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.

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 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 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.

In the title compound, C27H29BrN2, the carbazole ring system is essentially planar, with an r.m.s. deviation of 0.0781 (16) Å. An intra­molecular N—H⋯N hydrogen bond forms an S(6) ring motif. One of the tert-butyl substituents shows rotational disorder over two sites with occupancies of 0.592 (3) and 0.408 (3). In the crystal, two mol­ecules are associated into an inversion dimer through a pair of C—H⋯π inter­actions. The dimers are further linked by another pair of C—H⋯π inter­actions, forming a ribbon along the c-axis direction. A C—H⋯π inter­action involving the minor disordered component and the carbazole ring system links the ribbons, generating a network sheet parallel to (100).

Instances of crystal structures that remain isomorphous in spite of some minor changes in their respective mol­ecules, such as change in a substituent atom/group, can provide insights into the factors that govern crystal packing. In this context, an accurate description of the crystal structures of an isomorphous pair that differ from each other only by a chlorine–methyl substituent, viz. 5''-(2-chloro­benzyl­idene)-4'-(2-chloro­phen­yl)-1'-methyl­dispiro­[acenaphthene-1,2'-pyrrolidine-3',3''-piperidine]-2,4''-dione, C34H28Cl2N2O2, (I), and its analogue 1'-methyl-5''-(2-methyl­benzyl­idene)-4'-(2-methyl­phen­yl)di­spiro­[acenaphthene-1,2'-pyrrolidine-3',3''-piperidine]-2,4''-dione, C36H34N2O2, (II), is presented. While there are two C—H⋯O weak inter­molecular inter­actions present in both (I) and (II), the change of substituent from chlorine to methyl has given rise to an additional weak C—H⋯O inter­molecular inter­action that is relatively stronger than the other two. However, the presence of the stronger C—H⋯O inter­action in (II) has not disrupted the validity of the chloro-methyl exchange rule. Details of the crystal structures and Hirshfeld analyses of the two compounds are presented.

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].

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.

The PtII atom in the title complex, [Pt(C15H18N4O4S)(C2H6OS)], exists within a square-planar NS2O donor set provided by the N, S, O atoms of the di-anionic tridentate thio­semicarbazo ligand and a dimethyl sulfoxide S atom. The two chelate rings are coplanar, subtending a dihedral angle of 1.51 (7)°. The maximum deviation from an ideal square-planar geometry is seen in the five-membered chelate ring with an S—Pt—S bite angle of 96.45 (2)°. In the crystal, mol­ecules are linked via N—H⋯O, C—H⋯O, C—H⋯N and C—H⋯π inter­actions into two-dimensional networks lying parallel to the ab plane. The conformations of related cyclo­hexyl­hydrazine-1-carbo­thio­amide ligands are compared to that of the title compound.

Twelve 4-(4-meth­oxy­phen­yl)piperazin-1-ium salts containing organic anions have been prepared and structurally characterized. The monohydrated benzoate, 4-fluoro­benzoate, 4-chloro­benzoate and 4-bromo­benzoate salts, C11H17N2O+·C7H5O2−·H2O (I), C11H17N2O+·C7H4FO2−·H2O (II), C11H17N2O+·C7H4ClO2−·H2O (III), and C11H17N2O+·C7H4BrO2−·H2O (IV), respectively, are isomorphous and all exhibit disorder in the 4-meth­oxy­phenyl unit: the components are linked by N—H⋯O and O—H⋯O hydrogen bond to form chains of rings. The unsolvated 2-hy­droxy­benzoate, pyridine-3-carboxyl­ate and 2-hy­droxy-3,5-di­nitro­benzoate salts, C11H17N2O+·C7H5O3− (V), C11H17N2O+·C6H4NO2− (VI) and C11H17N2O+·C7H3N2O7− (VII), respectively, are all fully ordered: the components of (V) are linked by multiple N—H⋯O hydrogen bonds to form a chain of rings; those of (VI) are linked into a three-dimensional framework by a combination of N—H⋯O, C—H⋯O and C—H⋯N hydrogen bonds and those of (VII), where the anion has a structure reminiscent of the picrate anion, are linked into a three-dimensional array by N—H⋯O and C—H⋯O hydrogen bonds. The hydrogensuccinate and hydrogenfumarate salts, C11H17N2O+·C4H5O4− (VIII) and C11H17N2O+·C4H3O3− (IX), respectively, are isomorphous, and both exhibit disorder in the anionic component: N—H⋯O and O—H⋯O hydrogen bonds link the ions into sheets, which are further linked by C—H⋯π(arene) inter­actions. The anion of the hydrogenmaleate salt, C11H17N2O+·C4H3O3− (X), contains a very short and nearly symmetrical O⋯H⋯O hydrogen bond, and N—H⋯O hydrogen bonds link the anions into chains of rings. The ions in the tri­chloro­acetate salt, C11H17N2O+·C2Cl3O2− (XI), are linked into simple chains by N—H⋯O hydrogen bonds. In the hydrated chloranilate salt, 2C11H17N2O+·C6Cl2O42−·2H2O (XII), which crystallizes as a non-merohedral twin, the anion lies across a centre of inversion in space group P21/n, and a combination of N—H⋯O and O—H⋯O hydrogen bonds generates complex sheets. Comparisons are made with the structures of some related compounds.

