In the title mol­ecule, C17H23NO2, the di­hydro­indole portion is planar (r.m.s. deviation = 0.0157 Å) and the nonyl substituent is in an `extended' conformation. In the crystal, the nonyl chains inter­calate and the di­hydro­indole­dione units are associated through C—H⋯O hydrogen bonds to form micellar blocks. Based on the Hirshfeld surface analysis, the most important inter­molecular inter­action is the H⋯H inter­action.

The heterobifunctional organic ligand, 3-(1,2,4-triazol-4-yl)adamantane-1-carboxyl­ate (tr-ad-COO−), was employed for the synthesis of the title silver(I) coordination polymer, {[Ag(C13H16N3O2)]·2H2O}n, crystallizing in the rare ortho­rhom­bic C2221 space group. Alternation of the double μ2-1,2,4-triazole and μ2-η2:η1-COO− (chelating, bridging mode) bridges between AgI cations supports the formation of sinusoidal coordination chains. The AgI centers possess a distorted {N2O3} square-pyramidal arrangement with τ5 = 0.30. The angular organic linkers connect the chains into a tetra­gonal framework with small channels along the c-axis direction occupied by water mol­ecules of crystallization, which are inter­linked via O—H⋯O hydrogen bonds with carboxyl­ate groups, leading to right- and left-handed helical dispositions.

The syntheses and crystal structures of the title compounds, C14H8F4N2O2 and C14H8F4N2O3, are reported. In each crystal, the packing is driven by C—H⋯F inter­tactions, along with a variety of C—H⋯O, C—O⋯π, and C—F⋯π contacts. Hirshfeld surface analysis was conducted to aid in the visualization of these various influences on the packing: they showed that the largest contributions to the surface contacts arise from H⋯F/F⋯H inter­actions, followed by H⋯H and O⋯H/H⋯O.

The title coordination polymer, {[Cu3(C4H4N3O9)3(SeO4)(OH)]·2H2O}n or ([Cu3(μ3-OH)(trgly)3(SeO4)]·2H2O), crystallizes in the monoclinic space group P21/c. The three independent Cu2+ cations adopt distorted square-pyramidal geometries with {O2N2+O} polyhedra. The three copper centres are bridged by a μ3-OH anion, leading to a triangular [Cu3(μ3-OH)] core. 2-(1,2,4-Triazol-4-yl)acetic acid (trgly-H) acts in a deprotonated form as a μ3-κ3N1:N2:O ligand. The three triazolyl groups bridge three copper centres of the hydroxo-cluster in an N1:N2 mode, thus supporting the triangular geometry. The [Cu3(μ3-OH)(tr)3] clusters serve as secondary building units (SBUs). Each SBU can be regarded as a six-connected node, which is linked to six neighbouring triangles through carboxyl­ate groups, generating a two-dimensional uninodal (3,6) coordination network. The selenate anion is bound in a μ3-κ3O1:O2:O3 fashion to the trinuclear copper platform. The [Cu3(OH)(trgly)3(SeO4)] coordination layers and guest water mol­ecules are linked together by numerous O—H⋯O and C—H⋯O hydrogen bonds, leading to a three-dimensional structure.

In the title compound, C27H30N4O6·H2O, the two dioxolo rings are in envelope conformations, while the pyran ring is in a twisted-boat conformation. The pyradizine ring is oriented at dihedral angles of 9.23 (6) and 12.98 (9)° with respect to the pyridine rings, while the dihedral angle between the two pyridine rings is 13.45 (10)°. In the crystal, O—Hwater⋯Opyran, O—Hwater⋯Ometh­oxy­meth­yl and O—Hwater⋯Npyridazine hydrogen bonds link the mol­ecules into chains along [010]. In addition, weak C—Hdioxolo⋯Odioxolo hydrogen bonds and a weak C—Hmeth­oxy­meth­yl⋯π inter­action complete the three-dimensional structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (55.7%), H⋯C/C⋯H (14.6%), H⋯O/O⋯H (14.5%) and H⋯N/N⋯H (9.6%) inter­actions. Hydrogen-bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Electrochemical measurements are also reported.

The crystal structure of the title compound, [Ni(C63H31F10N5S2)]·xCH2Cl2 (x > 1/2), consists of Ni–porphyrin complexes that are located in general positions and di­chloro­methane solvent mol­ecules that are disordered around centers of inversion. The NiII ions are in a square-pyramidal (CN5) coordination, with four porphyrin N atoms in the equatorial and a pyridine N atom in the apical position and are shifted out of the porphyrine N4 plane towards the coordinating pyridine N atom. The pyridine substituent is not exactly perpendicular to the N4 plane with an angle of inter­section between the planes planes of 80.48 (6)°. The di­chloro­methane solvent mol­ecules are hydrogen bonded to one of the four porphyrine N atoms. Two complexes are linked into dimers by two symmetry-equivalent C—H⋯S hydrogen bonds. These dimers are closely packed, leading to cavities in which additional di­chloro­methane solvent mol­ecules are embedded. These solvent mol­ecules are disordered and because no reasonable split model was found, the data were corrected for disordered solvent using the PLATON SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9–18].

The title salt, C16H15ClN3S+·Br−, is isotypic with (E)-3-[(4-fluoro­benzyl­idene)amino]-5-phenyl­thia­zolidin-2-iminium bromide [Khalilov et al. (2019). Acta Cryst. E75, 662–666]. In the cation of the title salt, the atoms of the phenyl ring attached to the central thia­zolidine ring and the atom joining the thia­zolidine ring to the benzene ring are disordered over two sets of sites with occupancies of 0.570 (3) and 0.430 (3). The major and minor components of the disordered thia­zolidine ring adopt slightly distorted envelope conformations, with the C atom bearing the phenyl ring as the flap atom. In the crystal, centrosymmetrically related cations and anions are linked into dimeric units via N—H⋯Br hydrogen bonds, which are further connected by weak C—H⋯Br contacts into chains parallel to the a axis. Furthermore, not existing in the earlier report of (E)-3-[(4-fluoro­benzyl­idene)amino]-5-phenyl­thia­zolidin-2-iminium bromide, C—H⋯π inter­actions and π–π stacking inter­actions [centroid-to-centroid distance = 3.897 (2) Å] between the major components of the disordered phenyl ring contribute to the stabilization of the mol­ecular packing. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contributions for the crystal packing are from H⋯H (30.5%), Br⋯H/H⋯Br (21.2%), C⋯H/H⋯C (19.2%), Cl⋯H/H⋯Cl (13.0%) and S⋯H/H⋯S (5.0%) inter­actions.

