br2N2O. In the title compound, the pyrrolidine ring adopts a distorted envelope configuration. In the crystal, mol­ecules are linked by inter­molecular N—H⋯O, C—H⋯O and C—H⋯Br hydrogen bonds, forming a three-dimensional network. In addition, pairs of mol­ecules along the c axis are connected by C—H⋯π inter­actions. According to a Hirshfeld surface study, H⋯H (36.9%), Br⋯H/H⋯Br (28.2%) and C⋯H/H⋯C (24.3%) inter­actions are the most significant contributors to the crystal packing.

The title compound, bis­[μ-2,2'-(4H-1,2,4-triazole-3,5-di­yl)di­acetato]­bis­[di­aqua­copper(II)] dihydrate, [Cu2(C6H5N3O4)2(H2O)4]·2H2O, is a dinuclear octa­hedral CuII triazole-based complex. The central copper atoms are hexa-coordinated by two nitro­gen atoms in the equatorial positions, two equatorial oxygen atoms of two carboxyl­ate substituents in position 3 and 5 of the 1,2,4-triazole ring, and two axial oxygen atoms of two water mol­ecules. Two additional solvent water mol­ecules are linked to the title mol­ecule by O—H⋯N and O⋯H—O hydrogen bonds. The crystal structure is built up from the parallel packing of discrete supra­molecular chains running along the a-axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H⋯O/O⋯H (53.5%), H⋯H (28.1%), O⋯O (6.3%) and H⋯C/C⋯H (6.2%) inter­actions. The crystal studied was twinned by a twofold rotation around [100].