In the title compound, C24H22N4O4, the four pyridine rings are tilted slightly with respect to each other. The dihedral angles between the inner and outer pyridine rings are 12.51 (8) and 9.67 (9)°, while that between inner pyridine rings is 20.10 (7)°. Within the mol­ecule, intra­molecular C—H⋯O and C—H⋯N contacts are observed. In the crystal, adjacent mol­ecules are linked by π–π stacking inter­actions between pyridine rings and weak C—H⋯π inter­actions between a methyl H atom and the centroid of a pyridine ring, forming a two-dimensional layer structure extending parallel to the ac plane. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contributions to the crystal packing are from H⋯H (52.9%) and H⋯C/C⋯H (17.3%) contacts.

The title compound, C18H18F2N2O3, crystallizes with two independent mol­ecules (A and B) in the asymmetric unit. They differ essentially in the orientation of the pyridine ring with respect to the benzene ring; these two rings are inclined to each other by 53.3 (2)° in mol­ecule A and by 72.9 (2)° in mol­ecule B. The 3-(cyclo­propyl­meth­oxy) side chain has an extended conformation in both mol­ecules. The two mol­ecules are linked by a pair of C—H⋯O hydrogen bonds and two C—H⋯π inter­actions, forming an A–B unit. In the crystal, this unit is linked by N—H⋯O hydrogen bonds, forming a zigzag –A–B–A–B– chain along [001]. The chains are linked by C—H⋯N and C—H⋯F hydrogen bonds to form layers parallel to the ac plane. Finally, the layers are linked by a third C—H⋯π inter­action, forming a three-dimensional structure. The major contributions to the Hirshfeld surface are those due to H⋯H contacts (39.7%), followed by F⋯H/H⋯F contacts (19.2%).

In the title compound, C16H14N2O3S, the 1,3-benzoxazole ring system is essentially planar (r.m.s deviation = 0.004 Å) and makes a dihedral angle of 66.16 (17)° with the benzene ring of the meth­oxy­phenyl group. Two intra­molecular N—H⋯O and N—H⋯N hydrogen bonds occur, forming S(5) and S(7) ring motifs, respectively. In the crystal, pairs of C—H⋯O hydrogen bonds link the mol­ecules into inversion dimers with R22(14) ring motifs, stacked along the b-axis direction. The inversion dimers are linked by C—H⋯π and π–π-stacking inter­actions [centroid-to-centroid distances = 3.631 (2) and 3.631 (2) Å], forming a three-dimensional network. Two-dimensional fingerprint plots associated with the Hirshfeld surface show that the largest contributions to the crystal packing come from H⋯H (39.3%), C⋯H/H⋯C (18.0%), O⋯H/H⋯O (15.6) and S⋯H/H⋯S (10.2%) inter­actions.

The title phospho­nate-based organic–inorganic hybrid framework, poly[bis(dimethylammonium) [(μ4-2,5-dihydroxybenzene-1,4-diphosphonato)zinc(II)]], {(C2H8N)2[Zn(C6H4O8P2)]}n, was formed unexpectedly when di­methyl­ammonium cations were formed from the in situ deca­rbonylation of the N,N-di­methyl­formamide solvent. The framework is built up from ZnO4 tetra­hedra and bridging di­phospho­nate tetra-anions to generate a three-dimensional network comprising [100] channels occupied by the (CH3)2NH2+ cations. Within the channels, an array of N—H⋯O hydrogen bonds help to establish the structure. In addition, intra­molecular O—H⋯O hydrogen bonds between the appended –OH groups of the phenyl ring and adjacent PO32− groups are observed.