The monocation product of the oxidative condensation–cyclization between two mol­ecules of pyridine-2-carbaldehyde and one mol­ecule of CH3NH2·HCl in methanol, 2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridinium, was isolated in the presence of metal ions as bis­[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] tetra­iodo­cadmate, (C13H12N3)2[CdI4], (I), and the mixed chloride/nitrate salt, bis­[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] 1.5-chlor­ide 0.5-nitrate trihydrate, 2C13H12N3+·1.5Cl−·0.5NO3−·3H2O, (II). Hybrid salt (I) crystallizes in the space group P21/n with two [L]2[CdI4] mol­ecules in the asymmetric unit related by pseudosymmetry. In the crystal of (I), layers of organic cations and of tetra­halometallate anions are stacked parallel to the ab plane. Anti­parallel L+ cations disposed in a herring-bone pattern form π-bonded chains through aromatic stacking. In the inorganic layer, adjacent tetra­hedral CdI4 units have no connectivity but demonstrate close packing of iodide anions. In the crystal lattice of (II), the cations are arranged in stacks propagating along the a axis; the one-dimensional hydrogen-bonded polymer built of chloride ions and water mol­ecules runs parallel to a column of stacked cations.

The mol­ecule of the title compound, C18H10Br2S4, has a C-shape, with Cs mol­ecular symmetry. The dihedral angle between the planes of the di­thiol and phenyl rings is 8.35 (9)°. In the crystal, mol­ecules form helical chains along [001], the shortest inter­actions being π⋯S contacts within the helices. The inter­molecular inter­actions were investigated by Hirshfeld surface analysis. Density functional theory (DFT) was used to calculate HOMO–LUMO energy levels of the title compound and its trans isomer.

In the two isotypic title compounds, C14H8BrCl2N3O2, (I), and C14H8Cl3N3O2, (II), the substitution of one of the phenyl rings is different [Br for (I) and Cl for (II)]. Aromatic rings form dihedral angles of 60.9 (2) and 64.1 (2)°, respectively. Mol­ecules are linked through weak X⋯Cl contacts [X = Br for (I) and Cl for (II)], C—H⋯Cl and C—Cl⋯π inter­actions into sheets parallel to the ab plane. Additional van der Waals inter­actions consolidate the three-dimensional packing. Hirshfeld surface analysis of the crystal structures indicates that the most important contributions for the crystal packing for (I) are from C⋯H/H⋯C (16.1%), O⋯H/H⋯O (13.1%), Cl⋯H/H⋯Cl (12.7%), H⋯H (11.4%), Br⋯H/H⋯Br (8.9%), N⋯H/H⋯N (6.9%) and Cl⋯C/C⋯Cl (6.6%) inter­actions, and for (II), from Cl⋯H / H⋯Cl (21.9%), C⋯H/H⋯C (15.3%), O⋯H/H⋯O (13.4%), H⋯H (11.5%), Cl⋯C/C⋯Cl (8.3%), N⋯H/H⋯N (7.0%) and Cl⋯Cl (5.9%) inter­actions. The crystal of (I) studied was refined as an inversion twin, the ratio of components being 0.9917 (12):0.0083 (12).

Three new isotypic heteropolynuclear complexes, namely penta­aqua­carbonato­penta­kis­(glycinehydroxamato)nitrato­penta­copper(II)lanthanide(III) x-hydrate, [LnCu5(GlyHA)5(CO3)(NO3)(H2O)5]·xH2O (GlyHA2− is glycine­hydrox­amate, N-hy­droxy­glycinamidate or amino­aceto­hydroxamate, C2H4N2O22−), with lanthanide(III) (LnIII) = gadolinium (Gd, 1, x = 3.5), dysprosium (Dy, 2, x = 3.28) and holmium (Ho, 3, x = 3.445), within a 15-metallacrown-5 class were obtained on reaction of lanthanide(III) nitrate, copper(II) acetate and sodium glycinehydroxamate. Complexes 1–3 contain five copper(II) ions and five bridging GlyHA2− anions, forming a [CuGlyHA]5 metallamacrocyclic core. The LnIII ions are coordinated to the metallamacrocycle through five O-donor hydroxamates. The electroneutrality of complexes 1–3 is achieved by a bidentate carbonate anion coordinated to the LnIII ion and a monodentate nitrate anion coordinated apically to one of the copper(II) ions of the metallamacrocycle. The lattice parameters of complexes 1–3 are similar to those previously reported for an EuIII–CuII 15-metallacrown-5 complex with glycine­hydroxamate of proposed composition [EuCu5(GlyHA)5(OH)(NO3)2(H2O)4]·3.5H2O [Stemmler et al. (1999). Inorg. Chem. 38, 2807–2817]. High-quality X-ray data obtained for 1–3 have allowed a re-evaluation of the X-ray data solution proposed earlier for the EuCu5 complex and suggest that the formula is actually [EuCu5(GlyHA)5(CO3)(NO3)(H2O)5]·3.5H2O.

The title compound, C8H4Br2O4·C2H6O2, crystallizes with one-half of a 2,5-di­bromo­terephthalic acid (H2Br2tp) mol­ecule and one-half of an ethyl­ene glycol (EG) mol­ecule in the the asymmetric unit. The whole mol­ecules are generated by application of inversion symmetry. The H2Br2tp mol­ecule is not planar, with the di­bromo­benzene ring system inclined by a dihedral angle of 18.62 (3)° to the carb­oxy­lic group. In the crystal, the H2Br2tp and EG mol­ecules are linked into sheets propagating parallel to (overline{1}01) through O—H⋯O hydrogen bonds, thereby forming R44 (12) and R44 (28) graph-set motifs. Br⋯O and weak π–π stacking inter­actions are also observed. Hirshfeld surface analysis was used to confirm the existence of these inter­actions.

