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Three homoleptic Hg(S2CNR2)2, for R = ethyl (1), isobutyl (2), and cyclohexyl (3), compounds apparently exhibit a steric-dependent supramolecular association in their crystals. The small group in 1 allows for dimer formation via covalent Hg–S interactions through an eight-membered {–HgSCS}2 ring as the dithiocarbamato ligands bridge centrosymmetrically related Hg atoms; intradimer Hg···S interactions are noted. By contrast, centrosymmetrically related molecules in 2 are aligned to enable intermolecular Hg···S interactions, but the separations greatly exceed the van der Waals radii. The large group in 3 precludes both dimerization and intermolecular Hg···S interactions. Computational chemistry indicates that the potential region at the Hg atom is highly dependent on the coordination geometry about the Hg atom. Intramolecular (1) and intermolecular (2) spodium bonding (SpB) is demonstrated. Even at separations approaching 0.4 Å beyond the sum of the assumed van der Waals radii, the energy of the stabilization afforded by the structure directs SpB in 2 amounts to approximately 2.5 kcal/mol. A natural bond orbital (NBO) analysis points to the importance of the LP(S) → σ*(Hg–S) charge transfer and to the dominance of the dispersion forces and electron correlation to the SpB in 2.

The title CuII macrocyclic complex salt tetrahydrate, [Cu(C22H46N6O2)](C2H3O2)2·4H2O, sees the metal atom located on a centre of inversion and coordinated within a 4 + 2 (N4O2) tetragonally distorted coordination geometry; the N atoms are derived from the macrocycle and the O atoms from weakly associated [3.2048 (15) Å] acetate anions. Further stability to the three-ion aggregate is provided by intramolecular amine-N—H...O(carboxylate) hydrogen bonds. Hydrogen bonding is also prominent in the molecular packing with amide-N—H...O(amide) interactions, leading to eight-membered {...HNCO}2 synthons, amide-N—H...O(water), water-O—H...O(carboxylate) and water-O—H...O(water) hydrogen bonds featuring within the three-dimensional architecture. The calculated Hirshfeld surfaces for the individual components of the asymmetric unit differentiate the water molecules owing to their distinctive supramolecular association. For each of the anion and cation, H...H contacts predominate (50.7 and 65.2%, respectively) followed by H...O/O...H contacts (44.5 and 29.9%, respectively).

Two monoclinic (P21/c; Z′ = 1) polymorphs, α (from methanol) and β (from ethanol, n-propanol and iso-propanol), of a bioactive pyrazolo[3,4-d]pyrimidine derivative have been isolated and characterised by X-ray crystallography as well as by a range of computational chemistry techniques. The different conformations observed for the molecules in the crystals are due to the dictates of molecular packing as revealed by geometry-optimisation calculations. The crucial difference in the molecular packing pertains to the formation of phenylamino-N–H···N(pyrazolyl) hydrogen bonding within supramolecular chains with either helical (α-form; 21-screw symmetry) or zigzag (β-form; glide symmetry). As a consequence, the molecular packing is quite distinct in the polymorphs. Lattice energy calculations indicate the β-form is more stable by 11 kJ/mol than the α-form.

The title thiourea derivative, C17H19N3OS, adopts a U-shaped conformation with the dihedral angle between the terminal aromatic rings being 73.64 (5)°. The major twist in the molecule occurs about the ethane bond with the Ci—Ce—Ce—Cb torsion angle being −78.12 (18)°; i = imine, e = ethane and b = benzene. The configuration about the imine bond is E, the N-bound H atoms lie on opposite sides of the molecule and an intramolecular amine-N—H...N(imine) hydrogen bond is evident. In the molecular packing, hydroxyl-O—H...S(thione) and amine-N—H...O hydrogen bonding feature within a linear, supramolecular chain. The chains are connected into a layer in the ab plane by a combination of methylene-C—H...S(thione), methylene-C—H...O(hydroxyl), methyl-C—H...π(phenyl) and phenyl-C—H...π(hydroxybenzene) interactions. The layers stack without directional interactions between them. The analysis of the calculated Hirshfeld surface highlights the presence of weak methyl-C—H...O(hydroxyl) and H...H interactions in the inter-layer region. Computational chemistry indicates that dispersion energy is the major contributor to the overall stabilization of the molecular packing.

The title zinc bis(thiosemicarbazone) complex, [Zn(C22H17N4O2S)2], comprises two N,S-donor anions, leading to a distorted tetrahedral N2S2 donor set. The resultant five-membered chelate rings are nearly planar and form a dihedral angle of 73.28 (3)°. The configurations about the endocyclic- and exocyclic-imine bonds are Z and E, respectively, and that about the ethylene bond is E. The major differences in the conformations of the ligands are seen in the dihedral angles between the chelate ring and nitrobenzene rings [40.48 (6) cf. 13.18 (4)°] and the N-bound phenyl and nitrobenzene ring [43.23 (8) and 22.64 (4)°]. In the crystal, a linear supramolecular chain along the b-axis direction features amine-N—H...O(nitro) hydrogen bonding. The chains assemble along the 21-screw axis through a combination of phenyl-C—H...O(nitro) and π(chelate ring)–π(phenyl) contacts. The double chains are linked into a three-dimensional architecture through phenyl-C—H...O(nitro) and nitro-O...π(phenyl) interactions.

The title diorganotin Schiff base derivative, [Sn(C4H9)2(C15H13N3O2S)], features a penta-coordinated tin centre defined by the N,O,S-donor atoms of the di-anionic Schiff base ligand and two methylene-C atoms of the n-butyl substituents. The resultant C2NOS donor set defines a geometry intermediate between trigonal–bipyramidal and square-pyramidal. In the crystal, amine-N—H...O(methoxy) hydrogen bonding is found in a helical, supramolecular chain propagating along the b-axis direction. The chains are assembled into a layer parallel to (\overline{1}01) with methylene-C—H...π(phenyl) interactions prominent; layers stack without directional interactions between them. The analysis of the calculated Hirshfeld surface showed the presence of weak methylene-C—H...π(phenyl) interactions and short H...H contacts in the inter-layer region. Consistent with the nature of the identified contacts, the stabilization of the crystal is dominated by the dispersion energy term.

Two complexes containing a soft sulfur-substituted tris(pyrazolyl)hydroborate ligand, namely [TlI(TmtBu)]2∙2H2O and [InIII(TmtBu)2](InCl4), where TmtBu is the tris(3-tert-butyl-2-sulfanylidene-1H-imidazol-1-yl)hydroborate anion, have been characterized. The {TlS}2 core of the former has the shape of a diamond. Each S atom of the TmtBu anion coordinates differently: one S is connected to one Tl atom, one bridges both Tl atoms, while the third S atom connects solely to the second Tl atom. The S4 donor set defines a seesaw geometry. The independent H2O molecule forms O–H···S and localized O–H···π(pyrazolyl) contacts. Flattened octahedral geometries defined by S6 donor sets are noted for the two independent cations in [InIII(TmtBu)2](InCl4). In the crystal of [TlI(TmtBu)]2∙2H2O, pyrazolyl-C–H···O(water) interactions connect the dimeric units into a linear supramolecular chain, chains pack without directional interactions between them. In the crystal of [InIII(TmtBu)2](InCl4), alternating rows of independent cations are interspersed by anions. The primary points of contact within a three-dimensional architecture are of the type In–Cl···π(pyrazolyl) and C–H···Cl. The assessment of the molecular packing was complemented by considering the calculated Hirshfeld surfaces and two-dimensional fingerprint plots (overall and delineated into individual contacts).

