The crystal structure of title salt, C22H46N42+·2NO3−·2H2O, has been determined using synchrotron radiation at 220 K. The structure determination reveals that protonation has occurred at diagonally opposite amine N atoms. The asymmetric unit contains half a centrosymmetric dication, one nitrate anion and one water mol­ecule. The mol­ecular dication, C22H46N42+, together with the nitrate anion and hydrate water mol­ecule are involved in an extensive range of hydrogen bonds. The mol­ecule is stabilized, as is the conformation of the dication, by forming inter­molecular N—H⋯O, O—H⋯O, together with intra­molecular N—H⋯N hydrogen bonds.

The asymmetric unit of the title compound, [Fe(NCS)2(C12H9NO)4], consists of an FeII ion that is located on a centre of inversion, as well as two 4-benzoyl­pyridine ligands and one thio­cyanate anion in general positions. The FeII ions are coordinated by two N-terminal-bonded thio­cyanate anions and four 4-benzoyl­pyridine ligands into discrete complexes with a slightly distorted octa­hedral geometry. These complexes are further linked by weak C—H⋯O hydrogen bonds into chains running along the c-axis direction. Upon heating, this complex loses half of the 4-benzoyl­pyridine ligands and transforms into a compound with the composition Fe(NCS)2(4-benzoyl­pyridine)2, that might be isotypic to the corresponding MnII compound and for which the structure is unknown.

The mol­ecular structure of the title compound, C17H14ClFO3, consists of a 4-chloro-3-fluoro­phenyl ring and a 3,4-di­meth­oxy­phenyl ring linked via a prop-2-en-1-one spacer. The mol­ecule has an E configuration about the C=C bond and the carbonyl group is syn with respect to the C=C bond. The F and H atoms at the meta positions of the 4-chloro-3-fluoro­phenyl ring are disordered over two orientations, with an occupancy ratio of 0.785 (3):0.215 (3). In the crystal, mol­ecules are linked via pairs of C—H⋯O inter­actions with an R22(14) ring motif, forming inversion dimers. The dimers are linked into a tape structure running along [10overline{1}] by a C—H⋯π inter­action. The inter­molecular contacts in the crystal were further analysed using Hirshfield surface analysis, which indicates that the most significant contacts are H⋯H (25.0%), followed by C⋯H/H⋯C (20.6%), O⋯H/H⋯O (15.6%), Cl⋯H/H⋯Cl (10.7%), F⋯H/H⋯F (10.4%), F⋯C/C⋯F (7.2%) and C⋯C (3.0%).

In the title quinoline derivative, C24H19NO3, the two benzyl rings are inclined to the quinoline ring mean plane by 74.09 (8) and 89.43 (7)°, and to each other by 63.97 (10)°. The carboxyl­ate group is twisted from the quinoline ring mean plane by 32.2 (2)°. There is a short intra­molecular C—H⋯O contact forming an S(6) ring motif. In the crystal, mol­ecules are linked by bifurcated C—H,H⋯O hydrogen bonds, forming layers parallel to the ac plane. The layers are linked by C—H⋯π inter­actions, forming a supra­molecular three-dimensional structure.

The asymmetric unit of the title compound, C15H12N2O2, contains two crystallographically independent mol­ecules in which the dihedral angles between the benzene rings in each are 13.26 (5) and 7.87 (5)°. An intra­molecular O—H⋯N hydrogen bonds results in the formation of an S(6) ring motif. In the crystal, mol­ecules are linked by weak C—H⋯O and C—H⋯N hydrogen bonds, forming layers parallel to (011). In addition, π–π stacking inter­actions with centroid–centroid distances in the range 3.693 (2)–3.931 (2) Å complete the three-dimensional network.

The structures of two isomers of the title compound, [RuCl2(C14H12N4)(C2H6OS)2], 2 and 3, are reported. Isomers 2 and 3 are produced by reaction of the pyridyl­triazole ligand 1-benzyl-4-(pyridin-2-yl)-1H-1,2,3-triazole (bpt) (1) with fac-[RuCl2(DMSO-S)3(DMSO-O)]. Reaction in acetone produces ca 95% 2, which is the OC-6-14 isomer, with cis DMSO and trans chlorido ligands, and 5% 3 (the OC-6-32 isomer, with cis DMSO and cis chlorido ligands, and the pyridyl moiety of bpt trans to DMSO). Reaction in refluxing toluene initially forms 2, which slowly isomerizes to 3.