The reaction of 2-methyl­thio-5-amino-1,3,4-thia­diazole (Me-SNTD; C3H5N3S2) with copper(II) acetate monohydrate [Cu(OAc)2·H2O; C4H8CuO5] resulted in the formation of the title binuclear compound, [Cu2(C2H3O2)4(C3H5N3S2)2] or [Cu2(OAc)4(Me-SNTD)2]. The structure has triclinic (P overline{1}) symmetry with a crystallographic inversion centre located at the midpoint of the line connecting the Cu atoms in the dimer. These two Cu atoms of the dimer [Cu⋯Cu = 2.6727 (6) Å] are held together by four carboxyl­ate groups. Each Cu atom is further coordinated to the N atom of an Me-SNTD mol­ecule and exhibits a Jahn–Teller-distorted octa­hedral geometry. The dimers are connected into infinite chains by hydrogen bonds between the NH (Me-SNTD) and the carboxyl­ate groups of neighbouring mol­ecules, generating an R22(12) ring motif. The mol­ecules are further linked by C—H⋯π inter­actions between the thia­diazole rings and the methyl groups of the acetate units.

The syntheses and crystal structures of three hybrid perovskites, viz. poly[1-methyl­piperizine-1,4-diium [tri-μ-bromido-potassium] hemihydrate], {(C5H14N2)[KBr3]·0.5H2O}n, (I), poly[1-methyl­piperizine-1,4-diium [tri-μ-bromido-rubidium] hemihydrate], {(C5H14N2)[RbBr3]·0.5H2O}n, (II), and poly[1-methyl­piperizine-1,4-diium [tri-μ-bromido-caesium] hemihydrate], {(C5H14N2)[CsBr3]·0.5H2O}n, (III), are described. These isostructural (space group Amm2) phases contain a three-dimensional, corner-sharing network of distorted ABr6 octa­hedra (A = K, Rb, Cs) with the same topology as the classical perovskite structure. The doubly protonated C5H14N22+ cations occupy inter­stices bounded by eight octa­hedra and the water mol­ecules lie in square sites bounded by four octa­hedra. N—H⋯Br, N—H⋯(Br,Br), N—H⋯O and O—H⋯Br hydrogen bonds consolidate the structures.

The isostructural title compounds, poly[piperazin-1-ium [di-μ-bromido-caesium]], {(C4H11N2)[CsBr2]}n, and poly[piperazin-1-ium [di-μ-bromido-rubidium]], {(C4H11N2)[RbBr2]}n, contain singly-protonated piperazin-1-ium cations and unusual ABr6 (A = Cs or Rb) trigonal prisms. The prisms are linked into a distinctive `curtain wall' arrangement propagating in the (010) plane by face and edge sharing. In each case, a network of N—H⋯N, N—H⋯Br and N—H⋯(Br,Br) hydrogen bonds consolidates the structure.

Bidentate and tridentate coordination of a 2,4-di-tert-butyl-substituted bridging amine bis­(phenolate) ligand to a palladium(II) center are observed within the same crystal structure, namely di­chlorido­({6,6'-[(ethane-1,2-diylbis(methyl­aza­nedi­yl)]bis­(methyl­ene)}bis­(2,4-di-tert-butyl­phenol))palladium(II) chlorido­(2,4-di-tert-butyl-6-{[(2-{[(3,5-di-tert-butyl-2-hy­droxy­phen­yl)meth­yl](meth­yl)amino}­eth­yl)(meth­yl)amino]­meth­yl}phenolato)palladium(II) methanol 1.685-solvate 0.315-hydrate, [PdCl2(C34H56N2O2)][PdCl(C34H55N2O2)]·1.685CH3OH·0.315H2O. Both complexes exhibit a square-planar geometry, with unbound phenol moieties participating in inter­molecular hydrogen bonding with co-crystallized water and methanol. The presence of both κ2 and κ3 coordination modes arising from the same solution suggest a dynamic process in which phenol donors may coordinate or dissociate from the metal center, and offers insight into catalyst speciation throughout Pd-mediated processes. The unit cell contains di­chlorido­({6,6'-[(ethane-1,2-diylbis(methyl­aza­nedi­yl)]bis­(methyl­ene)}bis­(2,4-di-tert-butyl­phenol))palladium(II), {(L2)PdCl2}, and chlorido­(2,4-di-tert-butyl-6-{[(2-{[(3,5-di-tert-butyl-2-hy­droxy­phen­yl)meth­yl](methyl)amino}eth­yl)(meth­yl)amino]­meth­yl}phenolato)palladium(II), {(L2X)PdCl}, mol­ecules as well as fractional water and methanol solvent mol­ecules.

In the title benzohydrazide derivative, C14H12N2O4, the azomethine C=N double bond has an E configuration. The hydrazide connecting bridge, (C=O)—(NH)—N=(CH), is nearly planar with C—C—N—N and C—N—N=C torsion angles of −177.33 (10) and −174.98 (12)°, respectively. The 4-hy­droxy­phenyl and 3,4-di­hydroxy­phenyl rings are slightly twisted, making a dihedral angle of 9.18 (6)°. In the crystal, mol­ecules are connected by N—H⋯O and O—H⋯O hydrogen bonds into a three-dimensional network, while further consolidated via π–π inter­actions [centroid–centroid distances = 3.6480 (8) and 3.7607 (8) Å]. The conformation is compared to those of related benzyl­idene-4-hy­droxy­benzohydrazide derivatives.

The crystal of 6-(3-nitro­phen­yl)-7-phenyl-5-thia-7-aza­spiro­[2.6]nonan-8-one (1), C19H18N2O3S, has monoclinic (P21/n) symmetry while that of its isomer 6-(4-nitro­phen­yl)-7-phenyl-5-thia-7-aza­spiro­[2.6]nonan-8-one (2), has ortho­rhom­bic (Pca21) symmetry: compound 1 has two mol­ecules, A and B, in the asymmetric unit while 2 has one. In all three mol­ecules, the seven-membered thia­zepan ring exhibits a chair conformation with Q2 and Q3 values (Å) of 0.521 (3), 0.735 (3) and 0.485 (3), 0.749 (3) in 1 and 0.517 (5), 0.699 (5) in 2. In each structure, the phenyl rings attached to adjacent atoms of the thia­zepan ring have inter­planar angles ranging between 41 and 47°. Except for the nitro groups, the three mol­ecules have similar conformations when overlayed in pairs. Both crystal structures are consolidated by C—H⋯O hydrogen bonds.