The title mol­ecular salt, (C7H11N2)2[Hg2Cl6], crystallizes with two 4-(di­methyl­amino)­pyridinium cations (A and B) and two half hexa­chlorido­dimercurate(II) anions in the asymmetric unit. The organic cations exhibit essentially the same features with an almost planar pyridyl ring (r.m.s. deviations of 0.0028 and 0.0109 Å), which forms an inclined dihedral angle with the dimethyamino group [3.06 (1) and 1.61 (1)°, respectively]. The di­methyl­amino groups in the two cations are planar, and the C—N bond lengths are shorter than that in 4-(di­methyl­amino)­pyridine. In the crystal, mixed cation–anion layers lying parallel to the (010) plane are formed through N—H⋯Cl hydrogen bonds and adjacent layers are linked by C—H⋯Cl hydrogen bonds, forming a three-dimensional network. The analyses of the calculated Hirshfeld surfaces confirm the relevance of the above inter­molecular inter­actions, but also serve to further differentiate the weaker inter­molecular inter­actions formed by the organic cations and inorganic anions, such as π–π and Cl⋯Cl inter­actions. The powder XRD data confirms the phase purity of the crystalline sample. Furthermore, the vibrational absorption bands were identified by IR spectroscopy and the optical properties were studied by using optical UV–visible absorption spectroscopy.

The title compound, [Fe(CF3SO3)2(C4H8O)4], is octa­hedral with two tri­fluoro­methane­sulfonate ligands in trans positions and four tetra­hydro­furane mol­ecules in the equatorial plane. By the conformation of the ligands the complex is chiral in the crystal packing. The compound crystallizes in the Sohncke space group P212121 and is enanti­omerically pure. The packing of the mol­ecules is determined by weak C—H⋯O hydrogen bonds. The crystal studied was refined as a two-component inversion twin.

The title pull–push chromophores, 2-[4-(di­methyl­amino)­benzyl­idene]-1H-indene-1,3(2H)-dione, C18H15NO2 (ID[1]) and (E)-2-{3-[4-(di­methyl­amino)­phen­yl]allyl­idene}-1H-indene-1,3(2H)-dione, C20H17NO2 (ID[2]), have donor–π-bridge–acceptor structures. The mol­ecule with the short π-bridge, ID[1], is almost planar while for the mol­ecule with a longer bridge, ID[2], is less planar. The benzene ring is inclined to the mean plane of the 2,3-di­hydro-1H-indene unit by 3.19 (4)° in ID[1] and 13.06 (8)° in ID[2]. The structures of three polymorphs of compound ID[1] have been reported: the α-polymorph [space group P21/c; Magomedova & Zvonkova (1978). Kristallografiya, 23, 281–288], the β-polymorph [space group P21/c; Magomedova & Zvonkova (1980). Kristallografiya, 25 1183–1187] and the γ-polymorph [space group Pna21; Magomedova, Neigauz, Zvonkova & Novakovskaya (1980). Kristallografiya, 25, 400–402]. The mol­ecular packing in ID[1] studied here is centrosymmetric (space group P21/c) and corresponds to the β-polymorph structure. The mol­ecular packing in ID[2] is non-centrosymmetric (space group P21), which suggests potential NLO properties for this crystalline material. In both compounds, there is short intra­molecular C—H⋯O contact present, enclosing an S(7) ring motif. In the crystal of ID[1], mol­ecules are linked by C—H⋯O hydrogen bonds and C—H⋯π inter­actions, forming layers parallel to the bc plane. In the crystal of ID[2], mol­ecules are liked by C—H⋯O hydrogen bonds to form 21 helices propagating along the b-axis direction. The mol­ecules in the helix are linked by offset π–π inter­actions with, for example, a centroid–centroid distance of 3.9664 (13) Å (= b axis) separating the indene rings, and an offset of 1.869 Å. Spectroscopic and electrochemical measurements show the ability of these compounds to easily transfer electrons through the π-conjugated chain.

In the title pyrazoline derivative, C16H16N2O3·H2O, the pyrazoline ring has an envelope conformation with the substituted sp2 C atom on the flap. The pyrazoline ring makes angles of 86.73 (12) and 13.44 (12)° with the tris­ubstituted and disubstituted benzene rings, respectively. In the crystal structure, the mol­ecules are connected into chains running in the b-axis direction by O—H⋯N hydrogen bonding. Parallel chains inter­act through N—H⋯O hydrogen bonds and π–π stacking of the tris­ubstituted phenyl rings. The major contribution to the surface contacts are H⋯H contacts (44.3%) as concluded from a Hirshfeld surface analysis.