The title phosphanegold(I) thiolate, C26H22AuFNOPS or [Au(C8H7FNOS)(C18H15P)], has the AuI centre coordinated by phosphane-P [2.2494 (8) Å] and thiolate-S [2.3007 (8) Å] atoms to define a close to linear geometry [P—Au—S = 176.10 (3)°]. The thiolate ligand is orientated so that the methoxy-O atom is directed towards the Au atom, forming an Au...O close contact of 2.986 (2) Å. In the crystal, a variety of intermolecular contacts are discerned with fluorobenzene-C—H...O(methoxy) and phenyl-C—H...F interactions leading to dimeric aggregates. These are assembled into a three-dimensional architecture by phenyl-C—H...S(thiolate) and phenyl-C—H...π(fluorobenzene, phenyl) interactions. Accordingly, the analysis of the calculated Hirshfeld surface shows 30.8% of all contacts are of the type C...H/H...C but this is less than the H...H contacts, at 44.9%. Other significant contributions to the surface come from H...F/F...H [8.1%], H...S/S...H [6.9%] and H...O/O...H [3.2%] contacts. Two major stabilization energies have contributions from the phenyl-C—H...π(fluorobenzene) and fluorobenzene-C—H...C(imine) interactions (−37.2 kcal mol−1), and from the fluorobenzene-C—H...F and phenyl-C—H...O interactions (−34.9 kcal mol−1), the latter leading to the dimeric aggregate.

The complete molecule of the title hydrazine carbodithioate derivative, C32H30N4O2S4, is generated by a crystallographic twofold axis that bisects the disulfide bond. The molecule is twisted about this bond with the C—S—S—C torsion angle of 90.70 (8)° indicating an orthogonal relationship between the symmetry-related halves of the molecule. The conformation about the imine bond [1.282 (2) Å] is E and there is limited delocalization of π-electron density over the CN2C residue as there is a twist about the N—N bond [C—N—N—C torsion angle = −166.57 (15)°]. An intramolecular hydroxyl-O—H...N(imine) hydrogen bond closes an S(6) loop. In the crystal, methylene-C—H...π(tolyl) contacts assemble molecules into a supramolecular layer propagating in the ab plane: the layers stack without directional interactions between them. The analysis of the calculated Hirshfeld surfaces confirm the importance of H...H contacts, which contribute 46.7% of all contacts followed by H...C/C...H contacts [25.5%] reflecting, in part, the C—H...π(tolyl) contacts. The calculation of the interaction energies confirm the importance of the dispersion term and the influence of the stabilizing H...H contacts in the inter-layer region.

The title compound, C23H24N2O9, is a tetra-substituted pyrrolidine derivative with a twisted conformation, with the twist evident in the C—C bond bearing the adjacent acetyloxy substituents. These are flanked on one side by a C-bound 4-methoxyphenyl group and on the other by a methylene group. The almost sp2-N atom [sum of angles = 357°] bears a 4-nitrobenzyloxycarbonyl substituent. In the crystal, ring-methylene-C—H...O(acetyloxy-carbonyl) and methylene-C—H...O(carbonyl) interactions lead to supramolecular layers lying parallel to (\overline{1}01); the layers stack without directional interactions between them. The analysis of the calculated Hirshfeld surfaces indicates the combined importance of H...H (42.3%), H...O/O...H (37.3%) and H...C/C...H (14.9%) surface contacts. Further, the interaction energies, largely dominated by the dispersive term, point to the stabilizing influence of H...H and O...O contacts in the inter-layer region.

The title compound, C20H20N4O3, is constructed about a tri-substituted 1,2,3-triazole ring, with the substituent at one C atom flanked by the C and N atoms being a substituted amide group, and with the adjacent C and N atoms bearing phenyl and benzyl groups, respectively; the dihedral angle between the pendant phenyl rings is 81.17 (12)°, indicative of an almost orthogonal disposition. In the crystal, pairwise amide-N—H...O(carbonyl) hydrogen bonds lead to a centrosymmetric dimer incorporating methylene-C—H...π(benzene) interactions. The dimers are linked into a supramolecular layer in the ab plane via methylene-C—H...N(azo) and benzene-C—H...O(amide) interactions; the layers stack along the c-axis direction without directional interactions between them. The above-mentioned intermolecular contacts are apparent in the analysis of the calculated Hirshfeld surface, which also provides evidence for short inter-layer H...C contacts with a significant dispersion energy contribution.

The title hydrazine carbodithioate chloroform hemisolvate, 2C15H14N2O2S2·CHCl3, comprises two independent hydrazine carbodithioate molecules, A and B, and a chloroform molecule; the latter is statistically disordered about its molecular threefold axis. The common features of the organic molecules include an almost planar, central CN2S2 chromophore [r.m.s. deviation = 0.0203 Å (A) and 0.0080 Å (B)], an E configuration about the imine bond and an intramolecular hydroxyl-O—H...N(imine) hydrogen bond. The major conformational difference between the molecules is seen in the relative dispositions of the phenyl rings as indicated by the values of the dihedral angles between the central plane and phenyl ring of 71.21 (6)° (A) and 54.73 (7)° (B). Finally, a difference is seen in the disposition of the outer hydroxyl-H atoms, having opposite relative orientations. In the calculated gas-phase structure, the entire molecule is planar with the exception of the perpendicular phenyl ring. In the molecular packing, the A and B molecules assemble into a two-molecule aggregate via N—H...S hydrogen bonds and eight-membered {...HNCS}2 synthons. The dimeric assemblies are connected into supramolecular chains via hydroxyl-O—H...O(hydroxyl) hydrogen bonds and these are linked into a double-chain through hydroxy-O—H...π(phenyl) interactions. The double-chains are connected into a three-dimensional architecture through phenyl-C—H...O(hydroxyl) and phenyl-C—H...π(phenyl) interactions. The overall assembly defines columns along the a-axis direction in which reside the chloroform molecules, which are stabilized by chloroform–methine-C—H...S(thione) and phenyl-C—H...Cl contacts. The analysis of the calculated Hirshfeld surfaces, non-covalent interaction plots and interaction energies confirm the importance of the above-mentioned interactions, but also of cooperative, non-standard interactions such as π(benzene)...π(hydrogen-bond-mediated-ring) contacts.