Six new 1-aroyl-4-(4-meth­oxy­phen­yl)piperazines have been prepared, using coupling reactions between benzoic acids and N-(4-meth­oxy­phen­yl)piperazine. There are no significant hydrogen bonds in the structure of 1-benzoyl-4-(4-meth­oxy­phen­yl)piperazine, C18H20N2O2, (I). The mol­ecules of 1-(2-fluoro­benzo­yl)-4-(4-meth­oxy­phen­yl)piperazine, C18H19FN2O2, (II), are linked by two C—H⋯O hydrogen bonds to form chains of rings, which are linked into sheets by an aromatic π–π stacking inter­action. 1-(2-Chloro­benzo­yl)-4-(4-meth­oxy­phen­yl)piperazine, C18H19ClN2O2, (III), 1-(2-bromo­benzo­yl)-4-(4-meth­oxy­phen­yl)piperazine, C18H19BrN2O2, (IV), and 1-(2-iodo­benzo­yl)-4-(4-meth­oxyphen­yl)piperazine, C18H19IN2O2, (V), are isomorphous, but in (III) the aroyl ring is disordered over two sets of atomic sites having occupancies of 0.942 (2) and 0.058 (2). In each of (III)–(V), a combination of two C—H⋯π(arene) hydrogen bonds links the mol­ecules into sheets. A single O—H⋯O hydrogen bond links the mol­ecules of 1-(2-hy­droxy­benzo­yl)-4-(4-meth­oxy­phen­yl)piperazine, C18H20N2O3, (VI), into simple chains. Comparisons are made with the structures of some related compounds.

Four manganese(II) bromide coordination complexes have been prepared with four pyridine N-oxides, viz. pyridine N-oxide (PNO), 2-methyl­pyridine N-oxide (2MePNO), 3-methyl­pyridine N-oxide (3MePNO), and 4-methyl­pyridine N-oxide (4MePNO). The compounds are bis­(μ-pyridine N-oxide)bis­[aqua­dibromido­(pyridine N-oxide)manganese(II)], [Mn2Br4(C5H5NO)4(H2O)2] (I), bis­(μ-2-methyl­pyridine N-oxide)bis­[di­aqua­dibromido­manganese(II)]–2-methyl­pyridine N-oxide (1/2), [Mn2Br4(C6H7NO)2(H2O)4]·2C6H7NO (II), bis­(μ-3-methyl­pyridine N-oxide)bis­[aqua­dibromido­(3-methyl­pyridine N-oxide)manganese(II)], [Mn2Br4(C6H7NO)4(H2O)2] (III), and bis­(μ-4-methyl­pyridine N-oxide)bis­[di­bromido­methanol(4-methyl­pyridine N-oxide)manganese(II)], [Mn2Br4(C6H7NO)4(CH3OH)2] (IV). All the compounds have one unique MnII atom and form a dimeric complex that contains two MnII atoms related by a crystallographic inversion center. Pseudo-octa­hedral six-coordinate manganese(II) centers are found in all four compounds. All four compounds form dimers of Mn atoms bridged by the oxygen atom of the PNO ligand. Compounds I, II and III exhibit a bound water of solvation, whereas compound IV contains a bound methanol mol­ecule of solvation. Compounds I, III and IV exhibit the same arrangement of mol­ecules around each manganese atom, ligated by two bromide ions, oxygen atoms of two PNO ligands and one solvent mol­ecule, whereas in compound II each manganese atom is ligated by two bromide ions, one O atom of a PNO ligand and two water mol­ecules with a second PNO mol­ecule inter­acting with the complex via hydrogen bonding through the bound water mol­ecules. All of the compounds form extended hydrogen-bonding networks, and compounds I, II, and IV exhibit offset π-stacking between PNO ligands of neighboring dimers.

A cadmium germanium arsenide compound, Cd3Ge2As4, was synthesized using a double-containment fused quartz ampoule method within a rocking furnace and a melt-quench technique. The crystal structure was determined from single-crystal X-ray diffraction (SC-XRD), scanning and transmission electron microscopies (i.e. SEM, STEM, and TEM), and selected area diffraction (SAD) and confirmed with electron backscatter diffraction (EBSD). The chemistry was verified with electron energy loss spectroscopy (EELS).

The synthesis and structure of 2,4,6,-tri­cyclo­butyl-1,3,5-trioxane, C15H24O3 1, is described. It was formed in 39% yield during the work-up of the Swern oxidation of cyclo­butyl­methanol and may serve as a stable precursor of the cyclo­butane carbaldehyde. The mol­ecule of 1 occupies a special position (3.m) located at the center of its 1,3,5-trioxane ring. The latter is in a chair conformation, with the symmetry-independent O and C atoms deviating by 0.651 (4) Å from the least-squares plane of the other atoms of the trioxane ring. All three cyclo­butane substituents, which have a butterfly conformation with an angle between the two planes of 25.7 (3)°, are in the cis conformation relative to the 1,3,5-trioxane ring. Inter­molecular C—H⋯O inter­actions between the 1,3,5-trioxane rings consolidate the crystal structure, forming stacks along the c-axis direction. The crystal studied was refined a as a racemic twin.

In the title di­thio­glycoluril derivative, C19H20N4O3S2, there is a difference in the torsion angles between the thio­imidazole moiety and the meth­oxy­phenyl groups on either side of the mol­ecule [C—N—Car—Car = 116.9 (2) and −86.1 (3)°, respectively]. The N—C—N bond angle on one side of the di­thio­glycoluril moiety is slightly smaller compared to that on the opposite side, [110.9 (2)° cf. 112.0 (2)°], probably as a result of the steric effect of the methyl group. In the crystal, N—H⋯S hydrogen bonds link adjacent mol­ecules to form chains propagating along the c-axis direction. The chains are linked by C—H⋯S hydrogen bonds, forming layers parallel to the bc plane. The layers are then linked by C—H⋯π inter­actions, leading to the formation of a three-dimensional supra­molecular network. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to investigate the mol­ecular inter­actions in the crystal.

A new mononuclear NiII complex with bis­(pyridin-2-yl)amine (dpyam) and benzoate (benz), [Ni(C7H5O2)2(C10H9N3)], crystallizes in the monoclinic space group P21/c. The NiII ion adopts a cis-distorted octa­hedral geometry with an [NiN2O4] chromophore. In the crystal, the complex mol­ecules are linked together into a one-dimensional chain by symmetry-related π–π stacking inter­actions [centroid-to-centroid distance = 3.7257 (17) Å], along with N—H⋯O and C—H⋯O hydrogen bonds. The crystal packing is further stabilized by C—H⋯π inter­actions, which were investigated by Hirshfeld surface analysis.