In the title hydrazinecarbodi­thio­ate derivative, C27H26N2O2S2, the asymmetric unit is comprised of four mol­ecules (Z = 8 and Z' = 4). The 4-meth­oxy­phenyl rings are slightly twisted away from their attached olefinic double bonds [torsion angles = 5.9 (4)–19.6 (4)°]. The azomethine double bond has an s-trans configuration relative to one of the C=C bonds and an s-cis configuration relative to the other [C=C—C= N = 147.4 (6)–175.7 (2) and 15.3 (3)–37.4 (7)°, respectively]. The torsion angles between the azomethine C=N double bond and hydrazine-1-carbodi­thio­ate moiety indicate only small deviations from planarity, with torsion angles ranging from 0.9 (3) to 6.9 (3)° and from 174.9 (3) to 179.7 (2)°, respectively. The benzyl ring and the methyl­enesulfanyl moiety are almost perpendicular to each other, as indicated by their torsion angles [range 93.7 (3)–114.6 (2)°]. In the crystal, mol­ecules are linked by C—H⋯O, N—H⋯S and C—H⋯π(ring) hydrogen-bonding inter­actions into a three-dimensional network. Structural details of related benzyl hydrazine-1-carbodi­thio­ate are surveyed and compared with those of the title compound.

In the title com­pound, C29H22N4O3, the carbazole system forms a dihedral angle of 68.45 (3)° with the mean plane of the bi­pyridine ring system. The bi­pyridine ring system, with two meth­oxy substituents, is approximately planar (r.m.s. deviation = 0.0670 Å), with a dihedral angle of 7.91 (13)° between the planes of the two pyridine rings. Intra­molecular C—H⋯O/N hydrogen bonds may promote the planarity of the bipyridyl ring system. In the pyridyl-substituted carbazole fragment, the pyridine ring is tilted by 56.65 (4)° with respect to the mean plane of the carbazole system (r.m.s. deviation = 0.0191 Å). In the crystal, adjacent mol­ecules are connected via C—H⋯O/N hydrogen bonds and C—H⋯π inter­actions, resulting in the formation of a three-dimensional (3D) supra­molecular network. In addition, the 3D structure contains inter­molecular π–π stacking inter­actions, with centroid–centroid distances of 3.5634 (12) Å between pyridine rings. The title com­pound exhibits a high energy gap (3.48 eV) and triplet energy (2.64 eV), indicating that it could be a suitable host material in organic light-emitting diode (OLED) applications.

The asymmetric units of the title compounds both contain one nonplanar mol­ecule. In 4-benzyl-6-phenyl-4,5-di­hydro­pyridazin-3(2H)-one, C17H14N2O, (I), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 46.69 (9)°; the phenyl ring of the benzyl group is nearly perpendicular to the plane of the pyridazine ring, the dihedral angle being 78.31 (10)°. In methyl 2-[5-(2,6-di­chloro­benz­yl)-6-oxo-3-phenyl-1,4,5,6-tetra­hydropyridazin-1-yl]acetate, C20H16Cl2N2O3, (II), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 21.76 (18)°, whereas the phenyl ring of the di­chloro­benzyl group is inclined to the pyridazine ring by 79.61 (19)°. In the crystal structure of (I), pairs of N—H⋯O hydrogen bonds link the mol­ecules into inversion dimers with an R22(8) ring motif. In the crystal structure of (II), C—H⋯O hydrogen bonds generate dimers with R12(7), R22(16) and R22(18) ring motifs. The Hirshfeld surface analyses of compound (I) suggests that the most significant contributions to the crystal packing are by H⋯H (48.2%), C⋯H/H⋯C (29.9%) and O⋯H/H⋯O (8.9%) contacts. For compound (II), H⋯H (34.4%), C⋯H/H⋯C (21.3%) and O⋯H/H⋯O (16.5%) inter­actions are the most important contributions.

The title com­pound, C22H16N4O2, contains two pyridine rings and one meth­oxy­carbonyl­phenyl group attached to a pyridazine ring which deviates very slightly from planarity. In the crystal, ribbons consisting of inversion-related chains of mol­ecules extending along the a-axis direction are formed by C—HMthy⋯OCarbx (Mthy = methyl and Carbx = carboxyl­ate) hydrogen bonds. The ribbons are connected into layers parallel to the bc plane by C—HBnz⋯π(ring) (Bnz = benzene) inter­actions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (39.7%), H⋯C/C⋯H (27.5%), H⋯N/N⋯H (15.5%) and O⋯H/H⋯O (11.1%) inter­actions. Hydrogen-bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Computational chemistry indicates that in the crystal, C—HMthy⋯OCarbx hydrogen-bond energies are 62.0 and 34.3 kJ mol−1, respectively. 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.