The asymmetric units of the title compounds, trans-di­aqua­(3-benzyl-1,3,5,8,12-penta­aza­cyclo­tetra­decane-κ4N1,N5,N8,N12)copper(II) isophthalate monohydrate, [Cu(C16H29N5)(H2O)2](C8H4O4)·H2O, (I), and trans-di­aqua­[3-(pyridin-3-ylmeth­yl)-1,3,5,8,12-penta­aza­cyclo­tetra­decane-κ4N1,N5,N8,N12]copper(II) iso­phthalate 0.9-hydrate, [Cu(C15H28N6)(H2O)2](C8H4O4)·0.9H2O, (II) consist of one di­aqua macrocyclic cation, one di­carboxyl­ate anion and uncoordinated water mol­ecule(s). In each compound, the metal ion is coordinated by the four secondary N atoms of the macrocyclic ligand and the mutually trans O atoms of the water mol­ecules in a tetra­gonally distorted octa­hedral geometry. The average equatorial Cu—N bond lengths are significantly shorter than the average axial Cu—O bond lengths [2.020 (9) versus 2.495 (12) Å and 2.015 (4) versus 2.507 (7) Å for (I) and (II), respectively]. The coordinated macrocyclic ligand in the cations of both compounds adopts the most energetically favorable trans-III conformation. In the crystals, the complex cations and counter-anions are connected via hydrogen-bonding inter­actions between the N—H groups of the macrocycles and the O—H groups of coordinated water mol­ecules as the proton donors and the O atoms of the carboxyl­ate as the proton acceptors. Additionally, as a result of O—H⋯O hydrogen bonding with the coordinated and water mol­ecules of crystallization, the isophthalate dianions form layers lying parallel to the (overline{1}01) and (100) planes in (I) and (II), respectively.

The title pyridazin-3(2H)-one derivative, C25H19FN2O2, crystallizes with two independent mol­ecules (A and B) in the asymmetric unit. In mol­ecule A, the 4-fluoro­phenyl ring, the benzyl ring and the phenyl ring are inclined to the central pyridazine ring by 86.54 (11), 3.70 (9) and 84.857 (13)°, respectively. In mol­ecule B, the corresponding dihedral angles are 86.80 (9), 10.47 (8) and 82.01 (10)°, respectively. In the crystal, the A mol­ecules are linked by pairs of C—H⋯F hydrogen bonds, forming inversion dimers with an R22(28) ring motif. The dimers are linked by C—H⋯O hydrogen bonds and a C—H⋯π inter­action, forming columns stacking along the a-axis direction. The B mol­ecules are linked to each other in a similar manner and form columns separating the columns of A mol­ecules.

The title compounds, C14H10ClFN2OS (1) and C14H10BrFN2OS (2), were synthesized by two-step reactions. The dihedral angles between the aromatic rings are 31.99 (3) and 9.17 (5)° for 1 and 2, respectively. Compound 1 features an intra­molecular bifurcated N—H⋯(O,Cl) link due to the presence of the ortho-Cl atom on the benzene ring, whereas 2 features an intra­molecular N—H⋯O hydrogen bond. In the crystal of 1, inversion dimers linked by pairs of N—H⋯S hydrogen bonds generate R22(8) loops. The extended structure of 2 features the same motif but an additional weak C—H⋯S inter­action links the inversion dimers into [100] double columns. Hirshfeld surface analyses indicate that the most important contributors towards the crystal packing are H⋯H (26.6%), S⋯H/H.·S (13.8%) and Cl⋯H/H⋯Cl (9.5%) contacts for 1 and H⋯H (19.7%), C⋯H/H⋯C (14.8%) and Br⋯H/H⋯Br (12.4%) contacts for 2.