Two compounds, 1,3-diethyl-5-{(2E,4E)-6-[(E)-1,3,3-tri­methyl­indolin-2-yl­idene]hexa-2,4-dien-1-yl­idene}pyrimidine-2,4,6(1H,3H,5H)-trione or TMI, C25H29N3O3, and 1,3-diethyl-2-sulfanyl­idene-5-[2-(1,3,3-tri­methyl­indolin-2-yl­idene)ethyl­idene]di­hydro­pyrimidine-4,6(1H,5H)-dione or DTB, C21H25N3O2S, have been crystallized and studied. These compounds contain the same indole derivative donor group and differ in their acceptor groups (in TMI it contains oxygen in the para position, and in DTB sulfur) and the length of the π-bridge. In both materials, mol­ecules are packed in a herringbone manner with differences in the twist and fold angles. In both structures, the mol­ecules are connected by weak C—H⋯O and/or C—H⋯S bonds.

Imidazolium salts are common building blocks for functional materials and in the synthesis of N-heterocyclic carbene (NHC) as σ-donor ligands for stable metal complexes. The title salt, 1,3-bis­(4-hy­droxy­phen­yl)-1H-imidazol-3-ium chloride (IOH·Cl), C15H13N2O2+·Cl−, is a new imidazolium salt with a hy­droxy functionality. The synthesis of IOH·Cl was achieved in high yield via a two-step procedure involving a di­aza­butadiene precursor followed by ring closure using tri­methylchloro­silane and paraformaldehyde. The structure of IOH·Cl consists of a central planar imidazolium ring (r.m.s. deviation = 0.0015 Å), with out-of-plane phenolic side arms. The dihedral angles between the 4-hy­droxy­phenyl substituents and the imidazole ring are 55.27 (7) and 48.85 (11)°. In the crystal, O—H⋯Cl hydrogen bonds connect the distal hy­droxy groups and Cl− anions in adjacent asymmetric units, one related by inversion (−x + 1, −y + 1, −z + 1) and one by the n-glide (x − {1over 2}, −y + {1over 2}, z − {1over 2}), with donor–acceptor distances of 2.977 (2) and 3.0130 (18) Å, respectively. The phenolic rings are each π–π stacked with their respective inversion-related [(−x + 1, −y + 1, −z + 1) and (−x, −y + 1, −z + 1)] counterparts, with inter­planar distances of 3.560 (3) and 3.778 (3) Å. The only other noteworthy inter­molecular inter­action is an O⋯O (not hydrogen bonded) close contact of 2.999 (3) Å between crystallographically different hy­droxy O atoms on translationally adjacent mol­ecules (x + 1, y, x + 1).

The title compound, C7H4F3NO2, 3-tri­fluoro­methyl-1H-pyrrolo­[1,2-c]oxazol-1-one, is the first crystal structure of the pyrrolo­[1,2-c]oxazole ring system: the fused ring system is almost planar (r.m.s. deviation = 0.006 Å). In the crystal, weak C—H⋯O and C—H⋯F hydrogen bonds link the mol­ecules into [001] chains and π–π stacking inter­actions consolidate the structure.

The asymmetric unit of the title compound, [Fe(C13H18BN6)2], contains two half independent complex mol­ecules. In each complex, the FeII atom is located on an inversion center and is surrounded by two scorpionate ligand butyl­tris­(1H-pyrazol-1-yl)borate mol­ecules that coordinate to the iron(II) ion through the N atoms of the pyrazole groups. The two independent complex mol­ecules differ essentially in the conformation of the butyl substituents. In the crystal, the complex mol­ecules are linked by a series of C—H⋯π inter­actions, which generate a supra­molecular three-dimensional structure. At 120 K, the average Fe—N bond distance is 1.969 Å, indicating the low-spin state of the iron(II) atom, which does not change upon heating, as demonstrated by high-temperature magnetic susceptibility measurements.

The title compound, C18H16N4O, consists of a 3,6-bis­(pyridin-2-yl)pyridazine moiety linked to a 4-[(prop-2-en-1-yl­oxy)meth­yl] group. The pyridine-2-yl rings are oriented at a dihedral angle of 17.34 (4)° and are rotated slightly out of the plane of the pyridazine ring. In the crystal, C—HPyrd⋯NPyrdz (Pyrd = pyridine and Pyrdz = pyridazine) hydrogen bonds and C—HPrp­oxy⋯π (Prp­oxy = prop-2-en-1-yl­oxy) inter­actions link the mol­ecules, forming deeply corrugated layers approximately parallel to the bc plane and stacked along the a-axis direction. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯H (48.5%), H⋯C/C⋯H (26.0%) and H⋯N/N⋯H (17.1%) contacts, hydrogen bonding and van der Waals inter­actions being the dominant inter­actions in the crystal packing. Computational chemistry indicates that in the crystal, the C—HPyrd⋯NPyrdz hydrogen-bond energy is 64.3 kJ mol−1. Density functional theory (DFT) optimized structures at the B3LYP/6–311 G(d,p) level are compared with the experimentally determined mol­ecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.

The sterically hindered silicon compound 2-methyl-1,1,2,3,3-penta­phenyl-2-sila­propane, C33H30Si (I), was prepared via the reaction of two equivalents of di­phenyl­methyl­lithium (benzhydryllithium) and di­chloro­methyl­phenyl­silane. This bis­benzhydryl-substituted silicon compound was then reacted with tri­fluoro­methane­sulfonic acid, followed by hydrolysis with water to give the silanol 2-methyl-1,1,3,3-tetra­phenyl-2-silapropan-2-ol, C27H26OSi (II). Key geometric features for I are the Si—C bond lengths that range from 1.867 (2) to 1.914 (2) Å and a τ4 descriptor for fourfold coordination around the Si atom of 0.97 (indicating a nearly perfect tetra­hedron). Key geometric features for compound II include Si—C bond lengths that range from 1.835 (4) to 1.905 (3) Å, a Si—O bond length of 1.665 (3) Å, and a τ4 descriptor for fourfold coordination around the Si atom of 0.96. In compound II, there is an intra­molecular C—H⋯O hydrogen bond present. In the crystal of I, mol­ecules are linked by two pairs of C—H⋯π inter­actions, forming dimers that are linked into ribbons propagating along the b-axis direction. In the crystal of II, mol­ecules are linked by C—H⋯π and O—H⋯π inter­actions that result in the formation of ribbons that run along the a-axis direction.