The title 1:1 solvate, C14H10O4S2·C3H7NO, features a twisted molecule of 2,2′-dithiodibenzoic acid (DTBA), with the central C—S—S—C torsion angle being −88.57 (6)°, and a molecule of dimethylformamide (DMF). The carboxylic acid groups are, respectively, close to co-planar and twisted with respect to the benzene rings to which they are connected as seen in the CO2/C6 torsion angles of 1.03 (19) and 7.4 (2)°. Intramolecular, hypervalent S←O interactions are noted [S...O = 2.6140 (9) and 2.6827 (9) Å]. In the crystal, four-molecule aggregates are formed via DTBA-O—H...O(DMF) and DTBA-O—H...O(DTBA) hydrogen bonding, the latter via an eight-membered {...OHCO}2 homosynthon. These are linked into supramolecular layers parallel to (011) via benzene-C—H...O(DTBA) and DTBA-C=O...π(benzene) interactions, with the connections between these, giving rise to a three-dimensional architecture, being of the type benzene-C—H...π(benzene). An analysis of the calculated Hirshfeld surfaces indicates, in addition to the aforementioned intermolecular contacts, the presence of stabilizing interactions between a benzene ring and a quasi-π-system defined by O—H...O hydrogen bonds between a DTBA dimer, i.e. the eight-membered {...OCOH}2 ring system, and between a benzene ring and a quasi-π(OCOH...OCH) system arising from the DTBA-O—H...O(DMF) hydrogen bond. The inter-centroid separations are 3.65 and 3.49 Å, respectively.

The CoII atom in the title complex, [Co(SO4)(C12H8N2)(H2O)3] (or C12H14CoN2O7S), is octahedrally coordinated within a cis-N2O4 donor set defined by the chelating N-donors of the 1,10-phenanthroline ligand, sulfate-O and three aqua-O atoms, the latter occupying an octahedral face. In the crystal, supramolecular layers lying parallel to (110) are sustained by aqua-O—H...O(sulfate) hydrogen bonding. The layers stack along the c-axis direction with the closest directional interaction between them being a weak phenanthroline-C—H...O(sulfate) contact. There are four significant types of contact contributing to the calculated Hirshfeld surface: at 44.5%, the major contribution comes from O—H...O contacts followed by H...H (28.6%), H...C/C...H (19.5%) and C...C (5.7%) contacts. The dominance of the electrostatic potential force in the molecular packing is also evident in the calculated energy frameworks. The title complex is isostructural with its manganese, zinc and cadmium containing analogues and isomeric with its mer-triaqua analogue.

Each of the title dis-symmetric di-Schiff base compounds, C15H12Cl2N2O2 (I) and C14H9BrCl2N2O (II), features a central azo-N—N bond connecting two imine groups, each with an E-configuration. One imine bond in each molecule connects to a 2,6-dichlorobenzene substituent while the other links a 2-hydroxyl-3-methoxy-substituted benzene ring in (I) or a 2-hydroxyl-4-bromo benzene ring in (II). Each molecule features an intramolecular hydroxyl-O—H...N(imine) hydrogen bond. The C—N—N—C torsion angles of −151.0 (3)° for (I) and 177.8 (6)° (II) indicates a significant twist in the former. The common feature of the molecular packing is the formation of supramolecular chains. In (I), the linear chains are aligned along the a-axis direction and the molecules are linked by methoxy-C—H...O(methoxy) and chlorobenzene-C—Cl...π(chlorobenzene) interactions. The chain in (II) is also aligned along the a axis but, has a zigzag topology and is sustained by Br...O [3.132 (4) Å] secondary bonding interactions. In each crystal, the chains pack without directional interactions between them. The non-covalent interactions are delineated in the study of the calculated Hirshfeld surfaces. Dispersion forces make the most significant contributions to the identified intermolecular interactions in each of (I) and (II).

The title di-substituted thiourea, C12H16N2O3S, has the hydroxylethyl and ethyl benzoate substituents bound to the same amine-N atom, and is twisted, having a (+)syn-clinal conformation with the Namine—C—C—O(hydroxyl, carbonyl) torsion angles of 49.39 (13) and 59.09 (12)°, respectively; the dihedral angle between the almost planar CN2S core and the pendent benzene ring is 69.26 (4)°. In the crystal, supramolecular layers propagating in the ac plane are formed via a combination of hydroxyl-O—H...S(thione), amine-N—H...O(hydroxyl, carbonyl) hydrogen-bonds. The layers stack along the b axis with inter-digitation of the benzene rings allowing the formation of π–π stacking [inter-centroid separation = 3.8722 (7) Å] and parallel C=O...π interactions. A computational chemistry study shows the conventional hydrogen bonding in the crystal leads to significant electrostatic stabilization but dispersion terms are also apparent, notably through the interactions involving the benzene residue.

The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2·2C7H5ClO2, comprises a half-molecule of oxalamide (4LH2), being located about a centre of inversion, and a molecule of3-chlorobenzoic acid (3-ClBA) in a general position. From symmetry, the 4LH2 molecule has a (+)antiperiplanar conformation with the 4-pyridyl residues lying to either side of the central, planar C2N2O2 chromophore with the dihedral angle between the core and pyridyl ring being 74.69 (11)°; intramolecular amide-N—H...O(amide) hydrogen bonds are noted. The 3-ClBA molecule exhibits a small twist as seen in the C6/CO2 dihedral angle of 8.731 (12)°. In the molecular packing, three-molecule aggregates are formed via carboxylic acid-O—H...N(pyridyl) hydrogen bonding. These are connected into a supramolecular tape along [111] through amide-N—H...O(carbonyl) hydrogen bonding. Additional points of contact between molecules include pyridyl and benzoic acid-C—H...O(amide), methylene-C—H...O(carbonyl) and C—Cl...π(pyridyl) interactions so a three-dimensional architecture results. The contributions to the calculated Hirshfeld surface are dominated by H...H (28.5%), H...O/O...H (23.2%), H...C/C...H (23.3%), H...Cl/Cl...H (10.0%) and C...Cl/C...Cl (6.2%) contacts. Computational chemistry confirms the C—Cl...π interaction is weak, and the importance of both electrostatic and dispersion terms in sustaining the molecular packing despite the strong electrostatic term provided by the carboxylic acid-O—H...N(pyridyl) hydrogen bonds.

The title compound, C13H19NO8, is based on a tetra-substituted pyrrolidine ring, which has a twisted conformation about the central C—C bond; the Cm—Ca—Ca—Cme torsion angle is 38.26 (15)° [m = methylcarboxylate, a = acetyloxy and me = methylene]. While the N-bound ethylcarboxylate group occupies an equatorial position, the remaining substituents occupy axial positions. In the crystal, supramolecular double-layers are formed by weak methyl- and methylene-C—H...O(carbonyl) interactions involving all four carbonyl-O atoms. The two-dimensional arrays stack along the c axis without directional interactions between them. The Hirshfeld surface is dominated by H...H (55.7%) and H...C/C...H (37.0%) contacts; H...H contacts are noted in the inter-double-layer region. The interaction energy calculations point to the importance of the dispersion energy term in the stabilization of the crystal.

The X-ray crystal structure of the title phthalazin-1-one derivative, C17H16N2O3S {systematic name: 2-[(2,4,6-trimethylbenzene)sulfonyl]-1,2-dihydrophthalazin-1-one}, features a tetrahedral sulfoxide-S atom, connected to phthalazin-1-one and mesityl residues. The dihedral angle [83.26 (4)°] between the organic substituents is consistent with the molecule having the shape of the letter V. In the crystal, phthalazinone-C6-C—H...O(sulfoxide) and π(phthalazinone-N2C4)–π(phthalazinone-C6) stacking [inter-centroid distance = 3.5474 (9) Å] contacts lead to a linear supramolecular tape along the a-axis direction; tapes assemble without directional interactions between them. The analysis of the calculated Hirshfeld surfaces confirm the importance of the C—H...O and π-stacking interactions but, also H...H and C—H...C contacts. The calculation of the interaction energies indicate the importance of dispersion terms with the greatest energies calculated for the C—H...O and π-stacking interactions.