In the title com­pound, C13H14N2O3, the dihydropyridazine ring (r.m.s. deviation = 0.166 Å) has a screw-boat conformation. The dihedral angle between its mean plane and the benzene ring is 0.77 (12)°. In the crystal, inter­molecular O—H⋯O hydrogen bonds generate C(5) chains and N—H⋯O hydrogen bonds produce R22(8) motifs. These types of inter­actions lead to the formation of layers parallel to (12overline{1}). The three-dimensional network is achieved by C—H⋯O inter­actions, including R24(8) motifs. Inter­molecular inter­actions were additionally investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots. The most significant contributions to the crystal packing are by H⋯H (43.3%), H⋯C/C⋯H (19.3%), H⋯O/H⋯O (22.6%), C⋯N/N⋯C (3.0%) and H⋯N/N⋯H (5.8%) contacts. C—H⋯π inter­actions and aromatic π–π stacking inter­actions are not observed.

Two thio­chromene com­pounds containing Br and F atoms, namely 2-(2-bromo-5-fluoro­phen­yl)-8-eth­oxy-3-nitro-2H-thio­chromene (C17H13BrFNO3S, A) and 2-(2-bromo-5-fluoro­phen­yl)-7-meth­oxy-3-nitro-2H-thio­chromene (C16H11BrFNO3S, B), were prepared via the condensation reaction between 2-mer­capto­benzaldehyde and nitro­styrene derivatives. In both com­pounds, the thio­chromene plane is almost perpendicular to the phenyl ring. In the structure of A, mol­ecules are assembled via π–π stacking and C—H⋯O and C—F⋯π inter­actions. In the crystal packing of B, mol­ecules are linked by C—H⋯F, C—H⋯O, C—H⋯π and π–π inter­actions.

The title mol­ecular salt, C9H12N3O2S+·HSO4−, was obtained through the protonation of the azomethine N atom in a sulfuric acid medium. The crystal com­prises two entities, a thio­semicarbazide cation and a hydrogen sulfate anion. The cation is essentially planar and is further stabilized by a strong intra­molecular O—H⋯N hydrogen bond. In the crystal, a three-dimensional network is established through O—H⋯O and N—H⋯O hydrogen bonds. A weak intermolecular C—H⋯O hydrogen bond is also observed. The hydrogen sulfate anion exhibits disorder over two sets of sites and was modelled with refined occupancies of 0.501 (6) and 0.499 (6).

In the title com­plex, [Cu(C18H12F6N2O4)]·0.5C6H6O2, the CuII ion has a square-planar coordination geometry, being ligated by two N and two O atoms of the tetra­dentate open-chain Schiff base ligand 6,6'-{(1E,1'E)-[ethane-1,2-diylbis(aza­nylyl­idene)]bis­(methanylyl­idene)}bis­[2-(tri­fluoro­meth­oxy)phenol]. The crystal packing is stabilized by intra­molecular O—H⋯O and inter­molecular C—H⋯F, C—H⋯O and C—H⋯π hydrogen bonds. In addition, weak π–π inter­actions form a three-dimensional structure. Hirshfeld surface analysis and two-dimensional fingerprint plots were performed and created to analyze the inter­molecular inter­actions present in the crystal, indicating that the most important contributions for the crystal packing are from F⋯H/H⋯F (25.7%), H⋯H (23.5%) and C⋯H/H⋯C (12.6%) inter­actions.

The title compound, [IrZnI2(C10H15)(C3H9P)2]·0.5C6H6 or [Cp*(PMe3)2Ir]-[ZnI2] (Cp* = cyclo-C5Me5) was obtained and characterized as its benzene solvate [Cp*(PMe3)2Ir]-[ZnI2]·0.5C6H6. The bimetallic complex in this structure contains the Lewis-acidic fragment ZnI2 bonded to the Lewis-basic fragment Cp*(PMe3)2Ir, with an Ir—Zn bond distance of 2.452 (1) Å. The compound was obtained by reacting [Cp*(PMe3)IrI2] with 2-Ad2Zn (2-Ad = 2-adamant­yl), resulting in the reduction of the IrIII complex and formation of the IrI–ZnII adduct. The crystal studied was a twin by non-merohedry with a refined BASF parameter of 0.223 (1).