The solid-state structures of the salts of two substituted tryptamines, namely N-isopropyl-N-methyl­tryptaminium (MiPT) fumarate {systematic name: [2-(1H-indol-3-yl)eth­yl](meth­yl)propan-2-yl­aza­nium 3-carb­oxy­prop-2-enoate}, C14H21N2+·C4H3O4−, and 4-hy­droxy-N-isopropyl-N-methyl­tryptaminium (4-HO-MiPT) fumarate monohydrate {systematic name: [2-(4-hy­droxy-1H-indol-3-yl)eth­yl](meth­yl)propan-2-yl­aza­nium 3-carb­oxy­prop-2-enoate monohydrate}, C14H21N2O+·C4H3O4−·H2O, are reported. Both salts possess a proton­ated tryptammonium cation and a 3-carb­oxy­acrylate (hydrogen fumarate) anion in the asymmetric unit; the 4-HO-MiPT structure also contains a water mol­ecule of crystallization. Both cations feature disorder of the side chain over two orientations, in a 0.630 (3):0.370 (3) ratio for MiPT and a 0.775 (5):0.225 (5) ratio for 4-HO-MiPT. In both extended structures, N—H⋯O and O—H⋯O hydrogen bonds generate infinite two-dimensional networks.

The title chalcone derivative, C19H20O5, adopts a trans configuration with respect to the olefinic C=C double bond. The 2-hy­droxy-4-methyl­phenyl ring is coplanar with the attached enone bridge [torsion angle = −179.96 (14)°], where this plane is nearly perpendicular to the 2,4,6-tri­meth­oxy­phenyl ring [dihedral angle = 75.81 (8)°]. In the crystal, mol­ecules are linked into chains propagating along [010] by an O—H⋯O hydrogen bond. These chains are further connected into centrosymmetric dimer chains via weak C—H⋯O inter­actions. The conformations of related chalcone derivatives are surveyed and all of these structures adopt a skeleton with two almost orthogonal aromatic rings.

Lapachol acetate [systematic name: 3-(3-methyl­but-2-en­yl)-1,4-dioxonaph­thalen-2-yl acetate], C17H16O4, was prepared using a modified high-yield procedure and its crystal structure is reported for the first time 80 years after its first synthesis. The full spectroscopic characterization of the mol­ecule is reported. The mol­ecular conformation shows little difference with other lapachol derivatives and lapachol itself. The packing is directed by inter­molecular π–π and C—H⋯O inter­actions, as described by Hirshfeld surface analysis. The former inter­actions make the largest contributions to the total packing energy in a ratio of 2:1 with respect to the latter.

The structure of the title compound, C32H51NO6, was determined from 62-year-old crystals at room temperature and refined with 100 K data in a monoclinic (C2) space group. This compound with a triterpenoid structure, now confirmed by this study, played an important role in the determination of the structure of lanosterol. The mol­ecules pack in linear O—H⋯O hydrogen-bonded chains along the short axis (b), while parallel chains display weak van der Waals inter­actions that explain the needle-shaped crystal morphology. The structure exhibits disorder of the flexible methyl­heptane chain at one end of the main mol­ecule with a small void around it. Crystals of the compounds were resistant to data collection for decades with the available cameras and Mo Kα radiation single-crystal diffractometer in our laboratory until a new instrument with Cu Kα radiation operating at 100 K allowed the structure to be solved and refined.

The synthesis, crystal structure and structural motif of two thio­phene-based cyano­acrylate derivatives, namely, ethyl (E)-2-cyano-3-(3-methyl­thio­phen-2-yl)acrylate (1), C11H11NO2S, and ethyl (E)-2-cyano-3-(thio­phen-2-yl)acrylate (2), C10H9NO2S, are reported. Derivative 1 crystallized with two independent molecules in the asymmetric unit, and derivative 2 represents a new monoclinic (C2/m) polymorph. The mol­ecular conformations of 1 and the two polymorphs of 2 are very similar, as all non-H atoms are planar except for the methyl of the ethyl groups. The inter­molecular inter­actions and crystal packing of 1 and 2 are described and compared with that of the reported monoclinic (C2/m) polymorph of derivative 2 [Castro Agudelo et al. (2017). Acta Cryst. E73, 1287–1289].

The title compound, C4H12N+·C11H5N4−, contains one tetra­methyl­ammonium cation and one 1,1,7,7-tetra­cyano­hepta-2,4,6-trienide anion in the asymmetric unit. The anion is in an all-trans conjugated C=C bonds conformation. Two terminal C(CN)2 di­nitrile moieties are slightly twisted from the polymethine main chain to which they are attached [C(CN)2/C5 dihedral angles = 6.1 (2) and 7.1 (1)°]. The C—C bond distances along the hepta­dienyl chain vary in the narrow range 1.382 (2)–1.394 (2) Å, thus indicating the significant degree of conjugation. In the crystal, the anions are linked into zigzag chains along the [10overline{1}] direction by C—H⋯N(nitrile) short contacts. The anti­parallel chains stack along the [110] direction with alternating separations between the neighboring anions in stacks of 3.291 and 3.504 Å. The C—H⋯N short contacts and stacking inter­actions combine to link the anions into layers parallel to the (overline{1}01) plane and separated by columns of tetra­methyl­ammonium cations.

The title compound, C11H9F3N4S, was synthesized from 2-(tri­fluoro­meth­yl)aniline by a multi-step reaction. It crystallizes in the non-centrosymmetric space group Pna21, with one mol­ecule in the asymmetric unit, and is constructed from a pair of aromatic rings [2-(tri­fluoro­meth­yl)phenyl and tetra­zole], which are twisted by 76.8 (1)° relative to each other because of significant steric hindrance of the tri­fluoro­methyl group at the ortho position of the benzene ring. In the crystal, very weak C—H⋯N and C—H⋯F hydrogen bonds and aromatic π–π stacking inter­actions link the mol­ecules into a three-dimensional network. To further analyse the inter­molecular inter­actions, a Hirshfeld surface analysis, as well as inter­action energy calculations, were performed.