The crystal and molecular structures of the title organotin dithiocarbamate compounds, [Sn(C6H5)3(C7H10NS2)] (I) and [Sn(C6H5)2(C7H10NS2)2] (II), present very distinct tin atom coordination geometries. In (I), the dithiocarbamate ligand is asymmetrically coordinating with the resulting C3S2 donor set defining a coordination geometry intermediate between square-pyramidal and trigonal–bipyramidal. In (II), two independent molecules comprise the asymmetric unit, which differ in the conformations of the allyl substituents and in the relative orientations of the tin-bound phenyl rings. The dithiocarbamate ligands in (II) coordinate in an asymmetric mode but the Sn—S bonds are more symmetric than observed in (I). The resulting C2S4 donor set approximates an octahedral coordination geometry with a cis-disposition of the ipso-carbon atoms and with the more tightly bound sulfur atoms approximately trans. The only directional intermolecular contacts in the crystals of (I) and (II) are of the type phenyl-C—H...π(phenyl) and vinylidene-C—H...π(phenyl), respectively, with each leading to a supramolecular chain propagating along the a-axis direction. The calculated Hirshfeld surfaces emphasize the importance of H...H contacts in the crystal of (I), i.e. contributing 62.2% to the overall surface. The only other two significant contacts also involve hydrogen, i.e. C...H/H...C (28.4%) and S...H/H...S (8.6%). Similar observations pertain to the individual molecules of (II), which are clearly distinguishable in their surface contacts, with H...H being clearly dominant (59.9 and 64.9%, respectively) along with C...H/H...C (24.3 and 20.1%) and S...H/H...S (14.4 and 13.6%) contacts. The calculations of energies of interaction suggest dispersive forces make a significant contribution to the stabilization of the crystals. The exception is for the C—H...π contacts in (II) where, in addition to the dispersive contribution, significant contributions are made by the electrostatic forces.

The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2·2C7H5ClO2, comprises two half molecules of oxalamide (4LH2), as each is disposed about a centre of inversion, and two molecules of 4-chlorobenzoic acid (CBA), each in general positions. Each 4LH2 molecule has a (+)antiperiplanar conformation with the pyridin-4-yl residues lying to either side of the central, planar C2N2O2 chromophore with the dihedral angles between the respective central core and the pyridyl rings being 68.65 (3) and 86.25 (3)°, respectively, representing the major difference between the independent 4LH2 molecules. The anti conformation of the carbonyl groups enables the formation of intramolecular amide-N—H...O(amide) hydrogen bonds, each completing an S(5) loop. The two independent CBA molecules are similar and exhibit C6/CO2 dihedral angles of 8.06 (10) and 17.24 (8)°, indicating twisted conformations. In the crystal, two independent, three-molecule aggregates are formed via carboxylic acid-O—H...N(pyridyl) hydrogen bonding. These are connected into a supramolecular tape propagating parallel to [100] through amide-N—H...O(amide) hydrogen bonding between the independent aggregates and ten-membered {...HNC2O}2 synthons. The tapes assemble into a three-dimensional architecture through pyridyl- and methylene-C—H...O(carbonyl) and CBA-C—H...O(amide) interactions. As revealed by a more detailed analysis of the molecular packing by calculating the Hirshfeld surfaces and computational chemistry, are the presence of attractive and dispersive Cl...C=O interactions which provide interaction energies approximately one-quarter of those provided by the amide-N—H...O(amide) hydrogen bonding sustaining the supramolecular tape.

The title hydrazine carbodithioate, C13H18N2OS2, is constructed about a central and almost planar C2N2S2 chromophore (r.m.s. deviation = 0.0263 Å); the terminal methoxybenzene group is close to coplanar with this plane [dihedral angle = 3.92 (11)°]. The n-butyl group has an extended all-trans conformation [torsion angles S—Cm—Cm—Cm = −173.2 (3)° and Cm—Cm—Cm—Cme = 180.0 (4)°; m = methylene and me = methyl]. The most prominent feature of the molecular packing is the formation of centrosymmetric eight-membered {...HNCS}2 synthons, as a result of thioamide-N—H...S(thioamide) hydrogen bonds; these are linked via methoxy-C–H...π(methoxybenzene) interactions to form a linear supramolecular chain propagating along the a-axis direction. An analysis of the calculated Hirshfeld surfaces and two-dimensional fingerprint plots point to the significance of H...H (58.4%), S...H/H...S (17.1%), C...H/H...C (8.2%) and O...H/H...O (4.9%) contacts in the packing. The energies of the most significant interactions, i.e. the N—H...S and C—H...π interactions have their most significant contributions from electrostatic and dispersive components, respectively. The energies of two other identified close contacts at close to van der Waals distances, i.e. a thione–sulfur and methoxybenzene–hydrogen contact (occurring within the chains along the a axis) and between methylene-H atoms (occurring between chains to consolidate the three-dimensional architecture), are largely dispersive in nature.

In the title compound, C12H15N3O5S, a trisubstituted thiourea derivative, the central CN2S chromophore is almost planar (r.m.s. deviation = 0.018 Å) and the pendant hydroxyethyl groups lie to either side of this plane. While to a first approximation the thione-S and carbonyl-O atoms lie to the same side of the molecule, the S—C—N—C torsion angle of −47.8 (2)° indicates a considerable twist. As one of the hydroxyethyl groups is orientated towards the thioamide residue, an intramolecular N—H...O hydrogen bond is formed which leads to an S(7) loop. A further twist in the molecule is indicated by the dihedral angle of 65.87 (7)° between the planes through the CN2S chromophore and the 4-nitrobenzene ring. There is a close match between the experimental and gas-phase, geometry-optimized (DFT) molecular structures. In the crystal, O—H...O and O—H...S hydrogen bonds give rise to supramolecular layers propagating in the ab plane. The connections between layers to consolidate the three-dimensional architecture are of the type C—H...O, C—H...S and nitro-O...π. The nature of the supramolecular association has been further analysed by a study of the calculated Hirshfeld surfaces, non-covalent interaction plots and computational chemistry, all of which point to the significant influence and energy of stabilization provided by the conventional hydrogen bonds.

The molecular structure of the title bis-pyridyl substituted diamide hydrate, C14H14N4O2·H2O, features a central C2N2O2 residue (r.m.s. deviation = 0.0205 Å) linked at each end to 3-pyridyl rings through methylene groups. The pyridyl rings lie to the same side of the plane, i.e. have a syn-periplanar relationship, and form dihedral angles of 59.71 (6) and 68.42 (6)° with the central plane. An almost orthogonal relationship between the pyridyl rings is indicated by the dihedral angle between them [87.86 (5)°]. Owing to an anti disposition between the carbonyl-O atoms in the core, two intramolecular amide-N—H...O(carbonyl) hydrogen bonds are formed, each closing an S(5) loop. Supramolecular tapes are formed in the crystal via amide-N—H...O(carbonyl) hydrogen bonds and ten-membered {...HNC2O}2 synthons. Two symmetry-related tapes are linked by a helical chain of hydrogen-bonded water molecules via water-O—H...N(pyridyl) hydrogen bonds. The resulting aggregate is parallel to the b-axis direction. Links between these, via methylene-C—H...O(water) and methylene-C—H...π(pyridyl) interactions, give rise to a layer parallel to (10\overline{1}); the layers stack without directional interactions between them. The analysis of the Hirshfeld surfaces point to the importance of the specified hydrogen-bonding interactions, and to the significant influence of the water molecule of crystallization upon the molecular packing. The analysis also indicates the contribution of methylene-C—H...O(carbonyl) and pyridyl-C—H...C(carbonyl) contacts to the stability of the inter-layer region. The calculated interaction energies are consistent with importance of significant electrostatic attractions in the crystal.