Reductive cyclization of 1,3,5-triphenyl- and 3-(2-meth­oxy­phen­yl)-1,5-di­phenyl­pentane-1,5-diones by zinc in acetic acid medium leads to the formation of 1,2,4-tri­phenyl­cyclo­pentane-1,2-diol [1,2,4-Ph3C5H5-1,2-(OH)2, C23H22O2, (I)] and 4-(2-meth­oxy­phen­yl)-1,2-di­phenyl­cyclo­pentane-1,2-diol [4-(2-MeOC6H4)-1,2-Ph2C5H5-1,2-(OH)2, C24H24O3, (II)]. Their single crystals have been obtained by crystallization from a THF/hexane solvent mixture. Diols (I) and (II) crystallize in ortho­rhom­bic (Pbca) and triclinic (Poverline{1}) space groups, respectively, at 150 K. Their asymmetric units comprise one [in the case of (I)] and three [in the case of (II)] crystallographically independent mol­ecules of the achiral (1R,2S,4r)-diol isomer. Each hydroxyl group is involved in one intra­molecular and one inter­molecular O—H⋯O hydrogen bond, forming one-dimensional chains. Compounds (I) and (II) have been used successfully as precatalyst activators for the ring-opening polymerization of ∊-caprolactone.

The reaction of 2,5-bis­(pyridin-4-yl)-1,3,4-oxa­diazole (4-pox) and thio­cyanate ions, used as co-ligand with nickel salt NiCl2·6H2O, produced the title complex, [Ni(NCS)2(C12H8N4O)2(H2O)2]. The NiII atom is located on an inversion centre and is octa­hedrally coordinated by four N atoms from two ligands and two pseudohalide ions, forming the equatorial plane. The axial positions are occupied by two O atoms of coordinated water mol­ecules. In the crystal, the mol­ecules are linked into a three-dimensional network through strong O—H⋯N hydrogen bonds. Hirshfeld surface analysis was used to investigate the inter­molecular inter­actions in the crystal packing.

The title mol­ecule crystallizes as a di­methyl­formamide monosolvate, C19H14N2O6S2·C3H7NO. The mol­ecule was expected to adopt mirror symmetry but slightly different conformational characteristics of the condensed benzo­thia­zine ring lead to point group symmetry 1. In the crystal, mol­ecules form two types of stacking dimers with distances of 3.464 (2) Å and 3.528 (2) Å between π-systems. As a result, columns extending parallel to [100] are formed, which are connected to inter­mediate di­methyl­formamide solvent mol­ecules by C—H⋯O inter­actions.

The synthesis, spectroscopic data, crystal and mol­ecular structures of two N'-(1-phenyl­benzyl­idene)-2-(thio­phen-3-yl)acetohydrazides, namely N'-[1-(4-hy­droxy­phen­yl)benzyl­idene]-2-(thio­phen-3-yl)acetohydrazide, C13H10N2O2S, (3a), and N'-[1-(4-meth­oxy­phen­yl)benzyl­idene]-2-(thio­phen-3-yl)acetohydrazide, C14H14N2O2S, (3b), are described. Both compounds differ in the substituent at the para position of the phenyl ring: –OH for (3a) and –OCH3 for (3b). In (3a), the thio­phene ring is disordered over two orientations with occupancies of 0.762 (3) and 0.238 (3). The configuration about the C=N bond is E. The thio­phene and phenyl rings are inclined by 84.0 (3) and 87.0 (9)° for the major- and minor-occupancy disorder components in (3a), and by 85.89 (12)° in (3b). Although these dihedral angles are similar, the conformation of the linker between the two rings is different [the C—C—C—N torsion angle is −ac for (3a) and −sc for (3b), while the C6—C7—N9—N10 torsion angle is +ap for (3a) and −sp for (3b)]. A common feature in the crystal packing of (3a) and (3b) is the presence of N—H⋯O hydrogen bonds, resulting in the formation of chains of mol­ecules running along the b-axis direction in the case of (3a), or inversion dimers for (3b). The most prominent contributions to the surface contacts are those in which H atoms are involved, as confirmed by an analysis of the Hirshfeld surface.