The title compound, C14H14N2S2, was obtained by transmetallation of 2,2'-bis­(tri­methyl­stann­yl)azo­benzene with methyl lithium, and subsequent quenching with dimethyl di­sulfide. The asymmetric unit comprises two half-mol­ecules, the other halves being completed by inversion symmetry at the midpoint of the azo group. The two mol­ecules show only slight differences with respect to N=N, S—N and aromatic C=C bonds or angles. Hirshfeld surface analysis reveals that except for one weak H⋯S inter­action, inter­molecular inter­actions are dominated by van der Waals forces only.

The crystal structure of the title compound, [Ni3(C8H4O4)3(C3H7NO)4], is a two-dimensional coordination network formed by trinuclear linear Ni3(tp)3(DMF)4 units (tp = terephthalate = benzene-1,4-di­carboxyl­ate and DMF = di­methyl­formamide) displaying a characteristic coordination mode of acetate groups in polynuclear metal–organic compounds. Individual trinuclear units are connected through tp anions in a triangular network that forms layers. One of the DMF ligands points outwards and provides inter­actions with equivalent planes above and below, leaving the second ligand in a structural void much larger than the DMF mol­ecule, which shows positional disorder. Parallel planes are connected mainly through weak C—H⋯O, H⋯H and H⋯C inter­actions between DMF mol­ecules, as shown by Hirshfeld surface analysis.

The reaction of t-Bu2Si(OH)2 with two equivalents of Cp2Zr(CH3)2 produces the title t-Bu2SiO2-siloxide bridged dimer, [Zr2(CH3)2(C5H5)4(C8H18O2Si)] or [Cp2Zr(CH3)]2[μ-t-Bu2SiO2] (1), where one methyl group is retained per zirconium atom. The same product is obtained at room temperature even when equimolar ratios of the silanediol and Cp2Zr(CH3)2 are used. Attempts to thermally eliminate methane and produce a bridging methyl­ene complex resulted in decomposition. The crystal structure of 1 displays typical Zr—CH3 and Zr—O distances but the Si—O distance [1.628 (2) Å] and O—Si—O angle [110.86 (15)°] are among the largest observed in this family of compounds suggesting steric crowding between the t-Bu substituents of the silicon atom and the cyclo­penta­dienyl groups. The silicon atom lies on a crystallographic twofold axis and both Cp rings are disordered over two orientations of equal occupancy.

In the paper by Gomes et al. [Acta Cryst. (2019), E75, 1403–1410], there was an error and omission in the author and affiliation list.

The title compound, C20H22N8O2, was synthesized by the coupling reaction of a sodium tetra­zolate salt and di­bromo­butane in a molar ratio of 2:1. The reaction can produce several possible regioisomers and the title compound was separated as the major product. The X-ray crystallographic study confirmed that the title compound crystallizes in the monoclinic P21/c space group and possesses a bridging butyl­ene group that connects two identical phenyl tetra­zole moieties. The butyl­ene group is attached not to the first but the second nitro­gen atoms of both tetra­zole rings. The dihedral angles between the phenyl groups and the adjacent tetra­zolyl rings are 5.32 (6) and 15.37 (7)°. In the crystal, the mol­ecules form centrosymmetric dimers through C—H⋯O hydrogen bonds between a C—H group of the butyl­ene linker and the O atom of a meth­oxy group.

In the title compound, C17H21NO4S, the 1,4-di­hydro­pyridine ring has an envelope conformation with the Csp3 atom at the flap. The thio­phene ring is nearly perpendicular to the best plane through the 1,4-di­hydro­pyridine ring, the dihedral angle being 82.19 (13)°. In the crystal, chains running along the b-axis direction are formed through N—H⋯O inter­actions between the 1,4-di­hydro­pyridine N atom and one of the O atoms of the ester groups. Neighbouring chains are linked by C—H⋯O and C—H⋯π inter­actions. A Hirshfeld surface analysis shows that the most prominent contributuion to the surface contacts are H⋯H contacts (55.1%).

A new polymorphic form of the title compound, C12H10O4, is described in the ortho­rhom­bic space group Pbca and Z = 8, as compared to polymorph I, which crystallizes in the monoclinic space group C2/c and Z = 8 [Li et al. (2012). Chin. J. Struct. Chem. 31, 1003–1007.]. In polymorph II, the coumarin ring system is almost planar (r.m.s. deviation = 0.00129 Å). In the crystal, mol­ecules are connected by Csp3—H⋯O and Car—H⋯O hydrogen bonds, forming mol­ecular sheets linked into zigzag shaped layers along the b-axis direction. The three-dimensional lattice is assembled through stacking of the zigzag layers by π–π inter­actions with a centroid-to-centroid distance of 3.600 (9) Å and anti­parallel C=O⋯C=O inter­actions with a distance of 3.1986 (17) Å, which give rise to a helical supra­molecular architecture.