The complete molecule of the binuclear title complex, bis[μ-1H-1,2,4-triazole-5(4H)-thione-κ2S:S]bis{(thiocyanato-κS)[1H-1,2,4-triazole-5(4H)-thione-κS]silver(I)}, [Ag2(SCN)2(C2H3N3S)4], is generated by crystallographic inversion symmetry. The independent triazole-3-thione ligands employ the exocyclic-S atoms exclusively in coordination. One acts as a terminal S-ligand and the other in a bidentate (μ2) bridging mode to provide a link between two AgI centres. Each AgI atom is also coordinated by a terminal S-bound thiocyanate ligand, resulting in a distorted AgS4 tetrahedral coordination geometry. An intramolecular N—H...S(thiocyanate) hydrogen bond is noted. In the crystal, amine-N—H...S(thione), N—H...N(triazolyl) and N—H...N(thiocyanate) hydrogen bonds give rise to a three-dimensional architecture. The packing is consolidated by triazolyl-C—H...S(thiocyanate), triazolyl-C—H...N(thiocyanate) and S...S [3.2463 (9) Å] interactions as well as face-to-face π–π stacking between the independent triazolyl rings [inter-centroid separation = 3.4444 (15) Å]. An analysis of the calculated Hirshfeld surfaces shows the three major contributors are due to N...H/H...N, S...H/H...S and C...H/H...C contacts, at 35.8, 19.4 and 12.7%, respectively; H...H contacts contribute only 7.6% to the overall surface.

The crystal and molecular structures of the title 1:2 co-crystal, C14H14N4O2·2C7H6O2, are described. The oxalamide molecule has a (+)-antiperiplanar conformation with the 4-pyridyl residues lying to either side of the central, almost planar C2N2O2 chromophore (r.m.s. deviation = 0.0555 Å). The benzoic acid molecules have equivalent, close to planar conformations [C6/CO2 dihedral angle = 6.33 (14) and 3.43 (10)°]. The formation of hydroxy-O—H...N(pyridyl) hydrogen bonds between the benzoic acid molecules and the pyridyl residues of the diamide leads to a three-molecule aggregate. Centrosymmetrically related aggregates assemble into a six-molecule aggregate via amide-N—H...O(amide) hydrogen bonds through a 10-membered {...HNC2O}2 synthon. These are linked into a supramolecular tape via amide-N—H...O(carbonyl) hydrogen bonds and 22-membered {...HOCO...NC4NH}2 synthons. The contacts between tapes to consolidate the three-dimensional architecture are of the type methylene-C—H...O(amide) and pyridyl-C—H...O(carbonyl). These interactions are largely electrostatic in nature. Additional non-covalent contacts are identified from an analysis of the calculated Hirshfeld surfaces.

The title homoleptic Schiff base complexes, [M(C14H9Cl2N2O)2], for M = CoII, (I), and CuII, (II), present distinct coordination geometries despite the Schiff base dianion coordinating via the phenolato-O and imine-N atoms in each case. For (I), the coordination geometry is based on a trigonal bipyramid whereas for (II), a square-planar geometry is found (Cu site symmetry \overline{1}). In the crystal of (I), discernible supramolecular layers in the ac plane are sustained by chlorobenzene-C—H...O(coordinated), chlorobenzene-C—H...π(fused-benzene ring) as well as π(fused-benzene, chlorobenzene)–π(chlorobenzene) interactions [inter-centroid separations = 3.6460 (17) and 3.6580 (16) Å, respectively]. The layers inter-digitate along the b-axis direction and are linked by dichlorobenzene-C—H...π(fused-benzene ring) and π–π interactions between fused-benzene rings and between chlorobenzene rings [inter-centroid separations = 3.6916 (16) and 3.7968 (19) Å, respectively] . Flat, supramolecular layers are also found in the crystal of (II), being stabilized by π–π interactions formed between fused-benzene rings and between chlorobenzene rings [inter-centroid separations = 3.8889 (15) and 3.8889 (15) Å, respectively]; these stack parallel to [10\overline{1}] without directional interactions between them. The analysis of the respective calculated Hirshfeld surfaces indicate diminished roles for H...H contacts [26.2% (I) and 30.5% (II)] owing to significant contributions by Cl...H/H...Cl contacts [25.8% (I) and 24.9% (II)]. Minor contributions by Cl...Cl [2.2%] and Cu...Cl [1.9%] contacts are indicated in the crystals of (I) and (II), respectively. The interaction energies largely arise from dispersion terms; the aforementioned Cu...Cl contact in (II) gives rise to the most stabilizing interaction in the crystal of (II).

The Cambridge Structural Database has been surveyed for crystals featuring organo-Hg···S secondary-bonding interactions within supramolecular aggregates. Nearly 50% of crystals where Hg···S interactions could potentially form, featured Hg···S contacts within zero- or one-dimensional supramolecular assemblies with only a few examples of two-dimensional arrays featuring Hg···S interactions. This high propensity of Hg···S contact formation reflects the inherent thiophilic nature of mercury but also the relatively open access to mercury owing to the linear C–Hg–S coordination geometries, the prevalence of close intramolecular Hg···S, Hg···O and Hg···N interactions notwithstanding.

Pyridyl- and indoleninyl-substituted pyrimido[1,2-b]indazole were synthesised in good to high yields from the condensation reaction of 1,3-dialdehydes with 3-aminoindazoles. The structural features of the compounds were determined by NMR (1H, 13C and 19F), FT-IR and HR-MS. The spectroscopic assignments were confirmed by X-ray crystallography for two derivatives, i.e., 9-Bromo-3-(pyridin-4-yl)pyrimido[1,2-b]indazole (1b) and 10-Methoxy-3-(pyridin-4-yl)pyrimido[1,2-b]indazole (1c), which further provides support for significant delocalisation of π-electron density over the entire fused ring system. The molecular packing was assessed by conventional methods together with Hirshfeld surface analyses. In 1b, the molecular packing features pyrimidyl-N–H···N(pyrimidyl), π(pyrazolyl)···π(pyrimidyl) and Br···N interactions within a two-dimensional array. In 1c, pyrimidyl-C–H···N(pyrazolyl) and pyridyl-C–H···O(methoxy) interactions feature within a three-dimensional architecture.