1-(2-Iodo­benzo­yl)-cyclo­pent-3-ene-1-carboxyl­ates are novel substrates to construct bi­cyclo­[3.2.1]octa­nes with anti­bacterial and anti­thrombotic activities. In this context, tert-butyl 1-(2-iodo­benzo­yl)-cyclo­pent-3-ene-1-carboxyl­ate, C17H19IO3, was synthesized and structurally characterized. The 2-iodo­benzoyl group is attached to the tertiary C atom of the cyclo­pent-3-ene ring. The dihedral angle between the benzene ring and the mean plane of the envelope-type cyclo­pent-3-ene ring is 26.0 (3)°. In the crystal, pairs of C-H⋯O hydrogen bonds link the mol­ecules to form inversion dimers.

Reaction of 2-(anthracen-9-yl)phenol (HOPhAn, 1) with divalent Yb[N(SiMe3)2]2·2THF in THF–toluene mixtures affords the mixed-valence YbII–YbIII dimer {[2-(anthracen-9-yl)phenolato-κO]bis­(tetra­hydro­furan)­ytterbium(III)}-tris­[μ-2-(anthracen-9-yl)phenolato]-κ4O:O;κO:1,2-η,κO-{[2-(anthracen-9-yl)phenolato-κO]ytterbium(II)} toluene tris­olvate, [Yb2(C20H13O)5(C4H8O)2]·3C7H7 or [YbIII(THF)2(OPhAn)](μ-OPhAn)3[YbII(OPhAn)]·3C7H7 (2), as the major product. It crystallized as a toluene tris­olvate. The Yb—O bond lengths in the crystal structure of this dimer clearly identify the YbII and YbIII centres. Inter­estingly, the formally four-coordinate YbII centre shows a close contact with one anthracene C—C bond of a bridging OPhAn ligand, bringing the formal coordination number to five.

In this paper, we describe the synthesis of a new di­hydro-2H-pyridazin-3-one derivative. The mol­ecule, C18H16N2O, is not planar; the benzene and pyridazine rings are twisted with respect to each other, making a dihedral angle of 11.47 (2)°, and the toluene ring is nearly perpendicular to the pyridazine ring, with a dihedral angle of 89.624 (1)°. The mol­ecular conformation is stabilized by weak intra­molecular C—H⋯N contacts. In the crystal, pairs of N—H⋯O hydrogen bonds link the mol­ecules into inversion dimers with an R22(8) ring motif. The inter­molecular inter­actions were investigated using Hirshfeld surface analysis and two-dimensional (2D) fingerprint plots, revealing that the most important contributions for the crystal packing are from H⋯H (56.6%), H⋯C/C⋯H (22.6%), O⋯H/H⋯O (10.0%) and N⋯C/C⋯N (3.5%) inter­actions.

The title compound, C14H15BrClNO4, consists of a 5-bromo­indoline-2,3-dione unit linked to a 1-{2-[2-(2-chloro­eth­oxy)eth­oxy]eth­yl} moiety. In the crystal, a series of C—H⋯O hydrogen bonds link the molecules to form a supramolecular three-dimensional structure, enclosing R22(8), R22(12), R22(18) and R22(22) ring motifs. π–π contacts between the five-membered dione rings may further stabilize the structure, with a centroid–centroid distance of 3.899 (2) Å. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (28.1%), H⋯O/O⋯H (23.5%), H⋯Br/Br⋯H (13.8%), H⋯Cl/Cl⋯H (13.0%) and H⋯C/C⋯H (10.2%) inter­actions. Hydrogen bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Density functional theory (DFT) optimized structures at the B3LYP/6-311G(d,p) level are compared with the experimentally determined mol­ecular structure in the solid state. The HOMO—LUMO behaviour was elucidated to determine the energy gap. The chloro­eth­oxy­ethoxyethyl side chain atoms are disordered over two sets of sites with an occupancy ratio of 0.665 (8):0.335 (6).

The crystal structure of [ZnCl2(NH3)2], diamminedi­chlorido­zinc, was re-investigated at low temperature, revealing the positions of the hydrogen atoms and thus a deeper insight into the hydrogen-bonding scheme in the crystal packing. In comparison with previous crystal structure determinations [MacGillavry & Bijvoet (1936). Z. Kristallogr. 94, 249–255; Yamaguchi & Lindqvist (1981). Acta Chem. Scand. 35, 727–728], an improved precision of the structural parameters was achieved. In the crystal, tetra­hedral [Zn(NH3)2Cl2] units (point-group symmetry mm2) are linked through N—H⋯Cl hydrogen bonds into a three-dimensional network.

The structure of the title complex, [Ag(C11H15N3S)2]PF6, has monoclinic (P21/c) symmetry, and the silver atom has a distorted square-planar geometry. The coordination complex crystallized from mixing silver hexa­fluorido­phosphate with a concentrated tetra­hydro­furan solution of N,N-di­ethyl­phenyl­azo­thio­formamide [ATF; systematic name: 3,3-diethyl-1-(phenyl­imino)­thio­urea] under ambient conditions. The resultant coordination complex exhibits a 2:1 ligand-to-metal ratio, with the silver(I) atom having a fourfold AgN2S2 coordination sphere, with a single PF6 counter-ion. In the crystal, however, one sulfur atom from an ATF ligand of a neighboring complex coordinates to the silver atom, with a bond distance of 2.9884 (14) Å. This creates a polymeric zigzag chain propagating along the c-axis direction. The chains are linked by C—H⋯F hydrogen bonds, forming slabs parallel to the ac plane.

The structure of the title compound (systematic name: N-{[(2-hy­droxy­phen­yl)methyl­idene]amino}­morpholine-4-carbo­thio­amide), C12H15N3O2S, was prev­iously determined (Koo et al., 1977) using multiple-film equi-inclination Weissenberg data, but has been redetermined with higher precision to explore its conformation and the hydrogen-bonding patterns and supra­molecular inter­actions. The mol­ecular structure shows intra­molecular O—H⋯N and C—H⋯S inter­actions. The configuration of the C=N bond is E. The mol­ecule is slightly twisted about the central N—N bond. The best planes through the phenyl ring and the morpholino ring make an angle of 43.44 (17)°. In the crystal, the mol­ecules are connected into chains by N—H⋯O and C—H⋯O hydrogen bonds, which combine to generate sheets lying parallel to (002). The most prominent contribution to the surface contacts are H⋯H contacts (51.6%), as concluded from a Hirshfeld surface analysis.