The title pyridazinone derivative, C20H18N2O3, is not planar. The phenyl ring and the pyridazine ring are inclined to each other by 10.55 (12)°, whereas the 4-methyl­benzyl ring is nearly orthogonal to the pyridazine ring, with a dihedral angle of 72.97 (10)°. In the crystal, mol­ecules are linked by pairs of O—H⋯O hydrogen bonds, forming inversion dimers with an R22(14) ring motif. The dimers are linked by C—H⋯O hydrogen bonds, generating ribbons propagating along the c-axis direction. The inter­molecular inter­actions were additionally investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots. They revealed that the most significant contributions to the crystal packing are from H⋯H (48.4%), H⋯O/O⋯H (21.8%) and H⋯C/C⋯H (20.4%) contacts. Mol­ecular orbital calculations providing electron-density plots of HOMO and LUMO mol­ecular orbitals and mol­ecular electrostatic potentials (MEP) were also computed, both with the DFT/B3LYP/6–311 G++(d,p) basis set.

The mononuclear title complex, [Eu(C24H34O4P)3(CH4O)5]·CH4O, (1), has been obtained as a minor product in the reaction between EuCl3(H2O)6 and lithium bis­(2,6-diiso­propyl­phen­yl) phosphate in a 1:3 molar ratio in a methanol medium. Its structure exhibits monoclinic (P21/c) symmetry at 120 K and is isostructural with the La, Ce and Nd analogs reported previously [Minyaev et al. (2018a). Acta Cryst. C74, 590–598]. In (1), all three bis­(2,6-diiso­propyl­phen­yl) phosphate ligands display the terminal κ1O-coordination mode. All of the hy­droxy H atoms are involved in O—H⋯O hydrogen bonding, exhibiting four intra­molecular and two inter­molecular hydrogen bonds. Photophysical studies have demonstrated luminescence of (1) with a low quantum yield.

The title compound, [FePt(C12H12O)(C18H15P)(C25H22P2)(CO)2]·2C7H8·CH2Cl2 or [(OC)2Fe(μ-dppm)(μ-C(=O)C(2,4,5-C6H2Me3)=CH)Pt(PPh3)], represents an example of a diphosphane-bridged heterobimetallic dimetalla­cyclo­pentenone complex resulting from a bimetallic activation of 1-ethynyl-2,4,5-tri­methyl­benzene and a metal-coordinated carbonyl ligand. The bridging μ2-C(=O)C(2,4,5-C6H2Me3)=CH unit (stemming from a carbon–carbon coupling reaction between CO and the terminal alkyne) forms a five-membered dimetalla­cyclo­pentenone ring, in which the C=C bond is π-coordinated to the Fe centre. The latter is connected to the Pt centre through a short metal–metal bond of 2.5770 (5) Å. In the crystal, the complex is solvated by one di­chloro­methane and two toluene mol­ecules.

The title compound, C14H12BrNO2, was synthesized by the condensation reaction of 2,3-di­hydroxy­benzaldehyde and 2-bromo-3-methyl­aniline. It crystallizes in the centrosymmetric triclinic space group Poverline{1}. The configuration about the C=N bond is E. The dihedral angle between the planes of the 5-(2-bromo-3-methyl­phenyl ring and the catechol ring is 2.80 (17)°. In the crystal, O—H⋯O hydrogen-bond inter­actions consolidate the crystal packing.

In the title hydrated hybrid compound C14H14N2OS2·H2O, the planar imidazo[1,2-a]pyridine ring system is linked to the 1,3-di­thiol­ane moiety by an enone bridge. The atoms of the C—C bond in the 1,3-di­thiol­ane ring are disordered over two positions with occupancies of 0.579 (14) and 0.421 (14) and both disordered rings adopt a half-chair conformation. The oxygen atom of the enone bridge is involved in a weak intra­molecular C—H⋯O hydrogen bond, which generates an S(6) graph-set motif. In the crystal, the hybrid mol­ecules are associated in R22(14) dimeric units by weak C—H⋯O inter­actions. O—H⋯O hydrogen bonds link the water mol­ecules, forming infinite self-assembled chains along the b-axis direction to which the dimers are connected via O—H⋯N hydrogen bonding. Analysis of inter­molecular contacts using Hirshfeld surface analysis and contact enrichment ratio descriptors indicate that hydrogen bonds induced by water mol­ecules are the main driving force in the crystal packing formation.