The synthesis and spectroscopic characterization of the glutaric acid-amide derivative, 2,4-Cl2C6H3N(H)C(=O)(CH2)3C(=O)OH (1), are described. The X-ray crystal structure determination of (1) shows the backbone of the molecule to be kinked about the methylene-C–N(amide) bond as seen in the C(p)–N–C(m)–C(m) torsion angle of −157.0(2)°; m = methylene and p = phenyl. An additional twist in the molecule is noted between the amide and phenyl groups as reflected in the C(m)–N–C(p)–C(p) torsion angle of 138.2(2)°. The most prominent feature of the molecular packing is the formation of supramolecular tapes assembled through carboxylic acid-O–H…O(carbonyl) and amide-N–H…O(amide) hydrogen bonding.

The crystal and molecular structures of the title CuII complex, isolated as a dihydrate, [Cu(C21H14N3O3)2]·2H2O, reveals a highly distorted coordination geometry intermediate between square-planar and tetrahedral defined by an N2O2 donor set derived from two mono-anionic bidentate ligands. Furthermore, each six-membered chelate ring adopts an envelope conformation with the Cu atom being the flap. In the crystal, imidazolyl-amine-N—H...O(water), water-O—H...O(coordinated, nitro and water), phenyl-C—H...O(nitro) and π(imidazolyl)–π(nitrobenzene) [inter-centroid distances = 3.7452 (14) and 3.6647 (13) Å] contacts link the components into a supramolecular layer lying parallel to (101). The connections between layers forming a three-dimensional architecture are of the types nitrobenzene-C—H...O(nitro) and phenyl-C—H...π(phenyl). The distorted coordination geometry for the CuII atom is highlighted in an analysis of the Hirshfeld surface calculated for the metal centre alone. The significance of the intermolecular contacts is also revealed in a study of the calculated Hirshfeld surfaces; the dominant contacts in the crystal are H...H (41.0%), O...H/H...O (27.1%) and C...H/H...C (19.6%).

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 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 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.

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 asymmetric unit of the centrosymmetric title salt solvate, 2C17H17F6N2O+· C4H4O42−·CH3CH2OH, (systematic name: 2-{[2,8-bis(trifluoromethyl)quinolin-4-yl](hydroxy)methyl}piperidin-1-ium butanedioate ethanol monosolvate) comprises two independent cations, with almost superimposable conformations and each approximating the shape of the letter L, a butanedioate dianion with an all-trans conformation and an ethanol solvent molecule. In the crystal, supramolecular chains along the a-axis direction are sustained by charge-assisted hydroxy-O—H...O(carboxylate) and ammonium-N—H...O(carboxylate) hydrogen bonds. These are connected into a layer via C—F...π(pyridyl) contacts and π–π stacking interactions between quinolinyl-C6 and –NC5 rings of the independent cations of the asymmetric unit [inter-centroid separations = 3.6784 (17) and 3.6866 (17) Å]. Layers stack along the c-axis direction with no directional interactions between them. The analysis of the calculated Hirshfeld surface reveals the significance of the fluorine atoms in surface contacts. Thus, by far the greatest contribution to the surface contacts, i.e. 41.2%, are of the type F...H/H...F and many of these occur in the inter-layer region. However, these contacts occur at separations beyond the sum of the van der Waals radii for these atoms. It is noted that H...H contacts contribute 29.8% to the overall surface, with smaller contributions from O...H/H...O (14.0%) and F...F (5.7%) contacts.

The asymmetric unit of the title 1:1 solvate, C14H14N4O2·C6H6 [systematic name of the oxalamide molecule: N,N′-bis(pyridin-4-ylmethyl)ethanediamide], comprises a half molecule of each constituent as each is disposed about a centre of inversion. In the oxalamide molecule, the central C2N2O2 atoms are planar (r.m.s. deviation = 0.0006 Å). An intramolecular amide-N—H...O(amide) hydrogen bond is evident, which gives rise to an S(5) loop. Overall, the molecule adopts an antiperiplanar disposition of the pyridyl rings, and an orthogonal relationship is evident between the central plane and each terminal pyridyl ring [dihedral angle = 86.89 (3)°]. In the crystal, supramolecular layers parallel to (10\overline{2}) are generated owing the formation of amide-N—H...N(pyridyl) hydrogen bonds. The layers stack encompassing benzene molecules which provide the links between layers via methylene-C—H...π(benzene) and benzene-C—H...π(pyridyl) interactions. The specified contacts are indicated in an analysis of the calculated Hirshfeld surfaces. The energy of stabilization provided by the conventional hydrogen bonding (approximately 40 kJ mol−1; electrostatic forces) is just over double that by the C—H...π contacts (dispersion forces).

The title CuII complex, [Cu(C13H11N2OS2)2], features a trans-N2S2 donor set as a result of the CuII atom being located on a crystallographic centre of inversion and being coordinated by thiolate-S and imine-N atoms derived from two dithiocarbazate anions. The resulting geometry is distorted square-planar. In the crystal, π(chelate ring)–π(furyl) [inter-centroid separation = 3.6950 (14) Å and angle of inclination = 5.33 (13)°] and phenyl-C—H...π(phenyl) interactions sustain supramolecular layers lying parallel to (\overline{1}02). The most prominent interactions between layers, as confirmed by an analysis of the calculated Hirshfeld surface, are phenyl-H...H(phenyl) contacts. Indications for Cu...Cg(furyl) contacts (Cu...Cg = 3.74 Å) were also found. Interaction energy calculations suggest the contacts between molecules are largely dispersive in nature.

The title compound, C15H13BrO2S, comprises three different substituents bound to a central (and chiral) methine-C atom, i.e. (4-bromophenyl)sulfanyl, benzaldehyde and methoxy residues: crystal symmetry generates a racemic mixture. A twist in the molecule is evident about the methine-C—C(carbonyl) bond as evidenced by the O—C—C—O torsion angle of −20.8 (7)°. The dihedral angle between the bromobenzene and phenyl rings is 43.2 (2)°, with the former disposed to lie over the oxygen atoms. The most prominent feature of the packing is the formation of helical supramolecular chains as a result of methyl- and methine-C—H...O(carbonyl) interactions. The chains assemble into a three-dimensional architecture without directional interactions between them. The nature of the weak points of contacts has been probed by a combination of Hirshfeld surface analysis, non-covalent interaction plots and interaction energy calculations. These point to the importance of weaker H...H and C—H...C interactions in the consolidation of the structure.

The crystal and molecular structures of C14H12Cl2, (I), and C14H12Br2, (II), are described. The asymmetric unit of (I) comprises two independent molecules, A and B, each disposed about a centre of inversion. Each molecule approximates mirror symmetry [the Cb—Cb—Ce—Ce torsion angles = −83.46 (19) and 95.17 (17)° for A, and −83.7 (2) and 94.75 (19)° for B; b = benzene and e = ethylene]. By contrast, the molecule in (II) is twisted, as seen in the dihedral angle of 59.29 (11)° between the benzene rings cf. 0° in (I). The molecular packing of (I) features benzene-C—H...π(benzene) and Cl...Cl contacts that lead to an open three-dimensional (3D) architecture that enables twofold 3D–3D interpenetration. The presence of benzene-C—H...π(benzene) and Br...Br contacts in the crystal of (II) consolidate the 3D architecture. The analysis of the calculated Hirshfeld surfaces confirm the influence of the benzene-C—H...π(benzene) and X...X contacts on the molecular packing and show that, to a first approximation, H...H, C...H/H...C and C...X/X...C contacts dominate the packing, each contributing about 30% to the overall surface in each of (I) and (II). The analysis also clearly differentiates between the A and B molecules of (I).