Two CuII complexes [Cu(C14H13N4O2)Cl]n, I, and [Cu4(C8H10NO2)4Cl4]n, II, have been synthesized. In the structure of the mononuclear complex I, each ligand is coordinated to two metal centers. The basal plane around the CuII cation is formed by one chloride anion, one oxygen atom, one imino and one pyridine nitro­gen atom. The apical position of the distorted square-pyramidal geometry is occupied by a pyridine nitro­gen atom from a neighbouring unit, leading to infinite one-dimensional polymeric chains along the b-axis direction. Each chain is connected to adjacent chains by inter­molecular C—H⋯O and C—H⋯Cl inter­actions, leading to a three-dimensional network structure. The tetra­nuclear complex II lies about a crystallographic inversion centre and has one core in which two CuII metal centers are mutually inter­connected via two enolato oxygen atoms while the other two CuII cations are linked by a chloride anion and an enolato oxygen. An open-cube structure is generated in which the two open-cube units, with seven vertices each, share a side composed of two CuII ions bridged by two enolato oxygen atoms acting in a μ3-mode. The CuII atoms in each of the two CuO3NCl units are connected by one μ2-O and two μ3-O atoms from deprotonated hydroxyl groups and one chloride anion to the three other CuII centres. Each of the penta­coordinated CuII cations has a distorted NO3Cl square-pyramidal environment. The CuII atoms in each of the two CuO2NCl2 units are connected by μ2-O and μ3-O atoms from deprotonated alcohol hy­droxy groups and one chloride anion to two other CuII ions. Each of the penta­coordinated CuII cations has a distorted NO2Cl2 square-pyramidal environment. In the crystal, a series of intra­molecular C—H⋯O and C—H⋯Cl hydrogen bonds are observed in each tetra­nuclear monomeric unit, which is connected to four tetra­nuclear monomeric units by inter­molecular C—H⋯O hydrogen bonds, thus forming a planar two-dimensional structure in the (overline{1}01) plane.

In each of the two independent mol­ecules in the asymmetric unit of the title compound, [CdI2(C18H14N4O)], the N,O,N'-tridentate N'-[(E)-(phen­yl)(pyridin-2-yl-κN)methyl­idene]pyridine-2-carbohydrazide ligand and two iodide anions form an I2N2O penta­coordination sphere, with a distorted square-pyramidal geometry, with an I atom in the apical position. Both mol­ecules feature an intra­molecular N—H⋯N hydrogen bond. In the crystal, weak aromatic π–π stacking inter­actions [centroid–centroid separation = 3.830 (2) Å] link the mol­ecules into dimers.

The asymmetric unit of the title compound, C15H21N3OS, comprises of two crystallographically independent mol­ecules (A and B). Each mol­ecule consists of a cyclo­hexane ring and a 2-hy­droxy-3-methyl­benzyl­idene ring bridged by a hydrazinecarbo­thio­amine unit. Both mol­ecules exhibit an E configuration with respect to the azomethine C=N bond. There is an intra­molecular O—H⋯N hydrogen bond in each mol­ecule forming an S(6) ring motif. The cyclo­hexane ring in each mol­ecule has a chair conformation. The benzene ring is inclined to the mean plane of the cyclo­hexane ring by 47.75 (9)° in mol­ecule A and 66.99 (9)° in mol­ecule B. The mean plane of the cyclo­hexane ring is inclined to the mean plane of the thio­urea moiety [N—C(=S)—N] by 55.69 (9) and 58.50 (8)° in mol­ecules A and B, respectively. In the crystal, the A and B mol­ecules are linked by N—H⋯S hydrogen bonds, forming `dimers'. The A mol­ecules are further linked by a C—H⋯π inter­action, hence linking the A–B units to form ribbons propagating along the b-axis direction. The conformation of a number of related cyclo­hexa­nehydrazinecarbo­thio­amides are compared to that of the title compound.