In the title mol­ecule, C11H10N2O, the di­hydro­benzimidazol-2-one moiety is essentially planar, with the prop-2-yn-1-yl substituent rotated well out of this plane. In the crystal, C—HMthy⋯π(ring) inter­actions and C—HProp⋯ODhyr (Mthy = methyl, Prop = prop-2-yn-1-yl and Dhyr = di­hydro) hydrogen bonds form corrugated layers parallel to (10overline{1}), which are associated through additional C—HBnz⋯ODhyr (Bnz = benzene) hydrogen bonds and head-to-tail, slipped, π-stacking [centroid-to-centroid distance = 3.7712 (7) Å] inter­actions between di­hydro­benzimidazol-2-one moieties. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (44.1%), H⋯C/C⋯H (33.5%) and O⋯H/H⋯O (13.4%) inter­actions. Hydrogen-bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Computational chemistry calculations indicate that in the crystal, C—H⋯O hydrogen-bond energies are 46.8 and 32.5 (for C—HProp⋯ODhyr) and 20.2 (for C—HBnz⋯ODhyr) 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 title compound, C15H22N4O5S, was prepared via alkyl­ation of 3-(chloro­meth­yl)-5-(pentan-3-yl)-1,2,4-oxa­diazole in anhydrous dioxane in the presence of tri­ethyl­amine. The thia­diazine ring has an envelope conformation with the S atom displaced by 0.4883 (6) Å from the mean plane through the other five atoms. The planar 1,2,4-oxa­diazole ring is inclined to the mean plane of the thia­diazine ring by 77.45 (11)°. In the crystal, mol­ecules are linked by C—H⋯N hydrogen bonds, forming chains propagating along the b-axis direction. Hirshfeld surface analysis and two-dimensional fingerprint plots have been used to analyse the inter­molecular contacts present in the crystal. Mol­ecular docking studies were use to evaluate the title compound as a potential system that inter­acts effectively with the capsid of the Hepatitis B virus (HBV), supported by an experimental in vitro HBV replication model.

Three title compounds, namely, 2-(4-chloro­benz­yl)-5-[(1H-indol-3-yl)meth­yl]-6-phenyl­imidazo[2,1-b][1,3,4]thia­diazole, C26H19ClN4S, (I), 2-(4-chloro­benz­yl)-6-(4-fluoro­phen­yl)-5-[(1H-indol-3-yl)meth­yl]imidazo[2,1-b][1,3,4]thia­diazole, C26H18ClFN4S, (II), and 6-(4-bromo­phen­yl)-2-(4-chloro­benz­yl)-5-[(1H-indol-3-yl)meth­yl]imidazo[2,1-b][1,3,4]thia­diazole, C26H18BrClN4S, (III), have been prepared using a reductive condensation of indole with the corresponding 6-aryl-2-(4-chloro­benz­yl)imidazo[2,1-b][1,3,4]thia­diazole-5-carbaldehydes (aryl = phenyl, 4-fluoro­phenyl or 4-bromo­phen­yl), and their crystal structures have been determined. The asymmetric unit of compound (I) consists of two independent mol­ecules and one of the mol­ecules exhibits disorder of the 4-chloro­benzyl substituent with occupancies 0.6289 (17) and 0.3711 (17). Each type of mol­ecule forms a C(8) chain motif built from N—H⋯N hydrogen bonds, which for the fully ordered mol­ecule is reinforced by C—H⋯π inter­actions. In compound (II), the chloro­benzyl unit is again disordered, with occupancies 0.822 (6) and 0.178 (6), and the mol­ecules form C(8) chains similar to those in (I), reinforced by C—H⋯π inter­actions involving only the major disorder component. The chloro­benzyl unit in compound (III) is also disordered with occupancies of 0.839 (5) and 0.161 (5). The mol­ecules are linked by a combination of one N—H⋯N hydrogen bond and four C—H⋯π inter­actions, forming a three-dimensional framework.

In the mol­ecule of the title anthracene derivative, C22H17NO2, the benzene ring is inclined to the mean plane of the anthracene ring system (r.m.s. deviation = 0.024 Å) by 75.21 (9)°. In the crystal, mol­ecules are linked by pairs of O—H⋯O hydrogen bonds, forming classical carb­oxy­lic acid inversion dimers with an R22(8) ring motif. The dimers are linked by C—H⋯π inter­actions, forming a supra­molecular framework.