The title compound, 2C14H14N4O·H2O, comprises a neutral molecule containing a central pyrazol-3-one ring flanked by an N-bound phenyl group and a C-bound 5-methyl-1H-pyrazol-3-yl group (at positions adjacent to the carbonyl substituent), its zwitterionic tautomer, whereby the N-bound proton of the central ring is now resident on the pendant ring, and a water molecule of crystallization. Besides systematic variations in geometric parameters, the two independent organic molecules have broadly similar conformations, as seen in the dihedral angle between the five-membered rings [9.72 (9)° for the neutral molecule and 3.32 (9)° for the zwitterionic tautomer] and in the dihedral angles between the central and pendant five-membered rings [28.19 (8) and 20.96 (8)° (neutral molecule); 11.33 (9) and 11.81 (9)°]. In the crystal, pyrazolyl-N—H...O(carbonyl) and pyrazolium-N—H...N(pyrazolyl) hydrogen bonds between the independent organic molecules give rise to non-symmetric nine-membered {...HNNH...NC3O} and {...HNN...HNC3O} synthons, which differ in the positions of the N-bound H atoms. These aggregates are connected into a supramolecular layer in the bc plane by water-O—H...N(pyrazolide), water-O—H...O(carbonyl) and pyrazolyl-N—H...O(water) hydrogen bonding. The layers are linked into a three-dimensional architecture by methyl-C—H...π(phenyl) interactions. The different interactions, in particular the weaker contacts, formed by the organic molecules are clearly evident in the calculated Hirshfeld surfaces, and the calculated electrostatic potentials differentiate the tautomers.

The asymmetric unit of the three-component title compound, 2,2′-dithiodibenzoic acid–2-chlorobenzoic acid–N,N-dimethylformamide (1/1/1), C14H10O4S2·C7H5ClO2·C3H7NO, contains a molecule each of 2,2′-dithiodibenzoic acid (DTBA), 2-chlorobenzoic acid (2CBA) and dimethylformamide (DMF). The DTBA molecule is twisted [the C—S—S—C torsion angle is 88.37 (17)°] and each carboxylic group is slightly twisted from the benzene ring to which it is connected [CO2/C6 dihedral angles = 7.6 (3) and 12.5 (3)°]. A small twist is evident in the molecule of 2CBA [CO2/C6 dihedral angle = 4.4 (4)°]. In the crystal, the three molecules are connected by hydrogen bonds with the two carboxylic acid residues derived from DTBA and 2CBA forming a non-symmetric eight-membered {...HOCO}2 synthon, and the second carboxylic acid of DTBA linked to the DMF molecule via a seven-membered {...HOCO...HCO} heterosynthon. The three-molecule aggregates are connected into a supramolecular chain along the a axis via DTBA-C—H...O(hydroxyl-2CBA), 2CBA-C—H...O(hydroxyl-DTBA) and DTBA-C—H...S(DTBA) interactions. Supramolecular layers in the ab plane are formed as the chains are linked via DMF-C—H...S(DTBA) contacts, and these inter-digitate along the c-axis direction without specific points of contact between them. A Hirshfeld surface analysis points to additional but, weak contacts to stabilize the three-dimensional architecture: DTBA-C=O...H(phenyl-DTBA), 2CBA-Cl...H(phenyl-DTBA), as well as a π–π contact between the delocalized eight-membered {...HOC=O}2 carboxylic dimer and the phenyl ring of 2CBA. The latter was confirmed by electrostatic potential (ESP) mapping.

The asymmetric unit of the title compound, C13H11N3O2S2, comprises two independent molecules (A and B); the crystal structure was determined by employing synchrotron radiation. The molecules exhibit essentially the same features with an almost planar benzothiazole ring (r.m.s. deviation = 0.026 and 0.009 Å for A and B, respectively), which forms an inclined dihedral angle with the phenyl ring [28.3 (3) and 29.1 (3)°, respectively]. A difference between the molecules is noted in a twist about the N—S bonds [the C—S—N—N torsion angles = −56.2 (5) and −68.8 (5)°, respectively], which leads to a minor difference in orientation of the phenyl rings. In the molecular packing, A and B are linked into a supramolecular dimer via pairwise hydrazinyl-N—H...N(thiazolyl) hydrogen bonds. Hydrazinyl-N—H...O(sulfonyl) hydrogen bonds between A molecules assemble the dimers into chains along the a-axis direction, while links between centrosymmetrically related B molecules, leading to eight-membered {...HNSO}2 synthons, link the molecules along [001]. The result is an undulating supramolecular layer. Layers stack along the b-axis direction with benzothiazole-C—H...O(sulfonyl) points of contact being evident. 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 independent molecules, such as π–π interactions. This is also highlighted in distinctive energy frameworks calculated for the individual molecules.

The analysis of atom-to-atom and/or residue-to-residue contacts remains a favoured mode of analysing the molecular packing in crystals. In this contribution, additional tools are highlighted as methods for analysis in order to complement the `crystallographer's tool', PLATON [Spek (2009). Acta Cryst. D65, 148–155]. Thus, a brief outline of the procedures and what can be learned by using Crystal Explorer [Spackman & Jayatilaka (2009). CrystEngComm 11, 19–23] is presented. Attention is then directed towards evaluating the nature, i.e. attractive/weakly attractive/repulsive, of specific contacts employing NCIPLOT [Johnson et al. (2010). J. Am. Chem. Soc. 132, 6498–6506]. This is complemented by a discussion of the calculation of energy frameworks utilizing the latest version of Crystal Explorer. All the mentioned programs are free of charge and straightforward to use. More importantly, they complement each other to give a more complete picture of how molecules assemble in molecular crystals.

The title compound, C16H18N2O3, is constructed about a central oxopyridazinyl ring (r.m.s. deviation = 0.0047 Å), which is connected to an ethylacetate group at the N atom closest to the carbonyl group, and benzyl and methyl groups second furthest and furthest from the carbonyl group, respectively. An approximately orthogonal relationship exists between the oxopyridazinyl ring and the best plane through the ethylacetate group [dihedral angle = 77.48 (3)°]; the latter lies to one side of the central plane [the Nr—Nr—Cm—Cc (r = ring, m = methylene, c = carbonyl) torsion angle being 104.34 (9)°]. In the crystal, both H atoms of the N-bound methylene group form methylene-C—H...O(ring carbonyl) or N(pyridazinyl) interactions, resulting in the formation of a supramolecular tape along the a-axis direction. The tapes are assembled into a three-dimensional architecture by methyl- and phenyl-C—H...O(ring carbonyl) and phenyl-C—H...O(ester carbonyl) interactions. The analysis of the calculated Hirshfeld surface indicates the dominance of H...H contacts to the overall surface (i.e. 52.2%). Reflecting other identified points of contact between molecules noted above, O...H/H...O (23.3%), C...H/H...C (14.7%) and N...H/H...N (6.6%) contacts also make significant contributions to the surface.