The title compound, C12H21NO7, (I), is conformationally unstable; the predominant form present in its solution is the β-pyran­ose form (74.3%), followed by the β- and α-furan­oses (12.1 and 10.2%, respectively), α-pyran­ose (3.4%), and traces of the acyclic carbohydrate tautomer. In the crystalline state, the carbohydrate part of (I) adopts the 2C5 β-pyran­ose conformation, and the amino acid portion exists as a zwitterion, with the side chain cyclo­pentane ring assuming the E9 envelope conformation. All heteroatoms are involved in hydrogen bonding that forms a system of anti­parallel infinite chains of fused R33(6) and R33(8) rings. The mol­ecule features extensive intra­molecular hydrogen bonding, which is uniquely multicentered and involves the carboxyl­ate, ammonium and carbohydrate hy­droxy groups. In contrast, the contribution of inter­molecular O⋯H/H⋯O contacts to the Hirshfeld surface is relatively low (38.4%), as compared to structures of other d-fructose-amino acids. The 1H NMR data suggest a slow rotation around the C1—C2 bond in (I), indicating that the intra­molecular heteroatom contacts survive in aqueous solution of the mol­ecule as well.

The asymmetric unit of the title compound, [Zn(C6H8N4B)2(C12H8N2)], comprises one half of a ZnII cation (site symmetry 2), one di­hydro­bis­(pyrazol-1-yl)borate ligand in a general position, and one half of a phenanthroline ligand, the other half being completed by twofold rotation symmetry. The ZnII cation is coordinated in form of a slightly distorted octa­hedron by the N atoms of a phenanthroline ligand and by two pairs of N atoms of symmetry-related di­hydro­bis­(pyrazol-1-yl)borate ligands. The discrete complexes are arranged into columns that elongate in the c-axis direction with a parallel alignment of the phenanthroline ligands, indicating weak π–π inter­actions.

Five new crystal structures of perfluoro­pyridine substituted in the 4-position with phen­oxy, 4-bromo­phen­oxy, naphthalen-2-yl­oxy, 6-bromo­naphthalen-2-yl­oxy, and 4,4'-biphen­oxy are reported, viz. 2,3,5,6-tetra­fluoro-4-phen­oxy­pyridine, C11H5F4NO (I), 4-(4-bromo­phen­oxy)-2,3,5,6-tetra­fluoro­pyridine, C11H4BrF4NO (II), 2,3,5,6-tetra­fluoro-4-[(naphthalen-2-yl)­oxy]pyridine, C15H7F4NO (III), 4-[(6-bromo­naphthalen-2-yl)­oxy]-2,3,5,6-tetra­fluoropyridine, C15H6BrF4NO (IV), and 2,2'-bis­[(perfluoro­pyridin-4-yl)­oxy]-1,1'-biphenyl, C22H8F8N2O2 (V). The dihedral angles between the aromatic ring systems in I–IV are 78.74 (8), 56.35 (8), 74.30 (7), and 64.34 (19)°, respectively. The complete mol­ecule of V is generated by a crystallographic twofold axis: the dihedral angle between the pyridine ring and adjacent phenyl ring is 80.89 (5)° and the equivalent angle between the biphenyl rings is 27.30 (5)°. In each crystal, the packing is driven by C—H⋯F inter­actions, along with a variety of C—F⋯π, C—H⋯π, C—Br⋯N, C—H⋯N, and C—Br⋯π contacts. Hirshfeld surface analysis was conducted to aid in the visualization of these various influences on the packing.

Phenanthroline ligands are important metal-binding mol­ecules which have been extensively researched for applications in both material science and medicinal chemistry. Azo­benzene and its derivatives have received significant attention because of their ability to be reversibly switched between the E and Z forms and so could have applications in optical memory and logic devices or as mol­ecular machines. Herein we report the formation and crystal structure of a highly unusual novel diazo-diphenanthroline compound, C24H14N6O2·2CHCl3.

In the title compound, C16H11Cl2N3O, the 4-meth­oxy-substituted benzene ring makes a dihedral angle of 41.86 (9)° with the benzene ring of the benzo­nitrile group. In the crystal, mol­ecules are linked into layers parallel to (020) by C—H⋯O contacts and face-to-face π–π stacking inter­actions [centroid–centroid distances = 3.9116 (14) and 3.9118 (14) Å] between symmetry-related aromatic rings along the a-axis direction. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from Cl⋯H/H⋯Cl (22.8%), H⋯H (21.4%), N⋯H/H⋯N (16.1%), C⋯H/H⋯C (14.7%) and C⋯C (9.1%) inter­actions.