The title compounds, 4-(5-acetamido-3-acetyl-2-methyl-2,3-di­hydro-1,3,4-thia­diazol-2-yl)phenyl benzoate, C20H19N3O4S (I), 4-(5-acetamido-3-acetyl-2-methyl-2,3-di­hydro-1,3,4-thia­diazol-2-yl)phenyl isobutyrate 0.25-hydrate, C17H21N3O4S·0.25H2O (II), 4-(5-acetamido-3-acetyl-2-methyl-2,3-di­hydro-1,3,4-thia­diazol-2-yl)phenyl propionate, C16H19N3O4S (III) and 4-(5-acetamido-3-acetyl-2-methyl-2,3-di­hydro-1,3,4-thia­diazol-2-yl)phenyl cinnamate chloro­form hemisolvate, C22H21N3O4S·0.5CHCl3 (IV), all crystallize with two independent mol­ecules (A and B) in the asymmetric unit in the triclinic Poverline{1} space group. Compound II crystallizes as a quaterhydrate, while compound IV crystallizes as a chloro­form hemisolvate. In compounds I, II, III (mol­ecules A and B) and IV (mol­ecule A) the five-membered thia­diazole ring adopts an envelope conformation, with the tetra­substituted C atom as the flap. In mol­ecule B of IV this ring is flat (r.m.s. deviation 0.044 Å). The central benzene ring is in general almost normal to the mean plane of the thia­diazole ring in each mol­ecule, with dihedral angles ranging from 75.8 (1) to 85.5 (2)°. In the crystals of all four compounds, the A and B mol­ecules are linked via strong N—H⋯O hydrogen bonds and generate centrosymmetric four-membered R44(28) ring motifs. There are C—H⋯O hydrogen bonds present in the crystals of all four compounds, and in I and II there are also C—H⋯π inter­actions present. The inter­molecular contacts in the crystals of all four compounds were analysed using Hirshfeld surface analysis and two-dimensional fingerprint plots.

The title salt, C10H21N2O+·C7H12NO4S−, comprises a 3-methacryl­amido-N,N,N-tri­methyl­propan-1-aminium cation and a 2-acryl­amido-2-methyl­propane-1-sulfonate anion. The salt crystallizes with two unique cation–anion pairs in the asymmetric unit of the ortho­rhom­bic unit cell. The crystal studied was an inversion twin with a 0.52 (4):0.48 (4) domain ratio. In the crystal, the cations and anions stack along the b-axis direction and are linked by an extensive series of N—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network. Hirshfeld surface analysis was carried out on both the asymmetric unit and the two individual salts. The contribution of inter­atomic contacts to the surfaces of the individual cations and anions are also compared.

The crystal structures of the disordered hemi-DMSO solvate of (E)-2-oxo-N'-(3,4,5-tri­meth­oxy­benzyl­idene)-2H-chromene-3-carbohydrazide, C20H18N2O6·0.5C2H6OS, and (E)-N'-benzyl­idene-2-oxo-2H-chromene-3-carbohydrazide, C17H12N2O3 (4: R = C6H5), are discussed. The non-hydrogen atoms in compound [4: R = (3,4,5-MeO)3C6H2)] exhibit a distinct curvature, while those in compound, (4: R = C6H5), are essential coplanar. In (4: R = C6H5), C—H⋯O and π–π intra­molecular inter­actions combine to form a three-dimensional array. A three-dimensional array is also found for the hemi-DMSO solvate of [4: R = (3,4,5-MeO)3C6H2], in which the mol­ecules of coumarin are linked by C—H⋯O and C—H⋯π inter­actions, and form tubes into which the DMSO mol­ecules are cocooned. Hirshfeld surface analyses of both compounds are reported, as are the lattice energy and inter­molecular inter­action energy calculations of compound (4: R = C6H5).

The synthesis and crystal structure of the title compound, C30H29NO, are described. This compound is a member of the chiral di­hydro­iso­quinoline-derived family, used as building blocks for functional materials and as source of chirality in asymmetric synthesis, and was isolated as one of two diastereomeric β-amino alcohols, the title mol­ecule being found to be the (S,R) diastereoisomer. In the crystal, mol­ecules are packed in a herringbone manner parallel to (103) and (10overline{3}) via weak C—H⋯O and C—H⋯π(ring) inter­actions. Hirshfeld surface analysis showed that the surface contacts are predominantly H⋯H inter­actions (ca 75%). The crystal studied was refined as a two-component inversion twin.

In the title compound, C25H12Cl6O4, the two carbonyl groups are oriented in a same direction with respect to the naphthalene ring system and are situated roughly parallel to each other, while the two 2,4,6-tri­chloro­benzene rings are orientated in opposite directions with respect to the naphthalene ring system: the carbonyl C—(C=O)—C planes subtend dihedral angles of 45.54 (15) and 30.02 (15)° to the naphthalene ring system are. The dihedral angles formed by the carbonyl groups and the benzene rings show larger differences, the C=O vectors being inclined to the benzene rings by 46.39 (16) and 79.78 (16)°. An intra­molecular O—H⋯O=C hydrogen bond forms an S(6) ring motif. In the crystal, no effective inter­molecular hydrogen bonds are found; instead, O⋯Cl and C⋯Cl close contacts are observed along the 21 helical-axis direction. The Hirshfeld surface analysis reveals several weak interactions, the major contributor being Cl⋯H/H⋯Cl contacts.

The title compound, C15H12ClNO3, consists of a 1,2-di­hydro­quinoline-4-carb­oxyl­ate unit with 2-chloro­ethyl and propynyl substituents, where the quinoline moiety is almost planar and the propynyl substituent is nearly perpendicular to its mean plane. In the crystal, the mol­ecules form zigzag stacks along the a-axis direction through slightly offset π-stacking inter­actions between inversion-related quinoline moieties which are tied together by inter­molecular C—HPrpn­yl⋯OCarbx and C—HChlethy⋯OCarbx (Prpnyl = propynyl, Carbx = carboxyl­ate and Chlethy = chloro­eth­yl) hydrogen bonds. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (29.9%), H⋯O/O⋯H (21.4%), H⋯C/C⋯ H (19.4%), H⋯Cl/Cl⋯H (16.3%) and C⋯C (8.6%) inter­actions. Hydrogen bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Computational chemistry indicates that in the crystal, the C—HPrpn­yl⋯OCarbx and C—HChlethy⋯OCarbx hydrogen bond energies are 67.1 and 61.7 kJ mol−1, respectively. Density functional theory (DFT) optimized structures at the B3LYP/ 6–311 G(d,p) level are compared with the experimentally determined mol­ecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.