The asymmetric unit of the title 1:2 co-crystal, C14H10O4S2·2C7H6O2, comprises half a molecule of dithiodibenzoic acid [systematic name: 2-[(2-carboxyphenyl)disulfanyl]benzoic acid, DTBA], as the molecule is located about a twofold axis of symmetry, and a molecule of benzoic acid (BA). The DTBA molecule is twisted about the disulfide bond [the C—S—S—C torsion angle is −83.19 (8)°] resulting in a near perpendicular relationship between the benzene rings [dihedral angle = 71.19 (4)°]. The carboxylic acid group is almost co-planar with the benzene ring to which it is bonded [dihedral angle = 4.82 (12)°]. A similar near co-planar relationship pertains for the BA molecule [dihedral angle = 3.65 (15)°]. Three-molecule aggregates are formed in the crystal whereby two BA molecules are connected to a DTBA molecule via hydroxy-O—H...O(hydroxy) hydrogen bonds and eight-membered {...HOC=O}2 synthons. These are connected into a supramolecular layer in the ab plane through C—H...O interactions. The interactions between layers to consolidate the three-dimensional architecture are π–π stacking interactions between DTBA and BA rings [inter-centroid separation = 3.8093 (10) Å] and parallel DTBA-hydroxy-O...π(BA) contacts [O...ring centroid separation = 3.9049 (14) Å]. The importance of the specified interactions as well as other weaker contacts, e.g. π–π and C—H...S, are indicated in the analysis of the calculated Hirshfeld surface and interaction energies.

The asymmetric unit of the title co-crystal, 2,2′-thiodibenzoic acid–triphenylphosphane oxide (1/2), C14H10O4S·2C18H15OP, comprises two molecules of 2,2′-thiodibenzoic acid [TDBA; systematic name: 2-[(2-carboxyphenyl)sulfanyl]benzoic acid] and four molecules of triphenylphosphane oxide [TPPO; systematic name: (diphenylphosphoryl)benzene]. The two TDBA molecules are twisted about their disulfide bonds and exhibit dihedral angles of 74.40 (5) and 72.58 (5)° between the planes through the two SC6H4 residues. The carboxylic acid groups are tilted out of the planes of the rings to which they are attached forming a range of CO2/C6 dihedral angles of 19.87 (6)–60.43 (8)°. Minor conformational changes are exhibited in the TPPO molecules with the range of dihedral angles between phenyl rings being −2.1 (1) to −62.8 (1)°. In the molecular packing, each TDBA acid molecule bridges two TPPO molecules via hydroxy-O—H...O(oxide) hydrogen bonds to form two three-molecule aggregates. These are connected into a three-dimensional architecture by TPPO-C—H...O(oxide, carbonyl) and TDBA-C—H...(oxide, carbonyl) interactions. The importance of H...H, O...H/H...O and C...H/H...C contacts to the calculated Hirshfeld surfaces has been demonstrated. In terms of individual molecules, O...H/H...O contacts are more important for the TDBA (ca 28%) than for the TPPO molecules (ca 13%), as expected from the chemical composition of these species. Computational chemistry indicates the four independent hydroxy-O—H...O(oxide) hydrogen bonds in the crystal impart about the same energy (ca 52 kJ mol−1), with DTBA-phenyl-C—H...O(oxide) interactions being next most stabilizing (ca 40 kJ mol−1).

The asymmetric unit of the centrosymmetric title salt, C17H17F6N2O+·C2Cl3O2−, comprises a single ion-pair. The hydroxy-O and ammonium-N atoms lie to the same side of the cation, a disposition maintained by a charge-assisted ammonium-N—H...O(hydroxy) hydrogen bond [the Oh—Cm—Cm–Na (h = hydroxy, m = methine, a = ammonium) torsion angle is 58.90 (19)°]. The piperidin-1-ium group is approximately perpendicular to the quinolinyl residue [Cq—Cm—Cm–Na (q = quinolinyl) is −178.90 (15)°] so that the cation, to a first approximation, has the shape of the letter L. The most prominent feature of the supramolecular association in the crystal is the formation of chains along the a-axis direction, being stabilized by charge-assisted hydrogen-bonds. Thus, ammonium-N+—H...O−(carboxylate) hydrogen bonds are formed whereby two ammonium cations bridge a pair of carboxylate-O atoms, leading to eight-membered {...O...HNH}2 synthons. The resulting four-ion aggregates are linked into the supramolecular chain via charge-assisted hydroxyl-O—H...O−(carboxylate) hydrogen bonds. The connections between the chains, leading to a three-dimensional architecture, are of the type C—X...π, for X = Cl and F. The analysis of the calculated Hirshfeld surface points to the importance of X...H contacts to the surface (X = F, 25.4% and X = Cl, 19.7%) along with a significant contribution from O...H hydrogen-bonds (10.2%). Conversely, H...H contacts, at 12.4%, make a relatively small contribution to the surface.

The crystal and molecular structures of the title molecular salts, C4H12NO+·C7H5N2O4−, (I), C6H16NO+·C7H5N2O4−, (II), and C4H12NO3+·C7H5N2O4−, (III), are described. The common feature of these salts is the presence of the 2-amino-4-nitrobenzoate anion, which exhibit non-chemically significant variations in the conformational relationships between the carboxylate and nitro groups, and between these and the benzene rings they are connected to. The number of ammonium-N—H H atoms in the cations increases from one to three in (I) to (III), respectively, and this variation significantly influences the supramolecular aggregation patterns in the respective crystals. Thus, a linear supramolecular chain along [100] sustained by charge-assisted tertiary-ammonium-N—H...O(carboxylate), hydroxy-O—H...O(carboxylate) and amino-N—H...O(carboxylate) hydrogen-bonds is apparent in the crystal of (I). Chains are connected into a three-dimensional architecture by methyl-C—H...O(hydroxy) and π–π interactions, the latter between benzene rings [inter-centroid separation = 3.5796 (10) Å]. In the crystal of (II), a supramolecular tube propagating along [901] arises as a result of charge-assisted secondary-ammonium-N—H...O(carboxylate) and hydroxy-O—H...O(carboxylate) hydrogen-bonding. These are connected by methylene- and methyl-C—H...O(nitro) and π–π stacking between benzene rings [inter-centroid separation = 3.5226 (10) Å]. Finally, double-layers parallel to (100) sustained by charge-assisted ammonium-N—H...O(carboxylate), ammonium-N—H...O(hydroxy) and hydroxy-O—H...O(carboxylate) hydrogen-bonds are apparent in the crystal of (III). These are connected in a three-dimensional architecture by amine-N—H...O(nitro) hydrogen-bonds.

The X-ray crystal structure determination of the glutaric acid-amide derivative, 4-ClC6H4N(H)C(=O)(CH2)3C(=O)OH (1), is described. The backbone of the molecule adopts an extended, all-trans configuration but the terminal carboxylic acid and phenyl resides are twisted out of the plane through the bridging atoms, as seen in the torsion angles of O(carboxylic acid)–C(m)–C(m)–C(m) [13.9(5)°] and C(m)–N–C(p)–C(p) [47.1(4)°]; m = methylene and p = phenyl. The most striking feature of the molecular packing is the formation of supramolecular tapes mediated by carboxylic acid-O–H⋯O(carbonyl) and amide-N–H⋯O(amide) hydrogen bonding.