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 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 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).

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 di-substituted acetyl­ene residue in the title compound, C11H11NO3, is capped at either end by di-methyl­hydroxy and 4-nitro­benzene groups; the nitro substituent is close to co-planar with the ring to which it is attached [dihedral angle = 9.4 (3)°]. The most prominent feature of the mol­ecular packing is the formation, via hy­droxy-O—H⋯O(hy­droxy) hydrogen bonds, of hexa­meric clusters about a site of symmetry overline{3}. The aggregates are sustained by 12-membered {⋯OH}6 synthons and have the shape of a flattened chair. The clusters are connected into a three-dimensional architecture by benzene-C—H⋯O(nitro) inter­actions, involving both nitro-O atoms. The aforementioned inter­actions are readily identified in the calculated Hirshfeld surface. Computational chemistry indicates there is a significant energy, primarily electrostatic in nature, associated with the hy­droxy-O—H⋯O(hy­droxy) hydrogen bonds. Dispersion forces are more important in the other identified but, weaker inter­molecular contacts.

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.

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.

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 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.

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 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 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.

The title Schiff base compound, C14H10Cl2N2O, features an E configuration about each of the C=N imine bonds. Overall, the mol­ecule is approximately planar with the dihedral angle between the central C2N2 residue (r.m.s. deviation = 0.0371 Å) and the peripheral hy­droxy­benzene and chloro­benzene rings being 4.9 (3) and 7.5 (3)°, respectively. Nevertheless, a small twist is evident about the central N—N bond [the C—N—N—C torsion angle = −172.7 (2)°]. An intra­molecular hy­droxy-O—H⋯N(imine) hydrogen bond closes an S(6) loop. In the crystal, π–π stacking inter­actions between hy­droxy- and chloro­benzene rings [inter-centroid separation = 3.6939 (13) Å] lead to a helical supra­molecular chain propagating along the b-axis direction; the chains pack without directional inter­actions between them. The calculated Hirshfeld surfaces point to the importance of H⋯H and Cl⋯H/H⋯Cl contacts to the overall surface, each contributing approximately 29% of all contacts. However, of these only Cl⋯H contacts occur at separations less than the sum of the van der Waals radii. The aforementioned π–π stacking inter­actions contribute 12.0% to the overall surface contacts. The calculation of the inter­action energies in the crystal indicates significant contributions from the dispersion term.

The reaction of bis­(3-oxo-1,3-di­phenyl­prop-1-enolato-κ2O,O')zinc(II), [Zn(dbm)2], with tris­[4-(pyridin-3-yl)phen­yl]amine (T3PyA) in tetra­hydro­furan (THF) afforded the title crystalline coordination polymer, {[Zn(C15H11O2)2(C33H24N4)]·C4H8O}n. The asymmetric unit contains two independent halves of Zn(dbm)2, one T3PyA and one THF. Each ZnII atom is located on an inversion centre and adopts an elongated octa­hedral coordination geometry, ligated by four O atoms of two dbm ligands in equatorial positions and by two N atoms of pyridine moieties from two different bridging T3PyA ligands in axial positions. The crystal packing shows a one-dimensional polymer chain in which the two pyridyl groups of the T3PyA ligand bridge two independent Zn atoms of Zn(dbm)2. In the crystal, the coordination polymer chains are linked via C—H⋯π inter­actions into a sheet structure parallel to (010). The sheets are cross-linked via further C—H⋯π inter­actions into a three-dimensional network. The solvate THF mol­ecule shows disorder over two sets of atomic sites having occupancies of 0.631 (7) and 0.369 (7).

The title compound, [Ni(C64H33F10N5S2)]·xCH2Cl2, consists of discrete NiII porphyrin complexes, in which the five-coordinate NiII cations are in a distorted square-pyramidal coordination geometry. The four porphyrin nitro­gen atoms are located in the basal plane of the pyramid, whereas the pyridine N atom is in the apical position. The porphyrin plane is strongly distorted and the NiII cation is located above this plane by 0.241 (3) Å and shifted in the direction of the coordinating pyridine nitro­gen atom. The pyridine ring is not perpendicular to the N4 plane of the porphyrin moiety, as observed for related compounds. In the crystal, the complexes are linked via weak C—H⋯F hydrogen bonds into zigzag chains propagating in the [001] direction. Within this arrangement cavities are formed, in which highly disordered di­chloro­methane solvate mol­ecules are located. No reasonable structural model could be found to describe this disorder and therefore the contribution of the solvent to the electron density was removed using the SQUEEZE option in PLATON [Spek (2015). Acta Cryst. C71, 9–18].

The crystal and mol­ecular structures of the title triorganotin di­thio­carbamate, [Sn(C6H5)3(C7H14NS2)], are described. The mol­ecular geometry about the metal atom is highly distorted being based on a C3S tetra­hedron as the di­thio­carbamate ligand is asymmetrically chelating to the tin centre. The close approach of the second thione-S atom [Sn⋯S = 2.9264 (4) Å] is largely responsible for the distortion. The mol­ecular packing is almost devoid of directional inter­actions with only weak phenyl-C—H⋯C(phen­yl) inter­actions, leading to centrosymmetric dimeric aggregates, being noted. An analysis of the calculated Hirshfeld surface points to the significance of H⋯H contacts, which contribute 66.6% of all contacts to the surface, with C⋯H/H⋯C [26.8%] and S⋯H/H⋯H [6.6%] contacts making up the balance.

In the title tri-substituted thio­urea derivative, C13H18N2O3S, the thione-S and carbonyl-O atoms lie, to a first approximation, to the same side of the mol­ecule [the S—C—N—C torsion angle is −49.3 (2)°]. The CN2S plane is almost planar (r.m.s. deviation = 0.018 Å) with the hy­droxy­ethyl groups lying to either side of this plane. One hy­droxy­ethyl group is orientated towards the thio­amide functionality enabling the formation of an intra­molecular N—H⋯O hydrogen bond leading to an S(7) loop. The dihedral angle [72.12 (9)°] between the planes through the CN2S atoms and the 4-tolyl ring indicates the mol­ecule is twisted. The experimental mol­ecular structure is close to the gas-phase, geometry-optimized structure calculated by DFT methods. In the mol­ecular packing, hydroxyl-O—H⋯O(hydrox­yl) and hydroxyl-O—H⋯S(thione) hydrogen bonds lead to the formation of a supra­molecular layer in the ab plane; no directional inter­actions are found between layers. The influence of the specified supra­molecular inter­actions is apparent in the calculated Hirshfeld surfaces and these are shown to be attractive in non-covalent inter­action plots; the inter­action energies point to the important stabilization provided by directional O—H⋯O hydrogen bonds.

The title compound, C10H13Cl2NO2·C6H4Cl2O, was formed from the incomplete Mannich condensation reaction of 3-amino­propan-1-ol, formaldehyde and 2,4-di­chloro­phenol in methanol. This resulted in the formation of a co-crystal of the zwitterionic Mannich base, 2,4-di­chloro-6-{[(3-hy­droxy­prop­yl)azaniumyl]­meth­yl}phenolate and the unreacted 2,4-di­chloro­phenol. The compound crystallizes in the monoclinic crystal system (in space group Cc) and the asymmetric unit contains a mol­ecule each of the 2,4-di­chloro­phenol and 2,4-di­chloro-6-{[(3-hy­droxy­prop­yl)azaniumyl]­meth­yl}phenolate. Examination of the crystal structure shows that the two components are clearly linked together by hydrogen bonds. The packing patterns are most inter­esting along the b and the c axes, where the co-crystal in the unit cell packs in a manner that shows alternating aromatic di­chloro­phenol fragments and polar hydrogen-bonded channels. The 2,4-di­chloro­phenol rings stack on top of one another, and these are held together by π–π inter­actions. The crystal studied was refined as an inversion twin.